Differential Association Between Surrounding Greenness and Mortality in Individuals With Coronary Heart Disease

Residential greenness has been linked to lower mortality; however, whether this association varies by cardiovascular disease status remains unclear.

The objectives of the study were to examine the association between greenness and mortality among individuals with and without coronary heart disease (CHD), distinguishing between stable and acute patients, and to assess modification by individual- and neighborhood-level factors, including walkability.

We analyzed data from 4 Israeli cohorts: 2 CHD patient-based cohorts and 2 population-based cohorts (inception years 1992-2004; mortality follow-up through 2020). Long-term greenness exposure was estimated using satellite-based Normalized Difference Vegetation Index within an 800m buffer around participants' homes.

We included 17,431 participants (mean [SD] age 63.6 [15.3] years; 5,286/17,431 [30.3%] women), of whom 3,959/17,431 (22.7%) were CHD-free, 4,771/17,431 (27.3%) had stable CHD, and 8,701/17,431 (49.9%) had acute CHD at baseline. During a median (IQR) follow-up of 11.8 (7.6-15.7) years, 6,055 deaths occurred. Greenness was associated with lower mortality among stable CHD (HR: 0.90; 95% CI: 0.81 to 0.99, per IQR increase in normalized difference vegetation index) and acute CHD (HR: 0.88; 95% CI: 0.82-0.94), but not among CHD-free individuals (HR: 1.01; 95% CI: 0.88-1.16) (P_interaction = 0.004). Stratified analysis among all participants demonstrated strongest greenness-mortality association in the high walkability tertile (HR: 0.83; 95% CI: 0.75-0.91) compared with the medium (0.95; 0.88-1.04) and low (0.90; 0.82-0.98) tertiles (P_interaction = 0.05).

Residential greenness is associated with better survival among individuals with CHD. Variation by walkability suggests that built environment characteristics may modify greenness-related health benefits.