Spatial Variations in the Associations of Birth Weight with Socioeconomic, Environmental, and Behavioral Factors in Georgia, USA


Geography & Anthropology

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Birth weight is an important indicator of overall infant health and a strong predictor of infant morbidity and mortality, and low birth weight (LBW) is a leading cause of infant mortality in the United States. However, the factors that affect birth weight remain unclear. A spatial statistical technique, Geographically Weighted Regression (GWR) is applied to study the spatial variations in the associations of birth weight with six socioeconomic, environmental, and behavioral factors, including individual-level factors such as maternal smoking, maternal drinking, and prenatal care, as well as community-level family median income, educational attainment, and percentage of urban land. Data acquisition and analysis was limited to the State of Georgia, USA. Analyses of these data suggest considerable spatial variation in the associations between birth weight and these factors. Maternal smoking is the most spatially consistent factor and analysis indicated this behavior has adverse impact on birth weight in most parts of the study area. Moreover, the effects of other factors studied are only significant in some parts of the study area and the results are mixed depending on the socioeconomic and environmental characteristics of communities in which births occurred. The positive impacts of prenatal care and educational attainment, negative impacts of maternal smoking and drinking on birth weight are more significant in communities with lower income and lower educational attainment, typically characterized as more rural areas. The positive impact of family income is more significant in communities with higher educational attainment. The negative impact of urban land is more significant in rural communities. These findings suggest that targeting specific factors at a local level is more likely to reduce the risk of LBW. Therefore, health policies should be tailored to address the needs of community based on the factors relevant to that specific community. This study also suggests that GWR is a useful exploratory tool to study birth outcomes, and this technique has the potential to be applied to study other health outcomes.