Office of Environmental Health Hazard Assessment, California EPA, 1515 Clay Street, 16th floor, Oakland, CA 94612, USA; School of Public Health, University of California, Berkeley, 50 University Hall, #7360, Berkeley, CA 94720, USA.
Office of Environmental Health Hazard Assessment, California EPA, 1515 Clay Street, 16th floor, Oakland, CA 94612, USA.
Sci Total Environ. 2017 Dec 15;605-606:647-654. doi: 10.1016/j.scitotenv.2017.06.053. Epub 2017 Jul 1.
Previous studies have demonstrated associations between fine particulate matter (PM) and risk of term low birth weight (TLBW; birth weight<2500g and gestational weeks≥37weeks). However, it remains unclear which PM sources mainly contribute to these associations, and which subgroups (e.g. by residential region and maternal characteristics) may be more susceptible to these exposures. Using California birth records and PM data from eight monitoring sites from 2002 to 2009, we examined the relationship between exposures to total PM and PM sources and risk of TLBW. Source apportionment was performed for each site using Positive Matrix Factorization, and five PM sources (i.e., secondary ammonium sulfate, secondary ammonium nitrate, vehicular emissions, biomass burning, and resuspended soil) were included in our analysis. Mean gestational and trimester exposures were calculated for mothers with ZIP codes located within a 20km radius of monitors (N=1,050,330). Logistic regression was conducted and adjusted for maternal age, race/ethnicity, and education, as well as gestational age, year of birth, apparent temperature exposure during gestation, and neighborhood level percentage of households below poverty level. Increased risks of TLBW associated with each interquartile range increase in exposure were 4.9% (95% confidence interval: 2.6, 7.3) for total PM, 7.7% (4.7, 10.7) for secondary ammonium sulfate, 5.6% (3.5, 7.7) for resuspended soil, and 3.1% (1.3, 4.9) for secondary ammonium nitrate. Differences in associations were found between inland and coastal regions, and between northern and southern regions for several sources. Results also showed effect measure modification by maternal race/ethnicity and education, with the lowest risk of TLBW associated with PM exposures found in mothers with at least a college education and Asian mothers. Some PM sources may be more harmful than others, and a better understanding of the relative toxicity of PM from each source could lead to more targeted and cost-effective regulations to protect public health.
先前的研究表明，细颗粒物（PM）与足月低体重儿（TLBW；出生体重<2500 克且孕周≥37 周）的风险之间存在关联。然而，目前尚不清楚主要是哪些 PM 来源导致了这些关联，以及哪些亚组（例如，按居住地区和产妇特征划分）可能更容易受到这些暴露的影响。本研究使用加利福尼亚州的出生记录和 2002 年至 2009 年八个监测点的 PM 数据，研究了总 PM 和 PM 来源暴露与 TLBW 风险之间的关系。每个站点的源分配均使用正矩阵因子化（Positive Matrix Factorization）进行，我们的分析中包括了五种 PM 来源（即二次硫酸铵、二次硝酸铵、机动车排放、生物质燃烧和再悬浮土壤）。对于位于监测器 20 公里半径范围内邮政编码的母亲，计算了平均孕周和孕早期暴露（N=1,050,330）。进行了逻辑回归分析，并根据母亲的年龄、种族/民族和教育程度，以及孕周、出生年份、妊娠期间的表观温度暴露和邻里贫困水平百分比进行了调整。与暴露增加一个四分位距相关的 TLBW 风险增加幅度分别为：总 PM 增加 4.9%（95%置信区间：2.6，7.3）、二次硫酸铵增加 7.7%（4.7，10.7）、再悬浮土壤增加 5.6%（3.5，7.7）、二次硝酸铵增加 3.1%（1.3，4.9）。在内陆和沿海地区以及北部和南部地区，几种来源的关联存在差异。结果还显示，母亲的种族/民族和教育程度对效应衡量有修饰作用，具有至少大学学历和亚裔母亲的 PM 暴露与 TLBW 风险最低相关。一些 PM 来源可能比其他来源更具危害性，更好地了解每个来源的 PM 相对毒性可能会导致更有针对性和更具成本效益的法规来保护公众健康。
