A time series analysis of effects of diurnal temperature range on children with bronchopneumonia in Huzhou, 2014–2019

Background In the context of global warming, the impact of meteorological factors on human health has gradually become a research hotspot at home and abroad.

Objective To describe the distribution of children's bronchopneumonia in Huzhou City, and explore the influence of diurnal temperature range (DTR) on children with bronchopneumonia, so as to provide guidance for identifying vulnerable populations and developing targeted measures.

Methods A distributed lag nonlinear model (DLNM) was used to explore the potential nonlinear lag effect of DTR on admission of children with bronchopneumonia in Huzhou City from 2014 to 2019. Then a generalized additive model (GAM) was used to calculate the hospital admission risk of exposure to DTR in total population and sex-, age-, season-stratified populations.

Results A total of 17658 hospitalized children with bronchopneumonia were included in the study. When DTR exceeded 7.5 ℃, the relative risk rose abruptly. When DTR reached 17 ℃, the risk of admission to hospital of children with bronchopneumonia was the greatest. In terms of the single-day lag effect, the admission risk of DTR for bronchopneumonia in children began on the same day and persisted until lag day 2; it peaked on the same day, and RR was 1.353 (95%CI: 1.220-1.502). The cumulative lag effect occurred from lag0 to lag0-6, and the highest RR value was at lag0-3, which was 1.938 (95%CI:1.483-2.533). The results of stratified analysis showed that the maximum effect values for boys and girls appeared at lag0-3 (RR_boys=2.301, 95%CI: 1.671-3.169) and lag0-2(RR_girls=1.566, 95%CI: 1.152-2.129) respectively, and the effect value and duration of DTR in boys were higher and longer than those in girls. Among different age groups, both children of 0-3 years old and 4-14 years old had the maximum effect value at lag 0-3, the RR values were 1.734 (95%CI: 1.454-2.572) and 1.998 (95%CI: 1.226-2.254) respectively, and the effect value and duration of DTR on the children of 4-14 years old were higher and longer than those of the children of 0-3 years old. As to seasons, no significant increase was found in cumulative effect in summer and autumn (P>0.05); in winter and spring, the maximum effect value appeared at lag0-10, and the RR value was 4.164 (95%CI:1.191-14.561).

Conclusion The impact of DTR on bronchopneumonia in children is acute. Boys and children aged 4-14 years old are more sensitive to DTR changes. Therefore, we should be alert to severe DTR changes and take protective measures in advance