Objectives

We investigated the association between outdoor air pollutants exposure in the first trimester of pregnancy, and growth and cardio-metabolic risk at four years of age, and evaluated the mediating role of birth weight.

Methods

We included mother-child pairs (N = 1,724) from the Spanish INMA birth cohort established in 2003–2008. First trimester of pregnancy nitrogen dioxide (NO₂) and fine particles (PM_2.5) exposure levels were estimated. Height, weight, waist circumference, blood pressure, and lipids were measured at four years of age. Body mass index (BMI) trajectories from birth to four years were identified.

Results

Increased PM_2.5 exposure in the first trimester of pregnancy was associated with decreased z-scores of weight (zWeight) and BMI (zBMI) (zWeight change per interquartile range increase in PM_2.5 exposure = −0.12; 95% CI: −0.23, −0.01; zBMI change = −0.12; 95% CI: −0.23, −0.01). Higher NO₂ and PM_2.5 exposure was associated to a reduced risk of being in a trajectory with accelerated BMI gain, compared to children with the average trajectory. Birth weight partially mediated the association between PM_2.5 and zWeight and zBMI. PM_2.5 and NO₂ were not associated with the other cardio-metabolic risk factors.

Conclusions

This comprehensive study of many growth and cardio-metabolic risk related outcomes suggests that air pollution exposure during pregnancy may be associated with delays in physical growth in the early years after birth. These findings imply that pregnancy exposure to air pollutants has a lasting effect on growth after birth and require follow-up at later child ages.

中文翻译：

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学龄前儿童的产前空气污染暴露和增长以及心脏代谢风险

目标

我们调查了怀孕初期的室外空气污染物暴露与4岁时生长和心脏代谢风险之间的关系，并评估了出生体重的中介作用。

方法

我们纳入了2003-2008年建立的西班牙INMA出生队列中的母子对（N = 1,724）。估计妊娠初期的二氧化氮（NO ₂）和微粒（PM _2.5）暴露水平。在四岁时测量身高，体重，腰围，血压和脂质。确定了从出生到四年的体重指数（BMI）轨迹。

结果

妊娠前三个月PM _2.5暴露增加与体重的z得分（z体重）和BMI（z BMI）降低有关（z每四分位间距的体重变化导致PM _2.5暴露增加= -0.12; 95％CI：- 0.23，-0.01; z BMI变化= -0.12; 95％CI：-0.23，-0.01）。与具有平均轨迹的儿童相比，较高的NO ₂和PM _2.5暴露与降低BMI增长轨迹的风险降低有关。出生体重部分介导了PM _2.5与z体重和z BMI之间的关联。下午_2.5和NO ₂与其他心脏代谢危险因素无关。

结论

这项对许多生长和心脏代谢风险相关结果的综合研究表明，怀孕期间暴露于空气污染可能与出生后早年身体生长的延迟有关。这些发现表明，孕妇暴露于空气污染物会对出生后的生长产生持久影响，因此需要在以后的儿童年龄进行随访。