| BackgroundPrevious studies have tended to focus on individual risk factors for CVD,such as metabolic risk factors and health-related behavioral factors.In recent years,there has been an increasing interest in the impact of environmental factors on CVD.Studies on green space and cardiovascular disease(CVD)are mostly from Western countries,and those from China have focused on mortality outcomes,with a lack of evidence from prospective studies on green space and CVD.In low-and middle-income countries,the evidence of excess risk of cardiovascular disease(CVD)morbidity and mortality in populations exposed to high levels of outdoor PM2.5 is controversial.Therefore,this study aimed to explore the independent effects of green space and chronic exposure to ambient fine particulate matter<2.5μg/m3(PM2.5)on the risk of CVD morbidity and mortality,as well as the combined effects of green space and PM2.5 on CVD morbidity and mortality,in a large cohort study in 115 communities.The combined effect of green space and PM2.5 on CVD morbidity and mortality was explored.MethodsThis study included 42,160 subjects aged 35-70 years who participated in the Prospective Urban and Rural Epidemiology Study conducted in China(PURE-China)between 2005 and 2009 and underwent baseline survey and follow-up.The 42,160 study participants were analyzed and the Normalized Difference Vegetation Index(NDVI)and outdoor PM2.5 concentrations were estimated for their residential environment,and all study participants were followed up until August 2021.A Cox frailty model was used to estimate the strength of the association between outdoor PM2.5 concentrations and CVD incidence(including heart attack,stroke,heart failure,and other CVD),CVD mortality,and all-cause mortality.ResultsDuring a median follow-up period of 11.8 years,2190 deaths were recorded,including 732 CVD deaths.Of the 42,160 study subjects,4559(10.8%)had CVD,including 861 myocardial infarctions(MI)and 2338 strokes(Stroke).The 3-year median ambient NDVI and PM2.5 concentrations during baseline were 0.44 units(IQR 0.33-0.55)and 52.7 μg/m3(interquartile range[IQR]30.3-74.6),respectively.NDVI of the population residential environment showed a significant negative correlation with total and major CVD.After full model adjustment,each 0.1 unit increase in NDVI was associated with a 12%(5%18%),10%(3%-16%),20%(10%-29),and 8%(1%-15%)reduction in the risk of total CVD,major CVD,MI,and all-cause mortality,respectively.No such association was found between stroke and CVD deaths.Long-term outdoor PM2.5 showed a significant positive association with CVD and all-cause mortality.After full model adjustment,for each 10 μg/m3 increase in PM2.5 concentration,the Hazard Ratio(HR)and 95%Confidence Interval(CI)for major CVD was 1.12(1.11-1.14)and the HR and 95%CI for all-cause mortality was 1.03(95%CI 1.01-1.05).1.05).In addition,a significant positive association between outdoor PM2.5 exposure and other CVDs was also observed in this study.ConclusionThe present study showed that population-dwelling NDVI was significantly and negatively associated with CVD and all-cause mortality among adults aged 35-70 years in China.Long-term outdoor PM2.5 exposure was significantly and positively associated with increased risk of CVD and all-cause mortality.There was also a joint effect of both on the risk of CVD and all-cause mortality.This finding provides evidence for policy makers on the need to develop policies to improve air quality and also provides important evidence for green space planning,which is of great importance for public health policy development. |
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