Wagenaar Alexander C, Livingston Melvin D, Markowitz Sara, Komro Kelli A
Department of Behavioral Sciences and Health Education, Rollins School of Public Health, Emory University, 1518 Clifton Road, NE, GCR 556, Atlanta, GA 30322, USA.
Department of Economics, Emory University, Atlanta, GA, USA.
SSM Popul Health. 2019 Jan 16;7:100356. doi: 10.1016/j.ssmph.2019.100356. eCollection 2019 Apr.
Poverty has numerous deleterious effects on health, and the Earned Income Tax Credit (EITC) is the major policy tool used to alleviate poverty in the U.S. We evaluate effects of four distinct changes in earned income tax credit law in Washington, DC on maternal behaviors and infant outcomes. An interrupted time-series design was used with 312 monthly measures from 1990 through 2015 analyzed in 2018 (total n = 225,933 births). States with no EITC were included as the comparison group; analyses involved ARIMA modeling. Outcomes were derived from birth certificates, and included percent of live births below 2500 g, mean birth weight, mean gestation weeks, first trimester prenatal care, and maternal smoking during pregnancy. We found a pattern of significant improvements across all three infant outcome measures, with the size of the effect estimate monotonically matching the magnitude of the tax credit-ranging from a 1.9 (-2.9, -0.9) reduction in rate per 100 births of low birth weight for the smaller 10% credit, to a 4.7 (-5.4, -4.0) reduction with the 40% credit. Results for maternal smoking and prenatal care were mixed. Results suggest that earned income tax credit policies improve birth outcomes; mechanisms for this effect deserve further study.
贫困对健康有诸多有害影响，而劳动所得税收抵免（EITC）是美国用于缓解贫困的主要政策工具。我们评估了华盛顿特区劳动所得税收抵免法的四项不同变化对孕产妇行为和婴儿结局的影响。采用了中断时间序列设计，对1990年至2015年的312个月度指标进行分析，分析于2018年完成（总出生数n = 225,933）。没有劳动所得税收抵免的州被作为对照组；分析采用自回归积分移动平均（ARIMA）建模。结局数据来自出生证明，包括出生体重低于2500克的活产儿百分比、平均出生体重、平均孕周、孕早期产前检查以及孕期母亲吸烟情况。我们发现，在所有三项婴儿结局指标上都有显著改善的模式，效应估计值的大小与税收抵免幅度呈单调匹配——对于较小的10%税收抵免，每100例低出生体重儿的发生率降低1.9（-2.9，-0.9）；对于40%的税收抵免，降低4.7（-5.4，-4.0）。母亲吸烟和产前检查的结果喜忧参半。结果表明，劳动所得税收抵免政策改善了出生结局；这种效应的机制值得进一步研究。
