Background Non-occupational carbon monoxide (CO) poisoning is a public health problem that seriously affect people’s health and lives. Objective To describe the prevalence of non-occupational CO poisoning during 2007—2018 in Shanghai, analyze its epidemiological characteristics and potential influencing factors, and explore effective prevention and control measures. Methods Daily reported non-occupational CO poisoning cases and meteorological factors from 2007 to 2018 were collected in Shanghai, epidemiological characteristics were analyzed by descriptive epidemiology methods, and a distributed lag nonlinear model was used to assess the association between temperature and non-occupational CO poisoning. Results A total of 2264 non-occupational CO poisoning events and 3866 cases from 2007 to 2018 were reported in Shanghai, including 59 death cases. More than half of the poisoning cases were female (56.3%), and young adults accounted for more cases than any other age group (54.8%). The poisoning events mainly occurred in winter (from December to next February); however, cases reported in summer increased in recent years. The peak period of the events was from 20:00 to 24:00. Households (85.2%) and restaurants (8.0%) were the common places of non-occupational CO poisoning events, and the main cause was improper use of gas water heater (36.9%). A nonlinear curve was found between daily average temperature of current day and the occurrence of non-occupational CO poisoning. Temperature was negatively associated with the risk of non-occupational CO poisoning when the temperature was lower than 9.6 ℃, while a positive association was found during 9.7-26.0 ℃. Conclusion Winter is a high season for non-occupational CO poisoning in Shanghai, rising cases reported in summer is also worthy of attention. Supervision should be strengthened to ban sales of unqualified gas water heaters, and health education on CO poisoning prevention and control should be conducted through multiple channels, in order to reduce the incidence of CO poisoning.

Background The substantial health damage attributed to heat waves, along with their increasing intensity and frequency in the context of global warming, highlights the importance of exploring the health effects of heat waves. Objective To calculate the excess heat stroke cases during heat waves in the summer of 2013—2023 in Shanghai, analyze the association between heat waves and heat stroke, and to further explore the modifying effects of heat wave characteristics on heat stroke. Methods Using a retrospective ecological study design, data on heat stroke cases were collected from the heat stroke case reporting system of the Chinese Center for Disease Control and Prevention, and concurrent meteorological data from Xujiahui Meteorological Station. A heat wave was defined as at least 3 consecutive days with daily maximum temperature meeting or exceeding 35 ℃ in this study, excess heat stroke cases related to heat waves were assessed as the difference between the numbers of heat stroke cases observed on a given day and the corresponding 31 d (15 d before and after that day) moving average, and statistical analyses using generalized linear model based on time series study were performed to assess the impact of heat waves on heat stroke. Results Overall 25 heat waves during the study period were observed, leading to a total of estimated 792.6 extra heat stroke cases. The risk of heat stroke significantly increased during heat waves (RR=2.60, 95%CI: 2.08, 3.26), but no statistically significant differences in heat wave effects were observed among different genders, ages, or regions. In terms of the timing of heat waves, the risk of heat stroke was highest during the first heat wave (RR=3.58, 95%CI: 2.82, 4.55), which was significantly higher than that during the second heat wave (RR=2.19, 95%CI: 1.66, 2.90), and no significant effect was observed during the third or subsequent heat waves. The impact of heat waves on heat stroke persisted for more than 4 d, with the risk higher on the fourth day and beyond (RR=2.95, 95%CI: 2.28, 3.83), significantly higher than on the first day of heat wave (RR=1.74, 95%CI: 1.18, 2.56). Conclusion Heat waves had a substantial effect on heat stroke in Shanghai from 2013 to 2023, and special attention need to be paid to heat waves with early onset and long duration.