Occupational Medicine 2015;65:147–153 Advance Access publication 29 January 2015 doi:10.1093/occmed/kqu190
Combined effect of back pain and stress on work ability C. Oberlinner, M. Yong, M. Nasterlack, R.-P. Pluto and S. Lang Department of Occupational Medicine and Health Protection, BASF SE, Ludwigshafen 67056, Germany. Correspondence to: M. Yong, Department of Occupational Medicine and Health Protection, BASF SE, GUA/CS, Carl-Bosch-Str. 38, 67056 Ludwigshafen, Germany. Tel: +49 621 60 93860; fax: +49 621 60 43322; e-mail: [email protected]
Aims
To examine the prevalence of BP and perceived stress among employees of different occupational status and to investigate their combined impact on work ability.
Methods
A comprehensive survey combining questionnaire data and medical examination offered in one division of a major chemical company in Germany. Self-rated health and work ability were assessed using the Work Ability Index (WAI). A synergy index was used to assess a potential interaction between both exposures under an additive model.
Results
Of 867 voluntary participants, 653 returned complete questionnaires on BP and job stress perception. Although occupational stressors were perceived differently, there was no difference in the prevalence of BP between the occupational groups. Back pain and stress perception are correlated with each other and both are negatively associated with work ability. After adjustment for occupational status, demographic and lifestyle factors, we found a synergy effect of BP and stress perception with a modest to strong impact on declining WAI.
Conclusions Corporate health promotion interventions to reduce the impact of BP and stress perception on work ability should target both physical and psychological dimensions. Such interventions may be initiated in the context of regular (occupational) medical examinations. Key words
Back pain; combined effect; corporate health promotion; cross-sectional study; stress perception; synergy index; Work Ability Index (WAI).
Introduction For decades, musculoskeletal disorders, and more specifically back pain (BP), have been the leading cause of sickness absence in Germany, responsible for up to one quarter of all workdays lost [1]. BP is a common problem that most people experience at some point in their life, although to varying degrees [2]. Occasional mild episodes usually result in full recovery, but most people who experience activity-limiting BP go on to have recurrent episodes [2,3]. It is therefore unsurprising that recurrent BP has been described as a factor significantly influencing work ability [4]. BP and psychosocial stress are known risk factors for both absenteeism and presenteeism [5,6]. The relationship between BP and psychosocial stressors has been
examined in numerous studies and reviews [7,8]. Most, but not all, have found evidence for some relationship between psychosocial factors and incidence or prevalence of BP, and some go as far as proposing the term ‘psychosocial pain syndrome’ to cover these aspects of BP [9]. Furthermore, the negative association between work-related stress and work ability has been reported in diverse occupational groups [10–12] and work ability has also been shown to have a significant predictive value for disability and early retirement [13]. Job-related stress can also affect employee productivity through increased absenteeism and presenteeism, imposing a direct economic cost on employers and society [14]. To date, we are not aware of a study addressing the combined effect of BP and perceived stress on work ability. The aim of this study was to examine the prevalence
© The Author 2015. Published by Oxford University Press on behalf of the Society of Occupational Medicine. All rights reserved. For Permissions, please email: [email protected]
Downloaded from http://occmed.oxfordjournals.org/ at Dalhousie University on May 18, 2015
Background Back pain and occupational stress are known risk factors for absenteeism and presenteeism. In addition, the relationship between back pain (BP) and psychosocial stressors has been examined in numerous studies.
148 OCCUPATIONAL MEDICINE
of BP and perceived stress across employees of different occupational status, to investigate their combined impact on work ability and to identify appropriate measures for future corporate health promotion activities.
Methods
Results At the time of the study, there were a total of 1250 employees in this division. Of these, 867 (70%) participated in
Downloaded from http://occmed.oxfordjournals.org/ at Dalhousie University on May 18, 2015
This cross-sectional study was carried out in a major chemical company in Germany between 1 January 2008 and 31 March 2009 as a part of a health promotion campaign in a representative division of the company. Details of the programme have been described elsewhere [12]. The examination programme comprised a medical examination focusing on risk factors for coronary heart disease and diabetes mellitus as well as questionnaires on stress perception, BP and the Work Ability Index (WAI). For the purposes of the study, the participants were classified according to job activity and responsibility as frontline operators (FO), skilled workers (SW) and professional and managerial staff (PM). This classification roughly represents the socio-economic status of the employees. The study was conducted and the data were collected in accordance with standard ethical procedures [15]. The aim and scope of the examination was stated at the beginning of the questionnaire, and a consent form was enclosed with the questionnaire. Participants were able to ask questions during their medical examination, which was conducted by a physician. Study participation was voluntary and could be declined at any part of the examination programme without a need for explanation. The study protocol had been approved in advance by the workers’ council. The questions used to assess BP were taken from the standardized Nordic Musculoskeletal Questionnaires [16]. The questions provided a measure of common symptoms used in epidemiological studies on musculoskeletal disorders. A sum score was created from all items without weighting them, and the outcomes were then divided at quartiles into excellent (0 or 1), good (2 or 3), moderate (4, 5 or 6) and poor (≥7). The questions used to assess stress perception were taken from validated published instruments and have been used in the employees’ opinion survey in the company for several years [12]. The questions were aimed at ascertaining perception of safety in the workplace, self-rated health status, frequency of experienced stress symptoms, unrealistic job demands, time pressure and impaired worklife balance. Each question was answered on a five-point Likert scale. For the analysis, the lower two and the top two categories were grouped together so that three categories remained, with the lower two categories referring to the highest stress perception. The WAI [17] assesses a person’s perception of how well they are able to perform their work, compared with their lifetime best. A short version in German [18] was used. The WAI is calculated by summing the responses to each dimension, with a possible range of scores from 7 to 49. For a binary outcome,
WAI was dichotomized at the median of sum scores into poor to moderate (7–41) and good to excellent (42–49). Information about general characteristics and health behaviour of participants was obtained from the medical information system used in the occupational medicine department. During the medical examination, further information (data not shown) such as smoking status, alcohol consumption, physical activity and information on the incidence and prevalence of chronic health conditions was obtained. Participants were classified according to their smoking status into current smokers, former smokers and non-smokers. Physical activity was classified according to the median time spent on physical exercise each week (2 hr/week). Body mass index was used to define the subjects as normal (
Combined effect of back pain and stress on work ability C. Oberlinner, M. Yong, M. Nasterlack, R.-P. Pluto and S. Lang Department of Occupational Medicine and Health Protection, BASF SE, Ludwigshafen 67056, Germany. Correspondence to: M. Yong, Department of Occupational Medicine and Health Protection, BASF SE, GUA/CS, Carl-Bosch-Str. 38, 67056 Ludwigshafen, Germany. Tel: +49 621 60 93860; fax: +49 621 60 43322; e-mail: [email protected]
Aims
To examine the prevalence of BP and perceived stress among employees of different occupational status and to investigate their combined impact on work ability.
Methods
A comprehensive survey combining questionnaire data and medical examination offered in one division of a major chemical company in Germany. Self-rated health and work ability were assessed using the Work Ability Index (WAI). A synergy index was used to assess a potential interaction between both exposures under an additive model.
Results
Of 867 voluntary participants, 653 returned complete questionnaires on BP and job stress perception. Although occupational stressors were perceived differently, there was no difference in the prevalence of BP between the occupational groups. Back pain and stress perception are correlated with each other and both are negatively associated with work ability. After adjustment for occupational status, demographic and lifestyle factors, we found a synergy effect of BP and stress perception with a modest to strong impact on declining WAI.
Conclusions Corporate health promotion interventions to reduce the impact of BP and stress perception on work ability should target both physical and psychological dimensions. Such interventions may be initiated in the context of regular (occupational) medical examinations. Key words
Back pain; combined effect; corporate health promotion; cross-sectional study; stress perception; synergy index; Work Ability Index (WAI).
Introduction For decades, musculoskeletal disorders, and more specifically back pain (BP), have been the leading cause of sickness absence in Germany, responsible for up to one quarter of all workdays lost [1]. BP is a common problem that most people experience at some point in their life, although to varying degrees [2]. Occasional mild episodes usually result in full recovery, but most people who experience activity-limiting BP go on to have recurrent episodes [2,3]. It is therefore unsurprising that recurrent BP has been described as a factor significantly influencing work ability [4]. BP and psychosocial stress are known risk factors for both absenteeism and presenteeism [5,6]. The relationship between BP and psychosocial stressors has been
examined in numerous studies and reviews [7,8]. Most, but not all, have found evidence for some relationship between psychosocial factors and incidence or prevalence of BP, and some go as far as proposing the term ‘psychosocial pain syndrome’ to cover these aspects of BP [9]. Furthermore, the negative association between work-related stress and work ability has been reported in diverse occupational groups [10–12] and work ability has also been shown to have a significant predictive value for disability and early retirement [13]. Job-related stress can also affect employee productivity through increased absenteeism and presenteeism, imposing a direct economic cost on employers and society [14]. To date, we are not aware of a study addressing the combined effect of BP and perceived stress on work ability. The aim of this study was to examine the prevalence
© The Author 2015. Published by Oxford University Press on behalf of the Society of Occupational Medicine. All rights reserved. For Permissions, please email: [email protected]
Downloaded from http://occmed.oxfordjournals.org/ at Dalhousie University on May 18, 2015
Background Back pain and occupational stress are known risk factors for absenteeism and presenteeism. In addition, the relationship between back pain (BP) and psychosocial stressors has been examined in numerous studies.
148 OCCUPATIONAL MEDICINE
of BP and perceived stress across employees of different occupational status, to investigate their combined impact on work ability and to identify appropriate measures for future corporate health promotion activities.
Methods
Results At the time of the study, there were a total of 1250 employees in this division. Of these, 867 (70%) participated in
Downloaded from http://occmed.oxfordjournals.org/ at Dalhousie University on May 18, 2015
This cross-sectional study was carried out in a major chemical company in Germany between 1 January 2008 and 31 March 2009 as a part of a health promotion campaign in a representative division of the company. Details of the programme have been described elsewhere [12]. The examination programme comprised a medical examination focusing on risk factors for coronary heart disease and diabetes mellitus as well as questionnaires on stress perception, BP and the Work Ability Index (WAI). For the purposes of the study, the participants were classified according to job activity and responsibility as frontline operators (FO), skilled workers (SW) and professional and managerial staff (PM). This classification roughly represents the socio-economic status of the employees. The study was conducted and the data were collected in accordance with standard ethical procedures [15]. The aim and scope of the examination was stated at the beginning of the questionnaire, and a consent form was enclosed with the questionnaire. Participants were able to ask questions during their medical examination, which was conducted by a physician. Study participation was voluntary and could be declined at any part of the examination programme without a need for explanation. The study protocol had been approved in advance by the workers’ council. The questions used to assess BP were taken from the standardized Nordic Musculoskeletal Questionnaires [16]. The questions provided a measure of common symptoms used in epidemiological studies on musculoskeletal disorders. A sum score was created from all items without weighting them, and the outcomes were then divided at quartiles into excellent (0 or 1), good (2 or 3), moderate (4, 5 or 6) and poor (≥7). The questions used to assess stress perception were taken from validated published instruments and have been used in the employees’ opinion survey in the company for several years [12]. The questions were aimed at ascertaining perception of safety in the workplace, self-rated health status, frequency of experienced stress symptoms, unrealistic job demands, time pressure and impaired worklife balance. Each question was answered on a five-point Likert scale. For the analysis, the lower two and the top two categories were grouped together so that three categories remained, with the lower two categories referring to the highest stress perception. The WAI [17] assesses a person’s perception of how well they are able to perform their work, compared with their lifetime best. A short version in German [18] was used. The WAI is calculated by summing the responses to each dimension, with a possible range of scores from 7 to 49. For a binary outcome,
WAI was dichotomized at the median of sum scores into poor to moderate (7–41) and good to excellent (42–49). Information about general characteristics and health behaviour of participants was obtained from the medical information system used in the occupational medicine department. During the medical examination, further information (data not shown) such as smoking status, alcohol consumption, physical activity and information on the incidence and prevalence of chronic health conditions was obtained. Participants were classified according to their smoking status into current smokers, former smokers and non-smokers. Physical activity was classified according to the median time spent on physical exercise each week (2 hr/week). Body mass index was used to define the subjects as normal (
