[Association between ambient air pollution and stroke mortality in Wuhan, China: A time-series analysis]

Using time-series analyses to determine the association between ambient air pollution and stroke mortality in Jiang'an District of Wuhan, China from 2003 to 2010.

Data on daily stroke mortality for the period 2003 January 1 to 2010 December 31 was obtained from Jiang'an District Center for Disease Control and Prevention, Wuhan and data on relevant air pollution and meteorological factors from the local municipal environmental monitoring center and meteorology bureau of Wuhan, respectively. Application of a time-series analysis in generalized additive model was applied to evaluate the association between air pollution and stroke mortality.

Annual average concentrations of PM10, SO(2) and NO(2) during the study period were (115.0 ± 60.0), (50.2 ± 33.7), and (57.6 ± 25.3) µg/m³ respectively. The total stroke death was 9 204, including 4 495 women, and 7 628 people aged over 65-years old. In single-pollutant model, a 10 µg/m³ increase in previous day (lag 1 d) ambient pollutants was associated with 0.67% (95% CI: 0.25%-1.10%) excess risk in stroke mortality for PM10, 0.87% (95% CI: 0.13%-1.63%) excess risk for SO(2) and 2.07% (95% CI: 1.08%-3.07%) excess risk for NO(2), respectively. When co-pollutants were involved into the models, only NO(2) remained strongly associated with stroke mortality (β = 2.07, 95% CI: 1.08-3.07, P < 0.001). A 10 µg/m³, increase of NO(2) in lag 1 d was associated with 1.77% (95% CI: 0.54%-3.01%), 2.27% (95% CI: 0.98%-3.57%) and 2.00% (95% CI: 0.59%-3.43%) excess risk in stroke mortality, respectively, after adjusting for PM10, SO(2)th PM10 and SO(2) e-specific and gender-specific analyses showed that the association between ambient air pollution and stroke mortality was stronger in the elderly (≥ 65 years old) people and women. A 10 µg/m, increase of PM10, SO(2) NO(2) in lag 1 d was associated with excess stroke mortality of 0.97% (95% CI: 0.37%-1.57%), 1.73% (95% CI: 0.69%-2.78%) and 2.98% (95% CI: 1.59%-4.39%) for women, respectively and 0.94% (95% CI: 0.47%-1.42%), 1.06% (95% CI: 0.23%-1.90%) and 2.50% (95% CI: 1.40%-3.62%) for the elderly people (> 65 years old), respectively.

PM10 and gaseous pollutants (SO(2), NO(2)) were significant risk factors for acute stroke death, and people aged over 65-years old and women were more susceptible to the effect of ambient pollutants on stroke mortality.