Residential greenspace and risk of cancer: A prospective cohort study from the UK Biobank

Growing evidence suggests that proximity to greenspace is linked to multiple health outcomes, but its association with the risk of cancer is not fully understood. The mechanism for greenspace's influences on cancer incidence may be through reducing depressive symptoms and increasing physical activity. Our study aimed to investigate the associations between exposure to residential greenspace and the risk of common types of cancer and whether the associations were modified or mediated by depressive symptoms and physical activity.This prospective cohort study included 401,189 participants in the UK Biobank between 2006 and 2010 who were free of cancer and followed up until 2021. Residential greenspace was defined as the percentage of outdoor greenspace surrounding the residential location of each participant across 1000 m and 300 m buffers, which were estimated with land use data. Electronic health records were used to assess the incidence of 25 types of cancer. Cox proportional hazards regressions were performed to estimate hazard ratios (HRs) and 95 % confidence intervals (CIs) per an interquartile range (IQR) increase of greenspace after multiple comparisons using Bonferroni correction.During a median follow-up of 12.4 years, a total of 43,273 incident cancer cases were documented. We found that exposure to greenspace at a 1000 m buffer was significantly associated with prostate cancer (HR = 0.93, 95 % CI: 0.89-0.96), and suggestively associated with oral cavity (HR = 0.86, 95 % CI: 0.76-0.98) and bladder cancer (HR = 1.08, 95 % CI: 1.01-1.15), but not with other cancers. Moreover, the association between greenspace and prostate cancer was mediated by physical activity, and was modified by depressive symptoms (P for heterogeneity = 0.022). Similar findings were also observed for greenspace at a 300 m buffer.Our study revealed an association between exposure to greenspace and prostate cancer, but not with other cancers.