Curtin School of Population Health, Curtin University, Perth, Kent Street, Bentley, Western Australia 6102, Australia; Education, Culture, and Health Opportunities (ECHO) Ghana, ECHO Research Group International, Aflao, Ghana.
Curtin School of Population Health, Curtin University, Perth, Kent Street, Bentley, Western Australia 6102, Australia; School of Public Health, University of Adelaide, Adelaide, South Australia 5000, Australia.
Sci Total Environ. 2022 Aug 25;836:155750. doi: 10.1016/j.scitotenv.2022.155750. Epub 2022 May 6.
The extreme thermal environment driven by climate change disrupts thermoregulation in pregnant women and may threaten the survival of the developing fetus.
To investigate the acute effect of maternal exposure to thermophysiological stress (measured with Universal Thermal Climate Index, UTCI) on the risk of stillbirth and modification of this effect by sociodemographic disparities.
We conducted a space-time-stratified case-crossover analysis of daily UTCI and 2835 singleton stillbirths between 1st January 2000 and 31st December 2015 across multiple small areas in Western Australia. Distributed lag non-linear models were combined with conditional quasi-Poisson regression to investigate the effects of the UTCI exposure from the preceding 6 days to the day of stillbirth. We also explored effect modification by fetal and maternal sociodemographic factors.
The median UTCI was 13.9 °C (representing no thermal stress) while the 1st and 99th percentiles were 0.7 °C (slight cold stress) and 31.7 °C (moderate heat stress), respectively. Relative to median UTCI, we found positive associations between acute maternal cold and heat stresses and higher risks of stillbirth, increasing with the intensity and duration of the thermal stress episodes. The cumulative risk from the preceding 6 days to the day of stillbirth was stronger in the 99th percentile (RR = 1.19, 95% CI: 1.17, 1.21) than the 1st percentile (RR = 1.14, 95% CI: 1.12, 1.15), relative to the median UTCI. The risks were disproportionately higher in term and male stillborn fetuses, smoking, unmarried, ≤19 years old, non-Caucasian, and low socioeconomic status mothers.
Acute maternal exposure to both cold and heat stresses may contribute to the risk of stillbirth and be exacerbated by sociodemographic disparities. The findings suggest public health attention, especially for the identified higher-risk groups. Future studies should consider the use of a human thermophysiological index, rather than surrogates such as ambient temperature.
气候变化导致的极端热环境扰乱了孕妇的体温调节，可能威胁到胎儿的生存。
研究母体暴露于热生理应激（以通用热气候指数 UTCI 衡量）对死产风险的急性影响，并探讨社会人口差异对此影响的修饰作用。
我们对 2000 年 1 月 1 日至 2015 年 12 月 31 日期间，西澳大利亚多个小地区的 2835 例单胎死产病例和 2835 例对照进行了时空分层病例交叉分析。分布式滞后非线性模型与条件准泊松回归相结合，以研究前 6 天至死产日 UTCI 暴露的影响。我们还探讨了胎儿和产妇社会人口因素的修饰作用。
中位数 UTCI 为 13.9°C（表示无热应激），第 1 和第 99 百分位数分别为 0.7°C（轻度冷应激）和 31.7°C（中度热应激）。与中位数 UTCI 相比，我们发现母体急性冷应激和热应激与死产风险增加之间存在正相关关系，且随着热应激事件的强度和持续时间的增加而增加。从前 6 天到死产日的累积风险在前 99 百分位（RR=1.19，95%CI：1.17，1.21）比第 1 百分位（RR=1.14，95%CI：1.12，1.15）更高，相对中位数 UTCI。在足月和男性死产胎儿、吸烟、未婚、≤19 岁、非白人和社会经济地位较低的母亲中，风险更高。
母体急性暴露于冷应激和热应激都可能导致死产风险增加，并且会因社会人口差异而加剧。研究结果表明，应引起公共卫生关注，特别是针对已确定的高风险群体。未来的研究应考虑使用人体热生理指数，而不是替代指标（如环境温度）。
