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Work ability and perceived work stress
International Congress Series 1280 (2005) 79 – 83
www.ics-elsevier.com
Work ability and perceived work stress Robert G. Goedharda,T, Willem J.A. Goedhardb a Social Security Agency UWV, Utrecht, The Netherlands The Netherlands Foundation of Occupational Health and Aging, Middelburg, The Netherlands
b
Abstract. In this study, work ability was examined in a group of civil and military servants of the Netherlands Army. Work ability was assessed by using the Work Ability Index (WAI); this instrument was developed by the Finnish Institute of Occupational Health to monitor aging workers. The relationship of WAI and perceived work stress was examined using a stress questionnaire. Statistical analysis indicated negative correlations of WAI scores and several different stress factors. The most prominent relationship was observed between WAI and qualitative overload (r= 0.49). WAI scores were also negatively associated with increasing age, a finding comparable to studies with the WAI in several other countries. Absenteeism from work seems to be associated with increased perceived work stress. D 2005 Published by Elsevier B.V. Keywords: Aging worker; Work ability index; Work ability; Work stress; Absenteeism
1. Introduction Work Ability is a complex concept that can be assessed by using the Work Ability Index (WAI) questionnaire [1]. From earlier studies, it is known that the WAI is associated with various work-related variables like age [2] and physical fitness [3]. The aim of this study was to examine the possible effects of perceived work stress (PWS) on work ability. In many jobs, perceived work stress is an important part of the overall job demands. If work stress is becoming too high, this may result in negative consequences for job performance [4], absenteeism [5], work ability [6] and possibly the development of diseases.
T Corresponding author. Full postal address: UWV, Postbus 459, 3500 AL Utrecht, the Netherlands. Tel.: +31302844242. E-mail address: [email protected] (R.G. Goedhard). 0531-5131/ D 2005 Published by Elsevier B.V. doi:10.1016/j.ics.2005.02.051
80
R.G. Goedhard, W.J.A. Goedhard / International Congress Series 1280 (2005) 79–83
Table 1 Differentiation of the study group according to WAI category WAI category
Mean age
Number
Percentage
MeanFS.D.
7–27 (poor) 28–36 (moderate) 37–43 (good) 44–49 (excellent) All
– 48.2 42.7 41.7 43.0
0 17 58 51 126
–
– 34.0F1.80 40.8F1.83 45.8F1.39 41.9F4.25
13.5% 46.0% 40.5% 100%
2. Material and methods This study was performed at a Dutch military support unit. We selected a group of employees that met our inclusion criteria (N=144). They were asked to fill out two questionnaires. One is the Work Ability Index (WAI), the other a work stress questionnaire developed by Frommer et al. [7]. The perceived work stress questionnaire comprises six stress factors (boredom, lack of support, quantitative and qualitative overload, unsatisfactory prospects or salary and unsatisfactory physical working conditions) and scores on a five-point scale (1=no stress, 5=high stress). We also gathered information about the frequency of sickness claims during the preceding year in order to obtain information about possible relationship between sickness and stress. 3. Results 3.1. Work ability and age 126 employees (104 males, 22 females; age-range: 21–61 years) complied with the request to participate in the study. They filled out the two questionnaires. Table 1 shows the percentages of workers in the different WAI categories. Their mean age was 43.0F10.5 years. The mean WAI-score was 41.9 (S.D. 4.25). In 13.5% of the WAI vs. Age 55
WAI
45
35
25
15
y = -0.101x + 46.108 R2 = 0.0616
5 15
25
35
45
55
Age (years)
Fig. 1. Work Ability Index (WAI) scores in relation to age.
65
R.G. Goedhard, W.J.A. Goedhard / International Congress Series 1280 (2005) 79–83
81
Table 2 Means and standard deviations of PWS scores of the study group (N=126) Stress factor (sf)
Mean score
Standard deviation
Boredom (sf1) Lack of support (sf2) Quantitative overload (sf3) Qualitative overload (sf4) Unsatisfactory prospects or salary (sf5) Unsatisfactory physical working conditions (sf6)
1.95 2.11 2.54 1.72 2.08 2.05
0.55 0.45 0.67 0.45 0.59 0.74
participants, a WAI-score lower than 37 was observed i.e. poor–moderate work ability. Fig. 1 shows individual WAI scores in relation to age. Linear regression analysis indicated a significant decrease of WAI score with age; an explained variance of 6.1% was found. The scatter of individual data seems to increase with age. 3.2. Perceived work stress (PWS) Results obtained by means of the stress questionnaire demonstrated elevated stress levels in the majority of examined workers. Details for the different stress factors are shown in Table 2. By separating the workers into two age-groups (younger than 45 years and 45 years or older), an increasing trend of perceived work stress was observed in five out of six stress factors (see Table 3). Linear regression analysis showed a significant increase of perceived stress for the factors sf2–sf5, although a wide scatter was observed. Regression analysis was also used to examine the relationship between the WAI score of each worker and his (or her) PWS scores for the different stress factors. With the WAI score as the dependent variable, a significant decrease was observed in five out of six stress factors with increasing stress. The most significant decrease was found in the relationship of work ability with sf4 (qualitative overload; correlation coefficient: 0.49; explained variance: 24%). In Table 4, mean stress scores are given for the groups with moderate WAI scores and good–excellent WAI scores, respectively. 3.3. Absenteeism and work stress Mean absenteeism in the preceding 12 months before the onset of this study was 4.6% which was equivalent to 8.4 working days per year. The average number of sickness claims was 2.24 times per year. A significant negative association was observed between WAI-score and the number of sickness claims per year (r= 0.345; pb0.001). Table 3 Mean PWS scores of the age-groups younger and older than 45 years; for stress factors 2 and 5, the differences are statistically significant Age
Number
sf1
sf2
sf3
sf4
sf5
sf6
b45 N45 t-test
63 63
1.90 1.99 NS
2.03 2.19 b0.05
2.45 2.62 NS
1.68 1.75 NS
1.97 2.20 b0.05
2.06 2.04 NS
82
R.G. Goedhard, W.J.A. Goedhard / International Congress Series 1280 (2005) 79–83
Table 4 Mean stress scores in workers with moderate and good–excellent work ability, respectively WAI score
N
sf1
sf2
sf3
sf4
sf5
sf6
Low (7–36) High (37–49) t-test ( P-value)
17 109
2.29 1.89 b0.005
2.38 2.07 b0.005
2.79 2.50 b0.05
2.11 1.65 b0.000
2.54 2.01 b0.001
1.88 2.07 NS
Student t-tests indicate a significant difference in 5 of the 6 stress factors.
In the group of workers with low–moderate perceived stress, the average number of sickness claims (2.11 claims per year) was lower than in the group with relatively high work stress (2.37 claims per year). This may indicate a possible association between absenteeism from work and perceived work stress. 4. Discussion and conclusions In several studies in which the WAI was assessed in relation to age, a negative correlation was found. However, like in this study as well as in several others, the average change in WAI score with age is relatively small. Usually, age is accounting for less than 10% decline in work ability over the working life period. Possibly, the WAI score is affected more by factors that are based on work environment or work conditions as well as on individual health characteristics of the worker. In a study by Kumashiro et al. [6], a negative relationship was observed between WAI score categories and the levels of stress. Stress perception was about 35% higher in workers with low–moderate WAI scores than in the good–excellent group of workers. V77n7nen et al. [8] found a negative correlation between mental strain and working capacity (r= 0.50). In our study, negative correlations were found for various stress factors; correlation coefficients were ranging from 0.25 to 0.48. It can therefore be concluded that work ability is negatively associated with high levels of perceived work stress. Possibly, workers utilize options of absenteeism to diminish their exposure to high work demands. References [1] J. Ilmarinen, K. Tuomi, M. Klockars, Changes in the work ability of active employees over an 11-year period, Scand. J. Work, Environ. Health 23 (Suppl. 1) (1997) 49 – 57. [2] W.J.A. Goedhard, WAI scores and its different items in relation to age: a study in two different companies in the Netherlands, in: J. Ilmarinen, S. Lehtinen (Eds.), Past, Present and Future of Work Ability, FIOH, Helsinki, 2004, pp. 26 – 32. [3] W.J.A. Goedhard, T.S.H.W. Rijpstra, P.H.J. Puttiger, Work ability and its relationship with age and maximal oxygen uptake, in: 2. Kilbom, P. Westerholm, L. Hallsten, B. Fur3ker (Eds.), Work After 45? Arbetslivsinstitutet, Solna, Sweden, 1997, pp. 106 – 111. [4] P. Huuhtanen, et al., Changes in stress symptoms and their relationship to changes at work in 1981–1992 among elderly workers in municipal occupations, Scand. J. Work, Environ. Health 23 (Suppl. 1) (1997) 36 – 48. [5] W.J.A. Goedhard, The relation between psychosocial stress and age in a working population, in: J. Ilmarinen (Ed.), Aging and Work, FIOH, Helsinki, 1993, pp. 25 – 32. [6] M. Kumasiro, et al., The improvement of stress moods and the increase in negative emotions toward work have a major impact on declines in WAI scores: the first WAI research in Japan, in: J. Pokorski (Eds.), Book of Abstracts, 4th ICOH Conference on Ageing and Work, Jagiellonian Univ, Krakow, 2002, p. 50.
R.G. Goedhard, W.J.A. Goedhard / International Congress Series 1280 (2005) 79–83
83
[7] S. Frommer, et al., Systolic blood pressure in relation to occupation and perceived work stress, Scad. J. Work, Environ. Health 12 (1986) 476 – 485. [8] I. V77n7nen-Tomppo, E. Janatuinen, R. Tfrnqvist, All well at work? Overall working capacity and work ability index in the context of early rehabilitation, in: J. Ilmarinen, S. Lehtinen (Eds.), Past, Present and Future of Work Ability, FIOH, Helsinki, 2004, pp. 124 – 132.
www.ics-elsevier.com
Work ability and perceived work stress Robert G. Goedharda,T, Willem J.A. Goedhardb a Social Security Agency UWV, Utrecht, The Netherlands The Netherlands Foundation of Occupational Health and Aging, Middelburg, The Netherlands
b
Abstract. In this study, work ability was examined in a group of civil and military servants of the Netherlands Army. Work ability was assessed by using the Work Ability Index (WAI); this instrument was developed by the Finnish Institute of Occupational Health to monitor aging workers. The relationship of WAI and perceived work stress was examined using a stress questionnaire. Statistical analysis indicated negative correlations of WAI scores and several different stress factors. The most prominent relationship was observed between WAI and qualitative overload (r= 0.49). WAI scores were also negatively associated with increasing age, a finding comparable to studies with the WAI in several other countries. Absenteeism from work seems to be associated with increased perceived work stress. D 2005 Published by Elsevier B.V. Keywords: Aging worker; Work ability index; Work ability; Work stress; Absenteeism
1. Introduction Work Ability is a complex concept that can be assessed by using the Work Ability Index (WAI) questionnaire [1]. From earlier studies, it is known that the WAI is associated with various work-related variables like age [2] and physical fitness [3]. The aim of this study was to examine the possible effects of perceived work stress (PWS) on work ability. In many jobs, perceived work stress is an important part of the overall job demands. If work stress is becoming too high, this may result in negative consequences for job performance [4], absenteeism [5], work ability [6] and possibly the development of diseases.
T Corresponding author. Full postal address: UWV, Postbus 459, 3500 AL Utrecht, the Netherlands. Tel.: +31302844242. E-mail address: [email protected] (R.G. Goedhard). 0531-5131/ D 2005 Published by Elsevier B.V. doi:10.1016/j.ics.2005.02.051
80
R.G. Goedhard, W.J.A. Goedhard / International Congress Series 1280 (2005) 79–83
Table 1 Differentiation of the study group according to WAI category WAI category
Mean age
Number
Percentage
MeanFS.D.
7–27 (poor) 28–36 (moderate) 37–43 (good) 44–49 (excellent) All
– 48.2 42.7 41.7 43.0
0 17 58 51 126
–
– 34.0F1.80 40.8F1.83 45.8F1.39 41.9F4.25
13.5% 46.0% 40.5% 100%
2. Material and methods This study was performed at a Dutch military support unit. We selected a group of employees that met our inclusion criteria (N=144). They were asked to fill out two questionnaires. One is the Work Ability Index (WAI), the other a work stress questionnaire developed by Frommer et al. [7]. The perceived work stress questionnaire comprises six stress factors (boredom, lack of support, quantitative and qualitative overload, unsatisfactory prospects or salary and unsatisfactory physical working conditions) and scores on a five-point scale (1=no stress, 5=high stress). We also gathered information about the frequency of sickness claims during the preceding year in order to obtain information about possible relationship between sickness and stress. 3. Results 3.1. Work ability and age 126 employees (104 males, 22 females; age-range: 21–61 years) complied with the request to participate in the study. They filled out the two questionnaires. Table 1 shows the percentages of workers in the different WAI categories. Their mean age was 43.0F10.5 years. The mean WAI-score was 41.9 (S.D. 4.25). In 13.5% of the WAI vs. Age 55
WAI
45
35
25
15
y = -0.101x + 46.108 R2 = 0.0616
5 15
25
35
45
55
Age (years)
Fig. 1. Work Ability Index (WAI) scores in relation to age.
65
R.G. Goedhard, W.J.A. Goedhard / International Congress Series 1280 (2005) 79–83
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Table 2 Means and standard deviations of PWS scores of the study group (N=126) Stress factor (sf)
Mean score
Standard deviation
Boredom (sf1) Lack of support (sf2) Quantitative overload (sf3) Qualitative overload (sf4) Unsatisfactory prospects or salary (sf5) Unsatisfactory physical working conditions (sf6)
1.95 2.11 2.54 1.72 2.08 2.05
0.55 0.45 0.67 0.45 0.59 0.74
participants, a WAI-score lower than 37 was observed i.e. poor–moderate work ability. Fig. 1 shows individual WAI scores in relation to age. Linear regression analysis indicated a significant decrease of WAI score with age; an explained variance of 6.1% was found. The scatter of individual data seems to increase with age. 3.2. Perceived work stress (PWS) Results obtained by means of the stress questionnaire demonstrated elevated stress levels in the majority of examined workers. Details for the different stress factors are shown in Table 2. By separating the workers into two age-groups (younger than 45 years and 45 years or older), an increasing trend of perceived work stress was observed in five out of six stress factors (see Table 3). Linear regression analysis showed a significant increase of perceived stress for the factors sf2–sf5, although a wide scatter was observed. Regression analysis was also used to examine the relationship between the WAI score of each worker and his (or her) PWS scores for the different stress factors. With the WAI score as the dependent variable, a significant decrease was observed in five out of six stress factors with increasing stress. The most significant decrease was found in the relationship of work ability with sf4 (qualitative overload; correlation coefficient: 0.49; explained variance: 24%). In Table 4, mean stress scores are given for the groups with moderate WAI scores and good–excellent WAI scores, respectively. 3.3. Absenteeism and work stress Mean absenteeism in the preceding 12 months before the onset of this study was 4.6% which was equivalent to 8.4 working days per year. The average number of sickness claims was 2.24 times per year. A significant negative association was observed between WAI-score and the number of sickness claims per year (r= 0.345; pb0.001). Table 3 Mean PWS scores of the age-groups younger and older than 45 years; for stress factors 2 and 5, the differences are statistically significant Age
Number
sf1
sf2
sf3
sf4
sf5
sf6
b45 N45 t-test
63 63
1.90 1.99 NS
2.03 2.19 b0.05
2.45 2.62 NS
1.68 1.75 NS
1.97 2.20 b0.05
2.06 2.04 NS
82
R.G. Goedhard, W.J.A. Goedhard / International Congress Series 1280 (2005) 79–83
Table 4 Mean stress scores in workers with moderate and good–excellent work ability, respectively WAI score
N
sf1
sf2
sf3
sf4
sf5
sf6
Low (7–36) High (37–49) t-test ( P-value)
17 109
2.29 1.89 b0.005
2.38 2.07 b0.005
2.79 2.50 b0.05
2.11 1.65 b0.000
2.54 2.01 b0.001
1.88 2.07 NS
Student t-tests indicate a significant difference in 5 of the 6 stress factors.
In the group of workers with low–moderate perceived stress, the average number of sickness claims (2.11 claims per year) was lower than in the group with relatively high work stress (2.37 claims per year). This may indicate a possible association between absenteeism from work and perceived work stress. 4. Discussion and conclusions In several studies in which the WAI was assessed in relation to age, a negative correlation was found. However, like in this study as well as in several others, the average change in WAI score with age is relatively small. Usually, age is accounting for less than 10% decline in work ability over the working life period. Possibly, the WAI score is affected more by factors that are based on work environment or work conditions as well as on individual health characteristics of the worker. In a study by Kumashiro et al. [6], a negative relationship was observed between WAI score categories and the levels of stress. Stress perception was about 35% higher in workers with low–moderate WAI scores than in the good–excellent group of workers. V77n7nen et al. [8] found a negative correlation between mental strain and working capacity (r= 0.50). In our study, negative correlations were found for various stress factors; correlation coefficients were ranging from 0.25 to 0.48. It can therefore be concluded that work ability is negatively associated with high levels of perceived work stress. Possibly, workers utilize options of absenteeism to diminish their exposure to high work demands. References [1] J. Ilmarinen, K. Tuomi, M. Klockars, Changes in the work ability of active employees over an 11-year period, Scand. J. Work, Environ. Health 23 (Suppl. 1) (1997) 49 – 57. [2] W.J.A. Goedhard, WAI scores and its different items in relation to age: a study in two different companies in the Netherlands, in: J. Ilmarinen, S. Lehtinen (Eds.), Past, Present and Future of Work Ability, FIOH, Helsinki, 2004, pp. 26 – 32. [3] W.J.A. Goedhard, T.S.H.W. Rijpstra, P.H.J. Puttiger, Work ability and its relationship with age and maximal oxygen uptake, in: 2. Kilbom, P. Westerholm, L. Hallsten, B. Fur3ker (Eds.), Work After 45? Arbetslivsinstitutet, Solna, Sweden, 1997, pp. 106 – 111. [4] P. Huuhtanen, et al., Changes in stress symptoms and their relationship to changes at work in 1981–1992 among elderly workers in municipal occupations, Scand. J. Work, Environ. Health 23 (Suppl. 1) (1997) 36 – 48. [5] W.J.A. Goedhard, The relation between psychosocial stress and age in a working population, in: J. Ilmarinen (Ed.), Aging and Work, FIOH, Helsinki, 1993, pp. 25 – 32. [6] M. Kumasiro, et al., The improvement of stress moods and the increase in negative emotions toward work have a major impact on declines in WAI scores: the first WAI research in Japan, in: J. Pokorski (Eds.), Book of Abstracts, 4th ICOH Conference on Ageing and Work, Jagiellonian Univ, Krakow, 2002, p. 50.
R.G. Goedhard, W.J.A. Goedhard / International Congress Series 1280 (2005) 79–83
83
[7] S. Frommer, et al., Systolic blood pressure in relation to occupation and perceived work stress, Scad. J. Work, Environ. Health 12 (1986) 476 – 485. [8] I. V77n7nen-Tomppo, E. Janatuinen, R. Tfrnqvist, All well at work? Overall working capacity and work ability index in the context of early rehabilitation, in: J. Ilmarinen, S. Lehtinen (Eds.), Past, Present and Future of Work Ability, FIOH, Helsinki, 2004, pp. 124 – 132.