Association between air pollution and cardiovascular mortality in Hefei, China: A time-series analysis

In recent years, air pollution has become an alarming problem in China. However, evidence on the effects of air pollution on cardiovascular mortality is still not conclusive to date. This research aimed to assess the short-term effects of air pollution on cardiovascular morbidity in Hefei, China. Data of air pollution, cardiovascular mortality, and meteorological characteristics in Hefei between 2010 and 2015 were collected. Time-series analysis in generalized additive model was applied to evaluate the association between air pollution and daily cardiovascular mortality. During the study period, the annual average concentration of PM_10, SO₂, and NO₂ was 105.91, 20.58, and 30.93 μg/m³, respectively. 21,816 people (including 11,876 man, and 14,494 people over 75 years of age) died of cardiovascular diseases. In single pollutant model, the effects of multi-day exposure were greater than single-day exposure of the air pollution. For every increase of 10 μg/m³ in SO₂, NO₂, and PM₁₀ levels, CVD mortality increased by 5.26% (95%CI: 3.31%-7.23%), 2.71% (95%CI: 1.23%-4.22%), and 0.68% (95%CI: 0.33%-1.04%) at a lag03, respectively. The multi-pollutant models showed that PM₁₀ and SO₂ remained associated with CVD mortality, although the effect estimates attenuated. However, the effect of NO₂ on CVD mortality decreased to statistically insignificant. Subgroup analyses further showed that women were more vulnerable than man upon air pollution exposure. These findings showed that air pollution could significantly increase the CVD mortality.