BACKGROUND Children in India are exposed to high levels of ambient fine particulate matter (PM2.5). However, population-level evidence of associations with adverse health outcomes from within the country is limited. The aim of our study is to estimate the association of early-life exposure to ambient PM2.5 with child health outcomes (height-for-age) in India. METHODS We linked nationally-representative anthropometric data from India's 2015-2016 Demographic and Health Survey (n = 218,152 children under five across 640 districts of India) with satellite-based PM2.5 exposure (concentration) data. We then applied fixed effects regression to assess the association between early-life ambient PM2.5 and subsequent height-for-age, analyzing whether deviations in air pollution from the seasonal average for a particular place are associated with deviations in child height from the average for that season in that place, controlling for trends over time, temperature, and birth, mother, and household characteristics. We also explored the timing of exposure and potential non-linearities in the concentration-response relationship. RESULTS Children in the sample were exposed to an average of 55 μ g/m3 of PM2.5 in their birth month. After controlling for potential confounders, a 100 μg/m3 increase in PM2.5 in the month of birth was associated with a 0.05 [0.01-0.09] standard deviation reduction in child height. For an average 5 year old girl, this represents a height deficit of 0.24 [0.05-0.43] cm. We also found that exposure to PM2.5 in the last trimester in utero and in the first few months of life are significantly (p < 0.05) associated with child height deficits. We did not observe a decreasing marginal risk at high levels of exposure. CONCLUSIONS India experiences some of the worst air pollution in the world. To our knowledge, this is the first study to estimate the association of early-life exposure to ambient PM2.5 on child height-for-age at the range of ambient pollution exposures observed in India. Because average exposure to ambient PM2.5 is high in India, where child height-for-age is a critical challenge in human development, our results highlight ambient air pollution as a public health policy priority.

中文翻译：

---

印度早年暴露于环境 PM2.5 与儿童年龄别身高的关系：一项观察性研究。

背景 印度的儿童暴露在高浓度的环境细颗粒物 (PM2.5) 中。然而，来自国内的与不良健康结果相关的人口水平证据是有限的。我们研究的目的是估计印度儿童早期暴露于环境 PM2.5 与儿童健康结果（年龄别身高）的关系。方法 我们将印度 2015-2016 年人口与健康调查（印度 640 个地区的 218,152 名五岁以下儿童）中具有全国代表性的人体测量数据与基于卫星的 PM2.5 暴露（浓度）数据联系起来。然后，我们应用固定效应回归来评估生命早期环境 PM2.5 与随后的年龄别身高之间的关联，分析特定地点的空气污染与季节平均值的偏差是否与该地点儿童身高与该季节平均值的偏差有关，控制随时间、温度以及出生、母亲和家庭特征的趋势。我们还探讨了暴露时间和浓度-反应关系中的潜在非线性。结果 样本中的儿童在其出生月份平均暴露于 55 μ g/m3 的 PM2.5。在控制了潜在的混杂因素后，出生月份 PM2.5 增加 100 μg/m3 与儿童身高降低 0.05 [0.01-0.09] 标准差相关。对于一个平均 5 岁的女孩来说，这表示身高不足 0.24 [0.05-0.43] 厘米。我们还发现暴露于 PM2. 5 在子宫内的最后三个月和生命的最初几个月与儿童身高缺陷显着相关（p < 0.05）。我们没有观察到高暴露水平下的边际风险降低。结论 印度经历了一些世界上最严重的空气污染。据我们所知，这是第一项在印度观察到的环境污染暴露范围内估计早期暴露于环境 PM2.5 与儿童年龄别身高之间关系的研究。由于印度的环境 PM2.5 平均暴露量很高，儿童的年龄别身高是人类发展的一个关键挑战，我们的研究结果强调环境空气污染是公共卫生政策的优先事项。我们没有观察到高暴露水平下的边际风险降低。结论 印度经历了一些世界上最严重的空气污染。据我们所知，这是第一项在印度观察到的环境污染暴露范围内估计早期暴露于环境 PM2.5 与儿童年龄别身高之间关系的研究。由于印度的环境 PM2.5 平均暴露量很高，儿童的年龄别身高是人类发展的一个关键挑战，我们的研究结果强调环境空气污染是公共卫生政策的优先事项。我们没有观察到高暴露水平下的边际风险降低。结论 印度经历了一些世界上最严重的空气污染。据我们所知，这是第一项在印度观察到的环境污染暴露范围内估计早期暴露于环境 PM2.5 与儿童年龄别身高之间关系的研究。由于印度的环境 PM2.5 平均暴露量很高，儿童的年龄别身高是人类发展的一个关键挑战，我们的研究结果强调环境空气污染是公共卫生政策的优先事项。