妊娠期大气二氧化氮暴露与孕妇维生素D缺乏症的关联

目的 孕妇维生素D缺乏症与妊娠期糖尿病、妊娠期高血压、孕妇贫血以及胎儿生长受限和早产等不良妊娠结局密切相关。本研究旨在探讨妊娠期大气二氧化氮（nitrogen dioxide，NO2）暴露与孕妇维生素D缺乏症的关联。方法 选取2013年5月-至2014年５月，在某市妇幼保健院建卡的孕妇作为初始研究对象。按照入选和排除标准最终纳入3244名孕妇进入本研究。通过问卷调查收集孕妇的一般人口学信息；利用环境监测站点的数据模拟孕妇在妊娠期间大气NO2的暴露水平；采用酶联免疫吸附法检测孕晚期孕妇血清中25（OH）D的浓度。结果 孕妇在孕早期、中期、晚期以及整个孕期NO2暴露水平的中位数分别为:39.52、36.84、28.09以及31.90μg/m3。孕晚期血清中25(OH)D浓度的平均值为42.09nmol/L。多元线性回归分析的结果显示，孕中期、孕晚期以及整个孕期NO2的暴露水平每增加10μg / m3，孕妇血清中25（OH）D的水平分别降低2.224nmol/L（95%CI:-2.777，-1.671），2.240nmol/L（95%CI:-2.665，-1.816）以及5.299 nmol/L（95%CI:-6.481，-4.177）。多元logistic回归分析的结果显示，随着孕中期、孕晚期以及整个孕期NO2的暴露水平的增加，孕妇VD缺乏症发生的风险增加，其OR值分别为1.338（95%CI:1.225,1.461），1.347（95%CI:1.259,1.442）以及2.049（95%CI:1.709～2.456）。结论 孕期NO2暴露是孕妇维生素D缺乏症发生的一个危险因素。在制订维生素D缺乏症的防控措施时需要考虑孕期NO2的暴露。

Prenatal exposure to nitrogen dioxide in association with maternal vitamin D deficiency during pregnancy

To investigate the association between prenatal NO2 exposure and vitamin D deficiency in pregnant women. Methods Participating women who set up their health card in a Maternal and Child Health Hospital were selected as the initial participants. According to the inclusion and exclusion criteria, 3244 pregnant women were finally included in this study. Population characteristics of the pregnant women were collected through self-design questionnaire. The average NO2 exposure of each trimester and of the whole pregnancy was calculated using daily air pollution concentration data. Maternal serum 25(OH) D levels were determined by Enzyme Linked Immunosorbent assay(ELISA). Results The median NO2 exposure levels during the first trimester, second trimester, third trimester and the whole pregnancy were 39.52, 36.84, 28.09 and 31.90μg/m3, respectively. The mean 25(OH)D levels in maternal serum were 42.09 ng/ml. For every 10 g/m3 increase in NO2 exposure during the second trimester, the third trimester and the whole pregnancy, the 25(OH)D levels in pregnant women’s serum decrease 2.224 nmol/L(95%CI:-2.777,-1.671), 2.240 nmol/L(95%CI:-2.665,-1.816) and 5.299 nmol/L(95%CI:-6.481,-4.177), respectively. Results of logistic regression analysis showed that the odds ratios for maternal VD deficiency were 1.338(95%CI:1.225,1.461), 1.347(95%CI:1.259,1.442) and 2.049(95%CI:1.709-2.456) for a 10 g/m3 increase in NO2 exposure during the second trimester, the third trimester and the whole trimester. Conclusion Our results suggest that exposure to NO2 during late pregnancy may play a role in maternal vitamin D deficiency. NO2 exposure should be incorporated into future guidelines for the prevention of maternal vitamin D deficiency.