Precision greenness exposure is associated with lung cancer risk in medicare beneficiaries

This study examines whether lung cancer risk is influenced by block-level greenness, controlling for age, sex, race/ethnicity, area deprivation index (ADI), and walkability in older adults, and whether age, sex, race/ethnicity, ADI, or walkability plays a moderating role in this relationship.

Data from US Medicare beneficiaries aged 65 years and older were included for the years 2011 and 2016. Beneficiaries included in this study received a lung cancer diagnosis for the first time between 2012 and 2016. All resided in Miami-Dade County, Florida (M_age = 74.31 ± 6.95, 58.69% females, 20.24% White, 68.12% Hispanic, 11.63% Black). Greenness was measured using normalized difference vegetation index. Greenness in 2011 was used to predict lung cancer risk in 2012-2016. Generalized estimating equation (GEE) analyses were performed.

Results indicated that 754 out of 234,360 individuals (0.32%) were diagnosed with lung cancer in 2012-2016. Higher neighborhood greenness in 2011 was associated with lower lung cancer risk from 2012 to 2016 after adjustment for age, sex, race/ethnicity, ADI, and walkability, with each 0.1-unit increase in NDVI corresponding to an approximately 9% lower lung cancer risk (OR = 0.91, 95% CI: 0.85-0.98, p = .008). In the best-fit model, walkability moderated the associations between greenness and lung cancer risk, with the beneficiaries living in non-car dependent neighborhoods experiencing a lower risk. In stratified analyses, inverse associations were observed among beneficiaries younger than 75 years, men, Hispanic beneficiaries, and non-car dependent neighborhoods.

Our findings suggest that higher greenness at the Census block level may be associated with reduced lung cancer risk in older adults. This underscores the critical role of environmental factors, particularly access to green spaces, in cancer prevention strategies. Future research should further explore the interplay among biological, behavioral, or social factors that may shape the association between greenness and lung cancer risk.