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

Abstract

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 (≤ 3 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.

Introduction

Regardless of all the efforts to promote physical activity, physical inactivity has increased and is a major threat to public health worldwide (Beaglehole et al., 2011). There is much evidence from epidemiological studies linking physical activity to decreased risk of chronic diseases (Physical Activity Guidelines Advisory Committee, 2008) such as type II diabetes (Hu et al., 2003) and cardiovascular disease (Kohl, 2001), and to better health related functioning (Lahti et al., 2010a, Wolin et al., 2007) and lower all-cause mortality (Byberg et al., 2009).

Sickness absence is a major public health and work life problem in many Western countries, causing costs for employees, workplaces and society (Alexanderson and Norlund, 2004). Previous studies have shown that physical activity is associated with lower sickness absence rates (Eriksen and Bruusgaard, 2002, Jacobson and Aldana, 2001, van Amelsvoort et al., 2006). One study suggests that high leisure-time physical activity is associated with a lower risk of sickness absence, whereas high occupational activity increases the risk (Holtermann et al., 2012). Some studies suggest that vigorous physical activity is important in preventing sickness absence (Lahti et al., 2010b, Proper et al., 2006). Previous studies on various health outcomes also suggest that vigorous activity may provide additional health benefits to moderate intensity activity (Janssen and Ross, 2012, Lahti et al., 2010a, Lahti et al., in press, Lee and Paffenbarger, 2000, Samitz et al., 2011). Sufficient intensity of physical activity is important for fitness (American College of Sports Medicine Position Stand, 1998) and functioning (Lahti et al., 2010a) and may thereby contribute to reduced sickness absence (Lahti et al., 2010b).

Adopting physical activity during middle age contribute to a reduced risk of major chronic diseases (Wannamethee et al., 1998) and better health related functioning (Wolin et al., 2007). Previous studies on physical activity and sickness absence have examined physical activity at only one time point. To provide stronger evidence for the functional health benefits of adopting leisure-time physical activity at middle age we examined whether changes in leisure-time physical activity contribute to subsequent sickness absence rates. We hypothesised that employees who increase their leisure-time physical activity, and in particular engage in vigorous activity, would have a lower risk of subsequent sickness absence compared with those who remain inactive. We pose the following research questions: Are increases in leisure-time physical activity associated with subsequent sickness absence spells of different length among middle-aged women and men? Does the intensity modify the associations of leisure-time physical activity with sickness absence?