Department of Biostatistics, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.
Department of Epidemiology and Biostatistics, Drexel University, Philadelphia, PA, USA.
Am Heart J. 2018 Mar;197:94-102. doi: 10.1016/j.ahj.2017.11.007. Epub 2017 Nov 22.
Chronic exposure to fine particulate matter (PM) is accepted as a causal risk factor for coronary heart disease (CHD). However, most of the evidence for this hypothesis is based upon cohort studies in whites, comprised of either only males or females who live in urban areas. It is possible that many estimates of the effect of chronic exposure to PM on risk for CHD do not generalize to more diverse samples.
Therefore, we estimated the relationship between chronic exposure to PM and risk for CHD in among participants in the REasons for Geographic And Racial Differences in Stroke (REGARDS) cohort who were free from CHD at baseline (n=17,126). REGARDS is a sample of whites and blacks of both genders living across the continental United States. We fit Cox proportional hazards models for time to CHD to estimate the hazard ratio for baseline 1-year mean PM exposure, adjusting for environmental variables, demographics, and other risk factors for CHD including the Framingham Risk Score.
The hazard ratio (95% CI) for a 2.7-μg/m increase (interquartile range) 1-year mean concentration of PM was 0.94 (0.83-1.06) for combined CHD death and nonfatal MI, 1.13 (0.92-1.40) for CHD death, and 0.85 (0.73-0.99) for nonfatal MI. We also did not find evidence that these associations depended upon overall CHD risk factor burden.
Our results do not provide strong evidence for an association between PM and incident CHD in a heterogeneous cohort, and we conclude that the effects of chronic exposure to fine particulate matter on CHD require further evaluation.
慢性暴露于细颗粒物（PM）被认为是冠心病（CHD）的一个因果风险因素。然而，这一假设的大多数证据都是基于对居住在城市的白人男性或女性的队列研究得出的。许多关于慢性暴露于 PM 对 CHD 风险的估计可能不适用于更多样化的样本。
因此，我们在基线时无 CHD 的 REasons for Geographic And Racial Differences in Stroke（REGARDS）队列参与者中估计了慢性暴露于 PM 与 CHD 风险之间的关系（n=17,126）。REGARDS 是一个居住在美国大陆各地的白人和黑人群体的样本，包括两性。我们拟合了 Cox 比例风险模型来估计 CHD 发生时间，以估计基线 1 年平均 PM 暴露的风险比，同时调整了环境变量、人口统计学因素和其他 CHD 风险因素，包括弗雷明汉风险评分。
1 年平均 PM 浓度增加 2.7μg/m（四分位间距）时，综合 CHD 死亡和非致死性 MI 的风险比（95%CI）为 0.94（0.83-1.06），CHD 死亡的风险比为 1.13（0.92-1.40），非致死性 MI 的风险比为 0.85（0.73-0.99）。我们也没有发现这些关联取决于总体 CHD 风险因素负担的证据。
我们的结果没有为混杂队列中 PM 与新发 CHD 之间的关联提供有力证据，我们得出结论，慢性暴露于细颗粒物对 CHD 的影响需要进一步评估。
