ORIGINAL ARTICLE Physical workload, leisure-time physical activity, obesity and smoking as predictors of multisite musculoskeletal pain. A 2-year prospective study of kitchen workers Eija Haukka, 1,2 Anneli Ojaja ¨rvi, 3 Esa-Pekka Takala, 1,2 Eira Viikari-Juntura, 2 Pa ¨ivi Leino-Arjas 1,2 ABSTRACT Objectives The aim of this prospective study was to examine the role of physical workload, leisure-time physical activity, obesity and smoking in predicting the occurrence and course of multisite musculoskeletal pain (MSP). Methods Data on physical and psychosocial workload, lifestyle factors and MSP were based on questionnaire surveys of 385 Finnish female kitchen workers. MSP (defined as pain at three or more of seven sites) during the past 3 months was measured repeatedly at 3-month intervals over 2 years. Four different patterns (trajectories) in the course of MSP were identified. The authors analysed whether the determinants at baseline predicted the occurrence of MSP (1) at the 2-year follow-up and (2) over the total of nine measurements during the 2 years by exploiting the MSP trajectories. Logistic regression was used. Results High physical workload at baseline was an independent predictor of MSP at the 2-year follow-up (OR 3.8, 95% CI 1.7 to 8.5) in a model allowing for age, psychosocial factors at work and lifestyle. High physical workload (OR 2.0, 95% CI 1.0 to 4.0) and moderate (OR 2.4, 95% CI 1.2 to 4.9) or low (OR 2.3, 95% CI 1.1 to 4.7) physical activity predicted persistent MSP. Obesity (OR 2.8, 95% CI 1.0 to 7.8) predicted an increased, and not being obese (OR 3.7, 95% CI 1.1 to 12.7) a decreased, prevalence of MSP in models similarly including all covariates. Smoking had no effect. Conclusion The results emphasise the importance of high physical workload, low to moderate physical activity and obesity as potential modifiable risk factors for the occurrence and course of MSP over time. INTRODUCTION Recent population-based studies in several Euro- pean countries have shown that multisite muscu- loskeletal pain (MSP) is more frequent than single- site pain. 1e6 MSP is common also in various occu- pational groups, such as scaffolders, 7 manual workers, 8 dentists, 9 industrial workers, 10 kitchen workers, 11 nurses, office workers and postal clerks. 12 Women report more MSP than men 246 and the prevalence increases with age. 4 11 Consequences of MSP seem to be more severe compared with single- site pain with respect to short- and long-term sickness absence, 13 14 work disability, 3 15e17 func- tional ability 18 and frequency of consultations in primary care. 19 The majority of epidemiological studies to date have examined pain at a specific anatomical site. 20 The current understanding is that both work- related physical and psychosocial load 21 and life- style factors, such as smoking 22 and overweight or obesity, 23 play a role in the multifactorial aetiology of MSP. Evidence on the role of physical exercise is less consistent. 24 There is an expressed need of longitudinal studies with repeated measurements to better understand the course of pain and to identify subgroups of individuals with a similar development, as well as the determinants of the course of pain. 25e27 The importance of finding risk factors of multi- site pain, thus far largely unknown, has recently been highlighted. 28 29 In some cross-sectional studies of occupational samples, physical workload has been associated with the occurrence of MSP. 9 12 Low physical activity during leisure-time, high 1 Centre of Expertise for Health and Work Ability, Finnish Institute of Occupational Health, Helsinki, Finland 2 Disability Prevention Centre, Finnish Institute of Occupational Health, Helsinki, Finland 3 Creating Solutions, Statistics and Health Economics Team, Finnish Institute of Occupational Health, Helsinki, Finland Correspondence to Eija Haukka, Centre of Expertise for Health and Work Ability, Finnish Institute of Occupational Health, Topeliuksenkatu 41 a A, FI-00250, Helsinki, Finland; eija.haukka@ttl.fi Accepted 1 March 2012 Published Online First 26 April 2012 What this paper adds < Multisite MSP is common but its risk factors are largely unknown. We used two prospective analysis strategies to identify predictors of MSP in a 2-year follow-up study among female municipal kitchen workers. < High physical workload had an important role in predicting the overall occurrence of MSP at the 2-year follow-up. < Making use of nine repeated measurements of MSP that identified latent groups within the study material, we found that high physical workload and low/moderate leisure-time phys- ical activity at baseline predicted a persistently high prevalence of MSP. Obesity predicted an increased prevalence and not being obese a decreased prevalence of MSP over the 2 years. < Attention to physical workload, exercising during leisure and obesity may be useful in the screening of high-risk groups of MSP and in allocation of preventive interventions. Occup Environ Med 2012;69:485e492. doi:10.1136/oemed-2011-100453 485 Workplace group.bmj.com on February 6, 2013 - Published by oem.bmj.com Downloaded from