Student Research Committee, Department of Epidemiology and Biostatistics, School of Health, Isfahan University of Medical Sciences, Isfahan, Iran.
Department of Community and Preventive Medicine, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran.
Environ Health. 2021 Oct 28;20(1):112. doi: 10.1186/s12940-021-00797-w.
Evidence concerning the impact of long-term exposure to fine Particulate Matter ≤2.5 μm (PM) on Cardio-Vascular Diseases (CVDs) for those people subject to ambient air pollution in developing countries remains relatively scant. This study assessed the relationship of 15-year PM exposure with cardiovascular incidence and mortality rate in Isfahan province, Iran.
The cohort comprised 3081 participants over 35 years old who were free of CVDs. They were selected through multi-stage cluster sampling in Isfahan, Iran. PM exposure was determined separately for each individual via satellite-based spatiotemporal estimates according to their residential addresses. In this context, CVD is defined as either fatal and non-fatal Acute Myocardial Infarctions (AMI) or stroke and sudden cardiac death. The incidence risk for CVD and the ensuing mortality was calculated based on the average PM exposure within a study period of 15 years using the Cox proportional hazards frailty model upon adjusting individual risk factors. The mean annual rate of PM and the follow-up data of each residential area were combined.
Mean three-year PM exposure for the cohort was measured at 45.28 μg/m, ranging from 20.01 to 69.80 μg/m. The median time period for conducting necessary follow-ups was 12.3 years for the whole population. Notably, 105 cardiovascular and 241 all-cause deaths occurred among 393,786 person-months (27 and 61 per 100,000 person-months, respectively). In well-adjusted models, 10 μg/m increase in PM corresponded to a 3% increase in the incidence rate of CVDs [0.95 CI = 1.016, 1.036] (in case of p = 0.000001 per 10 μg/m increase in PM, the Hazard Ratio (HR) for AMI and Ischemic Heart Disease (IHD) was 1.031 [0.95 CI = 1.005, 1.057] and 1.028 [0.95 CI = 1.017, 1.039]), respectively. No consistent association was observed between PM concentration and fatal CVD (fatal AMI, fatal stroke, SCD (Sudden Cardiac Death)) and all-cause mortality.
Results from analyses suggest that the effect of PM on cardiovascular disease occurrence was stronger in the case of older people, smokers, and those with high blood pressure and diabetes. The final results revealed that long-term exposure to ambient PM with high concentrations positively correlated with IHD incidence and its major subtypes, except for mortality. The outcome accentuates the need for better air quality in many countries.
发展中国家的环境空气污染下，长期暴露于细颗粒物≤2.5μm（PM）对心血管疾病（CVDs）的影响证据仍然相对较少。本研究评估了伊朗伊斯法罕省 15 年 PM 暴露与心血管发病率和死亡率之间的关系。
该队列包括 3081 名年龄在 35 岁以上且无 CVD 的参与者。他们是通过伊朗伊斯法罕的多阶段聚类抽样选择的。根据他们的居住地址，通过基于卫星的时空估计分别确定每个个体的 PM 暴露情况。在这种情况下，CVD 定义为致命和非致命性急性心肌梗死（AMI）或中风和心源性猝死。基于 Cox 比例风险脆弱模型，根据 15 年的研究期内的平均 PM 暴露，计算 CVD 的发病风险和随后的死亡率，同时调整个体风险因素。对每个居住区域的平均年 PM 率和随访数据进行了合并。
该队列的三年平均 PM 暴露量为 45.28μg/m，范围为 20.01-69.80μg/m。整个人群进行必要随访的中位时间为 12.3 年。值得注意的是，在 393786 人月（27 人和 61 人/100000 人月）中，发生了 105 例心血管和 241 例全因死亡。在充分调整的模型中，PM 每增加 10μg/m，CVDs 的发病率增加 3%[0.95 CI=1.016, 1.036]（每增加 10μg/m 的 PM，p=0.000001，AMI 和缺血性心脏病（IHD）的风险比（HR）分别为 1.031[0.95 CI=1.005, 1.057]和 1.028[0.95 CI=1.017, 1.039]）。PM 浓度与致命 CVD（致命 AMI、致命中风、SCD（心源性猝死））和全因死亡率之间没有一致的关联。
分析结果表明，PM 对心血管疾病发生的影响在老年人、吸烟者以及高血压和糖尿病患者中更强。最终结果表明，长期暴露于高浓度的环境 PM 与 IHD 发病率及其主要亚型呈正相关，除了死亡率。这一结果强调了许多国家改善空气质量的必要性。
