Long-Term Exposure to Residential Green Spaces and Site-Specific Cancer Mortality in Urban Belgium: A 13-Year Follow-Up Cohort Study

Abstract

BackgroundResiding in greener areas may decrease the burden of chronic diseases, but the association with cancer is unclear. We studied the associations between residential green spaces and site-specific cancer mortality in urban Belgium.MethodologyWe linked the 2001 Belgian census, register mortality data for 2001-2014, and environmental information (green spaces and air pollution) at baseline residence (2001). We included residents from the largest Belgian urban areas aged ≥30 years at baseline. Exposure to residential green spaces was assessed using the Normalized Difference Vegetation Index (NDVI), Urban Atlas, and perceived neighbourhood greenness (from the 2001 census). We used Cox proportional hazards models to obtain hazard ratios (HR) and their 95% confidence intervals (95%CI) of the mortality risk from lung, colorectal, breast (in women) and prostate cancer (in men) per interquartile range increment in residential green spaces. We further analyzed the role of outdoor air pollution and effect modification by age and socioeconomic position (SEP) in main models.Results2,441,566 individuals were included at baseline. During follow-up, 1.2% died from lung cancer, 0.6% from colorectal cancer, 0.8% from breast cancer, and 0.6% from prostate cancer. After adjustment, higher exposure to green spaces was associated with a reduced mortality risk from lung cancer and breast cancer [e.g., for NDVI within 500-m HR:0.957 (95%CI:0.932,0.982), and HR:0.927 (95%CI:0.892,0.964), respectively], but not with colorectal and prostate cancer mortality. Air pollution seemed to have a marginal role in main associations. The beneficial effects of green spaces were generally stronger in people aged <65 years, but by SEP no clear trend of effect modification was found.ConclusionsOur findings suggest that residing in green areas is linked to decreased mortality risk from lung and breast cancer, potentially independent from air pollution. Prevention strategies improving the residential environment might be key to reduce the cancer-related burden of disease.

Keywords: Cancer mortality, Green spaces, Built environment, Perception, Air pollution, Social factors