Short-term effects of ambient ozone exposure on daily hospitalizations for circulatory diseases in Ganzhou, China: A time-series study

Adverse health effects of ambient ozone are getting widespread attention, but the evidence on the relationship between ozone levels and circulatory system diseases are limited and inconsistent. Daily data for ambient ozone levels and hospitalizations for total circulatory diseases and five subtypes in Ganzhou, China from January 1, 2016 to December 31, 2020 were collected. We constructed a generalized additive model with quasi-Poisson regression accounting for lag effects to estimate the associations between ambient ozone levels and the num-ber of hospitalized cases of total circulatory diseases and five subtypes. The differences among gender, age, and season subgroups were furtherly assessed through stratified analysis. A total of 201,799 hospitalized cases of total circulatory diseases were included in the present study, including 94,844 hypertension (HBP), 28,597 coronary heart disease (CHD), 42,120 cerebrovascular disease (CEVD), 21,636 heart failure (HF), and 14,602 arrhythmia. Significantly positive associations were observed between ambient ozone levels and daily hospi-talizations for total circulatory diseases and all subtypes except arrhythmia. Each 10 mu g/m3 increase in ozone concentration, the risk of hospitalizations for total circulatory diseases, HBP, CHD, CEVD, and HF increased by 0.718% (95% confidence interval, 0.156%-1.284%), 0.956% (0.346%-1.570%), 0.499% (0.057%-0.943%), 0.386% (0.025%-0.748%), and 0.907% (0.118%-1.702%), respectively. The above associations remained significant after adjusting for other air pollutants. The risk of hospitalization for circulatory diseases was higher in warm season (May to October) and varied in gender and age subgroups. This study suggested that short-term exposure to ambient ozone may increase the risk of hospitalizations for circulatory diseases. Our findings reinforce the importance of reducing ambient ozone pollution levels for protecting public health.