REVIEW article
Front. Public Health
Sec. Environmental Health and Exposome
Ambient temperature and ozone exposure increase the risk of preterm birth in Northern China: A time series analysis
Provisionally accepted
- Harbin Medical University, Harbin, China
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Background: Prenatal exposure to meteorological factors and air pollutants may increase preterm birth (PTB) risk, but existing research is limited and inconsistent. Heilongjiang Province is located in northeastern China and is the northernmost and highest latitude province. Yet the association between meteorological factors, air pollutants, and PTB in this region remains unclear. Methods: PTB cases were collected between July 1, 2019, and June 30, 2023. Meteorological factors were collected for the same period. The exposure-response relationships and lagged effects of meteorological factors and air pollutants on PTB were analyzed using the Distributed Lag Non-linear Model (DLNM), with a maximum lag of 30 days. Results: A total of 3267 PTB cases were included. Low and extremely low ambient temperatures were associated with an increased risk of PTB at lag day 20 (RR=1.09, 95% CI: 1.01-1.18 and RR=1.09, 95% CI: 1.02-1.16, respectively). In contrast, extremely high ambient temperatures were associated with an increased risk of PTB at lag day 0 (RR=1.12, 95% CI: 1.00-1.25). An extremely high Humidex was associated with an increased risk of PTB at lag day 0 (RR=1.15, 95% CI: 1.01– 1.30). For ozone, each IQR increase (27.8 μg/m³) was associated with an increased risk of PTB, with the highest risk observed at lag day 0 (RR=1.08, 95% CI: 1.01-1.15). Conclusions: This study indicated that extreme temperatures, as well as an extremely high Humidex and increased ozone concentrations, may be associated with an increased risk of PTB, with significant lag effects.
Keywords: Preterm Birth, ambient temperature, Humidex, Ozone, Distributed Lag non-linear mode
Received: 25 Sep 2025; Accepted: 21 Nov 2025.
Copyright: © 2025 Geng, Yuan, Li, Wu, Xu, Sun, Zhang, Tao and Zhao. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence:
Song Tao, shutiao1981@sina.com
Yan Zhao, amyzhaosb@163.com
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