Changes in Leisure-Time Physical Activity and Subsequent Sickness Absence Due to Any Cause, Musculoskeletal, and Mental Causes

Background: The association between changes in physical activity and sickness absence is poorly understood. The aim of this study was to examine the association between changes in leisure-time physical activity and long-term sickness absence due to any cause and musculoskeletal and mental causes. Methods: We measured physical activity at baseline in 2000-2002 (response rate 67%) and at follow-up in 2007 (response rate 83%) among middle-aged employees of the City of Helsinki, Finland. The survey data were linked to the Finnish Social Insurance Institute's register data on sickness benefit periods > 9 days, including diagnoses (ICD-10; International Statistical Classification of Diseases and Related Health Problems, 10th revision) (mean follow-up 2.3 years). We used a negative binomial model to calculate rate ratios. The analyses included 4010 respondents (81% women). Results: Those who were persistently vigorously active and those whose physical activity level changed from low to moderate or vigorous, from moderate to vigorous, or from vigorous to moderate were at lower risk for sickness absence than were the persistently low-activity group. For sickness absence due to musculoskeletal causes, vigorous activity showed stronger associations, whereas mental causes showed no such associations. Conclusions: To reduce sickness absence due to both musculoskeletal and mental causes, middle-aged and aging employees should be encouraged to engage in physical activity.