Rationale, design, and baseline data for commit to quit ii: an evaluation of the efficacy of moderate-intensity physical activity as an aid to smoking cessation in women☆

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Rationale, design, and baseline data for Commit to Quit II: an evaluation of the efficacy of moderate-intensity physical activity as an aid to smoking cessation in women夞 Bess H. Marcus, Ph.D.,a,* Beth A. Lewis, Ph.D.,a Teresa K. King, Ph.D.,a Anna E. Albrecht, R.N., M.S.,a Joseph Hogan, Sc.D.,b Beth Bock, Ph.D.,a Alfred F. Parisi, M.D.,a and David B. Abrams, Ph.D.a a

Centers for Behavioral and Preventive Medicine and Division of Cardiology, Brown Medical School and The Miriam Hospital, Providence, RI, USA b Center for Statistical Sciences, Brown University, Providence, RI, USA

Abstract Background. Commit to Quit II is a 4-year randomized controlled trial comparing the efficacy of a cognitive-behavioral smoking cessation treatment plus moderate-intensity physical activity with the same cessation treatment plus contact control. Methods. Sedentary women smokers (n ⫽ 217) were randomized to receive 8 weeks of treatment followed by 12 months of follow-up. This article outlines the study design, presents baseline data about the sample, and compares the sample to national samples and to our previous study examining vigorous-intensity exercise as an aid to smoking cessation. Results. Married and white participants reported significantly higher levels of nicotine dependence than nonmarried and minority participants. Higher levels of nicotine dependence were also significantly related to lower smoking cessation self-efficacy and higher levels of self-reported depression, anxiety, and perceived stress. Additionally, participants smoked significantly more cigarettes (mean 20.6) than a national sample of female smokers (mean 16.1). On average, participants were significantly older, weighed significantly more, and scored significantly higher on a measure of anxiety than participants in our previous trial. Conclusions. Our sample consisted of women who were heavier smokers than national samples seeking treatment. It remains to be determined how this will impact their ability to attain cessation in the present study. © 2003 American Health Foundation and Elsevier Science (USA). All rights reserved. Keywords: Smoking cessation; Women; Exercise; Weight gain

Introduction Tobacco dependence continues to be the leading, preventable cause of coronary heart disease, emphysema, respiratory infections, and bronchitis [1]. Twenty-two percent of women currently smoke cigarettes in the United States [2] and the prevalence of smoking is highest among women 夞 This project was supported in part through grants from the National Cancer Institute (#CA77249) and the National Heart, Lung, and Blood Institute (#HL64342 and #HL68422). * Corresponding author. The Centers for Behavioral and Preventive Medicine, Brown Medical School and The Miriam Hospital, 1 Hoppin Street, Coro Building, Suite 500, Providence, RI 02903, USA. E-mail address: [email protected] (B.H. Marcus).

ages 18 – 44 [1]. In 1987, lung cancer surpassed breast cancer as the leading cause of death by cancer among women and lung cancer is projected to be double the rate of breast cancer by 2003 [2]. Unlike breast cancer that has a 5-year survival rate of over 85%, lung cancer survival is less than 13% at 5 years. Thus, the best “treatment” for reducing the chronic disease burden of smoking is smoking cessation. The fear of weight gain and actual weight gain following smoking cessation may contribute to women continuing to smoke. Compared to male smokers, females gain more weight and are also more likely to expect to gain weight following smoking cessation [3,4]. Women are also more likely than men to report using smoking as a weight-loss strategy [5]. Weight concerns among female smokers have

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been shown to predict dropout rates from smoking cessation treatment [6] and young women are almost four times more likely to report weight gain as the cause for smoking cessation relapse than men [7]. Overall, smokers reporting concerns about cessation-related weight gain have poorer cessation rates than smokers not reporting weight gain concerns [8,9]. Therefore, the relationship between cigarette use and weight gain is two-fold in that women may use cigarettes as a means to manage their weight and fear of weight gain may contribute to unsuccessful maintenance of quit attempts. Participation in regular physical activity among female smokers may aid in cessation efforts by serving both as an alternative to smoking and by reducing the weight gain associated with smoking cessation. Participation in regular physical activity increases caloric expenditure, and may therefore increase metabolic rate [10] and offset the increases in caloric intake, which often occur with smoking cessation [11]. Additionally, physical activity may aid in smoking cessation by addressing physiological and psychosocial issues including reducing depressed affect [12] and attenuating stress in women reporting being “negative-affect” smokers [13,14]. Finally, research indicates that physical activity participation leads to reductions in withdrawal symptoms and nicotine craving [15,16], which also may aid in smoking cessation. Prior to 1992, four studies had examined the efficacy of vigorous exercise as an aid for smoking cessation [17–20]. Only one study found significant differences between the exercise and control groups at the end of treatment; however, this study did not find significant differences between the treatment groups at 1-, 3-, or 12-month assessments [18]. Limitations of these studies included small sample sizes [17–20], lack of increase in fitness level in the physical activity group [19], no formal smoking cessation treatment [20], relatively short programs [17], and lack of a comparison group controlling for contact time [17,18]. Since 1992, four studies have examined physical activity as an aid to smoking cessation [21–24]. Martin and colleagues [24] found that among recovering alcoholic participants, behavioral counseling plus exercise was more efficacious than behavioral counseling plus nicotine gum and standard treatment at posttest but not 6 or 12 months. Hill and colleagues [23] found that among older smokers (50 years of age or older) behavioral treatment plus exercise, behavioral treatment plus nicotine gum, and behavioral treatment only were equally effective in reducing smoking at 12 months. One problem with both of these studies is that they were conducted in populations (i.e., older adults and recovering alcoholics) that are not generalizable to a community sample of adult smokers. Marcus and colleagues [21] addressed the limitations of these previous studies by conducting an adequately powered study under “ideal” controlled conditions in a hospital outpatient setting. This study found significant differences between vigorous activity and contact control through 12 months of follow-up [21].

The current study was designed to test the efficacy of moderate-intensity physical activity as an aid for smoking cessation. This study was a logical progression of prior work on the efficacy of vigorous exercise to aid smoking cessation and weight regulation in women smokers as moderate-intensity exercise is a more disseminable form of exercise that can be performed by healthy individuals without medical supervision. This article describes: (1) the study design, (2) the sample of women who participated in this trial, (3) the relationship among baseline variables in the domains of weight, mood, and smoking behavior, (4) information comparing the sample to national samples, and (5) comparison of our sample (i.e., treatment sample) to participants who expressed interest in the study but did not participate for various reasons (i.e., recruitment sample) and to the group of women who participated in our previous trial of vigorous intensity exercise as an aid to smoking cessation.

Methods Research design Commit to Quit II (CTQII) was a randomized controlled clinical trial that compared the efficacy of two conditions, (1) cognitive-behavioral smoking cessation plus supervised group and home-based moderate-intensity exercise (Moderate Exercise), and (2) cognitive-behavioral smoking cessation plus equal contact time from staff (Contact). Our design allowed for a rigorous comparison of the effects of moderate-intensity physical activity plus standard smoking cessation with the effect of a standard smoking cessation intervention that equated for contact time. Therefore, the effect of physical activity was separated from the effects of contact time with staff and other participants. All participants received a state-of-the-art cognitive-behavioral smoking cessation treatment program specially designed for women. The exercise program was a supervised moderateintensity class and home-based program of sufficient frequency, intensity, and duration to produce cardiovascular adaptations [25]. Treatment regimen Subjects participated in an 8-week cognitive-behavioral group-based smoking cessation treatment. Doctoral level psychologists and masters level therapists, who were supervised by doctoral level psychologists, conducted the sessions. To control for any differences in skill level between the masters and doctoral level therapists, the same therapists provided treatment to both groups within each cohort. Additionally, the doctoral level therapist provided close supervision of the masters level therapist and all therapists were provided a standardized manual created by doctoral level psychologists (B.H.M. and T.K.K.). Treatment focused on topics relevant to women including managing weight,

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healthy eating, balancing and managing time, and managing stress due to multiple roles and multiple demands. Traditional cognitive-behavioral topics such as self-monitoring, stimulus control, coping with cravings and high-risk situations, stress management, and relaxation techniques were also included. To ensure standard delivery of the program across the 13 replications (mean 16.7 participants per cohort), written therapist and participant manuals were used and followed at all times. To enhance adherence, participants who failed to attend a session were telephoned and encouraged to resume their participation in the program. Replacement sessions were conducted by therapists in person or by telephone. With respect to the blinding of therapists, we felt it was more important to minimize dropout by having consistency of therapists, and it was impossible to have therapists blinded in a study such as this. Independent manipulation checks in the form of consumer ratings, and group cohesion scales, were administered to evaluate and control for any effect on outcomes. Additionally, a masters or doctoral level therapist not directly involved in the delivery of treatment to participants listened to a random subset (25%) of the taped smoking cessation sessions in order to provide a quality control check on the delivery of cessation treatment to participants in the two conditions. Recruitment Healthy women between the ages of 18 – 65 who had regularly smoked five or more cigarettes a day for at least 1 year and who had routinely participated in moderate or vigorous intensity physical activity for 90 minutes or less each week were recruited. We chose this physical activity participation criteria because it refers to three 30-minute exercise sessions or less per week, which is substantially less than the Centers for Disease Control/American College of Sports Medicine (CDC/ACSM) recommendation that individuals engage in 30 minutes or more of moderate-intensity physical activity on most, preferably all, days of the week. Participants were excluded from the study for having a history of coronary artery disease (history of myocardial infarction or symptoms of angina), stroke, diabetes, osteoporosis, osteoarthritis or orthopedic problems that would limit treadmill testing or exercise training, or any other serious medical condition that might make exercise unsafe or unwise. Other exclusion criteria were a schedule that made adherence unlikely (such as very frequent travel), plans to move from the area within the year, pregnancy or plans to attempt pregnancy, self-report of five or more alcoholic drinks per day on 3 days of the week, hospitalization for a psychiatric disorder in the previous 3 years or currently suicidal or psychotic, currently receiving individual mental health counseling, taking medications for severe psychopathology (schizophrenia or bipolar disorder), currently using smokeless tobacco, nicotine replacement therapy, or other smoking cessation treatment, and currently

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using prescription medication that might impair exercise performance or tolerance, specifically beta blockers. Participants who were being treated for high blood pressure were included with written permission from their primary care provider. Participants with respiratory or lung problems such as asthma or chronic bronchitis were also included with written permission from their physicians. Participants taking medications for any condition had to be stable on the same medication for at least 3 months. Additionally, participants who used oral contraceptives or estrogen replacement therapy had to be on a stable dose for at least 3 months prior to study onset. Participants agreed to be assigned randomly to either of the investigational conditions and read and signed a consent form approved by the Institutional Review Board. Two hundred seventeen women were recruited into 13 cohorts averaging 16.7 participants per cohort. Participants were randomly assigned to one of the two conditions (Moderate Exercise or Contact), which resulted in approximately two groups averaging approximately eight women each. Smoking status was determined via self-report and carbon monoxide testing at each session and by self-report of 7-day point prevalence abstinence with saliva cotinine verification at end of treatment and at 1, 3, 6, and 12 months following the conclusion of the treatment protocol. We administered questionnaires and weighed participants at each assessment session. Additionally, we weighed participants on a weekly basis during the 8 weeks of treatment. At baseline and at the end of treatment, subjects participated in a maximal exercise test and provided anthropometric measures. Moderate exercise condition Participants in the moderate exercise condition were given an exercise prescription calculated from the peak heart rate achieved on their baseline exercise test. The target heart rate range for exercise training was resting heart rate plus 45 to 59% of heart rate reserve (50 to 69% of maximum heart rate) [26]. Participants were instructed to exercise in a perceived exertion range of fairly light to somewhat hard (11–13 on the Borg perceived exertion scale of 6 –20) [27] and to achieve a walking pace of 3 to 4 mph. Participants were required to attend one supervised exercise session per week that occurred on their smoking cessation treatment night. In addition, participants were given the opportunity to perform make-ups and/or do supervised exercise during open gym, which was offered two times per week. During the supervised exercise session, participants were instructed to do a 5-minute active warm-up, 45 minutes of exercise, and a 5-minute cool-down. Participants were required to spend at least 15 minutes walking on the track or using the treadmill in their training range. The other 30 minutes could be additional walking or could be done on any of the available equipment (e.g., cycle ergometer, stair-stepper, and rower) in 15-minute time blocks. The duration and

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intensity of the exercise was gradually increased to decrease injury and allow participants to adapt to the increased exercise level. In addition, participants were instructed to do stretches, which were specific to a walking program. An exercise specialist supervised the sessions and verified and documented perceived exertion level and heart rates obtained in each exercise session. Additionally, the exercise specialist monitored physical activity participation during the supervised exercise sessions by using a physical activity log, which assessed type, intensity, and minutes of exercise. The exercise specialist telephoned participants who missed an exercise session and scheduled the participant for a replacement session. Reinforcement of participant home exercise program was also done at this time. Participants were given written instructions for home exercise and a schedule for advancing the duration of their exercise with a goal of 165 minutes of moderate intensity exercise per week to be accomplished via class and homebased exercise. During weeks 1 and 2, participants were instructed to participate in 105 minutes of exercise. This was increased to 135 minutes in week 3 and 165 minutes for weeks 4 – 8. Participants were invited to attend open gym, which was held weekly and was supervised by exercise specialists. Adherence was assessed by attendance at program sessions and participants were given and instructed on the use of exercise log books to document their home exercise. The exercise logs books required the participants to document the date, duration in minutes of physical activity, and type of physical activity. An exercise specialist reviewed the documentation with the participant on a weekly basis and barriers to exercise adherence were addressed. Adherence was also assessed by using an objective measure of physical activity. Participants wore a CSA motion monitor (Computer Science and Applications, Inc., Shalimar, FL) during every home exercise session. This monitor was small and lightweight, could be worn on the wrist, waist, or ankle, and recorded activity by measuring movement via an internal accelerometer. This monitor was used to provide validation of the self-report of home exercise behavior as it measures both movement and intensity. Reliability and validity of this monitor has been established [28,29]. At the end of the 8-week treatment, participants were given self-help exercise guides [30] to assist them in maintaining the exercise habit. In addition, participants were encouraged to participate in open gym that occurred twice weekly. Participants were telephoned monthly by the exercise specialist to problem solve barriers to exercise and provide support for continued exercise during the 12 months following treatment. Participants also received a monthly mailing of exercise-related materials. Examples of topics for the monthly mailing included stretching exercises, warm and cold weather exercise suggestions, and how to make time for exercise.

Contact condition The participants in the contact condition participated in an 8-week wellness program, which was an adjunct to the smoking cessation program. Participants in this condition were provided with a description and rationale for the wellness program. Lectures, films, handouts, and discussions focused on a variety of health and lifestyle issues including cancer prevention, cardiovascular disease prevention, and healthy eating. Attendance was documented at each session. Therapists telephoned participants who failed to attend a session and scheduled the participants for a replacement session. This protocol was pilot tested [22,31] to ensure its credibility and acceptability. During the 12 months of follow-up, participants were called on a monthly basis to discuss topics pertinent to the wellness program and to answer any questions they had. Participants in the wellness program were also given the opportunity to attend a weekly open wellness session in which materials were made available to the participants that attended. In addition, participants received monthly mailings of materials relevant to health and wellness. This included materials on topics such as allergies, skin cancer detection, low-fat dietary guidelines, and stress management. Participants in the wellness program did not self-monitor their exercise behavior. This program provided a credible treatment program as a contact and time control for the exercise condition. The informational nature of the program reduced the chance of differential attrition between groups. In our previous study utilizing this type of contact control, Commit to Quit I (CTQI), there was no differential dropout between Exercise and Contact conditions [21]. Because this was an active treatment, rather than an attention-placebo control, it provided a conservative test of the additive effect of exercise training. Nicotine patch In response to the Agency for Healthcare Research and Quality guidelines [32], beginning with cohort 5, the option of using the nicotine patch was available free of charge to participants in both conditions. Participants were given the option of using the patch before being randomized to the exercise or contact control conditions. To use the patch within our existing 8-week treatment program, we reviewed the recommendations from the Center for Tobacco Research and Intervention [33]. In their 1992 review of clinical guidelines for the effective use of the nicotine patch, they reported that 6 to 8 weeks is sufficient for managing withdrawal symptoms and to learn strategies for staying abstinent from nicotine. Our patch protocol was slightly abbreviated to allow for 1 week of total abstinence from nicotine at the end of the treatment phase. Specifically, participants choosing to use the nicotine patch used one patch (Nicoderm Cq) per day for 5 weeks beginning on “Quit Day” (day 8). Patch dosage was as follows: 14 mg if smoking less than 10 cigarettes per day or weight less than

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Table 1 Schedule of assessments Baseline Demographics; medical, smoking, exercise, and weight history; Fagerstrom Body weight Group cohesion Consumer satisfaction Maximal exercise stress test and anthropometrics Eating inventory, smoking situations, revised restraint, weight-related questions Seven Day Physical Activity Recall Questionnaire Exercise stages and exercise self-efficacy Saliva cotinine Daily smoking rate, 24-hr, 7-day, and continuous abstinence, and CO Withdrawal Symptom Scale Smoking stages and smoking self-efficacy CES-D, TMAS, PANAS, Perceived Stress Scale, Spielberger, IDD

Weekly

End of Tx

1-month follow-up

3-month follow-up

6-month follow-up

12-month follow-up

X

X X X X X

X

X

X

X

X

X

X

X X X X

X X X X

X X X X

X X X

X X X

X X X

X X

X X X X X

X X

X X X

X X X X X X X

X X

Tx ⫽ treatment; CO ⫽ carbon monoxide; CES-D ⫽ Center for Epidemiologic Studies Depression Scale; TMAS ⫽ Taylor Manifest Anxiety Scale; PANAS ⫽ Positive and Negative Affect Schedule; IDD ⫽ Inventory to Diagnose Depression.

100 lb.; otherwise 21 mg. We used the following three different protocols for tapering: (1) 21 mg for 3 weeks and 14 mg for 2 weeks, (2) 21 mg for 2 weeks, 14 mg for 2 weeks, and 7 mg for 1 week, or (3) 14 mg for 3 weeks and 7 mg for 2 weeks. Protocols were chosen based on specific characteristics such as previous experience with the patch and number of cigarettes smoked each day. A medical doctor was on call in case there were complications associated with using nicotine replacement. Measures Questionnaires were administered to examine smoking behavior, nicotine dependence, exercise behavior, eating behavior, level of depression, anxiety level, and group cohesion. The schedule for all measures and time points is summarized in Table 1. Smoking measures Smoking variables were measured at several levels including historical and person variables, and short- and longterm maintenance of cessation. Historical factors included age of onset; previous quit attempts and duration; current rate, brand, and content of cigarettes; and number of household smokers. The Fagerstrom Test for Nicotine Dependence [34] was administered, which has adequate reliability and validity [35,36]. The Withdrawal Symptom Scale [37] was used to examine various smoking-related symptoms occurring in the evening. We also administered the 20-item self-efficacy questionnaire, which can be scored to form a total self-efficacy index, and subscales can be constructed tapping confidence at being able to resist smoking in pleasant and unpleasant situations, as well as in situations where smoking is habitual [38].

Outcome measures for smoking status Seven-day point-prevalence abstinence, which was verified with saliva cotinine (cutoff ⫽ 10 ng/ml) [39] at the end of treatment and 1, 3, 6, and 12 months following the end of treatment, was the main outcome variable. We also examined continuous abstinence, which was defined as abstinence from “Quit Day” (day 8) to the end of treatment and 1, 3, 6, and 12 months following the end of treatment. Eating habits, weight history, and fear of weight gain The Eating Inventory [40] was used to assess the following three dimensions of eating behavior: (1) Cognitive Restraint, a measure of restrained eating patterns, (2) Disinhibition, the tendency to overeat in response to a preload or stressor, and (3) Hunger, the tendency to eat in response to physical hunger versus other stimuli. The Revised Restraint Scale [41] was administered to examine dietary restraint. The Smoking Situations Questionnaire was used to measure smoking-specific weight concerns [42]. Research indicates that intentions to not quit smoking are associated with higher levels of weight control smoking [42]. Participants also answered questions about their weight and diet history (e.g., maximum body weight as an adult and weight gain after last quit attempt). Body image was assessed by using the Appearance Evaluation and Body Areas Satisfaction scales of the Multidimensional Body-Self Relations Questionnaire [43], which provides a standardized, attitudinal assessment of body image, normed from a national body-image survey [44]. This measure has adequate internal consistency and has adequate test-retest reliability [45]. Participants also completed The Silhouette Choosing Task [46,47], which presents female figures ranging from very thin to morbidly obese [47]. Participants indicated the figure that best represented their

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actual figure (actual score), and the figure that best represented what they would like to look like (ideal score). A body dissatisfaction score is calculated by subtracting the ideal score from the actual score. Silhouette choosing tasks are one of the most widely used methods of assessing body image [48]. Adequate test-retest reliability has been reported for this measure [49]. Self-efficacy for controlled eating in various situations was assessed by using the Weight Efficacy Life-Style Questionnaire (WEL) [50]. This 20-item scale consists of five subscales, which have been shown to be reliable in clinical populations. Mood measures Depressive symptoms were assessed by using the 20item Center for Epidemiologic Studies Depression Scale (CES-D), which has been extensively validated and used widely [51]. To further assess participants’ affect, the Positive and Negative Affect Schedule (PANAS) was used. This measure consists of two uncorrelated scales, which assess both positive and negative affect [52]. We also administered the Inventory to Diagnose Depression, which is a 22-item measure designed to assess major depressive disorder [53]. This instrument has adequate reliability and validity; for example, the Inventory to Diagnose Depression has been shown to have “good to excellent” agreement with diagnostic interviews for depression [53]. The 20-item state version of the State-Trait Anxiety Inventory [54] was administered to examine participant anxiety level. This scale has adequate internal consistency and construct validity [54,55]. We also administered the 20-item version of the Taylor Manifest Anxiety Scale (TMAS) to examine trait anxiety [56,57]. Additionally, we used the four-item version of the Perceived Stress Scale (PSS) to examine perceived stress level. Research indicates adequate reliability and validity for the PSS [52] and this measure is predictive of smoking rate [58]. Group cohesion and consumer satisfaction Participants completed a group cohesion questionnaire [59,60], which was an adaptation of the one used in the CTQI trial [21]. Participants also answered consumer satisfaction questions regarding how satisfied they were with the treatment protocol. These measures were completed at the end of treatment. Exercise measures We administered a stage of change measure for exercise behavior [61], which consisted of a five-item algorithm that classifies participants into one of five stages of readiness to exercise. Self-efficacy for exercise was measured by using a measure developed by Marcus and colleagues [62]. We measured physical activity behavior by using the interviewer-administered 7-Day Physical Activity Recall Questionnaire [63]. This questionnaire provided an estimate of kilocalories burned each day, which was calculated by

multiplying an individual’s metabolic equivalents per day by a person’s weight in kilograms. The 7-Day Physical Activity Recall Questionnaire also provided information on the number of minutes per week of physical activity of varying intensities (e.g., moderate, hard, or very hard). Outcome measures for fitness level Participants completed a graded maximal exercise test performed on a treadmill prior to randomization into the study. The exercise test was used to determine eligibility for the study, calculate an exercise prescription, and assess fitness level at baseline. The exercise tests were performed by a registered nurse and a technician. A physician familiar with exercise testing was on call and in close proximity to the testing lab. Participants were instructed to avoid caffeine and alcohol during the 3 hours prior to testing [64] and to not smoke or eat for 1 hour before testing. The exercise tests were performed by using the Quinton 4500 stress testing system (Quinton Inc., Bothell, WA). A supine, seated, and standing 12-lead electrocardiogram was performed before each test. The supine electrocardiogram was read by the on-call physician before proceeding with the test. Electrocardiograms were obtained during testing at the end of every minute, at peak, and immediately post exercise; after minute 2 of active recovery; and at 1, 3, 5, and 10 minutes of seated recovery. A modified Balke protocol was used and consisted of 2-minute stages beginning at 3 mph and 2.5% grade [65]. Blood pressure was assessed during seated rest, standing, at the end of each stage, at peak and immediately post exercise, and at 1, 3, and 5 minutes of recovery and end recovery. Participants reported their perceived exertion level at peak exercise and at the end of each stage. Participants engaged in a 2-minute active recovery by walking at 2 mph. Seated recovery continued for 10 minutes or until the participant’s heart rate was within 15% of baseline. To examine fitness level between the exercise and contact conditions, we used functional capacity expressed as estimated peak VO2 [65]. Cardiorespiratory fitness at baseline was compared to norms published by The Cooper Institute [66]. Values were calculated based on body weight as ml/kg/min and categorized according to standardized values for women in different age categories. Measures of body composition At baseline, body weight and composition were measured with participants wearing an examining gown. A calibrated scale (Detecto medical scale) was used to measure body height and weight to the nearest quarter inch and quarter pound. A Lange caliper was used to estimate body fat percentage, which was measured based on skinfold thickness measured on the right side at the suprailiac crest, triceps, and thigh [67]. The “natural waist” was used as the site for the waist measurement, which is the narrowest part of the torso. The measurement of hip circumference was assessed at the level of maximum extension of the buttocks posteriorly [68]. Because body fat distribution is affected by

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exercise [69] and smoking [70], the waist-circumference to hip-circumference ratio was utilized to assess if exercise adoption and/or smoking cessation impacted body fat distribution. Participants repeated the anthropometric measures and exercise test at the end of treatment. Data analyses The goals of the analyses were to provide information on the relationships among various variables in the domains of smoking behavior, weight, and mood in addition to how the present sample compared to normative data, the women who expressed interest in the study by completing a telephone screen but were not randomized (i.e., recruitment sample), and our previous study sample, which examined vigorous physical activity as an aid to smoking cessation (Commit to Quit I). The following results will be reported in this article: (1) descriptive statistics of the demographic variables and other descriptors of the sample including smoking behavior, mood variables, weight variables, exercise behavior, and fitness level; (2) one-way analyses of variance to assess baseline differences between participants randomized to the moderate exercise and contact conditions; (3) summary information on use of the nicotine patch; (4) pairwise bivariate correlation coefficients (Spearman’s rho) between demographic variables and nicotine dependence; (5) pairwise bivariate correlation coefficients (Spearman’s rho) between smoking variables and depression and anxiety variables; (6) pairwise bivariate correlation coefficients (Spearman’s rho) between smoking and weight/ weight concerns variables; (7) pooled t tests to compare participants in the present study to normative or comparative samples on measures of mood and anxiety variables; (8) one-way analyses of variance to compare participants randomized into the study (i.e., treatment sample) to potential participants who initially expressed interest in the study but were either excluded or declined to participate (i.e., recruitment sample); and (9) one-way analyses of variance to compare the present sample to participants in the previous CTQI trial. The goal of the bivariate correlations was to conduct pairwise comparisons.

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the remainder of the participants were 6.9% African American, 3.7% Hispanic, 3.2% Cape Verdian, 2.3% Portuguese, and 0.5% Asian (0.9% endorsed “other”). Forty-four percent of the sample were married and 82.5% were employed. Of the participants employed, 45.0% reported official/professional occupations, 30.0% were employed in clerical positions, 9.4% reported themselves to be in sales, and the remaining 15.6% reported being in technical, skilled crafts, or unskilled/semiskilled positions. The median household income level reported was in the range of $30,000 –39,999. Patch use Participants in cohorts 1– 4 were not offered the nicotine patch (N ⫽ 41) and participants in cohorts 5–13 were offered the nicotine patch (n ⫽ 176). Of the participants offered the use of the patch, 88.6% of the participants chose to use it. There were no differences in patch usage by condition. Smoking behavior At baseline, participants reported smoking an average of 20.6 (standard deviation [SD] ⫽ 9.35) cigarettes per day. The 1998 National Health Interview Survey data from a representative sample of Americans ages 18 or older indicate that the mean number of cigarettes smoked per day by female smokers is 16.1 [2], which is significantly lower than the rate reported in our sample, t ⫽ 5.28, P ⬍ 0.01. The average score on the Fagerstrom was 4.84 (SD ⫽ 2.33), which falls in the moderate range of nicotine dependence. According to participants’ responses on the stage of change for smoking cessation measure, 99 participants were in the contemplation stage (seriously considering quitting within the next 6 months; 45.6%), 101 were in the preparation stage (planning to quit in the next 30 days; 46.5%), and one participant was in the precontemplation stage (not considering quitting within the next 6 months; 0.5%). The distribution is comparable to representative samples of smokers seeking treatment [71]. Sixteen participants (7.4%) were not staged due to missing data.

Results Demographics

Demographics associated with nicotine dependence

Baseline characteristics of the participants randomized into the trial are summarized in Table 2. There were no significant differences between conditions on any of the variables measured with the exception of the disinhibition subscale of the Eating Inventory in which the contact group scored significantly higher than the exercise group, F(1,211) ⫽ 5.17, P ⬍ 0.05. The sample consisted predominantly of white (82.5%) middle-aged (mean 42.77) women. Ethnicity and race for

Minority status was significantly associated with daily smoking rate, r(209) ⫽ ⫺0.19, P ⬍ 0.01, such that minority individuals smoked significantly fewer cigarettes per day than white individuals. No other demographic variables were related to smoking rate. Higher scores on the Fagerstrom Test for Nicotine Dependence were significantly related to being married, r(215) ⫽ 0.143, P ⬍ 0.05, and lower education level, r(215) ⫽ ⫺0.16, P ⬍ 0.05. No other demographic variables were related to the Fagerstrom Test.

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Table 2 Baseline characteristics of study groups and total sample Variable

Contact

Age (years) Education (years) Weight (lb) Height (in.) Body mass index Waist-to-hip ratio Percentage body fat Fagerstrom Nicotine Dependence Cigarettes per day Years of smoking Smoking self-efficacy Smoking stage of change Carbon monoxide level Perceived stress scale Trait Anxiety (TMAS) Positive Affect (PANAS) Negative Affect (PANAS) Depression (CES-D) Depression Inventory Spielberger Score Estimated VO2 peak (ml/kg/min) Daily METS (7-day PAR) Eating Inventory: Restraint Eating Inventory: Disinihbition* Eating Inventory: Hunger Weight Efficacy Lifestyle (WEL) Body image (MBSRQ-AE; appearance) Body image (MBSRQ-BAS; body areas) Body dissatisfaction (SCT) Revised restraint scale Smoking Situations Q

Exercise

n

Mean

SD

n

Mean

SD

108 107 106 106 106 106 106 107 107 107 102 99 107 107 100 106 106 107 105 99 108 105 104 104 104 103 94 102 106 106 107

43.02 13.36 152.22 64.20 25.96 0.78 35.91 4.71 20.15 26.22 2.58 2.49 20.21 5.18 7.98 31.84 14.70 12.06 0.70 41.57 30.68 36.79 7.03 6.22 4.63 116.72 1.99 1.90 13.39 12.76 16.48

10.33 1.97 34.99 2.41 5.55 0.08 6.76 2.39 9.38 9.77 0.73 0.50 10.60 3.09 2.77 7.78 5.86 9.01 1.33 5.10 5.67 3.25 4.43 3.83 3.05 33.05 0.82 0.68 10.95 6.61 7.06

109 109 105 105 105 106 106 108 102 109 103 102 103 108 102 107 107 106 106 105 107 107 109 109 109 105 90 103 108 108 108

42.52 13.58 156.43 64.52 26.48 0.80 35.71 4.98 21.04 26.49 2.67 2.50 19.20 4.82 8.30 32.42 13.50 10.54 0.58 41.98 30.71 36.57 7.04 5.12 4.46 118.97 1.95 1.93 13.65 12.28 15.58

10.39 2.40 33.91 2.39 5.59 0.08 7.06 2.27 9.34 10.39 0.71 0.52 10.61 3.18 2.61 7.81 4.49 8.31 1.19 4.45 6.12 2.79 4.68 3.23 3.23 36.63 0.83 0.66 12.16 5.99 7.36

* P ⬍ 0.05.

Smoking and mood and anxiety measures The relationships between smoking and mood measures are summarized in Table 3. Specifically, higher scores on the Fagerstrom Test of Nicotine Dependence were related to

lower scores on smoking self-efficacy and lower smoking stage of change, in addition to higher scores on the PSS, CES-D (i.e., depressed mood), and TMAS (i.e., anxiety). Lower scores on the smoking self-efficacy scale were related to higher scores on the PSS, CES-D, and TMAS in

Table 3 Correlations between nicotine dependence, cessation readiness, smoking self-efficacy, mood, anxiety, and stress Measures

1

2

1. 2. 3. 4. 5. 6. 7. 8. 9. 10.

X ⫺0.16* ⫺0.21** ⫺0.08 0.16* 0.18* 0.01 0.03 0.00 0.17*

X ⫺0.08 ⫺0.13 ⫺0.26** ⫺0.29** 0.01 0.23** ⫺0.03 ⫺0.17*

Fagerstrom Test Smoke self-efficacy Smoking stage Spielberger scale Perceived stress CES-D IDD Positive PANAS Negative PANAS Trait Anxiety (TMAS)

3

4

5

6

7

8

9

10

X ⫺0.09 0.15* 0.05

X ⫺0.18** ⫺0.20**

X 0.27**

X

X 0.04 ⫺0.11 0.02 0.00 0.01 0.04 0.05

X ⫺0.03 ⫺0.03 0.07 0.23** 0.18* 0.00

X 0.61** 0.24** ⫺0.36** 0.35** 0.31**

X 0.24** ⫺0.35** 0.53** 0.42**

CES-D ⫽ Center for Epidemiologic Studies Depression Scale; IDD ⫽ Inventory to Diagnose Depression; PANAS ⫽ The Positive and Negative Affect Schedule. * P ⬍ 0.05; ** P ⬍ 0.01. Correlations of interest are included in the box.

B.H. Marcus et al. / Preventive Medicine 36 (2003) 479 – 492

487

Table 4 Correlations between nicotine dependence, cessation readiness, smoking self-efficacy, weight concerns, and body image Measures

1

2

1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13.

X ⫺0.16* ⫺0.21* ⫺0.03 ⫺0.02 ⫺0.10 0.06 0.05 ⫺0.06 ⫺0.07 ⫺0.04 0.04 ⫺0.07

X ⫺0.08 0.11 ⫺0.11 0.00 ⫺0.07 ⫺0.09 0.04 0.02 ⫺0.08 0.25* 0.08

Fagerstrom Test Smoke self-efficacy Smoking stage Body mass index Smoking situations EI: Restraint EI: Disinihbition* EI: Hunger BAS Revised Restraint MBSRQAE WEL Silhouette task

3

4

5

6

7

8

9

10

11

12

13

X 0.04 ⫺0.07 0.07 ⫺0.04 ⫺0.05 0.03 0.07 ⫺0.09 0.05 0.10

X 0.09 0.16* 0.43** 0.11 ⫺0.42** 0.46** ⫺0.42** ⫺0.15* 0.69**

X 0.25** 0.40** 0.28** ⫺0.23** 0.37** ⫺0.11 ⫺0.38** 0.18*

X 0.22** 0.03 ⫺0.16* 0.59** ⫺0.12 ⫺0.13 0.16*

X 0.55** ⫺0.38** 0.66** ⫺0.37** ⫺0.54** 0.44**

X ⫺0.24** X 0.28** ⫺0.35** X ⫺0.17* 0.74** ⫺0.35** X ⫺0.48** 0.20** ⫺0.33** 0.16* X 0.17* ⫺0.57** 0.43** ⫺0.52** ⫺0.15* X

* P ⬍ 0.05; ** P ⬍ 0.01. Correlations of interest are included in the box. BAS ⫽ Body Areas Satisfaction; MBSRQAE ⫽ Body-Self Relations Questionnaire; WEL ⫽ Weight Efficacy Lifestyle Questionnaire.

addition to lower scores on the positive affect portion of the PANAS. As expected, several of the mood measures were related to one another as summarized in Table 3. Smoking and weight/weight concerns measures The relationships between smoking and weight measures are summarized in Table 4. Scores on the Fagerstrom Test for Nicotine Dependence were not related to any of the weight measures. Higher smoking self-efficacy was significantly related to higher scores on the WEL. As expected, several of the weight measures were related to one another. Mood variables Norms have not been established for the CES-D, but mean scores for the CES-D in community samples range from 7.5 to 12.7 and SDs range from 7.5 to 9.8 [72]. The mean for the present sample was 11.30 (SD ⫽ 8.68), indicating that our sample fell in the upper portion of the range of mean scores found in community samples. A score of 16 or greater has been used as the standard cutoff score for indicating depression [51]. Twenty-nine percent of the present sample obtained scores of 16 or more, which is greater than what was found in a community sample (N ⫽ 1674) of smokers and nonsmokers (i.e., 21%) [73]. The present sample scored significantly higher than the normative sample on the positive affect portion of the PANAS [52], 32.13 versus 29.70, t ⫽ 3.92, P ⬍ 0.05. For the negative affect portion of the PANAS, our sample scored approximately equivalent to the normative sample, 14.10 versus 14.80, respectively. No normative data could be found for the TMAS, but scores greater than 5 have been used to indicate high anxiety in at least one study [74]. The mean score for the present sample was 8.14 (SD ⫽ 2.69), indicating the presence of relatively high anxiety. Although no norms have been established for the PSS,

scores of 6.2 and 5.9 have been found for female smokers at 1 and 3 months following smoking cessation treatment [58]. The average for the present sample was 5.00 (SD ⫽ 3.13), indicating our sample reported a similar level of perceived stress compared to the other samples of female smokers. Weight and concerns about weight gain For the present sample, we used body mass index (BMI) to assess weight relative to height. Approximately half of the participants (49.3%) were categorized as desirable weight (i.e., BMI less than 25 kg/m2). Approximately onefourth (27.6%) were classified as overweight (i.e., a BMI between 25 and 29.9 kg/m2), 11.5% were class 1 obesity (i.e., between 30 and 34.9 kg/m2), 6.5% were class 2 obesity (i.e., between 35.0 and 39.9 kg/m2), and 2.3% were class 3 obesity (i.e., 40 kg/m2 or more) [64]. BMI was not calculated for six cases (2.8%) due to missing data. Health risks related to obesity increase with a BMI of 25 or over [64]. Body fat distribution was assessed using waist-to-hip ratio (WHR). For women ages 17–39, average WHR approximates 0.80 and increases with age to 0.90 [75]. A WHR above 0.86 is associated with elevated risk of disease [76]. The average WHR for the present sample was 0.79, which is considered average. Percent body fat was computed based on equations developed by Jackson and colleagues [77]. The mean percent body fat for the present sample was 35.81% (SD ⫽ 6.90), which falls in the “very poor” category (less than 20th percentile) based on the Cooper Institute norms [66]. The mean estimates of normal samples (not obese or eating-disordered) for the three subscales of the Eating Inventory are 6.6 (SD ⫽ 4.1) for Cognitive Restraint, 6.2 (SD ⫽ 3.0) for Disinhibition, and 4.9 (SD ⫽ 2.9) for Hunger [78]. Participants in the present sample scored similarly to the comparison group on the Cognitive Restraint and Hunger subscales but scored significantly higher on the

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Disinhibition scale, indicating higher disinhibition (t ⫽ 2.07, P ⬍ 0.05). A score higher than 17 on the Revised Restraint Scale has been used to indicate “highly restrained” individuals [79]. A majority of the participants (94.5%) were not categorized as “highly restrained.” Smoking-specific weight concerns Almost one-fifth (17.1%) of the sample reported that they intentionally smoke to control their weight or shape. Of those who had quit smoking in the past, 70.5% reported gaining weight following the quit attempt and half of the participants reported that they were able to lose the weight before they began smoking again (50.4%). Among the women acknowledging that they anticipated gaining weight during the present quit attempt (68.7%), they anticipated gaining an average of 13.86 lbs. Research indicates that female smokers gain an average of 8 lbs. following smoking cessation [4]. Exercise behavior Based on the norms published by the Cooper Institute [66], approximately half of the sample was categorized as having a poor (32.6%) or fair (20.9%) level of fitness. Among those remaining, 13.0% were categorized as good, 21.4% as excellent, and 12.1% as superior. Two participants were not included due to missing data. Ninety-eight percent of the participants reached 85% of their age-predicted maximum heart rate on the exercise test. Participants’ responses to the stage of change for exercise measure indicated that more than half were in the contemplation stage of exercise adoption (intend to exercise in the next 6 months; 57.6%, n ⫽ 125), 10.6% were in preparation (currently exercise, but not regularly, n ⫽ 23), 7.4% were in precontemplation (no intention of beginning exercise in the next 6 months, n ⫽ 16), 3.7% were in action (exercise regularly but for less than 6 months, n ⫽ 8), and 3.7% reported being in maintenance (exercising regularly for at least 6 months; n ⫽ 8). Thirty-seven participants (17.1%) were not staged due to missing data. Participants were screened prior to the study to ensure that they were not regularly participating in moderate or vigorous physical activity; however, a small percentage of the sample seems to have provided inconsistent data between the screening and stage of change measure. Furthermore, participants could have begun exercising between the initial telephone screen and baseline assessment. Demographic variables were not significantly associated with any of the exercise variables. Comparison of the treatment sample to the recruitment sample Participants who took part in the study (treatment sample, n ⫽ 217) were compared to participants who expressed interest in the study by completing a telephone screening

but were ineligible or declined to participate (recruitment sample, n ⫽ 849). Participants randomized into the trial weighed significantly more than participants not randomized into the study, F(1,980) ⫽ 5.21, P ⬍ 0.05. There were no differences between the treatment and recruitment samples on race, age, education level, and daily smoking rate. The most frequent reasons that participants were ineligible for the study included health-related issues (35.6%) and exercising more than 90 minutes per week (22.1%). Additionally, approximately 28.0% of the participants who met the criteria for the study declined to participate. Comparison of the CTQII sample to the CTQI sample The comparison of the present sample to the previous CTQ I trial (CTQI) is presented in Table 5. Results indicated that the CTQII sample was significantly older, heavier, had a higher body fat percentage, and included a larger percentage of minority individuals than the CTQI sample. Regarding mood and weight variables, the CTQII sample scored significantly higher on the TMAS and scored significantly lower on the Restraint factor of the Eating Inventory and the WEL scale compared to the CTQI sample.

Discussion This trial was designed to move the field forward by examining moderate, rather than vigorous-intensity, physical activity, as this is a form of physical activity (typically walking) that anyone can embark on as well as being a form of physical activity preferred by women [80]. Therefore, smoking cessation programs involving moderate-intensity physical activity have the potential to have a greater public health impact than programs involving vigorous-intensity physical activity because they can be disseminated or diffused to a broader population. As such, this trial represents, as far as we know, the first and only randomized controlled clinical trial comparing the relative efficacy of a cognitivebehavioral smoking cessation treatment program plus supervised class and home-based moderate-intensity exercise with the same cessation treatment plus contact control. Findings from this trial will have implications for the translation of clinical treatments under “ideal” conditions to reach more female smokers in the population and thereby could significantly reduce morbidity and mortality in this group. Because our previous vigorous activity efficacy trial was conducted under ideal conditions and the present trial moves toward diffusion and dissemination, it is important to compare the two study samples. The present study differed from the previous CTQI trial in several ways in that the exercise program in CTQI was group based (i.e., exercising at the research facility) rather than group and home based (i.e., exercising at the research facility and outside the re-

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Table 5 Comparison of current moderate physical activity trial to previous vigorous physical activity trial Variable

Age (years)** Race (% minority)** Marital status (% married) Education (years) Percent employed Weight* Body mass index Percent body fat** Cigarettes per day TMAS** CES-D EI: Restraint* EI: Disinhibition EI: Hunger WEL** Revised Restraint Scale

CTQII sample

CTQI sample

N

Mean

SD

N

Mean

SD

217 217 217 216 216 211 211 212 209 216 213 213 213 213 208 214

42.77 0.18 0.44 13.47 0.83 154.32 26.22 35.81 20.58 8.19 11.30 7.03 5.66 4.54 117.85 13.51

10.34 0.38 0.50 2.20 0.38 34.44 5.56 6.90 9.35 2.68 8.68 4.55 3.57 3.14 34.84 6.31

281 281 281 281 281 277 275 281 269 280 277 277 277 277 251 276

40.16 0.09 0.50 13.78 0.76 147.67 25.41 29.87 22.19 6.47 12.33 8.01 5.57 4.27 126.20 13.37

8.92 0.27 0.50 2.10 0.43 30.30 4.99 7.09 9.34 4.27 9.14 4.59 3.91 2.91 29.50 6.13

* P ⬍ 0.05; ** P ⬍ 0.01. TMAS ⫽ Taylor Manifest Anxiety Scale; CESD ⫽ Center for Epidemiologic Studies Depression Scale; EI ⫽ Eating Inventory; WEL ⫽ Weight Efficacy Lifestyle Questionnaire.

search facility) and focused on vigorous rather than moderate-intensity physical activity. To make comparisons on smoking cessation rates between CTQI and CTQII in future analyses, it is important to examine baseline differences between the two samples. The present sample was significantly older, heavier, had a higher body fat percentage, included a higher percentage of minority individuals, reported higher levels of anxiety, scored lower on the Restraint factor of the Eating Inventory, and scored lower on the WEL scale than the previous CTQI sample. It remains to be determined how these baseline differences, in addition to design differences, influence smoking cessation rates for the present study. Our sample smoked a significantly greater number of cigarettes per day than national samples [2]. White participants smoked more cigarettes per day than minority participants, which is consistent with findings from national samples [2]. Furthermore, participants who were married reported higher nicotine dependence when compared to nonmarried participants. Consistent with national samples [2], participants with lower education level reported higher nicotine dependence. Overall, our sample was consistent with national samples with the exception that women in this sample were heavier smokers. Nicotine dependence was related to three of the mood measures including the CES-D (i.e., depression), TMAS (i.e., anxiety), and PSS. The present study replicated previous studies indicating that depression is significantly related to higher nicotine dependence among female smokers [81,82]. Also consistent with our sample, other studies have found higher trait anxiety to be related to higher nicotine dependence among male and female smokers [83]. Furthermore, our results are consistent with another study that found that smokers who report higher levels of depression

and/or anxiety are at a greater risk of experiencing withdrawal symptoms associated with smoking cessation [84]. Regarding the impact of depression on smoking cessation, some research studies suggest that higher scores on the CES-D (our measure of depression) are related to a lower likelihood of successfully quitting smoking [73]. Approximately 30% of our sample met the criteria for depression based on the CES-D and it will be interesting to examine how depression scores influence smoking cessation. Perhaps physical activity will play a role in improving mood, which will increase the participants’ likelihood of successfully quitting. The present trial will examine the impact of physical activity on mood and how mood relates to smoking cessation, which will have important implications for smoking cessation treatment. Concern about postcessation weight gain was not related to nicotine dependence nor to body weight but was related to eating attitudes and body image. Weight concern was positively associated with eating restraint, eating disinhibition, and hunger. Jeffrey and colleagues [8] also found weight concern to be associated with eating behaviors. In this study, weight concern was negatively associated with body satisfaction. Our findings also replicate the study by Pomerleau and colleagues [85] who found a relationship between body image and weight concerns. Studies examining body image among female smokers suggest that women smokers report more body image concerns than women in general [86,87]. It is possible that body image evaluations play an important role in smoking behavior. For example, women who negatively evaluate the size or shape of their body may be more likely to initiate smoking to lose weight or to maintain their smoking habit to prevent weight gain. As Pomerleau and colleagues [85] suggest, it could be body image that is driving the weight concern. If this is the case,

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interventions such as exercise, which have the potential to directly impact body image may prove to be the most successful for women with weight concerns. Participants who were ineligible or declined to participate (i.e., recruitment sample) were compared to the participants randomized into the trial (i.e., treatment sample). The recruitment and treatment samples did not differ on race, age, education level, and daily smoking; however, the treatment sample weighed significantly more than the recruitment sample. The lack of differences between the two samples on several important baseline variables enhances the generalizability of our sample. To summarize, physical activity may serve as an aid to smoking cessation among women by reducing weight gain associated with cessation and managing mood and stress levels. The present study was designed to test the efficacy of moderate-intensity physical activity to aid in smoking cessation, which was a logical extension of prior work examining vigorous-intensity physical activity. Moderate-intensity physical activity has the potential to reach a greater number of female smokers than vigorous-intensity physical activity, given that female smokers may be more willing and able to participate in moderate-intensity activity compared to vigorous-intensity activity and that moderate-intensity activity does not require exercise testing or medical supervision among healthy adults.

Acknowledgments We thank Melissa Napolitano, Ph.D., Raymond Niaura, Ph.D., and John Jakicic, Ph.D., for their contributions to this study. We also thank Robin Cram, M.P.A., Heinrich Doll, M.S., Manoj Eapen, M.D., Santina Ficara, B.S., Greg Kelly, M.D., Christina Korkontzelou, M.S., Joyce Lee, B.A., Erica Norton, B.S., Mary Roberts, M.S., Janice Tripolone, M.S., and Regina Traficante, M.A., for their numerous contributions regarding the implementation of this trial. Finally, we would like to thank the participants for donating their time to the study.

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