Department of Medicine, University of Calgary, Calgary, Alta., Canada.
Cerebrovasc Dis. 2012;34(2):130-9. doi: 10.1159/000339680. Epub 2012 Aug 1.
Apart from the conventional risk factors, cerebro-cardiovascular disease (CVD) are also reported to be associated with air pollution, thus lowering the level of exposure might contribute in prevention activities to reduce the associated adverse outcomes. Though few studies conducted in Japan have reported on the CVD mortality but none have explored the effect of air pollutant exposure on the acute case-fatality of CVD. We investigated the effects of air pollution exposure on acute case-fatality of stroke and acute myocardial infarction (AMI) in a setting where pollutant levels are rather low.
We leveraged the data from the Takashima Stroke and AMI Registry, which covers a population of approximately 55,000 in Takashima County located in central Japan. The study period of 6,210 days (16 years, leap years also taken into account) were divided into quartiles of daily average pollutant concentration; suspended particulate matter (SPM), sulfur dioxide (SO(2)), nitrogen dioxide (NO(2)), and photochemical oxidants (Ox). The stroke and AMI events were categorized to corresponding quartiles based on the pollution levels of the onset day. To study the effects of air pollutants, we estimated the fatality rate ratio across quartiles of the pollutants where the lowest quartile served as the reference.
There were 307 (men: 153 and women: 154) fatal stroke cases within 28 days of onset among the 2,038 first ever stroke during 1988-2004. In the same period, there were 142 (men: 94 and women: 54) fatal AMI cases within 28 days of onset among the 429 first ever AMI events. The mean of the measured pollutant levels were as follows: SPM 26.9 µg/m(3), SO(2) 3.9 ppb, NO(2) 16.0 ppb, and Ox 28.4 ppb. Among the pollutants, higher levels of NO(2) showed increased fatality risk. In multi-pollutant model, the highest quartile of NO(2) was associated with 60% higher stroke case-fatality risk in comparison to lowest quartile of NO(2). In the fully adjusted model the fatality-rate ratio was 1.65 (95% CI 1.06-2.57). This association was more prominent among stroke subtype of cerebral infarction. Other pollutant levels did not show any association with stroke or AMI case-fatality.
We observed association between NO(2) levels, an index of traffic related air pollution, with the acute case-fatality of stroke, especially cerebral infarction in our study population. Further studies are needed in different regions to determine the association between ambient air pollutants and acute cardiovascular fatalities.
除了传统的危险因素外，据报道，脑血管疾病（CVD）也与空气污染有关，因此降低暴露水平可能有助于开展预防活动，以减少相关不良后果。尽管日本的一些研究报告了 CVD 死亡率，但没有研究探讨空气污染物暴露对 CVD 急性病例死亡率的影响。我们研究了在污染物水平相对较低的环境中，空气污染暴露对中风和急性心肌梗死（AMI）急性病例死亡率的影响。
我们利用了位于日本中部田岛县的田岛中风和 AMI 登记处的数据，该登记处覆盖了约 55000 人的人群。在 6210 天（16 年，包括闰年）的研究期间，我们将每日平均污染物浓度的四分位数；悬浮颗粒物（SPM）、二氧化硫（SO（2））、二氧化氮（NO（2））和光化学氧化剂（Ox）。根据发病当天的污染水平，将中风和 AMI 事件分类到相应的四分位区间。为了研究空气污染物的影响，我们估计了污染物四分位区间的死亡率比值，其中最低四分位区间作为参考。
在 1988-2004 年间，2038 例首发中风中，有 307 例（男性：153 例，女性：154 例）在发病后 28 天内死亡。同期，429 例首发 AMI 事件中，有 142 例（男性：94 例，女性：54 例）在发病后 28 天内死亡。测量的污染物水平平均值如下：SPM 26.9 µg/m（3）、SO（2）3.9 ppb、NO（2）16.0 ppb 和 Ox 28.4 ppb。在这些污染物中，较高水平的 NO（2）显示出更高的死亡风险。在多污染物模型中，与最低四分位的 NO（2）相比，最高四分位的 NO（2）与中风病例死亡率增加 60%相关。在完全调整的模型中，死亡率比值为 1.65（95%CI 1.06-2.57）。这种关联在脑梗死的中风亚型中更为明显。其他污染物水平与中风或 AMI 病例死亡率之间没有任何关联。
我们观察到在我们的研究人群中，NO（2）水平与交通相关空气污染指标与中风的急性病例死亡率之间存在关联，特别是脑梗死。需要在不同地区进行进一步的研究，以确定环境空气污染物与急性心血管死亡率之间的关联。
