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.