Associations between Different Ozone Indicators and Cardiovascular Hospital Admission: A Time-Stratified Case-Crossover Analysis in Guangzhou, China.

Epidemiological studies reported that ozone (O) is associated with cardiovascular diseases. However, only few of these studies examined the impact of multiple O indicators on cardiovascular hospital admissions. This study aimed to explore and compare the impacts of different O indicators on cardiovascular hospital admissions in Guangzhou, China. Based upon the data on daily cardiovascular hospital admissions, air pollution, and meteorological factors in Guangzhou from 2014 to 2018, a time-stratified case-crossover design model was used to analyze the associations between different O indicators and cardiovascular hospital admissions. Moreover, the sensitivities of different age and gender groups were analyzed for the whole year and different seasons (i.e., warm and cold). During the warm season, for the single-pollutant model, the odds ratio (OR) value of cardiovascular hospital admissions was 1.0067 (95% confidence interval (CI): 1.0037, 1.0098) for every IQR increase in MDA8 O at a lag of five days. The effect of O on people over 60 year was stronger than that on the 15-60 years age group. Females were more sensitive than males to O exposure. These results provided valuable references for further scientific research and environmental improvement in Guangzhou. Given that short-term O exposure poses a threat to human health, the government should therefore pay attention to prevention and control policies to reduce and eliminate O pollution and protect human health.