Effect of heat waves on non-accidental death among residents in Daxing district, Beijing, China, 2016—2022

Objective To assess the effect of heat waves on non-accidental death among residents in Daxing district.

Methods The daily meteorological data and the daily death data of Daxing district, Beijing from May to September in 2016—2022 were collected. Heat waves were defined as durations of threshold temperatures (the 90th, 92.5th and 95th percentiles of daily mean temperature) for two to four days, abbreviated as HW1-HW9. A time-stratified case-crossover design combined with a distributed lag nonlinear model (DLNM) was used to quantitatively analyze the effect of heat waves on non-accidental death among residents.

Results At a lag of 0-7 days, HW1-HW9 could increase the risk of non-accidental death among residents. Notably, HW4 (with a threshold temperature at the 92.5th percentile for a duration of ≥2 days) was associated with an increased risk of non-accidental death, with a risk ratio (RR) (95% confidence interval CI) of 1.50 (1.28, 1.76). Heat waves exhibited significant effects on populations aged 65-74 years and those aged ≥75 years, with RRs (95%CI) of 1.64 (1.17, 2.30) and 1.48 (1.20, 1.83), respectively. Heat waves also significantly impacted non-accidental death in both genders, with RRs (95% CI) of 1.62 (1.28, 2.06) for females and 1.41 (1.14, 1.75) for males. The most significant effect on the non-accidental death of residents was seen with HW9 (with a threshold temperature at the 95th percentile for a duration of ≥4 days), with an RR (95%CI) of 1.76 (1.29, 2.39). Heat waves had a significant effect on non-accidental death across all age groups: ≤64 years (RR=2.08, 95%CI: 1.05-4.14), 65-74 years (RR=2.12, 95%CI: 1.12-4.03), and ≥75 years (RR=1.54, 95%CI: 1.04-2.28). Heat waves also showed a significant effect on females (RR=2.19, 95%CI: 1.40-3.41).

Conclusion Heat waves increase the risk of death among residents in Daxing district, Beijing, with the elderly (≥65 years) and females being the most vulnerable populations. When temperatures exceed higher thresholds for prolonged durations (≥4 days), the risk of non-accidental death is greater.