Centre for Environmental Sciences, Hasselt University, Agoralaan Building D, 3590 Diepenbeek, Belgium; Department of Complex Genetics, NUTRIM School of Nutrition and Translational Research in Metabolism, Maastricht University Medical Centre, P.O. Box 616, 6200 MD Maastricht, The Netherlands.
Centre of Human Genetics, University Hospitals Leuven, Herestraat 49, 3000 Leuven, Belgium; Department of Obstetrics and Gynaecology, Ghent University Hospitals, 9000, Ghent, Belgium.
Environ Res. 2016 Jul;148:39-45. doi: 10.1016/j.envres.2016.03.006. Epub 2016 Mar 19.
Several studies in singletons have shown that maternal exposure to ambient air pollutants is associated with restricted fetal growth. About half of twins have low birth weight compared with six percent in singletons. So far, no studies have investigated maternal air pollution exposure in association with birth weight and small for gestational age in twins. We examined 4760 twins of the East Flanders Prospective Twins Survey (2002-2013), to study the association between in utero exposure to air pollution with birth weight and small for gestational age. Maternal particulate air pollution (PM10) and nitric dioxide (NO2) exposure was estimated using a spatial temporal interpolation method over various time windows during pregnancy. In the total group of twins, we observed that higher PM10 and NO2 exposure during the third trimester was significantly associated with a lower birth weight and higher risk of small for gestational age. However, the association was driven by moderate to late preterm twins (32-36 weeks of gestation). In these twins born between 32 and 36 weeks of gestation, birth weight decreased by 40.2g (95% CI: -69.0 to -11.3; p=0.006) and by 27.3g (95% CI: -52.9 to -1.7; p=0.04) in association for each 10µg/m³ increment in PM10 and NO2 concentration during the third trimester. The corresponding odds ratio for small for gestational age were 1.68 (95% CI: 1.27-2.33; p=0.0003) and 1.51 (95% CI: 1.18-1.95; p=0.001) for PM10 or NO2, respectively. No associations between air pollution and birth weight or small for gestational age were observed among term born twins. Finally, in all twins, we found that for each 10µg/m³ increase in PM10 during the last month of pregnancy the within-pair birth weight difference increased by 19.6g (95% CI: 3.7-35.4; p=0.02). Assuming causality, an achievement of a 10µg/m³ decrease of particulate air pollution may account for a reduction by 40% in small for gestational age, in twins born moderate to late preterm.
几项针对单胎妊娠的研究表明，母体暴露于环境空气污染物与胎儿生长受限有关。与单胎妊娠的 6%相比，大约一半的双胞胎出生体重较低。迄今为止，尚无研究调查母亲在双胞胎妊娠期间接触空气污染与出生体重和小于胎龄儿之间的关系。我们检查了东佛兰德前瞻性双胞胎研究（2002-2013 年）中的 4760 对双胞胎，以研究宫内暴露于空气污染与出生体重和小于胎龄儿之间的关系。使用时空插值方法在妊娠的不同时间窗估计母体颗粒状空气污染物（PM10）和二氧化氮（NO2）暴露。在双胞胎的总群体中，我们观察到妊娠晚期暴露于较高水平的 PM10 和 NO2 与较低的出生体重和较高的小于胎龄儿风险显著相关。然而，这种关联是由中晚期早产儿（32-36 孕周）驱动的。在这些妊娠 32-36 周之间出生的双胞胎中，出生体重分别下降了 40.2g（95%CI：-69.0 至-11.3；p=0.006）和 27.3g（95%CI：-52.9 至-1.7；p=0.04），与 PM10 或 NO2 浓度每增加 10μg/m³有关。小于胎龄儿的相应比值比分别为 1.68（95%CI：1.27-2.33；p=0.0003）和 1.51（95%CI：1.18-1.95；p=0.001）。在足月出生的双胞胎中，未观察到空气污染与出生体重或小于胎龄儿之间存在关联。最后，在所有双胞胎中，我们发现妊娠最后一个月 PM10 每增加 10μg/m³，双胞胎内出生体重差异增加 19.6g（95%CI：3.7-35.4；p=0.02）。假设存在因果关系，空气中颗粒物污染每降低 10μg/m³，可能会使中晚期早产儿的小于胎龄儿比例降低 40%。
