Objective: To investigate the association of mixed exposure to greenness and nitrogen dioxide(NO2) and hypertension among the older adults aged 65 years and over in China. Methods: The study subjects were from the Chinese Longitudinal Healthy Longevity Survey from 2017 to 2018. A total of 15 423 older adults aged 65 years and over meeting the criteria were finally included in the study. A questionnaire survey was used to collect information on demographic characteristics, lifestyle habits and self-reported prevalence of hypertension. Blood pressure values were obtained through physical examination. The level of normalized difference vegetation index(NDVI) was measured by the Medium-resolution Imaging Spectral Radiator(MODIS) of the National Aeronautics and Space Administration(NASA). The concentration of NO2 was from China's surface air pollutant data set. Meteorological data was from NASA MERRA-2. The exposure to NDVI and NO2 for each study subject was calculated based on the area within a 1 km radius around their residence. The association between mixed exposure of NDVI and NO2 as well as their interaction and hypertension in older adults was analyzed by using the multivariate logistic regression model. The restrictive cubic spline(RCS) function was used to explore the exposure-response relationship between greenness and NO2 and the risk of hypertension in study subjects. Results: The mean age of 15 423 older adults were (85.6±11.6). Women accounted for 56.3%(8 685/15 423) and 55.6%(8 578/15 423) lived in urban areas. The mean time of residence was (60.9±28.5) years. 59.8% of participants were with hypertension. The mean NDVI level was 0.41±0.13, and the mean NO2 concentration was (32.18±10.36) μg/cm3. The results of multivariate logistic regression analysis showed that NDVI was inversely and linearly associated with the hypertension in older adults, with the OR(95%CI) value of 0.959(0.928-0.992). Compared with the T1 group of NDVI, the risk of hypertension was lower in the T3 group, with the OR(95%CI) value of 0.852(0.769-0.944), and the trend test was statistically significant(P<0.05). Compared with the T1 group of NO2, the risk of hypertension was higher in the T2 and T3 groups, with OR(95%CI) values of 1.160(1.055-1.275) and 1.244(1.111-1.393), and the trend test was statistically significant (P<0.05). The result of the RCS showed that NDVI was inversely and linearly associated with hypertension in older adults. NO2 was nonlinearly associated with hypertension in older adults. The interaction analysis showed that NDVI and NO2 had a negative multiplicative interaction on the risk of hypertension, with OR(95%CI) value of 0.995(0.992-0.997). Conclusion: Exposure to greenness and NO2 are associated with hypertension in older adults.
目的： 探讨绿地空间和NO2暴露与中国老年人高血压的关联。 方法： 研究对象来自2017—2018年中国健康影响因素跟踪调查，最终纳入15 423名符合标准≥65岁老年人为研究对象。采用问卷调查收集人口学特征、生活习惯、自我报告高血压患病情况等信息，通过体格检查获取血压值等资料。归一化差异植被指数（NDVI）来源于美国宇航局的中分辨率成像光谱仪（MODIS）测量结果。NO2浓度来源于中国地面空气污染物数据集。气象数据来自美国宇航局MERRA-2。每个研究对象的NDVI、NO2的暴露量基于其居住地点周围1 000 m半径内的面积进行计算。通过多因素logistic回归模型分析NDVI、NO2混合暴露及其交互作用与老年人高血压患病的关联。采用限制性立方样条（RCS）函数分别探索绿地、NO2与中国老年人高血压患病风险的暴露-反应关系。 结果： 15 423名老年人年龄为（85.6±11.6）岁；女性占56.3%（8 685/15 423）；居住在城镇占55.6%（8 578/15 423）；居住时间为（60.9±28.5）年；高血压者占59.8%（9 225/15 423）；NDVI为0.41±0.13；NO2浓度为（32.18±10.36）μg/m3。多因素logistic回归模型分析结果显示，NDVI与老年人高血压患病风险呈负向线性关联，OR（95%CI）值为0.959（0.928~0.992）；与NDVI的T1组相比，T3组罹患高血压的风险较低，OR（95%CI）值为0.852（0.769~0.944），趋势检验具有统计学意义（P<0.05）；与NO2的T1组相比，T2组、T3组罹患高血压的风险较高，OR（95%CI）值分别为1.160（1.055~1.275）、1.244（1.111~1.393），趋势检验具有统计学意义（P<0.05）。RCS的分析结果显示，NDVI与老年人高血压患病风险呈负向线性关联；NO2与老年人高血压患病风险呈非线性关联。交互作用分析结果显示，NDVI与NO2对高血压患病风险具有负相乘交互作用［OR（95%CI）：0.995（0.992~0.997）］。 结论： 绿地空间、NO2暴露与老年人高血压患病均存在关联。.