Physical activity, sedentary behaviour and risk of oesophago-gastric cancer: a prospective cohort study within UK Biobank

Background: Few observational studies have assessed the role of physical activity in oesophago-gastric cancer risk.

Objective: This prospective cohort study aimed to assess the association between physical activity and risk of oesophageal or gastric cancer.

Methods: A cohort of 359,033 adults aged 40-69 years were identified from the UK Biobank, which recruited participants between 2006 and 2010. Adjusted hazard ratios (HRs) and 95% confidence intervals (CIs) for the associations between self-reported levels of physical activity and screen-based sedentary behaviour, and risk of oesophageal and gastric cancer were calculated using Cox proportional hazards models.

Results: During 8 years of follow-up (mean=5.5), 294 oesophageal cancer and 217 gastric cancer cases were identified. Physical activity and screen-based sedentary behaviour levels were not associated with overall oesophago-gastric cancer risk. However, when compared with low levels, high physical activity levels were associated with a significantly reduced risk of gastric non-cardia cancer (HR 0.58, 95% CI 0.37- 0.95). Moderate physical activity levels were associated with a 38% reduced risk of oesophageal adenocarcinoma (HR 0.62, 95% CI 0.43-0.89), although no doseresponse association was apparent.

Conclusion: Moderate, rather than high, physical activity levels were associated with the strongest reductions in oesophageal adenocarcinoma risk in this large UK prospective cohort.