Exposure to neighbourhood greenness and hypertension in adults: a cohort study in Taiwan
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Jockey Club School of Public Health and Primary Care, The Chinese University of Hong Kong, Hong Kong, China
Publication date: 2023-04-27
Popul. Med. 2023;5(Supplement):A212
Background and Objective: There is limited information on the health effects of long-term exposure to neighborhood greenness in a longitudinal setting, especially in the Asian area with high population densities. This study aims to investigate the association between long-term exposure to neighborhood greenness and hypertension among adults from Taiwan. Methods: We selected 125537 participants (≥18 years of age) without hypertension from Taiwan who joined the standard medical examination program between 2001 and 2016. Neighborhood greenness was estimated by normalized difference vegetation index (NDVI) derived from satellite images at a resolution of 250 m2. The two-year average of NDVI within a 500m buffer around participants residences was calculated. A time-varying Cox regression model was used to investigate the association between greenness and incident hypertension. Mediation analyses were performed to investigate whether the association was explained by air pollution, physical exercise, and body mass index (BMI). Results: Compared to participants living in the areas with the first quartile of neighborhood greenness, participants living in the areas with the second, third, and fourth quartiles of neighborhood greenness were associated with a lower risk of hypertension, with a hazard ratio (HR) (95% confidence intervals) of 0.95 (0.91, 1.00), 0.95 (0.90, 0.99), and 0.93 (0.88, 0.97), respectively. Each 0.1-unit increase in NDVI was associated with a 24% lower risk of developing hypertension (HR:0.76, 95%CI: 0.66, 0.87). The associations were stronger among males and individuals with higher education levels. BMI sightly mediated the association, but there was no evidence of mediating effects of air pollution and physical exercise. Conclusions: Our findings suggest the protective effects of neighborhood greenness on hypertension development, especially in males and well-educated persons. Our findings reinforced the importance of greenness for the neighborhood environment.