von Klot Stephanie, Mittleman Murray A, Dockery Douglas W, Heier Margit, Meisinger Christa, Hörmann Allmut, Wichmann H-Erich, Peters Annette
Institute of Epidemiology, Helmholtz Zentrum München, German Research Center for Environmental Health, Neuherberg, Germany.
Eur Heart J. 2008 Aug;29(15):1881-8. doi: 10.1093/eurheartj/ehn235. Epub 2008 Jun 5.
Acute myocardial infarction (AMI) can be precipitated or triggered by discrete transient exposures including physical exertion. We evaluated whether the risk of having an AMI triggered by physical exertion exhibits an exposure-response relationship, and whether it varies by ambient temperature or by taking place indoors or outdoors.
We conducted a case-crossover study within the Myocardial Infarction Registry in Augsburg, Germany in 1999-2003. One thousand three hundred and one patients reported levels of activity and time spent outdoors on the day of AMI and three preceding days in an interview. The case-crossover analyses showed an association of physical exertion with AMI symptom onset within 2 h, which was strong for strenuous exertion (METs >or= 6) [relative risk (RR) 5.7, 95% confidence interval (CI) 3.6-9.0), and still significant for moderate exertion (METs = 5) (RR 1.6, 95% CI 1.2-2.1) compared to very light or no exertion. Strenuous exertion outside was associated with a four-fold larger RR of AMI symptom onset than exertion performed indoors, which was not explained by temperature.
This study confirms previous results and shows a graded exposure-response relationship between physical exertion intensity and triggering of AMI onset. These findings may have implications for behavioural guidance of people at risk of AMI.
急性心肌梗死（AMI）可由包括体力活动在内的离散短暂暴露诱发或触发。我们评估了由体力活动触发AMI的风险是否呈现暴露-反应关系，以及它是否因环境温度或在室内还是室外发生而有所不同。
我们于1999年至2003年在德国奥格斯堡的心肌梗死登记处进行了一项病例交叉研究。1301名患者在访谈中报告了急性心肌梗死当天及之前三天的活动水平和户外活动时间。病例交叉分析显示，体力活动与2小时内急性心肌梗死症状发作有关，剧烈体力活动（代谢当量≥6）时这种关联很强（相对风险[RR] 5.7，95%置信区间[CI] 3.6 - 9.0），与极轻度或无体力活动相比，中度体力活动（代谢当量 = 5）时仍具有显著意义（RR 1.6，95% CI 1.2 - 2.1）。在室外进行剧烈体力活动与急性心肌梗死症状发作的RR比在室内进行体力活动大四倍，这无法用温度来解释。
本研究证实了先前的结果，并显示了体力活动强度与急性心肌梗死发作触发之间存在分级暴露-反应关系。这些发现可能对急性心肌梗死高危人群的行为指导有影响。
