Association between Air Pollutants and Cardiovascular Disease Mortality in Wuhan, China

We examined the associations of daily mean concentrations of ambient air pollutants (particulate matter (PM(10)), sulfur dioxide (SO(2)), nitric oxide (NO(2))) and daily cardiovascular diseases (CVD) mortality in Wuhan, China using a case-crossover design to analyze four years of data (2006–2009) collected from the Hubei Provincial Center for Disease Control and Prevention and the Wuhan Environmental Protection Bureau. From 2006 to 2009, daily average concentrations of PM(10), SO(2) and NO(2) were 115.60 µg/m(3), 53.21 µg/m(3) and 53.08 µg/m(3), respectively. After adjusting for temperature and relative humidity, a 10 µg/m(3) increase in SO(2) and NO(2) over a 24-h period was associated with CVD mortality relative risk (R.R.) of 1.010 (95% CI: 1.000, 1.020) for SO(2) and 1.019 (95% CI: 1.005, 1.033) for NO(2), but there was no significant association between increases in PM(10) and mortality. Subgroup analysis on by gender showed a significant association of 1.026 (95% CI: 1.007, 1.045) between NO(2) and CVD among males, while no significant statistical effect was shown among females. Subgroup analysis by age showed that for those older than 65 years, every 10 µg/m(3) increase in NO(2) was associated with a 1.6% (95% CI: 0.1%, 3.1%) increase in CVD mortality. Subgroup analysis on different types of CVD showed that every 10 µg/m(3) increase in PM(10) and SO(2) were significantly associated with an approximately 1.012 (95% CI: 1.002, 1.022) and 1.021 (95% CI: 1.002, 1.040) increase, respectively, in ischemic heart disease (ICH) mortality. In conclusion, exposure to NO(2) is significantly associated with CVD mortality. Larger, multi-center studies in Chinese cities are being currently conducted to validate these findings.