2019年12月30日出版的《英国医学杂志》发表了北京大学公共卫生学院胡永华教授研究组的最新成果，他们对环境细颗粒物污染与特定心血管疾病住院之间的关系进行了研究。

为了了解中国大气细颗粒物（空气动力学直径≤2.5m，即PM2.5）污染引起的心血管疾病风险，研究组在中国的184个主要城市进行了一项国家时间序列研究。研究组对国家城镇职工基本医疗保险数据库进行分析，2014年1月1日至2017年12月31日，共有8834533人因心血管原因而住院，其主要诊断为缺血性心脏病、心力衰竭、心律失常、缺血性中风和出血性中风。

在研究期间，每天平均有47例患者因心血管疾病而住院，其中缺血性心脏病26例，心力衰竭1例，心律失常2例，缺血性中风14例，出血性中风2例。在全国平均层面上，PM2.5每增加10μg/m³，当日因心血管疾病而住院的人数便增加0.26%，其中缺血性心脏病增加0.31%，心力衰竭增加0.27%，心律失常增加0.29%，缺血性中风增加0.29%，但出血性中风却降低0.02%。

全国PM2.5与心血管疾病的关联呈轻度非线性，PM2.5水平在50μg/m³以下有明显的斜率，在50-250μg/m³之间有中等斜率，浓度高于250μg/m³时则趋于平坦。与PM2.5不超过15μg/m³的天数相比，PM2.5浓度为15-25，25-35，35-75，以及75μg/m³以上时，心血管疾病住院率分别增加1.1%、1.9%、2.6%和3.8%。

根据预测，当PM2.5年平均浓度控制在中国2级（35μg/m³）、中国1级（15μg/m³）和世界卫生组织（WHO）标准（10μg/m³）以下时，将减少中国每年因心血管疾病而住院的人数。假设两者存在因果关系，经谨慎推算，预计每年将分别减少36448人、85270人和97516人住院。

研究结果表明，在中国，短期暴露于PM2.5可导致除出血性中风外的所有主要心血管疾病住院人数增加，即使暴露水平不超过当前的准则值。

附：英文原文

Title: Association between ambient fine particulate pollution and hospital admissions for cause specific cardiovascular disease: time series study in 184 major Chinese cities

Author: Yaohua Tian, Hui Liu, Yiqun Wu, Yaqin Si, Jing Song, Yaying Cao, Man Li, Yao Wu, Xiaowen Wang, Libo Chen, Chen Wei, Pei Gao, Yonghua Hu

Issue&Volume: 2019/12/30

Abstract: Objective To estimate the risks of daily hospital admissions for cause specific major cardiovascular diseases associated with short term exposure to ambient fine particulate matter (aerodynamic diameter ≤2.5 μm; PM2.5) pollution in China.

Design National time series study.

Setting 184 major cities in China.

Population 8 834 533 hospital admissions for cardiovascular causes in 184 Chinese cities recorded by the national database of Urban Employee Basic Medical Insurance from 1 January 2014 to 31 December 2017.

Main outcome measures Daily counts of city specific hospital admissions for primary diagnoses of ischaemic heart disease, heart failure, heart rhythm disturbances, ischaemic stroke, and haemorrhagic stroke among different demographic groups were used to estimate the associations between PM2.5 and morbidity. An overdispersed generalised additive model was used to estimate city specific associations between PM2.5 and cardiovascular admissions, and random effects meta-analysis used to combine the city specific estimates.

Results Over the study period, a mean of 47 hospital admissions per day (standard deviation 74) occurred for cardiovascular disease, 26 (53) for ischaemic heart disease, one (five) for heart failure, two (four) for heart rhythm disturbances, 14 (28) for ischaemic stroke, and two (four) for haemorrhagic stroke. At the national average level, an increase of 10 μg/m3 in PM2.5 was associated with a 0.26% (95% confidence interval 0.17% to 0.35%) increase in hospital admissions on the same day for cardiovascular disease, 0.31% (0.22% to 0.40%) for ischaemic heart disease, 0.27% (0.04% to 0.51%) for heart failure, 0.29% (0.12% to 0.46%) for heart rhythm disturbances, and 0.29% (0.18% to 0.40%) for ischaemic stroke, but not with haemorrhagic stroke (−0.02% (−0.23% to 0.19%)). The national average association of PM2.5 with cardiovascular disease was slightly non-linear, with a sharp slope at PM2.5 levels below 50 μg/m3, a moderate slope at 50-250 μg/m3, and a plateau at concentrations higher than 250 μg/m3. Compared with days with PM2.5 up to 15 μg/m3, days with PM2.5 of 15-25, 25-35, 35-75, and 75 μg/m3 or more were significantly associated with increases in cardiovascular admissions of 1.1% (0 to 2.2%), 1.9% (0.6% to 3.2%), 2.6% (1.3% to 3.9%), and 3.8% (2.1% to 5.5%), respectively.According to projections, achieving the Chinese grade 2 (35 μg/m3), Chinese grade 1 (15 μg/m3), and World Health Organization (10 μg/m3) regulatory limits for annual mean PM2.5 concentrations would reduce the annual number of admissions for cardiovascular disease in China. Assuming causality, which should be done with caution, this reduction would translate into an estimated 36 448 (95% confidence interval 24 441 to 48 471), 85 270 (57 129 to 113 494), and 97 516 (65 320 to 129 820), respectively.

Conclusions These data suggest that in China, short term exposure to PM2.5 is associated with increased hospital admissions for all major cardiovascular diseases except for haemorrhagic stroke, even for exposure levels not exceeding the current regulatory limits.

DOI: 10.1136/bmj.l6572

Source: https://www.bmj.com/content/367/bmj.l6572