Department of Epidemiology, Lazio Regional Health Service, Rome, Italy.
Department of Epidemiology, Lazio Regional Health Service, Rome, Italy.
Environ Int. 2016 Mar;88:153-159. doi: 10.1016/j.envint.2015.12.013. Epub 2016 Jan 4.
Environmental exposures have been linked to length of gestation but the question as to during which weeks of gestation pregnancies are most susceptible still remains little explored. We estimated the effect of maximum apparent temperature and air pollution levels on risk of birth by week of gestation.
We analyzed two cohorts of singleton live births in Rome (2001-2010) and Barcelona (2007-2012). Maximum apparent temperature (MAT), PM10, O3 and NO2 were analyzed in the warm period (1st April-31st October). Gestational week-specific hazard ratios of giving birth associated to a 1-unit increase in exposure were estimated fitting Cox regression models adjusted for seasonality, and demographic and clinical characteristics of the mother.
We observed 78,633 births (5.5% preterm) in Rome and 27,255 (4.5% preterm) in Barcelona. The highest hazard ratios for 1°C increase in MAT were in the 22nd-26th weeks of gestation, 1.071, (95% CI 1.052-1.091) in Rome and 1.071 (95% CI 1.036-1.106) in Barcelona, and decreased to 1.032 (95% CI 1.026-1.038) and 1.033 (95% CI 1.020-1.045) at the 36th week of gestation, respectively. Similar associations and trends were observed for PM10 and NO2 after adjusting for MAT. O3 showed similar trends but weaker associations.
We found, consistently in Rome and Barcelona, an increased risk of delivery for a unit increase in MAT, PM10, NO2 and O3, especially in the second half of the second trimester, thus effectively increasing the risk of preterm and particularly early preterm birth. Results may help to increase awareness of these risks among public-health regulators and clinicians, leading to better preventive strategies.
环境暴露与妊娠时间有关，但关于妊娠哪几周最容易受到影响的问题仍鲜有研究。我们评估了最大表观温度和空气污染水平对妊娠周分娩风险的影响。
我们分析了罗马（2001-2010 年）和巴塞罗那（2007-2012 年）两个单胎活产队列。在温暖期（4 月 1 日至 10 月 31 日）分析最大表观温度（MAT）、PM10、O3 和 NO2。使用 Cox 回归模型估计与暴露增加 1 个单位相关的妊娠周特异性分娩风险比，模型调整了季节性、母亲的人口统计学和临床特征。
我们观察到罗马有 78633 例分娩（5.5%早产），巴塞罗那有 27255 例（4.5%早产）。MAT 每升高 1°C，风险比最高的是妊娠 22-26 周，罗马为 1.071（95%CI 1.052-1.091），巴塞罗那为 1.071（95%CI 1.036-1.106），而在 36 周时降至 1.032（95%CI 1.026-1.038）和 1.033（95%CI 1.020-1.045）。调整 MAT 后，PM10 和 NO2 也观察到类似的关联和趋势。O3 显示出相似的趋势，但关联较弱。
我们在罗马和巴塞罗那一致发现，MAT、PM10、NO2 和 O3 每增加一个单位，分娩风险增加，尤其是在妊娠中期的后半段，从而有效增加早产和特别是早期早产的风险。研究结果可能有助于提高公共卫生监管者和临床医生对这些风险的认识，从而制定更好的预防策略。
