Author + information
We explore the acute effects of temperature and air pollution on the number of daily outpatient and emergency department visits of cardiovascular diseases in shanghai.
The air pollution data, temperature data and outpatient and emergency department visits of cardiovascular diseases data were collected between January 2013 and December 2014 in Shanghai, China. Poisson regression models incorporating natural spline smooth functions (generalized linear models, GLM) were used to adjust for long-term, seasonal trends and weekend effect, public holiday, as wells as other confounding factors. The associations among particulate air pollution and the number of cardiovascular diseases stratified by temperature were identified.
A total of 9, 906, 835 hospital patients of cardiovascular diseases were identified during study period. The primary pollutants were PM2.5, PM10, SO2 and NO2, and their average daily concentrations were 56.3 μg/m3, 76 μg/m3, 20.6 μg/m3 and 46.7 μg/m3, respectively. Cardiovascular incidence showed an association with temperature, the relative risks (RR) of cardiovascular incidence is 1.016 (95% CI: 1.013, 1.018) (-18°C versus 18°C). Significant correlations were showed between hospital patients and concentrations of each primary pollutant, respectively. In warm-season, with a 10-μg/m3 increase in concentrations of PM2.5, PM10, SO2 or NO2, percentages of outpatient and emergency patient of cardiovascular diseases increased by 0.502% (95% CI: 0.464%, 0.545%), 0.251% (95% CI: 0.221%, 0.282%), 2.716% (95% CI: 2.558%, 2.874%), 1.496% (95% CI: 1.421%, 1.571%), respectively. In those cold-season, the corresponding values were 0.543%(95% CI: 0.521%,0.570%), 0.568% (95% CI: 0.548%, 0.587%), 1.607%(95%CI:1.528%,1.685%), 1.923%(95%CI: 1.868%, 1.978%), respectively. Furthermore, each primary pollutant had different lag effect on hospital patients.
Low temperature increased daily numbers of hospital patients of cardiovascular diseases; Daily numbers of hospital patients increased with the increases in concentrations of daily primary air pollutants after adjusting some confounding factors.