[A retrospective cohort study of long-term nitrogen dioxide exposure and incident hypertension].

Objective: To investigate the effect of long-term exposure of nitrogen dioxide on the incidence of hypertension. Methods: From March to December 2009, 37 386 eligible residents from four cities in northern China (Tianjin, Shenyang, Taiyuan, and Rizhao) were enrolled in a follow-up study by using the random cluster sampling method. Demographic characteristics, lifestyle, history of diseases, and self-report situation of hypertension were collected by using questionnaire. Based on the average annual concentration of NO2 during the period from the cohort to the onset of hypertension as an estimate of exposure, the effect of NO2 exposure on hypertension was analyzed by employing Cox proportional hazards model. The interactions between NO2 exposure and different characteristics (age, sex, body mass index, smoking, alcohol consumption, education, economy, exercise, and fruit intake) were also examined. Results: The baseline age of residents was (43.74±13.78) years, and the body mass index (BMI) was (22.56±2.92) kg/m(2). During an average follow-up time of 11.40 years, 2 619 (7.0%) new cases of hypertension were reported. The overall mean environmental pollution levels during the study period for the entire cohort was (40.74±17.07) μg/m(3). After adjusting for age, sex, BMI, family history of hypertension, socio-economic information, and lifestyle, the hazard ratio (HR) of incident hypertension with a 10 μg/m(3) increase of NO2 was 1.21 (95%CI: 1.18-1.25). Compared with residents aged 60 years and over (HR=1.19, 95%CI: 1.14-1.26), former and current smoking (HR=1.20, 95%CI: 1.14-1.25), and high-frequency fruit consumption (HR=1.17, 95%CI: 1.13-1.21), residents younger than 60 years (HR=1.28, 95%CI: 1.25-1.32), non-smoker (HR=1.23, 95%CI: 1.19-1.27), and low-frequency fruit consumption (HR=1.27, 95%CI: 1.20-1.35) had stronger interaction effect with NO2 (all P values for interaction<0.05). Conclusion: NO2 exposure may lead to the onset of hypertension, which has a stronger effect on people younger than 60 years old, without smoking history and with low-frequency fruit consumption.目的： 探讨二氧化氮长期暴露对高血压发病的影响。 方法： 于2009年3—12月，采用随机整群抽样方法，将中国北方四城市天津、沈阳、太原、日照的37 386名符合标准的居民纳入研究，并开展随访调查。采用问卷调查的方法获得人口学、生活方式、疾病史等信息，由研究对象自述高血压的患病情况。以从纳入队列至高血压发病期间内NO2的年平均浓度作为暴露估计值，采用Cox比例风险回归模型分析NO2暴露对高血压发病的影响；并分析年龄、性别、体重指数、吸烟、饮酒、学历、经济、锻炼以及水果摄入等因素与NO2暴露的交互作用。 结果： 研究对象的基线年龄为（43.74±13.78）岁，体重指数为（22.56±2.92）kg/m(2)，平均随访11.40年，高血压新发病例2 619名（7.0%）。四城市1998—2008年NO2的年平均浓度为（40.74±17.07）μg/m(3)。调整年龄、性别、体重指数、高血压家族史、生活方式等混杂因素后，NO2每升高10 μg/m(3)，高血压发病的HR（95%CI）值为1.21（1.18，1.25）。与年龄≥60岁[HR（95%CI）：1.19（1.14~1.26）]、既往或现在吸烟[HR（95%CI）：1.20（1.14~1.25）]、食用水果每周≥4次[HR（95%CI）：1.17（1.13~1.21）]相比，年龄<60岁[HR（95%CI）：1.28（1.25~1.32）]、不吸烟[HR（95%CI）：1.23（1.19~1.27）]、食用水果每周≤1次[HR（95%CI）：1.27（1.20~1.35）]与NO2暴露的交互作用更强（P交互值均<0.05）。 结论： NO2暴露可能导致高血压发病，对年龄<60岁、不吸烟和食用水果较少者的影响更强。.