Ambient Air Pollutants and Acute Case-Fatality of Cerebro-Cardiovascular Events: Takashima Stroke and AMI Registry, Japan (1988–2004)

Abstract

Background: 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. Methods: 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 (SO₂), nitrogen dioxide (NO₂), 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. Results: 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/m³, SO₂ 3.9 ppb, NO₂ 16.0 ppb, and Ox 28.4 ppb. Among the pollutants, higher levels of NO₂ showed increased fatality risk. In multi-pollutant model, the highest quartile of NO₂ was associated with 60% higher stroke case-fatality risk in comparison to lowest quartile of NO₂. 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. Conclusion: We observed association between NO₂ 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.

Ambient Air Pollution and Stroke

“…Several studies reported associations between short-term exposure to particle matter, including several size fractions, or gases and any stroke mortality. Only a few studies further characterized stroke into ischemic and hemorrhagic stroke mortality 24, 33–35, 38 . Short-term exposure to particulate matter and gases were associated with both ischemic stroke and hemorrhagic stroke.…”

Acute and recent air pollution exposure and cardiovascular events at labour and delivery

“…[2][3][4][5][6][7][8][9][10][11] Our results were most robust for NO x , which remained associated with cardiovascular event risk even after accounting for unmeasured confounders and even showed some association after adjusting for other pollutants. However, we note that while performing multipollutant analyses is common practice within environmental epidemiology, the results should be interpreted cautiously, as the interpretation requires holding all other pollutants fixed, which may not be realistic for teasing out the 'independent' pollutant effect.…”

“…1 Increased risk of non-fatal cardiovascular or cerebrovascular events is seen with exposure to particulate matter with aerodynamic diameter <10 μm (PM 10 ) and <2.5 μm (PM 2.5 ), nitrogen oxide (NO x ), ozone, carbon monoxide (CO) and sulfur dioxide (SO 2 ). [2][3][4][5][6][7][8][9][10][11] Some subpopulations may be particularly sensitive to air pollution exposure, such as the elderly, diabetics and persons with obesity or existing cardiac disease. 12 13 Given the physiological changes in pregnancy, including increased oxygen requirements and cardiac output, elevation in plasma volume, changes in vascular resistance and blood pressure, hypercoagulability and higher risk of acute myocardial infarcts, 14 15 we hypothesise that air pollution may be associated with increased risk for maternal cardiovascular events during or immediately after labour and delivery.…”

Associations between Temperature and Hospital Admissions for Subarachnoid Hemorrhage in Korea

“…Many studies have evaluated risk factors for SAH, and the risk factors of age, female sex, hypertension, and tobacco use are supported by strong evidence [4,5]. In addition, genetic predisposition and alcohol and drug abuse are the most commonly discussed risk factors [6,7,8,9,10,11,12,13,14,15,16,17,18]. However, whether or not seasonal or meteorological factors influence SAH is still a matter of debate.…”