This study evaluated whether short term exposures to NO2, O3, particulate matter <10 mm in diameter (PM10) were associated with higher risk of mortality. A total of 223,287 hypertensive patients attended public health-care services and newly prescribed at least 1 antihypertensive agent were followed-up for up to 5 years. A time-stratified, bi-directional case-crossover design was adopted. For all-cause mortality, significant positive associations were observed for NO2 and PM10 at lag 0-3 days per 10 μg/m(3) increase in concentration (excess risks 1.187%-2.501%). Significant positive associations were found for O3 at lag 1 and 2 days and the excess risks were 1.654% and 1.207%, respectively. We found similarly positive associations between these pollutants and respiratory disease mortality. These results were significant among those aged ≥65 years and in cold seasons only. Older hypertensive patients are susceptible to all-cause and respiratory disease-specific deaths from these air pollutants in cold weather.
Keywords: Air pollutants; Case-crossover; Hypertension; Mortality; Particulate matter.
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