Department of Public Health, School of Social Sciences, Humanities and Arts, Health Science Research Institute, University of California, 5200 N Lake Rd, 95343, Merced, CA, USA.
Department of Management of Complex Systems, School of Engineering, University of California, Merced, USA.
Environ Res. 2024 Jul 1;252(Pt 4):119094. doi: 10.1016/j.envres.2024.119094. Epub 2024 May 7.
Climate change continues to increase the frequency, intensity, and duration of heat events and wildfires, both of which are associated with adverse pregnancy outcomes. Few studies simultaneously evaluated exposures to these increasingly common exposures.
We investigated the relationship between exposure to heat and wildfire smoke and preterm birth (PTB).
In this time-stratified case-crossover study, participants consisted of 85,806 California singleton PTBs (20-36 gestational weeks) from May through October of 2015-2019. Birthing parent ZIP codes were linked to high-resolution daily weather, PM from wildfire smoke, and ambient air pollution data. Heat day was defined as a day with apparent temperature >98th percentile within each ZIP code and heat wave was defined as ≥2 consecutive heat days. Wildfire-smoke day was defined as a day with any exposure to wildfire-smoke PM. Conditional logistic regression was used to calculate the odds ratio (OR) and 95% confidence intervals (CI) comparing exposures during a hazard period (lags 0-6) compared to control periods. Analyses were adjusted for relative humidity, fine particles, and ozone.
Wildfire-smoke days were associated with 3.0% increased odds of PTB (OR: 1.03, CI: 1.00-1.05). Compared with white participants, associations appeared stronger among Black, Hispanic, Asian, and American Indians/Alaskan Native participants. Heatwave days (OR: 1.07, CI: 1.02-1.13) were positively associated with PTB, with stronger associations among those simultaneously exposed to wildfire smoke days (OR: 1.19, CI: 1.11-1.27). Similar findings were observed for heat days and when other temperature metrics (e.g., maximum, minimum) were used.
Heat and wildfire increased PTB risk with evidence of synergism. As the occurrence and co-occurrence of these events increase, exposure reduction among pregnant people is critical, especially among racial/ethnic minorities.
气候变化持续增加了热浪和野火事件的频率、强度和持续时间，这两者都与不良妊娠结局有关。很少有研究同时评估这些日益常见的暴露。
我们研究了暴露于热浪和野火烟雾与早产（PTB）之间的关系。
在这项时间分层病例交叉研究中，参与者包括 2015 年至 2019 年 5 月至 10 月期间加利福尼亚州的 85806 名单胎 PTB（20-36 孕周）。分娩父母的邮政编码与高分辨率每日天气、野火烟雾中的 PM 以及环境空气污染数据相关联。热天定义为每个邮政编码内表观温度>第 98 百分位数的一天，热浪定义为≥2 天连续热天。野火烟雾天定义为暴露于野火烟雾 PM 的任何一天。使用条件逻辑回归计算了在危险期（滞后 0-6）与对照期相比暴露时的比值比（OR）和 95%置信区间（CI）。分析调整了相对湿度、细颗粒物和臭氧。
野火烟雾天与 PTB 的几率增加 3.0%相关（OR：1.03，CI：1.00-1.05）。与白人参与者相比，在黑人、西班牙裔、亚洲人和美洲印第安人/阿拉斯加原住民参与者中，相关性似乎更强。热浪天（OR：1.07，CI：1.02-1.13）与 PTB 呈正相关，同时暴露于野火烟雾天的相关性更强（OR：1.19，CI：1.11-1.27）。在暴露于热天和使用其他温度指标（例如，最高温度、最低温度）时也观察到了类似的发现。
热浪和野火增加了 PTB 的风险，且存在协同作用的证据。随着这些事件的发生和同时发生的增加，减少孕妇的暴露非常重要，尤其是在少数族裔中。
