Lanki T, Hoek G, Timonen K L, Peters A, Tiittanen P, Vanninen E, Pekkanen J
National Public Health Institute (KTL), Environmental Epidemiology Unit, PO Box 95, FI-70701 Kuopio, Finland.
Occup Environ Med. 2008 Nov;65(11):782-6. doi: 10.1136/oem.2007.037531. Epub 2008 Jun 4.
To evaluate whether hourly changes in fine particle (PM(2.5), diameter<2.5 microm) exposure or outdoor particle concentrations are associated with rapid ischaemic responses.
41 non-smoking elderly people with coronary heart disease were followed up with biweekly clinic visits in Helsinki, Finland. The occurrence of ST segment depressions >0.1 mV was recorded during submaximal exercise tests. Hourly variations in personal PM(2.5) exposure and outdoor levels of PM(2.5) and ultrafine particles (<0.1 microm) were recorded for 24 h before a clinic visit. Associations between particulate air pollution and ST segment depressions were evaluated using logistic regression.
Both personal and outdoor PM(2.5) concentrations, but not outdoor ultrafine particle counts, were associated with ST segment depressions. The odds ratio (per 10 microg/m(3)) for personal PM(2.5) concentration during the hour preceding a clinic visit was 3.26 (95% CI 1.07 to 9.99) and for 4 h average outdoor PM(2.5) it was 2.47 (95% CI 1.05 to 5.85).
Even very short-term elevations in fine particle exposure might increase the risk of myocardial ischaemia. The precise mechanism is still unknown but could involve changes in autonomic nervous control of the heart.
评估细颗粒物（PM2.5，直径<2.5微米）暴露或室外颗粒物浓度的每小时变化是否与快速缺血反应相关。
在芬兰赫尔辛基，对41名非吸烟老年冠心病患者进行随访，每两周门诊就诊一次。在次极量运动试验期间记录ST段压低>0.1 mV的发生情况。在每次门诊就诊前24小时记录个人PM2.5暴露以及室外PM2.5和超细颗粒物（<0.1微米）水平的每小时变化。使用逻辑回归评估颗粒物空气污染与ST段压低之间的关联。
个人和室外PM2.5浓度均与ST段压低相关，但室外超细颗粒物计数与ST段压低无关。门诊就诊前一小时个人PM2.5浓度的优势比（每10微克/立方米）为3.26（95%可信区间1.07至9.99），4小时平均室外PM2.5的优势比为2.47（95%可信区间1.05至5.85）。
即使细颗粒物暴露的短期升高也可能增加心肌缺血风险。确切机制尚不清楚，但可能涉及心脏自主神经控制的变化。
