Abstract Background Knowledge is lacking on the relationship between greenness exposure and cancer incidence and prognosis. It remains unclear whether individuals with coronary heart disease (CHD) and cancer, compounding risks, are similarly prone to this relationship. Methods Four cohorts were pooled, including two acute coronary syndrome patient registries (inception years: 1992-1993 and 2004-2014) and two cycles of the Israeli National Health and Nutrition Surveys (inception years: 1999-2001 and 2005-2006). Demographic, clinical, and behavioral information were retrieved at baseline. Mortality and cancer data were obtained from the Ministry of Health and the Israel National Cancer Registry (last follow-up, December 2021 for both). Residential greenness was estimated by the normalized difference vegetation index (NDVI), a satellite-based index derived from Landsat imagery at 30 m spatial resolution, with larger values indicating higher levels of vegetative density (ranging from -1 to 1); within a buffer of 300 m radius around each individual’s home address. Mean annual NDVI exposure was averaged from each cohort’s inception through 2019. In a nested case-control analysis, incident cancer cases were matched to cancer-free controls using risk set sampling based on age, sex, cohort, and enrollment year, and their mean annual NDVI exposure was compared. The case group was then followed for subsequent mortality. Individuals with preexisting cancer diagnoses (prevalent cases) at study entry were also followed for mortality. Conditional logistic and Cox regression models were used to estimate hazard ratios (HRs) for cancer incidence and all-cause mortality, as appropriate, per 1 SD increase in NDVI. Stratified analyses by CHD status were also conducted. Results A total of 17,216 individuals were pooled, of them 1,658 (9.6%) were prevalent cases. During a median follow-up period of 15.5 (IQR 11.5-16.0) years, 2,460 incident cases median age, 75 (IQR 67-82) y, 27% females were identified, of which 1,401 (57%) subsequently died. Among 2,460 matched pairs, mean (SD) NDVI-300 was 0.12 (0.03). Of the prevalent cases median age, 76 (IQR 68-82) y, 33% females, 1,121 (68%) died during a median follow-up of 13.5 (IQR 9.7–15.9) years. Adjusted for potential confounding factors, NDVI-300 was not significantly associated with lower cancer incidence HR (95% CI) = 0.99 (0.93, 1.05). NDVI-300 was inversely associated (HR, 95% CI) with post-cancer mortality in the incident (0.96, 0.90–1.01) and prevalent (0.92, 0.87–0.98) groups. The association was comparable (All p for interaction .20) for patients with and without CHD (Table). Conclusions Residential greenness exposure was consistently associated with lower post-cancer mortality risk, with no significant variation by baseline CHD status. In contrast, its association with cancer incidence was weaker and less consistent.
Ashri et al. (Sat,) studied this question.