Associations between commuting modes and risk of 16 site-specific cancers in the UK Biobank.

BACKGROUND: The choice of transport mode may influence cancer risk by affecting physical activity level, sedentary behaviour, and exposure to environmental pollution. This study investigated the associations between commuting modes and 16 site-specific cancers in the UK Biobank. METHODS: The UK Biobank is a prospective cohort study involving about 500 000 participants. Information on transport modes was collected at recruitment, and incident cancer cases were identified through linkage to national cancer registries. Multivariable Cox proportional hazards models were used. RESULTS: There were 252 334 employed participants included, and 15 828 incident cancer cases were identified over a median follow-up of 11.7 years. Compared to the car-only mode, cycling (exclusively or combined with any other modes) was associated with a lower risk of colon [hazard ratio (HR): 0.72; 95% confidence interval: 0.53-0.96], renal (HR: 0.60; 0.38-0.96), and stomach (HR: 0.27; 0.10-0.71) cancers. Walking (exclusively or combined with any motorized mode) was associated with a lower risk of renal (HR: 0.67; 0.49-0.92) and liver (HR: 0.55; 0.31-0.98) cancers. Public transport users were less engaged in other physical activities, and its use was associated with a higher risk of bladder cancer (HR: 1.39; 1.01-1.90). CONCLUSIONS: Active commuting, even combined with motorized modes, is associated with a lower risk of some common cancers.