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A comprehensive evaluation of a worksite nutrition and weight-control program
A Comprehensive Evaluation of a Worksite Nutrition and Weight-Control Program BARBARA SHANNON,l MARCIA HENDRICKS,l PIERCE ROLUNS,2 AND RONALD M. SCHWARTZ 3
lNutrition Program, The Pennsylvania State University, University Park, Pennsylvania 16802; 2Health Enhancement Resource Center, Los Angeles, California 90046; 30ccidental Petroleum Corporation, Los Angeles, California 90024 ABSTRACf We conducted a study at two worksites of a major corporation to ascertain whether our nutrition and weight-control program would lead volunteer participants to achieve a mean weight loss of 1 pound per week and would improve their nutrition knowledge, attitude toward nutrition, eating behavior, and leisure-time physical activity. Study participants were 103 employees; 47 were blue-collar workers at a petroleum refinery and 56 were white-collar workers at a chemical plant. We assigned approximately half the participants at each site to a treatment group that participated in the program and the other half to a delayed-treatment control group. The four groups' initial mean weights ranged from 120 to 127% of desirable body weight. Company nurses conducted the nine-week program. Of the 52 treatment group participants who enrolled, 32 (61 %) completed the program. These 32 individuals lost significantly (p :5 .001) more weight than controls, 8.5 ± 0.08 pounds and 0.7 ± 0.71bs., respectively; and the mean weekly weight loss of the treatment group was 0.94 pounds. Weight loss did not vary with study site. Questionnaire data indicated that at both sites the treatment group exhibited greater improvement than controls in their attitude toward the importance of nutrition to health, eating behavior, and leisure-time physical activity. At the refinery the treatment group had greater improvement in nutrition knowledge than did the controls. However, this was not the case at the chemical plant. The program led to attainment of most of the objectives, and both the nurses and participants gave the program high ratings. UNE 19:109-116, 1987)
RESUME Nous avons effectue une etude dans deux lieux de travail d'une importante entreprise, afin de verifier si notre programme de controle de l'alimentation et du poids inciterait les participants volontaires Ii perdre en moyenne lIb par semaine et Ii ameliorer leurs connaissances en matiere d'alimentation, leur attitude face Ii l'alimentation, leurs habitudes alimentaires et enfin, leurs activites physiques dans les moments de loisirs. Ont participe Ii cette etude 103 employes, dont 47 cols bleus d'une raffinerie de petrole et 56 cols blancs d'une usine de produits chimiques. Dans chacun des lieux de travail, nous avons designe environ la moitie des participants comme groupe de traitement inscrit au programme, tandis que l'autre moitie ferait partie d'un groupe temoin dont Ie traitement serait reporte. Au depart, Ie poids moyen des participants des quatre groupes variait de 120 Ii 127% du poids souhaitable. Les infirmieres de l'entreprise ont dirige Ie programme de neuf semaines. Des 52 participants du groupe de traitement, 32 (61 %) ont complete Ie programme. Ces 32 sujets ont perdu de far,:on significative (p s .001) plus de poids que les groupes de controle, soit 8.5 ± 0.081bs et 0.7 ± o. 7lbs, respectivement; la perte de poids hebdomadiare du groupe de traitement s'elevait en moyenne Ii 0.94 lb. Le lieu de travail n'a pas affecte la perte de poids en soL Les resultats des questionnaires ont indique que, dans les deux lieux de travail, les groupes de traitement ont demontre une plus grande amelioration que les groupes temoins en ce qui concerne l'attitude face Ii l'importance de l'alimentation pour la sante, les habitudes alimentaires et les activites physiques dans les moments de loisirs. A la raffinerie de petrole, Ie groupe de traitement a fait preuve d'une plus grande amelioration des connaissances en matiere d'alimentation que Ie groupe temoin. Cependant, il en va differemment dans Ie cas de l'usine de produits chimiques. Le programme a permis la realisation de la plupart des objectifs fixes et les infirmieres, tout comme les participants, ont hautement evalue Ie programme. (JNE 91:109-116, 1987) Translated by Louise Lambert-Lagace VOLUME 19 NUMBER 3
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RESUMEN Se llev6 a cabo un estudio en dos lugares distintos de trabajo de una importante corporaci6n para determinar si nuestro programa de control de nutrici6n-peso llevaria a los participantes voluntarios a alcanzar una perdida promedio de peso de una libra por semana, y si ellos mejorarian sus conocimientos nutricionales, su actitud hacia la nutrici6n, alimentaci6n, y actividad fisica en tiempo libre. Los participantes en el estudio fueron 103 empleados; 47 eran obreros de una refineria de petr6leo y 56 eran profesionales trabajando en una planta de productos quimicos. Se asign6 aproximadamente a la mitad de los participantes, en cada lugar de trabajo, a un grupo tratamiento que particip6 en el programa, y a un grupo control de tratamiento retardado. En los cuatro grupos, el peso promedio inicial variaba entre 120 y 127% de adecuaci6n para su peso ideal. EI programa de nueve semanas estuvo a cargo de enfermeras de la compaiiia. De los 52 participantes en el grupo tratamiento, solamente 32 (61%) completaron el programa. Estos 32 individuos perdieron significativamente (p s .001) mas peso que los del grupo control, 8.5 ± 0.08libras y 0.7 ± 0.7libras respectivamente; siendo la perdida de peso promedio semanal del grupo tratamiento de 0.94 libras. La perdida de peso no vari6 con ellugar de estudio. Los datos obtenidos de los cuestionarios indican que en ambos lugares, el grupo tratamiento mostr6 mayor incremento en su actitud hacia la importancia de la nutrici6n en la salud, comportamiento alimentario, y actividad fisica en su tiempo libre. En la refineria, el grupo tratamiento tuvo una gran mejora en conocimientos sobre nutrici6n sobre el grupo control. Sin embargo, no sucedi6 as! en la planta de productos qu!micos. EI programa logr6la mayoria de sus objetivos, y tanto las enfermeras como los participantes Ie dieron al mismo altos punteos. UNE 19:109-116,1987) Translated by Diva Sanjur
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Increasingly, corporate health-promotion activities include weight-management programs for employees. Recently, Glanz and Seewald-Klein (1) reviewed 23 reports, published between 1978 and 1985, of such worksite programs. Reports on several additional programs (2-5) have also been published. Most of these programs employ behavior-modification techniques, often in conjunction with other strategies, to motivate participants and enhance their knowledge of weight control. Employee weight-control programs have been conducted in a variety of settings (1) and led by a variety of professionals, both nutritionists (2, 3, 6, 7) and non-nutritionists (8-13). The number of worksite weight-management programs with interpretable evaluation data is small (1) and assessment of effectiveness has been limited mainly to some measure of body-weight change during and often following the program. Because body weight is a function of both food intake and energy expenditure, weight-management programs should attempt to appropriately influence both eating behavior and physical activity. Program evaluations should assess changes in these areas as well as weight changes. This article reports the outcomes of a study that evaluated a nutrition and weight-control program that we developed for use in Atlantic Richfield Companies (ARCO). We designed the program so that it could be presented by company health professionals and could be used by both blue-collar and white-collar employees. The program objectives were a) to lead participants to achieve a mean weight loss of approximately 1 pound per week during the nine-week program; and b) to improve participants' knowledge of and attitude toward nutrition, and to improve their eating behavior and increase their leisure-time physical activity level. We implemented the program at two company worksites and conducted a study to determine the degree to which program objectives were attained. Our hypothesis was that the employees who completed the program would exhibit greater weight loss and higher scores on instruments assessing nutrition knowledge, attitudes, eating behavior, and physical activity than would employees in a control group who did not participate in the program. METHODS Study design and participants. We used a pretestposttest study design with a delayed-treatment control group. Study participants were company employees who indicated their interest in attending a weightcontrol course by responding to an announcement in the company newsletter (Note 1). There was no weight criterion for acceptance into the program. At one site, a chemical plant, we randomly assigned respondents 110
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to either the treatment or control group. At the other site, a refinery, we had to handle recruitment and participant assignment through the employee relations officials who assigned respondents to groups according to job categories. At the chemical plant and refinery, respectively, the treatment groups contained 27 and 30 assignees, and the control groups contained 28 and 30 assignees. The chemical plant study participants were mainly white-collar employees involved in research and development while the refinery study participants were mainly blue-collar employees involved in various aspects of petroleum refining. The weight-control program, entitled "Food, Fitness and Your Lifestyle," has been described in detail elsewhere (14). It is a nine-week program with one 30minute session per week. These time periods were compatible with the needs and request of the company. The introductory session of the program deals with the relationship of nutrition to general health and can stand alone or introduce the subsequent eight sessions that deal with weight control. Company nurses (two at the refinery and one at the chemical plant) conducted the sessions after they attended a training meeting provided by the nutrition educators who developed the program. The chemical plant nurse opened the introductory session to all employees who wanted to attend, which included individuals in both the treatment and control groups. However, only the treatment group participants attended the follow-up weight-control sessions. Nurses at the refinery invited only treatment group participants to the introductory session. Employees attended sessions on their own time. At the chemical plant they met during the lunch period and at the refinery they met after the 4 P.M. shift. Members of the control groups at both sites attended a second offering of the program after the study was completed. One week prior to the introductory session the nurses at both sites sent, via company mail, a pretest questionnaire to treatment and control group members. The questionnaire included instruments that assessed nutrition knowledge, attitudes, eating behavior, and physical activity. Study participants returned the completed questionnaires through company mail and reported to the medical department where the nurses measured their weight and height. During the final week of the program, study participants in both the treatment and control groups completed a posttest questionnaire identical to the pretest and were again weighed. At each assessment period during the program and at follow-up, the nurses weighed study participants using a physician's Detecto scale with beam. The nurses measured participants' heights at the preassessment. Participants removed heavy coats or sweaters and shoes for these measurements. In addition, members of the treatment groups reported to the VOLUME 19
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stituting the two attitude scales were intermingled and study participants responded to each item on a five-point continuum, ranging from strongly agree (scored 5) to strongly disagree (scored 1). Responses to negatively worded statements were reversed when scored. To simplify discussion of the attitude scales, we have abbreviated their titles to "nutrition-health" and "weight-control" throughout the remainder of this article. The food-frequency form contained 30 items selected to reflect all five food groups. Respondents indicated how often they consumed each item by marking a six-point grid ranging from never (scored 6) to more than three times per day (scored 1). Factor analysis of study participants' pretest responses revealed the presence of two factors: one with 12 items having factor loadings above 0.4 and another with 6 items having loadings above 0.4. The former 12 items were relatively low in nutrient density (e.g., fried meat, fish, and poultry) compared to the latter 6 items (e.g., baked or broiled meat, fish, or poultry). We, therefore, designated these two sets of items, respectively, as the "low-nutrient-density" and' 'high-nutrient-density" food-frequency scales. Statements constituting the calorie "add-on" scale reflected frequency of adding calories to food (e.g., "I add cream to coffee or tea"). Study participants responded to each statement on a five-point continuum ranging from never (scored 1) to always (scored 5).
nurses for weekly "weigh-ins." The nurses completed session evaluation forms after each session and treatment group participants completed a program evaluation form after the last session. The plan was that after participants completed the nine-week program, the nurses would monitor the participants' weights every four to six weeks for six months and provide us with participants' six-month follow-up weights. However, shortly after completion of the study, the company underwent significant restructuring. Both the refinery and chemical plant were sold about three months later. This created so much upheaval af both sites that the weight monitoring and follow-up did not occur as planned. However, after the situation at both sites stabilized under new management (approximately one year after the study had been initiated), the nurses sent letters to members of the treatment groups who had completed the program and were still working at those sites. The letter requested study participants to report to the medical department for a follow-up weigh-in. To assess nutrition knowledge, attitudes, eating behavior, and physical activity, we developed paper/ pencil instruments and pilottested them among 54 blue- and white-collar employees at a company site not in the study. Table 1 provides descriptive information about the knowledge, attitude, and eating-behavior instruments. We used factor analysis to examine the construct validity of the attitude scales. Items con-
Table 1.
Instruments used to assess knowledge, attitude, and eating behavior Items
Type!
Instrument
Coefficients of Internal Consistency2
Number
Score Range
25
0-25
KR-20 = 0.76
"Don't know" responses scored as a wrong answer Higher scores reflected stronger feelings about the importance of nutrition to health Higher scores reflected more positive feelings about ability to control weight
Knowledge
True/false/"don't know"
Attitude scale Nutrition is important to health
Likert
5
5-25
Alpha = 0.65
Likert
5
5-25
Alpha = 0.75
I can control my weight Food-frequency scales Low-nutrient-density
Six-choice grid
12
12-72
Alpha = 0.86
High-nutrient-density
Six-choice grid
6
6-36
Alpha = 0.71
Likert
5
5-25
Alpha = 0.75
Calorie add-on scale
Comments
Higher scores refl~cted less frequent consumption of lownutrient-density foods Higher scores reflected more frequent consumption of lownutrient-density foods Higher scores reflected more frequent additions of caloriecontaining items to food
1 For the knowledge items, a "don't know" response was scored as incorrect; for the Likert-type items, responses were on a continuum scored from 1 to 5; for the six-choice grid, responses were scored from 1 to 6. 2KR-20 refers to the Kuder Richardson-20 coefficient and alpha refers to the Chronbach alpha coefficient.
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To assess level of physical activity, we adapted and pilottested the 16-item scale of Baecke et al. (15). Pilottest results indicated that respondents did not understand some of the items, and they preceived items dealing with physical activity on the job as threatening. For example, some employees feared that management might respond negatively to an "always" response to an item indicating that, when on the job, the employee sits rather than stands. We, therefore, selected three items from the scale that elicited responses which indicated how often study participants engaged in certain types of physical activity during their leisure time, e.g., "During leisure time I walk fast (10 minutes or more) for my exercise." Participants responded to these items on a five-point continuum ranging from never (scored 1) to always (scored 5). We summed the scores on these three items to yield a leisure-time physical-activity score that could range from 5 to 25, with higher scores being more desirable. The forms that members of the treatment group completed to evaluate the program contained items that elicited members' opinions of the overall program, the individual sessions, and the audiovisual and participatory activities included in the sessions. The nurses completed a similar form for each session. Before we used the forms at the test sites, an expert panel of nutrition educators reviewed them, and we revised the forms in keeping with the panel's recommendations. Data analysis. We examined all study participants' initial weight and percent of desirable body weight as well as the change in these two parameters between pre- and posttest times. To calculate percent of desirable body weight we divided each study participants' weight by the midpoint weight specified as desirable for individuals of the same sex, height, and age group in the 1983 Metropolitan Life Insurance tables. We used the Statistical Analysis System (SAS) programs (16) for all data analyses. To test our hypothesis that the program positively influenced weight change and scores on the questionnaire instruments, we included only study participants for whom we had complete pre- and posttest weight and questionnaire data. We used analysis of covariance with preweight or prescores as the covariates. In each analysis the independent variables were treatment (participation in the program), site (chemical plant or refinery), gender, interaction between treatment and gender, and interaction between treatment and site. This allowed us to control statistically for initial differences among groups in the study. We simplified the final model in each analysis by removing nonsignificant variables (or interactions) to produce the most parsimonious equation to describe the relationships that emerged.
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To assess the net relationship between independent variables and the dependent variable-weight change-we used multiple regression and controlled for variation in preweight. Preliminary regression analyses, using a bivariate model, identified independent variables that should be included in the multiple regression model. RESULTS Of the 115 employees initially assigned to the groups in the study, 103 chose to participate, completed the pretest questionnaire, and reported for the initial weigh-in. At the refinery, 24 ofthese were in the treatment group and 23 were in the control group; at the chemical plant 28 were in each of the respective groups. Table 2 shows the descriptive pretest data on these 103 study participants. The treatment and control groups at the chemical plant were quite similar with regard to age, height, weight, percent of desirable body weight, and distribution of males versus females. However, because we were unable to randomly assign study participants to the two groups at the refinery, there was an imbalance, with the refinery treatment group having a greater percentage of males than the refinery control group or either group at the chemical plant. This higher percentage of males in the refinery treatment group is reflected in a slightly higher mean height among that group compared to the other three groups. However, the four groups did not differ significantly with regard to mean weight, percent of desirable body weight, and age. Furthermore, the four groups had comparable prescores on the nutrition knowledge test, attitude scales, and the scales reflecting eating behavior and physical activity. Of the 52 study participants in the treatment groups at the two sites, 32 completed the program, i.e., attended at least five sessions and had complete preand posttest questionnaire and weight data. This yielded an overall completion rate of 61 %; 71 % completed the program at the chemical plant, and 50% completed it at the refinery. In the control groups, 43 of the 51 enrolled participants took the posttest and reported for the final weigh-in. Table 2 also shows the descriptive information, at pretest time, for the treatment and control participants who had complete data at the end of the program. Because these final groups are quite similar to the originally enrolled groups with regard to descriptive characteristics, attrition had little influence on the make up of the final four groups. Effect of the program. Neither gender nor site influenced participants' weight change, and there was no
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Table 2. study
Descriptive pretest characteristics of groups according to participants who enrolled in and completed the Mean ± S.D.
Group I
Chemical Plant Treatment group Enrolled (n = 28) Completed (n = 20) Control group Enrolled (n = 28) Completed (n = 23) Refinery Treatment group Enrolled (n = 20) Completed (n = 12) Control group Enrolled (n = 23) Completed (n = 20)
Percent Males
Age (years)
Height (inches)
Weight (pounds)
Percent Desirable Body Weight
57 a 53 d
43.8 ± 11 44.0 ± 11
65.5 ± 4a 66.3 ± 4d
192.48 ± 48.8 185.8 ± 38.7
127.7 ± 24 122.0 ± 24
57 b 48e
44.5 ± 11 45.4 ± 11
67.1 ± 4b 66.8 ± 3"
191.7 ± 39.9 193.2 ± 39.6
125.9 ± 19 127.2 ± 19
87 abc 83 del
43.5 ± 11 46.0 ± 12
69.5 ± 4abc 70.6 ± 3del
201.9 ± 50 207.2 ± 41
127.3 ± 24 126.8 ± 19
43 c 501
42.6 ± 13 43.2 ± 13
67.2 ± 4C 67.8 ± 4
181.5 ± 35 182.1 ± 35
120.4 ± 20 120.7 ± 21
lMeans of enrolled and of completed groups in the same vertical column, bearing like superscripts are significantly different (p ::s .05).
interaction between these two variables nor between site and treatment. However, treatment had a strong influence on weight change; the weight loss of the treatment group was significantly greater than that of the control group (Table 3). The mean weekly weight loss of the treatment group was 0.94 pounds during the nine-week program, and the final percent of desirable body weight at posttest time reflected this loss. The adjusted mean percent of desirable body weight for the treatment group was 117.8 % while that of the control group was 122.4% (p :5 .001). Treatment group participants who did not complete the program exhibited a mean weight loss of 4.4 ± 6.2 pounds between the initial weigh-in and the last week they reported for a weigh-in (average of 3.8 weeks). The program significantly influenced postscores on the nutrition-health attitude scale and the low-nutrient-density food-frequency scale (Table 3). Treatment group participants came to feel more positively than did controls about the importance of nutrition to health, and treatment group participants reported greater decreases than did controls in consumption of low-nutrient-density foods. This effect was independent of site and gender. Both treatment and gender had independent effects on participants' reported consumption of high-nutrient-density foods, addition of calorie-containing items to food, and level of leisuretime physical activity. Site did not influence any of these relationships. Table 3 shows the adjusted mean postscores for the treatment and control groups; Table 4 shows the means according to gender. At posttest time treatment group participants reported consum-
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ing foods of high nutrient-density more frequently than did control group participants, and females reported consuming these foods more frequently than males. Furthermore, at posttest time members of the treatment group reported adding calorie-containing items to food less often than did members of the control group, and males reported adding calorie-containing items to food less frequently than females. At posttest time members of the treatment group also reported participating in leisure-time physical activity more often than did the control group, and males reported such participation more often than females. The effect of the program on participants' nutrition knowledge scores was not influenced by gender but did vary according to site. Adjusted mean postscores of both chemical plant groups and the refinery treatment group were similar but were higher than the mean postscore of the refinery control group (Table 3). Therefore, since all four groups had equivalent pretest scores, the chemical plant control group gained a level of knowledge equivalent to the two treatment groups. The program's effect on the weight-control attitude scale was also not influenced by gender but varied with site (Table 3). Mean adjusted postscores of the two groups at the chemical plant and the control group at the refinery were equivalent and lower than the scores of the refinery treatment group. Thus, the program improved refinery participants' feelings about their ability to control their weight but had no effect on the chemical plant participants' feelings on that issue. The only variables that had a significant bivariate
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Table 3.
Treatment and control groups' adjusted mean weight loss and postscores (± standard error) on other variables assessed
Group I Treatment (n = 32)
Variable 2 Weight loss Nutrition-health attitude scale score (range = 5 to 25) Low-nutrient-density food-frequency scale score (range = 12-72) High-nutrient-density food-frequency scale score (range = 6-36) Calorie "add-on" scale score (range = 5-25) Leisure-time physical activity scale score (range = 5- 15) Nutrition knowledge test score (maximum score = 25) Refinery Chemical plant Weight-control attitude scale score (range = 5-25) Refinery Chemical plant
8.5 22.2 52.2 8.6 13.9 8.4
± ± ± ± ± ±
Control (n
0.8 0.4 1.0 0.5 0.5 0.3
0.7 20.7 48.5 10.3 16.9 7.4
=
43)
± 0.7 ± 0.3 ± 0.8 ± 0.4 ± 0.6 ± 0.2
20.0 ± 0.7 a 19.5 ± 0.6a
15.9 ± 0.6 18.6 ± 0.5 a
22.6 ± 0.6 19.6 ± 0.5 b
19.9 ± 0.5 b 19.2 + 0.5 b
, Posttest means from analysis of covariance with pretest weight or scores used as covariates; for each variable, means not bearing common superscripts are significantly different, p ::s .01; see Table 1 for directionality of scores. 2For the first six variables, means of the refinery and chemical plant groups are combined because scores did not vary according to site and there was no interaction between site and treatment; for the last two variables there was a significant interaction between site and treatment, so scores are presented according to site.
Table 4. Adjusted mean postscores' (± standard error) of males versus females on the variables that differed significantly according to gender
Variable 1 High-nutrient-density food-frequency scale score (range = 6-36) Calorie "add-on" scale score (range = 5-15) Physical activity scale score (range = 5-15)
Males In = 33)
Females In = 42)
10.1 ± 0.4
8.8 ± 0.5
14.4
± 0.6
16.0
± 0.6
8.3
± 0.2
7.5
± 0.3
, Postscores from analysis of covariance with prescores as the covariate; for each variable, means of males and females differed significantly, p ::S .05. For directionality of scale scores see Table 1. 2The gender effect was independent of treatment and site, so for each sex the scores of both groups at both sites were combined.
association with weight change were treatment and change (pretest minus posttest) in calorie "add-on" scale scores and in physical-activity scale scores. Table 5 shows the results of the multiple regression analysis when weight change was regressed on these three variables and variation in preweight was controlled. All three variables accounted for a significant amount of variance in weight change, and the model explained a total of 61 % of the variance in weight change. Nurses' and participants' assessment of the program. The 32 treatment group participants who completed the program gave it very favorable ratings. Of these, 79% indicated that the information provided was either very appropriate or extremely appropriate to their needs and interests, 64% rated the session ac-
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Table 5. Multiple regression model with weight change as the dependent variable (n = 75)
Independent Variable
R' 0.61
Preweight Treatment Change in calorie "add-on" scale score Change in physicalactivity scale score
8 Value ± S.E.
T-statistic
- 0.033 ± 0.01 - 5.435 ± 0.13
- 2.36* -4.81 ***
± 0.13
-3.54***
-1.051 ± 0.35
-3.01***
- 0.457
*p ::S .05 ***p ::S .001
tivities as very helpful to extremely helpful, 75% felt sufficient time was allowed for the activities in the 30minute sessions, and 100% said they would recommend the program to others. The most popular of the weight-control sessions was the one on calorie sources and portion control. The nurses' evaluation of the program was also positive. They indicated that "for the most part the objectives of the sessions were accomplished." They felt the information was appropriate for employees and that the employees enjoyed the sessions. The nurses identified no difficulties in conducting the sessions. Since all audiovisual and printed materials for program sessions were provided as part of the program package, the nurses' only preparation involved reviewing the background information and session materials. Follow-up. Of the 32 study participants who completed the program, 14 reported for the follow-up
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weigh-in, 8 had retired or changed jobs, and the remaining 10 failed to respond to the nurses' request for follow-up. Of the 14 for whom we obtained follow-up weights, 3 had returned to their pretest weight and 3 weighed more than at pretest time with their mean weight gain (± standard deviation) being 6.8 ± 5.8 pounds. Four had regained some, but not all, of the weight they had lost, with their mean follow-up weight being 8.3 ± 4.9 pounds less than their pretest weight. And 4 had continued to lose weight, with the mean follow-up weight of 3 of these individuals being 10.8 ± 2.4 pounds less than their pretest weight; 1 individual had lost 91 pounds since the pretest. DISCUSSION These results show that most of our program objectives were attained. The mean weekly weight loss of 0.94 pounds among treatment group participants was very close to the weight-loss goal of 1 pound per week. In addition the program led these participants to feel more strongly about the importance of nutrition, and to make improvements in self-reported eating behavior and level of physical activity. The treatment group's mean weight loss of 8.5 pounds was not as great as that reported by some of the 23 programs reviewed by Glanz and Seewald-Klein (1). In those programs, the weight losses ranged from 5 to 18 pounds; but the higher losses occurred in programs that were of greater duration than ours, Le., more than ten weeks. On a weekly basis the weight loss attained by our treatment group compares favorably with that in other programs. For example, it was similar to the 0.90 pounds weekly weight loss of participants in the "Weight Watchers at Work" reported by FrankIe et al. (17), and it exceeded the weekly range of 0.45 to 0.87 pounds lost by insurance company employees in a study reported by Sumner et al. (5). Weekly weight loss of participants in 9 programs that Foshee et al. reviewed (18) ranged from 0.46 to 3.59 pounds, but the average weekly weight loss across those programs was 1.07 pounds. Other investigators have provided little information about the impact of worksite weight-management programs on nutrition knowledge, attitude, eating behavior, and physical activity. Brownell and co-workers (19) did assess physical activity of their participants using a self-report instrument. Comparison of their outcomes with ours is difficult because we calculated a physical activity score for our participants while they specified the percent of participants who reported increases (Le., 3 to 22 % of their study participants said they increased various types of physical activity). Furthermore, our scale did not include all possible types of leisure-time physical activities, so it VOLUME 19 NUMBER 3
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may not have adequately assessed the activities of some participants. Sumner et al. (5) administered eating behavior inventories to their participants. Their outcomes, like ours, show improvements in what participants reported about their eating behavior. We believe that simple, easily administered instruments of the type we used provide valuable information about worksite intervention even though these instruments rely on self-reporting of behavior, which certainly may be biased. Nevertheless, the change in our study participants' scores on both the calorie "add-on" scale and the leisure-time physical activity scale accounted for a significant amount of the variation in their weight change. This supports our confidence in the use of such self-report instruments to assess trends among groups. The 61 % program completion rate among participants in our study compares favorably with the range of 40% to 70% completion rates reported for the 23 worksite weight-control programs reviewed by Glanz and Seewald-Klein (1). Two notable exceptions to this are the programs reported by Brownell et al. (13) and by Jeffery, Forster, and Snell (4). The former employed weight-loss competitions and attained 99.5% completion while the latter used payroll-based incentives and attained 94% completion. Because the unexpected corporate changes made it impossible to conduct the follow-up as originally planned, we cannot draw meaningful conclusions from the meager follow-up data we obtained. The difference in the nutrition knowledge test outcomes at the two sites likely reflects the difference in the way the introductory session was handled at those sites. At the chemical plant both the treatment group and the control group attended that session, but at the refinery only the treatment group attended. For the most part, the introductory session provided nutrition information while the eight sessions that followed were more behavior oriented. The control group at the chemical plant apparently gained enough information by attending the introductory session, and perhaps through discussing it afterward, to allow them to score as high on the nutrition knowledge posttest as the treatment group. At the refinery, the control group did not exhibit nutrition knowledge gain. We do not know why the chemical plant treatment group's attitude toward ability to control weight failed to become more positive during the study while the refinery treatment group's attitude toward ability to control weight improved. Perhaps the blue-collar workers in the refinery found the program information and techniques more convincing and persuasive than did the white-collar chemical plant workers. In conclusion, this study adds to the growing body of information which shows that weight-control proJOURNAL OF NUTRITION EDUCATION
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grams can be successfully implemented in the work setting among a wide spectrum of employees. It demonstrated a method whereby company nurses were able to effectively conduct such programs within the time constraints of both blue-collar and white-collar employees. 0 ACKNOWLEDGMENTS The work reported here was partially funded by the Atlantic Richfield Company. The authors gratefully acknowledge the following nurses who conducted the program at the worksites: Monica Hare, Isabela Kelly, and Mary Levinsky.
NOTE 1 The procedures for this study were approved by The Pennsylvania State University Human Subjects Committee.
UTERATURE CITED 1 Glanz, K., and T. Seewald-Klein. Nutrition at the worksite: An overview. Journal of Nutrition Education 18:S1-12,1986. 2 Loper, J. F., and K. K. Barrows. A nutrition and weightcontrol program in industry. Journal of the American Dietetic Association 85:1487-88, 1985. 3 Kneip, J. K., H. M. Fox, and J. K. Fruehling. A weightcontrol program for bank employees. Journal of the American Dietetic Association 85:1489-91, 1985. 4 Jeffery, R. W., J. L. Forster, and M. K. Snell. Promoting weight control at the worksite: A pilot program of self motivation using payroll-based incentives. Preventive Medicine 14:187-94,1985. 5 Sumner, S. K., E. L. Schiller, E. R. Marr, and D. I. Thompson. A weight control and nutrition education program for insurance company employees. Journal of Nutrition Education 18:(Supp. 1):S60-62, 1986. 6 Schumaker, N., B. Groth, J. Kleinsek, and N. Seay. Successful weight control program for employees. Journal of the American Dietetic Association 74:466, 67, 1979.
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7 Kelly, K. L. Evaluation of a group nutrition-education approach to effective weight loss and control. American Journal of Public Health 69:813, 14, 1979. 8 Colvin, R. H. Weight control on-the-job: Making use of the office environment. Journal of the American Dietetic Association 74:465, 1979. 9 Klug, P.M. Implementing health education programs at Australian Paper Manufacturers Limited, Botany Mills. Occupational Health Nursing 27:18-20, 1979. 10 Repport, J. T., and C. G. Shaw. A conceptual and statistical evaluation of a new obesity treatment program in a military population. Military Medicine 143:619-23, 1978. 11 Perin, L. A. Behavior modification for weight control. Journal of Occupational Medicine 24:935-37, 1982. 12 Abrams, D. B., and M. J. Follick. Behavioral weight-loss intervention at the worksite: Feasibility and maintenance. Journal of Consulting and Clinical Psychology 51:226-33, 1983. 13 Brownell, K. D., A. J. Stunkard, and P. E. McKeon. Weight reduction at the worksite: A promise partially fulfilled. American Journal of Psychiatry 142:47-52, 1985. 14 Shannon, B., B. Linton, L. Hsu, P. Rollins, and R. M. Schwartz. Development of a nutrition and weight-control program for Atlantic Richfield Company employees. Journal of Nutrition Education 18(Supp. 1):S47-50, 1986. 15 Baecke, J. A. H., J. Burema, and J. E. R. Frijters. A short questionnaire for the measurement of habitual physical activity in epidemiological studies. American Journal of Clinical Nutrition 36:936-41, 1982. 16 SAS Institute, Inc. SAS user's guide, 1979 ed. Raleigh, NC: SAS Institute, Inc., 1979, 495 pp. 17 FrankIe, R. T., J. McIntosh, M. Bianchi, and E. J. Kane. The Weight Watchers at work program. Journal of Nutrition Education 18(Supp. 1):S44-47, 1986. 18 Foshee, V., K. R. McLeory, S. K. Sumner, and D. L. Bibeau. Evaluation of worksite weight loss programs: A review of data issues. Journal of Nutrition Education 18(Supp. 1):S38-43, 1986. 19 Brownell, K. D., R. Y. Cohen, A. J. Stunkard, M. R. J. Felix, and N. B. Cooley. Weight loss competitions at the worksite: Impact on weight, morale, and cost-effectiveness. American Journal of Public Health 74:1283-85, 1984.
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lNutrition Program, The Pennsylvania State University, University Park, Pennsylvania 16802; 2Health Enhancement Resource Center, Los Angeles, California 90046; 30ccidental Petroleum Corporation, Los Angeles, California 90024 ABSTRACf We conducted a study at two worksites of a major corporation to ascertain whether our nutrition and weight-control program would lead volunteer participants to achieve a mean weight loss of 1 pound per week and would improve their nutrition knowledge, attitude toward nutrition, eating behavior, and leisure-time physical activity. Study participants were 103 employees; 47 were blue-collar workers at a petroleum refinery and 56 were white-collar workers at a chemical plant. We assigned approximately half the participants at each site to a treatment group that participated in the program and the other half to a delayed-treatment control group. The four groups' initial mean weights ranged from 120 to 127% of desirable body weight. Company nurses conducted the nine-week program. Of the 52 treatment group participants who enrolled, 32 (61 %) completed the program. These 32 individuals lost significantly (p :5 .001) more weight than controls, 8.5 ± 0.08 pounds and 0.7 ± 0.71bs., respectively; and the mean weekly weight loss of the treatment group was 0.94 pounds. Weight loss did not vary with study site. Questionnaire data indicated that at both sites the treatment group exhibited greater improvement than controls in their attitude toward the importance of nutrition to health, eating behavior, and leisure-time physical activity. At the refinery the treatment group had greater improvement in nutrition knowledge than did the controls. However, this was not the case at the chemical plant. The program led to attainment of most of the objectives, and both the nurses and participants gave the program high ratings. UNE 19:109-116, 1987)
RESUME Nous avons effectue une etude dans deux lieux de travail d'une importante entreprise, afin de verifier si notre programme de controle de l'alimentation et du poids inciterait les participants volontaires Ii perdre en moyenne lIb par semaine et Ii ameliorer leurs connaissances en matiere d'alimentation, leur attitude face Ii l'alimentation, leurs habitudes alimentaires et enfin, leurs activites physiques dans les moments de loisirs. Ont participe Ii cette etude 103 employes, dont 47 cols bleus d'une raffinerie de petrole et 56 cols blancs d'une usine de produits chimiques. Dans chacun des lieux de travail, nous avons designe environ la moitie des participants comme groupe de traitement inscrit au programme, tandis que l'autre moitie ferait partie d'un groupe temoin dont Ie traitement serait reporte. Au depart, Ie poids moyen des participants des quatre groupes variait de 120 Ii 127% du poids souhaitable. Les infirmieres de l'entreprise ont dirige Ie programme de neuf semaines. Des 52 participants du groupe de traitement, 32 (61 %) ont complete Ie programme. Ces 32 sujets ont perdu de far,:on significative (p s .001) plus de poids que les groupes de controle, soit 8.5 ± 0.081bs et 0.7 ± o. 7lbs, respectivement; la perte de poids hebdomadiare du groupe de traitement s'elevait en moyenne Ii 0.94 lb. Le lieu de travail n'a pas affecte la perte de poids en soL Les resultats des questionnaires ont indique que, dans les deux lieux de travail, les groupes de traitement ont demontre une plus grande amelioration que les groupes temoins en ce qui concerne l'attitude face Ii l'importance de l'alimentation pour la sante, les habitudes alimentaires et les activites physiques dans les moments de loisirs. A la raffinerie de petrole, Ie groupe de traitement a fait preuve d'une plus grande amelioration des connaissances en matiere d'alimentation que Ie groupe temoin. Cependant, il en va differemment dans Ie cas de l'usine de produits chimiques. Le programme a permis la realisation de la plupart des objectifs fixes et les infirmieres, tout comme les participants, ont hautement evalue Ie programme. (JNE 91:109-116, 1987) Translated by Louise Lambert-Lagace VOLUME 19 NUMBER 3
1987
RESUMEN Se llev6 a cabo un estudio en dos lugares distintos de trabajo de una importante corporaci6n para determinar si nuestro programa de control de nutrici6n-peso llevaria a los participantes voluntarios a alcanzar una perdida promedio de peso de una libra por semana, y si ellos mejorarian sus conocimientos nutricionales, su actitud hacia la nutrici6n, alimentaci6n, y actividad fisica en tiempo libre. Los participantes en el estudio fueron 103 empleados; 47 eran obreros de una refineria de petr6leo y 56 eran profesionales trabajando en una planta de productos quimicos. Se asign6 aproximadamente a la mitad de los participantes, en cada lugar de trabajo, a un grupo tratamiento que particip6 en el programa, y a un grupo control de tratamiento retardado. En los cuatro grupos, el peso promedio inicial variaba entre 120 y 127% de adecuaci6n para su peso ideal. EI programa de nueve semanas estuvo a cargo de enfermeras de la compaiiia. De los 52 participantes en el grupo tratamiento, solamente 32 (61%) completaron el programa. Estos 32 individuos perdieron significativamente (p s .001) mas peso que los del grupo control, 8.5 ± 0.08libras y 0.7 ± 0.7libras respectivamente; siendo la perdida de peso promedio semanal del grupo tratamiento de 0.94 libras. La perdida de peso no vari6 con ellugar de estudio. Los datos obtenidos de los cuestionarios indican que en ambos lugares, el grupo tratamiento mostr6 mayor incremento en su actitud hacia la importancia de la nutrici6n en la salud, comportamiento alimentario, y actividad fisica en su tiempo libre. En la refineria, el grupo tratamiento tuvo una gran mejora en conocimientos sobre nutrici6n sobre el grupo control. Sin embargo, no sucedi6 as! en la planta de productos qu!micos. EI programa logr6la mayoria de sus objetivos, y tanto las enfermeras como los participantes Ie dieron al mismo altos punteos. UNE 19:109-116,1987) Translated by Diva Sanjur
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Increasingly, corporate health-promotion activities include weight-management programs for employees. Recently, Glanz and Seewald-Klein (1) reviewed 23 reports, published between 1978 and 1985, of such worksite programs. Reports on several additional programs (2-5) have also been published. Most of these programs employ behavior-modification techniques, often in conjunction with other strategies, to motivate participants and enhance their knowledge of weight control. Employee weight-control programs have been conducted in a variety of settings (1) and led by a variety of professionals, both nutritionists (2, 3, 6, 7) and non-nutritionists (8-13). The number of worksite weight-management programs with interpretable evaluation data is small (1) and assessment of effectiveness has been limited mainly to some measure of body-weight change during and often following the program. Because body weight is a function of both food intake and energy expenditure, weight-management programs should attempt to appropriately influence both eating behavior and physical activity. Program evaluations should assess changes in these areas as well as weight changes. This article reports the outcomes of a study that evaluated a nutrition and weight-control program that we developed for use in Atlantic Richfield Companies (ARCO). We designed the program so that it could be presented by company health professionals and could be used by both blue-collar and white-collar employees. The program objectives were a) to lead participants to achieve a mean weight loss of approximately 1 pound per week during the nine-week program; and b) to improve participants' knowledge of and attitude toward nutrition, and to improve their eating behavior and increase their leisure-time physical activity level. We implemented the program at two company worksites and conducted a study to determine the degree to which program objectives were attained. Our hypothesis was that the employees who completed the program would exhibit greater weight loss and higher scores on instruments assessing nutrition knowledge, attitudes, eating behavior, and physical activity than would employees in a control group who did not participate in the program. METHODS Study design and participants. We used a pretestposttest study design with a delayed-treatment control group. Study participants were company employees who indicated their interest in attending a weightcontrol course by responding to an announcement in the company newsletter (Note 1). There was no weight criterion for acceptance into the program. At one site, a chemical plant, we randomly assigned respondents 110
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to either the treatment or control group. At the other site, a refinery, we had to handle recruitment and participant assignment through the employee relations officials who assigned respondents to groups according to job categories. At the chemical plant and refinery, respectively, the treatment groups contained 27 and 30 assignees, and the control groups contained 28 and 30 assignees. The chemical plant study participants were mainly white-collar employees involved in research and development while the refinery study participants were mainly blue-collar employees involved in various aspects of petroleum refining. The weight-control program, entitled "Food, Fitness and Your Lifestyle," has been described in detail elsewhere (14). It is a nine-week program with one 30minute session per week. These time periods were compatible with the needs and request of the company. The introductory session of the program deals with the relationship of nutrition to general health and can stand alone or introduce the subsequent eight sessions that deal with weight control. Company nurses (two at the refinery and one at the chemical plant) conducted the sessions after they attended a training meeting provided by the nutrition educators who developed the program. The chemical plant nurse opened the introductory session to all employees who wanted to attend, which included individuals in both the treatment and control groups. However, only the treatment group participants attended the follow-up weight-control sessions. Nurses at the refinery invited only treatment group participants to the introductory session. Employees attended sessions on their own time. At the chemical plant they met during the lunch period and at the refinery they met after the 4 P.M. shift. Members of the control groups at both sites attended a second offering of the program after the study was completed. One week prior to the introductory session the nurses at both sites sent, via company mail, a pretest questionnaire to treatment and control group members. The questionnaire included instruments that assessed nutrition knowledge, attitudes, eating behavior, and physical activity. Study participants returned the completed questionnaires through company mail and reported to the medical department where the nurses measured their weight and height. During the final week of the program, study participants in both the treatment and control groups completed a posttest questionnaire identical to the pretest and were again weighed. At each assessment period during the program and at follow-up, the nurses weighed study participants using a physician's Detecto scale with beam. The nurses measured participants' heights at the preassessment. Participants removed heavy coats or sweaters and shoes for these measurements. In addition, members of the treatment groups reported to the VOLUME 19
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stituting the two attitude scales were intermingled and study participants responded to each item on a five-point continuum, ranging from strongly agree (scored 5) to strongly disagree (scored 1). Responses to negatively worded statements were reversed when scored. To simplify discussion of the attitude scales, we have abbreviated their titles to "nutrition-health" and "weight-control" throughout the remainder of this article. The food-frequency form contained 30 items selected to reflect all five food groups. Respondents indicated how often they consumed each item by marking a six-point grid ranging from never (scored 6) to more than three times per day (scored 1). Factor analysis of study participants' pretest responses revealed the presence of two factors: one with 12 items having factor loadings above 0.4 and another with 6 items having loadings above 0.4. The former 12 items were relatively low in nutrient density (e.g., fried meat, fish, and poultry) compared to the latter 6 items (e.g., baked or broiled meat, fish, or poultry). We, therefore, designated these two sets of items, respectively, as the "low-nutrient-density" and' 'high-nutrient-density" food-frequency scales. Statements constituting the calorie "add-on" scale reflected frequency of adding calories to food (e.g., "I add cream to coffee or tea"). Study participants responded to each statement on a five-point continuum ranging from never (scored 1) to always (scored 5).
nurses for weekly "weigh-ins." The nurses completed session evaluation forms after each session and treatment group participants completed a program evaluation form after the last session. The plan was that after participants completed the nine-week program, the nurses would monitor the participants' weights every four to six weeks for six months and provide us with participants' six-month follow-up weights. However, shortly after completion of the study, the company underwent significant restructuring. Both the refinery and chemical plant were sold about three months later. This created so much upheaval af both sites that the weight monitoring and follow-up did not occur as planned. However, after the situation at both sites stabilized under new management (approximately one year after the study had been initiated), the nurses sent letters to members of the treatment groups who had completed the program and were still working at those sites. The letter requested study participants to report to the medical department for a follow-up weigh-in. To assess nutrition knowledge, attitudes, eating behavior, and physical activity, we developed paper/ pencil instruments and pilottested them among 54 blue- and white-collar employees at a company site not in the study. Table 1 provides descriptive information about the knowledge, attitude, and eating-behavior instruments. We used factor analysis to examine the construct validity of the attitude scales. Items con-
Table 1.
Instruments used to assess knowledge, attitude, and eating behavior Items
Type!
Instrument
Coefficients of Internal Consistency2
Number
Score Range
25
0-25
KR-20 = 0.76
"Don't know" responses scored as a wrong answer Higher scores reflected stronger feelings about the importance of nutrition to health Higher scores reflected more positive feelings about ability to control weight
Knowledge
True/false/"don't know"
Attitude scale Nutrition is important to health
Likert
5
5-25
Alpha = 0.65
Likert
5
5-25
Alpha = 0.75
I can control my weight Food-frequency scales Low-nutrient-density
Six-choice grid
12
12-72
Alpha = 0.86
High-nutrient-density
Six-choice grid
6
6-36
Alpha = 0.71
Likert
5
5-25
Alpha = 0.75
Calorie add-on scale
Comments
Higher scores refl~cted less frequent consumption of lownutrient-density foods Higher scores reflected more frequent consumption of lownutrient-density foods Higher scores reflected more frequent additions of caloriecontaining items to food
1 For the knowledge items, a "don't know" response was scored as incorrect; for the Likert-type items, responses were on a continuum scored from 1 to 5; for the six-choice grid, responses were scored from 1 to 6. 2KR-20 refers to the Kuder Richardson-20 coefficient and alpha refers to the Chronbach alpha coefficient.
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To assess level of physical activity, we adapted and pilottested the 16-item scale of Baecke et al. (15). Pilottest results indicated that respondents did not understand some of the items, and they preceived items dealing with physical activity on the job as threatening. For example, some employees feared that management might respond negatively to an "always" response to an item indicating that, when on the job, the employee sits rather than stands. We, therefore, selected three items from the scale that elicited responses which indicated how often study participants engaged in certain types of physical activity during their leisure time, e.g., "During leisure time I walk fast (10 minutes or more) for my exercise." Participants responded to these items on a five-point continuum ranging from never (scored 1) to always (scored 5). We summed the scores on these three items to yield a leisure-time physical-activity score that could range from 5 to 25, with higher scores being more desirable. The forms that members of the treatment group completed to evaluate the program contained items that elicited members' opinions of the overall program, the individual sessions, and the audiovisual and participatory activities included in the sessions. The nurses completed a similar form for each session. Before we used the forms at the test sites, an expert panel of nutrition educators reviewed them, and we revised the forms in keeping with the panel's recommendations. Data analysis. We examined all study participants' initial weight and percent of desirable body weight as well as the change in these two parameters between pre- and posttest times. To calculate percent of desirable body weight we divided each study participants' weight by the midpoint weight specified as desirable for individuals of the same sex, height, and age group in the 1983 Metropolitan Life Insurance tables. We used the Statistical Analysis System (SAS) programs (16) for all data analyses. To test our hypothesis that the program positively influenced weight change and scores on the questionnaire instruments, we included only study participants for whom we had complete pre- and posttest weight and questionnaire data. We used analysis of covariance with preweight or prescores as the covariates. In each analysis the independent variables were treatment (participation in the program), site (chemical plant or refinery), gender, interaction between treatment and gender, and interaction between treatment and site. This allowed us to control statistically for initial differences among groups in the study. We simplified the final model in each analysis by removing nonsignificant variables (or interactions) to produce the most parsimonious equation to describe the relationships that emerged.
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To assess the net relationship between independent variables and the dependent variable-weight change-we used multiple regression and controlled for variation in preweight. Preliminary regression analyses, using a bivariate model, identified independent variables that should be included in the multiple regression model. RESULTS Of the 115 employees initially assigned to the groups in the study, 103 chose to participate, completed the pretest questionnaire, and reported for the initial weigh-in. At the refinery, 24 ofthese were in the treatment group and 23 were in the control group; at the chemical plant 28 were in each of the respective groups. Table 2 shows the descriptive pretest data on these 103 study participants. The treatment and control groups at the chemical plant were quite similar with regard to age, height, weight, percent of desirable body weight, and distribution of males versus females. However, because we were unable to randomly assign study participants to the two groups at the refinery, there was an imbalance, with the refinery treatment group having a greater percentage of males than the refinery control group or either group at the chemical plant. This higher percentage of males in the refinery treatment group is reflected in a slightly higher mean height among that group compared to the other three groups. However, the four groups did not differ significantly with regard to mean weight, percent of desirable body weight, and age. Furthermore, the four groups had comparable prescores on the nutrition knowledge test, attitude scales, and the scales reflecting eating behavior and physical activity. Of the 52 study participants in the treatment groups at the two sites, 32 completed the program, i.e., attended at least five sessions and had complete preand posttest questionnaire and weight data. This yielded an overall completion rate of 61 %; 71 % completed the program at the chemical plant, and 50% completed it at the refinery. In the control groups, 43 of the 51 enrolled participants took the posttest and reported for the final weigh-in. Table 2 also shows the descriptive information, at pretest time, for the treatment and control participants who had complete data at the end of the program. Because these final groups are quite similar to the originally enrolled groups with regard to descriptive characteristics, attrition had little influence on the make up of the final four groups. Effect of the program. Neither gender nor site influenced participants' weight change, and there was no
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Table 2. study
Descriptive pretest characteristics of groups according to participants who enrolled in and completed the Mean ± S.D.
Group I
Chemical Plant Treatment group Enrolled (n = 28) Completed (n = 20) Control group Enrolled (n = 28) Completed (n = 23) Refinery Treatment group Enrolled (n = 20) Completed (n = 12) Control group Enrolled (n = 23) Completed (n = 20)
Percent Males
Age (years)
Height (inches)
Weight (pounds)
Percent Desirable Body Weight
57 a 53 d
43.8 ± 11 44.0 ± 11
65.5 ± 4a 66.3 ± 4d
192.48 ± 48.8 185.8 ± 38.7
127.7 ± 24 122.0 ± 24
57 b 48e
44.5 ± 11 45.4 ± 11
67.1 ± 4b 66.8 ± 3"
191.7 ± 39.9 193.2 ± 39.6
125.9 ± 19 127.2 ± 19
87 abc 83 del
43.5 ± 11 46.0 ± 12
69.5 ± 4abc 70.6 ± 3del
201.9 ± 50 207.2 ± 41
127.3 ± 24 126.8 ± 19
43 c 501
42.6 ± 13 43.2 ± 13
67.2 ± 4C 67.8 ± 4
181.5 ± 35 182.1 ± 35
120.4 ± 20 120.7 ± 21
lMeans of enrolled and of completed groups in the same vertical column, bearing like superscripts are significantly different (p ::s .05).
interaction between these two variables nor between site and treatment. However, treatment had a strong influence on weight change; the weight loss of the treatment group was significantly greater than that of the control group (Table 3). The mean weekly weight loss of the treatment group was 0.94 pounds during the nine-week program, and the final percent of desirable body weight at posttest time reflected this loss. The adjusted mean percent of desirable body weight for the treatment group was 117.8 % while that of the control group was 122.4% (p :5 .001). Treatment group participants who did not complete the program exhibited a mean weight loss of 4.4 ± 6.2 pounds between the initial weigh-in and the last week they reported for a weigh-in (average of 3.8 weeks). The program significantly influenced postscores on the nutrition-health attitude scale and the low-nutrient-density food-frequency scale (Table 3). Treatment group participants came to feel more positively than did controls about the importance of nutrition to health, and treatment group participants reported greater decreases than did controls in consumption of low-nutrient-density foods. This effect was independent of site and gender. Both treatment and gender had independent effects on participants' reported consumption of high-nutrient-density foods, addition of calorie-containing items to food, and level of leisuretime physical activity. Site did not influence any of these relationships. Table 3 shows the adjusted mean postscores for the treatment and control groups; Table 4 shows the means according to gender. At posttest time treatment group participants reported consum-
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ing foods of high nutrient-density more frequently than did control group participants, and females reported consuming these foods more frequently than males. Furthermore, at posttest time members of the treatment group reported adding calorie-containing items to food less often than did members of the control group, and males reported adding calorie-containing items to food less frequently than females. At posttest time members of the treatment group also reported participating in leisure-time physical activity more often than did the control group, and males reported such participation more often than females. The effect of the program on participants' nutrition knowledge scores was not influenced by gender but did vary according to site. Adjusted mean postscores of both chemical plant groups and the refinery treatment group were similar but were higher than the mean postscore of the refinery control group (Table 3). Therefore, since all four groups had equivalent pretest scores, the chemical plant control group gained a level of knowledge equivalent to the two treatment groups. The program's effect on the weight-control attitude scale was also not influenced by gender but varied with site (Table 3). Mean adjusted postscores of the two groups at the chemical plant and the control group at the refinery were equivalent and lower than the scores of the refinery treatment group. Thus, the program improved refinery participants' feelings about their ability to control their weight but had no effect on the chemical plant participants' feelings on that issue. The only variables that had a significant bivariate
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Table 3.
Treatment and control groups' adjusted mean weight loss and postscores (± standard error) on other variables assessed
Group I Treatment (n = 32)
Variable 2 Weight loss Nutrition-health attitude scale score (range = 5 to 25) Low-nutrient-density food-frequency scale score (range = 12-72) High-nutrient-density food-frequency scale score (range = 6-36) Calorie "add-on" scale score (range = 5-25) Leisure-time physical activity scale score (range = 5- 15) Nutrition knowledge test score (maximum score = 25) Refinery Chemical plant Weight-control attitude scale score (range = 5-25) Refinery Chemical plant
8.5 22.2 52.2 8.6 13.9 8.4
± ± ± ± ± ±
Control (n
0.8 0.4 1.0 0.5 0.5 0.3
0.7 20.7 48.5 10.3 16.9 7.4
=
43)
± 0.7 ± 0.3 ± 0.8 ± 0.4 ± 0.6 ± 0.2
20.0 ± 0.7 a 19.5 ± 0.6a
15.9 ± 0.6 18.6 ± 0.5 a
22.6 ± 0.6 19.6 ± 0.5 b
19.9 ± 0.5 b 19.2 + 0.5 b
, Posttest means from analysis of covariance with pretest weight or scores used as covariates; for each variable, means not bearing common superscripts are significantly different, p ::s .01; see Table 1 for directionality of scores. 2For the first six variables, means of the refinery and chemical plant groups are combined because scores did not vary according to site and there was no interaction between site and treatment; for the last two variables there was a significant interaction between site and treatment, so scores are presented according to site.
Table 4. Adjusted mean postscores' (± standard error) of males versus females on the variables that differed significantly according to gender
Variable 1 High-nutrient-density food-frequency scale score (range = 6-36) Calorie "add-on" scale score (range = 5-15) Physical activity scale score (range = 5-15)
Males In = 33)
Females In = 42)
10.1 ± 0.4
8.8 ± 0.5
14.4
± 0.6
16.0
± 0.6
8.3
± 0.2
7.5
± 0.3
, Postscores from analysis of covariance with prescores as the covariate; for each variable, means of males and females differed significantly, p ::S .05. For directionality of scale scores see Table 1. 2The gender effect was independent of treatment and site, so for each sex the scores of both groups at both sites were combined.
association with weight change were treatment and change (pretest minus posttest) in calorie "add-on" scale scores and in physical-activity scale scores. Table 5 shows the results of the multiple regression analysis when weight change was regressed on these three variables and variation in preweight was controlled. All three variables accounted for a significant amount of variance in weight change, and the model explained a total of 61 % of the variance in weight change. Nurses' and participants' assessment of the program. The 32 treatment group participants who completed the program gave it very favorable ratings. Of these, 79% indicated that the information provided was either very appropriate or extremely appropriate to their needs and interests, 64% rated the session ac-
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Table 5. Multiple regression model with weight change as the dependent variable (n = 75)
Independent Variable
R' 0.61
Preweight Treatment Change in calorie "add-on" scale score Change in physicalactivity scale score
8 Value ± S.E.
T-statistic
- 0.033 ± 0.01 - 5.435 ± 0.13
- 2.36* -4.81 ***
± 0.13
-3.54***
-1.051 ± 0.35
-3.01***
- 0.457
*p ::S .05 ***p ::S .001
tivities as very helpful to extremely helpful, 75% felt sufficient time was allowed for the activities in the 30minute sessions, and 100% said they would recommend the program to others. The most popular of the weight-control sessions was the one on calorie sources and portion control. The nurses' evaluation of the program was also positive. They indicated that "for the most part the objectives of the sessions were accomplished." They felt the information was appropriate for employees and that the employees enjoyed the sessions. The nurses identified no difficulties in conducting the sessions. Since all audiovisual and printed materials for program sessions were provided as part of the program package, the nurses' only preparation involved reviewing the background information and session materials. Follow-up. Of the 32 study participants who completed the program, 14 reported for the follow-up
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weigh-in, 8 had retired or changed jobs, and the remaining 10 failed to respond to the nurses' request for follow-up. Of the 14 for whom we obtained follow-up weights, 3 had returned to their pretest weight and 3 weighed more than at pretest time with their mean weight gain (± standard deviation) being 6.8 ± 5.8 pounds. Four had regained some, but not all, of the weight they had lost, with their mean follow-up weight being 8.3 ± 4.9 pounds less than their pretest weight. And 4 had continued to lose weight, with the mean follow-up weight of 3 of these individuals being 10.8 ± 2.4 pounds less than their pretest weight; 1 individual had lost 91 pounds since the pretest. DISCUSSION These results show that most of our program objectives were attained. The mean weekly weight loss of 0.94 pounds among treatment group participants was very close to the weight-loss goal of 1 pound per week. In addition the program led these participants to feel more strongly about the importance of nutrition, and to make improvements in self-reported eating behavior and level of physical activity. The treatment group's mean weight loss of 8.5 pounds was not as great as that reported by some of the 23 programs reviewed by Glanz and Seewald-Klein (1). In those programs, the weight losses ranged from 5 to 18 pounds; but the higher losses occurred in programs that were of greater duration than ours, Le., more than ten weeks. On a weekly basis the weight loss attained by our treatment group compares favorably with that in other programs. For example, it was similar to the 0.90 pounds weekly weight loss of participants in the "Weight Watchers at Work" reported by FrankIe et al. (17), and it exceeded the weekly range of 0.45 to 0.87 pounds lost by insurance company employees in a study reported by Sumner et al. (5). Weekly weight loss of participants in 9 programs that Foshee et al. reviewed (18) ranged from 0.46 to 3.59 pounds, but the average weekly weight loss across those programs was 1.07 pounds. Other investigators have provided little information about the impact of worksite weight-management programs on nutrition knowledge, attitude, eating behavior, and physical activity. Brownell and co-workers (19) did assess physical activity of their participants using a self-report instrument. Comparison of their outcomes with ours is difficult because we calculated a physical activity score for our participants while they specified the percent of participants who reported increases (Le., 3 to 22 % of their study participants said they increased various types of physical activity). Furthermore, our scale did not include all possible types of leisure-time physical activities, so it VOLUME 19 NUMBER 3
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may not have adequately assessed the activities of some participants. Sumner et al. (5) administered eating behavior inventories to their participants. Their outcomes, like ours, show improvements in what participants reported about their eating behavior. We believe that simple, easily administered instruments of the type we used provide valuable information about worksite intervention even though these instruments rely on self-reporting of behavior, which certainly may be biased. Nevertheless, the change in our study participants' scores on both the calorie "add-on" scale and the leisure-time physical activity scale accounted for a significant amount of the variation in their weight change. This supports our confidence in the use of such self-report instruments to assess trends among groups. The 61 % program completion rate among participants in our study compares favorably with the range of 40% to 70% completion rates reported for the 23 worksite weight-control programs reviewed by Glanz and Seewald-Klein (1). Two notable exceptions to this are the programs reported by Brownell et al. (13) and by Jeffery, Forster, and Snell (4). The former employed weight-loss competitions and attained 99.5% completion while the latter used payroll-based incentives and attained 94% completion. Because the unexpected corporate changes made it impossible to conduct the follow-up as originally planned, we cannot draw meaningful conclusions from the meager follow-up data we obtained. The difference in the nutrition knowledge test outcomes at the two sites likely reflects the difference in the way the introductory session was handled at those sites. At the chemical plant both the treatment group and the control group attended that session, but at the refinery only the treatment group attended. For the most part, the introductory session provided nutrition information while the eight sessions that followed were more behavior oriented. The control group at the chemical plant apparently gained enough information by attending the introductory session, and perhaps through discussing it afterward, to allow them to score as high on the nutrition knowledge posttest as the treatment group. At the refinery, the control group did not exhibit nutrition knowledge gain. We do not know why the chemical plant treatment group's attitude toward ability to control weight failed to become more positive during the study while the refinery treatment group's attitude toward ability to control weight improved. Perhaps the blue-collar workers in the refinery found the program information and techniques more convincing and persuasive than did the white-collar chemical plant workers. In conclusion, this study adds to the growing body of information which shows that weight-control proJOURNAL OF NUTRITION EDUCATION
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grams can be successfully implemented in the work setting among a wide spectrum of employees. It demonstrated a method whereby company nurses were able to effectively conduct such programs within the time constraints of both blue-collar and white-collar employees. 0 ACKNOWLEDGMENTS The work reported here was partially funded by the Atlantic Richfield Company. The authors gratefully acknowledge the following nurses who conducted the program at the worksites: Monica Hare, Isabela Kelly, and Mary Levinsky.
NOTE 1 The procedures for this study were approved by The Pennsylvania State University Human Subjects Committee.
UTERATURE CITED 1 Glanz, K., and T. Seewald-Klein. Nutrition at the worksite: An overview. Journal of Nutrition Education 18:S1-12,1986. 2 Loper, J. F., and K. K. Barrows. A nutrition and weightcontrol program in industry. Journal of the American Dietetic Association 85:1487-88, 1985. 3 Kneip, J. K., H. M. Fox, and J. K. Fruehling. A weightcontrol program for bank employees. Journal of the American Dietetic Association 85:1489-91, 1985. 4 Jeffery, R. W., J. L. Forster, and M. K. Snell. Promoting weight control at the worksite: A pilot program of self motivation using payroll-based incentives. Preventive Medicine 14:187-94,1985. 5 Sumner, S. K., E. L. Schiller, E. R. Marr, and D. I. Thompson. A weight control and nutrition education program for insurance company employees. Journal of Nutrition Education 18:(Supp. 1):S60-62, 1986. 6 Schumaker, N., B. Groth, J. Kleinsek, and N. Seay. Successful weight control program for employees. Journal of the American Dietetic Association 74:466, 67, 1979.
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7 Kelly, K. L. Evaluation of a group nutrition-education approach to effective weight loss and control. American Journal of Public Health 69:813, 14, 1979. 8 Colvin, R. H. Weight control on-the-job: Making use of the office environment. Journal of the American Dietetic Association 74:465, 1979. 9 Klug, P.M. Implementing health education programs at Australian Paper Manufacturers Limited, Botany Mills. Occupational Health Nursing 27:18-20, 1979. 10 Repport, J. T., and C. G. Shaw. A conceptual and statistical evaluation of a new obesity treatment program in a military population. Military Medicine 143:619-23, 1978. 11 Perin, L. A. Behavior modification for weight control. Journal of Occupational Medicine 24:935-37, 1982. 12 Abrams, D. B., and M. J. Follick. Behavioral weight-loss intervention at the worksite: Feasibility and maintenance. Journal of Consulting and Clinical Psychology 51:226-33, 1983. 13 Brownell, K. D., A. J. Stunkard, and P. E. McKeon. Weight reduction at the worksite: A promise partially fulfilled. American Journal of Psychiatry 142:47-52, 1985. 14 Shannon, B., B. Linton, L. Hsu, P. Rollins, and R. M. Schwartz. Development of a nutrition and weight-control program for Atlantic Richfield Company employees. Journal of Nutrition Education 18(Supp. 1):S47-50, 1986. 15 Baecke, J. A. H., J. Burema, and J. E. R. Frijters. A short questionnaire for the measurement of habitual physical activity in epidemiological studies. American Journal of Clinical Nutrition 36:936-41, 1982. 16 SAS Institute, Inc. SAS user's guide, 1979 ed. Raleigh, NC: SAS Institute, Inc., 1979, 495 pp. 17 FrankIe, R. T., J. McIntosh, M. Bianchi, and E. J. Kane. The Weight Watchers at work program. Journal of Nutrition Education 18(Supp. 1):S44-47, 1986. 18 Foshee, V., K. R. McLeory, S. K. Sumner, and D. L. Bibeau. Evaluation of worksite weight loss programs: A review of data issues. Journal of Nutrition Education 18(Supp. 1):S38-43, 1986. 19 Brownell, K. D., R. Y. Cohen, A. J. Stunkard, M. R. J. Felix, and N. B. Cooley. Weight loss competitions at the worksite: Impact on weight, morale, and cost-effectiveness. American Journal of Public Health 74:1283-85, 1984.
VOLUME 19
NUMBER 3
1987