Commute mode, commuting accidents and sickness absence among Finnish municipal employees

Abstract Background Commuting physical activity provides health benefits but also increases the risk of accidents. While the higher risk of accidents and injuries is particularly pronounced among cyclists, bicycle commuting may reduce the risk of sickness absence (SA). We examined the risk of commuting accidents across different commute modes and assessed the net health effects of active commuting by accounting for both accident and SA outcomes. To date, such evidence is limited particularly in Nordic winter conditions. Methods With up to two-year follow-up, we examined the relative risk of register-based commuting accident and SA across primary commute mode choices (vs. car) and levels of active commuting (vs. no walking or cycling) among Finnish public sector survey respondents (N = 22340-32562), adjusting the models for potential confounders. To estimate absolute risks and net effects on work disability, SA and accident incidence were modelled per 100 person-years (p-y) by each commute mode and by the weekly volume of walking and cycling. Results All-year-round cyclists had 4.1-fold (95% confidence interval 3.2-5.3) higher accident risk and, on average, 2.8 more accidents per 100 p-y than car commuters. Compared to daily car commuting, also walking and public transport use were associated with a higher risk of commuting accidents, up to twofold higher in winter. The incidence of cycling accidents was highest in the group with most commuted kilometres by bicycle, particularly in winter. The most active cyclists had, however, also a lower risk of SA days (0.90, 0.83-0.97) and long (>9 days) SA spells (0.81, 0.72-0.90), contributing to up to 531 fewer SA days, and 11 long spells less per 100 p-y compared to passive commuters. No similar benefits were observed for walking. Conclusions Cycling to work decreases the SA risk to the extent that it outweighs the increased risk of commuting accidents. Whether the benefits are related to improved mental or somatic health will be discussed.