Greenness exposure across the cancer continuum: The role of coronary heart disease.

Background: Whether residential greenness affects cancer outcomes across the cancer continuum and whether comorbid coronary heart disease (CHD) confers differential vulnerability remains an open question. We evaluated greenness-cancer associations and CHD effect modification in a pooled multicohort study. Methods: Four cohorts were pooled: two CHD patient registries and two Israeli National Health and Nutrition Surveys. Cancer and mortality data were obtained from national registries. Greenness was estimated using the Normalized Difference Vegetation Index (NDVI) within a 300 m buffer. Incident cancer cases were 1:1 matched to cancer-free controls by age, sex, cohort, and enrollment year and followed for second primary cancer incidence and mortality. Conditional logistic and Cox regression models estimated hazard ratios (HRs) per 1- standard deviation NDVI increase; CHD effect modification was tested. Results: Overall, 17,047 individuals were pooled, including 1,661 prevalent cancer cases. Over a median of 13.6 years, 2,481 incident cancer cases [age 74 (11.3) years, 27% females] were identified; 1,387 died. Prevalent cases [age 75 (10.9) years, 33% females] had 1,125 deaths over a median of 15.0 years. Greenness associations were specific to postcancer survival: NDVI-300 was not associated with first or second primary cancer incidence [HRs (95% confidence intervals) = 0.96 (0.90, 1.02) and 1.04 (0.93, 1.16), respectively]. NDVI-300 was inversely associated with postcancer mortality [HRs (95% confidence intervals) = 0.93 (0.88, 0.99) and 0.92 (0.86, 0.98) in incident and prevalent groups]. The association was consistent regardless of CHD status (all Conclusions: While no association was observed for cancer incidence, residential greenness was consistently associated with lower postcancer mortality, regardless of CHD status.