Changes in leisure-time physical activity and subsequent sickness absence: A prospective cohort study among middle-aged employees

Objective. The aim of this study was to examine how changes over time in leisure-time physical activity are associated with subsequent sickness absence. Methods. Helsinki Health Study cohort baseline questionnaire survey data were collected in 2000-2002 among 40-60-year-old employees of the City of Helsinki, Finland. A follow-up survey was conducted in 2007. 4182 (83% women) respondents were available for the analyses. Leisure-time physical activity was asked using identical questions in both surveys. Sickness absence data were derived from the employer's registers (mean follow-up time 2.8 years). Associations of changes over time in leisure-time physical activity with self-certified days) and medically certified (>3 days) sickness absence spells were examined, using Poisson regression analysis. Results. Inactive women and men who increased their physical activity to vigorously active had a significantly lower risk of both self-certified (RR = 0.80,95% CI 0.65-0.97) and medically certified (RR = 0.63, 95% CI 0.49-0.83) subsequent sickness absence spells compared with the persistently inactive. The persistently active with vigorous intensity had the lowest risk of sickness absence. Adjusting for changes in physical health functioning attenuated but did not abolish the lowered risk found. Conclusions. For reducing sickness absence more emphasis should be given to the potential contribution of vigorous physical activity. (C) 2012 Elsevier Inc. All rights reserved.