Department of Public Health and General Practice, Norwegian University of Science andTechnology, Håkon Jarls gate 11, Trondheim, Norway.
Am J Epidemiol. 2012 Jan 15;175(2):99-107. doi: 10.1093/aje/kwr404. Epub 2011 Dec 13.
Almost 10% of all births are preterm, and 2.2% are stillbirths. Recent research has suggested that environmental factors may be a contributory cause of these adverse birth outcomes. The authors examined the relation between ambient temperature and preterm birth and stillbirth in Brisbane, Australia, between 2005 and 2009 (n = 101,870). They used a Cox proportional hazards model with livebirth and stillbirth as competing risks. They also examined whether there were periods in pregnancy where exposure to high temperatures had a greater effect. Higher ambient temperatures in the last 4 weeks of the pregnancy increased the risk of stillbirth. The hazard ratio for stillbirth was 0.3 at 12°C relative to the reference temperature of 21°C. The temperature effect was greatest at less than 36 weeks of gestation. There was an association between higher temperature and shorter gestation, as the hazard ratio for livebirth was 0.96 at 15°C and 1.02 at 25°C. This effect was greatest at later gestational ages. These results provide strong evidence of an association between increased temperature and increased risk of stillbirth and shorter gestation.
近 10%的分娩为早产儿，2.2%的分娩为死产。最近的研究表明，环境因素可能是这些不良分娩结局的一个促成因素。作者在澳大利亚布里斯班（2005 年至 2009 年）检查了环境温度与早产和死产之间的关系（n = 101870）。他们使用竞争风险的 Cox 比例风险模型，将活产和死产作为竞争风险。他们还检查了怀孕期间是否存在高温暴露影响更大的时期。妊娠最后 4 周环境温度升高会增加死产的风险。与参考温度 21°C 相比，12°C 时死产的风险比为 0.3。在妊娠不足 36 周时，温度影响最大。较高的温度与较短的妊娠期之间存在关联，因为 15°C 时活产的风险比为 0.96，25°C 时风险比为 1.02。这种影响在较晚的妊娠年龄时最大。这些结果提供了强有力的证据，证明温度升高与死产和妊娠期缩短的风险增加之间存在关联。
