Greenspace Exposure Reduces the Risk of Hypertension: A Large Prospective Cohort Study in Northwestern China

BACKGROUND: The effects of greenspace on hypertension remain unconfirmed. This study aimed to validate this by performing a large prospective cohort study in China. METHODS: PEAHEN-China (Prospective Environment and Health Epidemiological Study in Northwestern China) recruited 5 484 119 adults in 2017 and followed them to 2021. Blood pressure levels and hypertension were measured and defined using recommended standards. Greenspace exposure was estimated using the normalized difference vegetation index and enhanced vegetation index. Cox regression models and generalized estimating equation models were used to assess the associations of greenspace with hypertension incidence and blood pressure levels, respectively. Sensitivity and subgroup analyses were also performed. RESULTS: During a median 3.21-year follow-up, 1 290 003 new hypertension cases occurred. Living in greener areas was significantly associated with a lower risk of hypertension and lower blood pressure levels. For example, in the adjusted models, compared with the first quartile of normalized difference vegetation index and enhanced vegetation index within a 500-m buffer, the hazard ratios of incident hypertension in the fourth quartile of the 2 metrics were 0.871 (95% CI, 0.861-0.881) and 0.896 (95% CI, 0.885-0.906). In addition, stronger associations of greenspace exposure with hypertension risk and blood pressure levels were observed in younger, male, rural, and less educated participants than their counterparts. CONCLUSIONS: Our study indicates that neighborhood greenspace may reduce residents' odds of having hypertension, offering robust evidence for developing policies and strategies to mitigate the burden of hypertension.