Funded Projects

Investigations into the Cause of Low Birth Weight in Hamilton County, TN

Grantee: University of Tennessee at Chattanooga
Principal Investigator: Sean Richards
Project Number: H1SMC10654
Project Date: 9/1/2008

Final Report

Investigations into the Cause of Low Birth Weight in Hamilton County, TN Final Report (PDF)

Age group(s)

• Prenatal
• Perinatal/Infancy (0-12 months)

Abstract

Objectives: Test the hypothesis that the low birth weight (LBW) of infants in Hamilton County, TN is correlated with heavy metal exposure. Aim 1: To test the relationship of placental heavy metals to LBW (outcome). Aim 2: To determine the reason why the birth weight of Hamilton County is significantly lower than the rest of the United States. Among the many possible factors contributing to low birth weight in infants is exposure in utero to environmental contaminants. We hypothesize that with the noted air and water pollution in this county as well as the 42 toxic waste sites, that environmental exposures are a major contributor to the incidence of not only low birth weight babies but especially very low birth weight babies.As the interface between mother and fetus, the placenta can open a window on the fetal environment, including the timing of specific exposures/events that may contribute to lifelong disease risks. To cause LBW, a biologically effective fetal dose must be delivered either to the placenta (compromising the placenta without substantial fetal transfer) or across the placenta (with direct fetal toxicant effects). The analytic goal is to determine if pollutants in Hamilton County are responsible for the decreased birth weight. LBW is relevant to public health not only for its association with neonatal morbidity and mortality and risk for poor neurodevelopmental outcome, but also for its association with longterm pediatric and adult health risks such as heart disease, obesity and diabetes. The contribution of intrauterine exposure to environmental toxicants to disease throughout the life course must be understood for environmental planning. Improved distinctions of those truly "at-risk" LBW infants would allow public health practice throughout the decades of human life to identify early those "at-risk" (and thus candidates for early intervention) for hypertension, heart attack, stroke, diabetes, obesity, osteoporosis, breast cancer and schizophrenia. We feel that this study is specifically related to MCH Strategic Research Initiative Issue #IV as it relates to longitudinal studies of health and normative development in special populations of children such as minority children; children with special health needs; and children of low socioeconomic status (SES), rural, migrant and homeless backgrounds. Project Proposed: To test this hypothesis we will analyze placentas from 400 LBW children and from 100 children born at term with birth weights >2500g for levels of heavy metals per year. We will measure placenta for metals to determine "fetal exposure." The validity of our hypothesis will be tested by the strength of association between metals and LBW. In addition, the LBW will be subcategorized into groups of Very Low Birth Weight (VLBW) as potential evidence of a greater environmental exposure to toxicants.