Environmental greenery and skin cancer risk: a prospective cohort study on incidence and mediating mechanisms

Skin cancer, including malignant melanoma (MM) and non-melanoma skin cancer (NMSC), is a growing global public health problem. Green spaces are generally beneficial to public health, yet their impact on skin cancer risk remains contentious.

Using data from 318,738 participants in a large cohort, we examined the association between green space, domestic gardens, and natural environments within 300-m and 1,000-m buffer zones and skin cancer incidence. Hazard ratios (HRs) were estimated using Cox regression. Genetic susceptibility was assessed through polygenic risk scores, susceptible populations were identified through gene-environment interaction, potential biomarkers were discovered through metabolomics, and potential pathways were explored through mediator analyses.

Domestic gardens are the main type of greenery associated with an increased risk of skin cancer. The highest quartile of exposure to gardens resulted in a 23% increased risk of developing MM (HR = 1.23, 95% CI: 1.08-1.41). People living within 300 m (HR = 1.10, 95% CI: 1.05-1.16) and 1,000 m (HR = 1.11, 95% CI: 1.06-1.17) of a garden had a higher risk of developing NMSC. Interaction analyses of domestic gardens with genetic characteristics showed that genetically susceptible, light-skinned, and sun-sensitive populations were at higher risk of cancer. Metabolomics identified metabolites (e.g., histidine) and NMSC markers (e.g., tyrosine) associated with MM. Unexpectedly, PM_2.5 appeared to be a mediator of reduced skin cancer risk.

We found that domestic gardens have a significant effect on skin cancer risk according to the type of greenery. Urban planning should target genetically and phenotypically susceptible populations with protective measures.