Racial Disparities in Birth Outcomes in Multiple South American Countries

Racial disparities in early infant health outcomes are common and have been well-documented in several racially admixed countries such the United States.  However, little is known about the extent of such disparities in South America, a continent with several racially admixed populations.  Identifying these disparities and their mechanisms is essential for designing effective policies to achieve population-wide improvement in early child health and subsequently in long-term health outcomes and to develop targeted interventions among the highly disadvantaged groups.

We investigate racial disparities in several birth outcomes including low and very low birth weight, and preterm and very preterm birth in eight South American countries including Argentina, Bolivia, Brazil, Chile, Colombia, Ecuador, Uruguay, and Venezuela.  We also aim at explaining the observed disparities as a function of household demographic, socioeconomic, and health characteristics and prenatal behaviors using an Oaxaca type model for binary outcomes and logistic regression.

The data were systematically collected beginning in the early 1980s and through 2011 using the same methodology and sampling and data collection methods across all countries through the Latin American Collaborative Study of Congenital Anomalies (ECLAMC), an epidemiological surveillance program for birth defects in South America.  ECLAMC involves a large network of hospitals in these South American countries; ECLAMC-affiliated physicians (mostly pediatricians) monitor and enroll all newborn cases with birth defects in their hospitals into ECLAMC.  They also identify and enroll and sample of infants born without birth defects.  Data on household characteristics, prenatal risk factors, and maternal and infant health outcomes are obtained through interviews with the mothers before discharge from the hospitals and birth record abstraction.  In this study, we only include infants born without birth defects as these modify birth outcomes.  For countries with an adequate sample size, we separately analyze two periods, 1982-1995 and 1996-2011, to evaluate changes in disparities over time.   The total sample size per country ranges from around 2,400 infants for Uruguay to 28,000 for Argentina.  Detailed measures of the child’s ethnic ancestries were obtained through maternal report, allowing for comparing multiple racial/ethnic groups. 

Preliminary results reveal significant disparities in all countries except Bolivia and Colombia.  Furthermore, some of the ancestries with the highest rates of the adverse birth outcomes in certain countries have the lowest rates of these outcomes in other countries, suggesting that the mechanisms for these disparities are entirely social and economic.  For example, children of native ancestry have higher rates of preterm and very preterm birth than those of European ancestry in Argentina but lower rates in Chile.  Also, children of African ancestry have highest low birth weight rates in Brazil but not in Venezuela.  Preliminary decomposition results reveal substantial heterogeneity in the extent to which the measured household, prenatal, and geographic variables explain the disparities by country, ancestry, and birth outcome.  The model variables explain between 10% and 88% of the disparities.  Prenatal care use was particularly relevant in several models.  The findings highlight several social and healthcare pathways that can be targeted by policies to reduce racial disparities in infant health.