Background

Unfavorable associations between air pollution and myocardial infarction are broadly investigated in recent studies and some of them revealed considerable associations; however, controversies exists between these investigations with regard to culprit components of air pollution and significance of correlation between myocardial infarction risk and air pollution.

Methods

The association between exposure to PM₁₀, PM_2.5, ozone, carbon monoxide, sulfur dioxide, and nitrogen dioxide concentration of background air that residents of Tehran, the capital city of Iran, which is ranked as the most air polluted city of Iran and the relative risk of developing ST-elevation myocardial infarction (STEMI) were investigated by a case-crossover design. Our study included 208 patients admitted with a diagnosis of STEMI and undergone primary percutaneous intervention. Air pollutant concentration was averaged in 24-h windows preceding the time of onset of myocardial infarction for the case period. Besides, the mean level of each element of air pollution of the corresponding time in one week, two weeks and three weeks before onset of myocardial infarction, was averaged separately for each day as one control periods. Thus, 624 control periods were included in our investigation such that. Each patient is matched and compared with him/herself.

Results

The mean level of PM₁₀ in case periods (61.47 µg/m³) was significantly higher than its level in control periods (57.86 µg/m³) (P-value = 0.019, 95% CI: 1.002–1.018, RR = 1.010). Also, the mean level of PM_2.5 in case periods (95.40 µg/m³) was significantly higher than that in control days (90.88 µg/m³) (P-value = 0.044, 95% CI: 1.001–1.011, RR = 1.006). The level of other components including NO₂, SO₂, CO and O₃ showed no significant differences between case and control periods. A 10 µg/m³ increase in PM₁₀ and PM_2.5 would result in 10.10% and 10.06% increase in STEMI event, respectively. Furthermore, the results of sub-group analysis showed that older patients (equal or more than 60 year-old), diabetic patients, non-hypertensive ones and patients with more than one diseased vessel may be more vulnerable to the harmful effect of particular matters including PM₁₀ and PM_2.5 on development of STEMI.

Conclusion

Air pollution is a worldwide pandemic with great potential to cause terrible events especially cardiovascular ones. PM_2.5 and PM₁₀ are amongst ambient air pollutant with a high risk of developing STEMI. Thus, more restrictive legislations should be applied to define a safe level of indoor and outdoor air pollutant production.

中文翻译：

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暴露于包括PM ₁₀，PM _2.5，臭氧，一氧化碳，二氧化硫和二氧化氮浓度的空气污染物与发生STEMI的相对风险之间的关联：案例交叉设计

背景

在最近的研究中，广泛研究了空气污染与心肌梗死之间的不利联系，其中一些揭示了相当大的联系。然而，这些研究之间存在着关于空气污染的罪魁祸首以及心肌梗塞风险与空气污染之间相关性的重要性的争论。

方法

暴露于PM ₁₀和PM _2.5之间的关联，伊朗首都德黑兰的居民的背景空气中的臭氧，一氧化碳，二氧化硫和二氧化氮的浓度，该城市被列为伊朗空气污染最严重的城市，并且发展为ST抬高型心肌梗塞的相对风险（ STEMI）通过案例交叉设计进行了研究。我们的研究包括208例确诊为STEMI并接受了初次经皮介入治疗的患者。在此期间，在心肌梗塞发作之前的24小时内，空气污染物的浓度取平均值。此外，将心肌梗塞发作前一周，两周和三周的相应时间的空气污染各要素的平均水平每天作为一个对照期分别进行平均。因此，我们的调查包括了624个控制期。每个患者都被匹配并与他/她自己进行比较。

结果

病例期间PM ₁₀的平均水平（61.47 µg / m ³）显着高于对照期间PM ₁₀的平均水平（57.86 µg / m ³）（P值= 0.019，95％CI：1.002–1.018，RR = 1.010 ）。另外，病例期间PM _2.5的平均水平（95.40 µg / m ³）显着高于对照日（90.88 µg / m ³）（P值= 0.044，95％CI：1.001–1.011，RR = 1.006）。病例期和对照期之间其他成分的含量（包括NO ₂，SO ₂，CO和O _3）没有显着差异。PM ₁₀和PM _2.5增加10 µg / m ³将分别导致STEMI事件增加10.10％和10.06％。此外，亚组分析的结果表明，老年患者（等于或大于60岁），糖尿病患者，非高血压患者以及血管多于一个的患者可能更容易受到特定物质的有害影响包括STEMI开发中的PM ₁₀和PM _2.5。

结论

空气污染是一种全球性流行病，极有可能引起可怕的事件，尤其是心血管事件。PM _2.5和PM ₁₀属于环境空气污染物，极有可能发展为STEMI。因此，应采用更严格的法规来定义室内和室外空气污染物产生的安全水平。