Purpose-Poor living conditions are posited as an underlying cause of American Indian (AI) infant mortality, which is unusually high in the post-neonatal period. We explore whether the effects of neighborhood poverty on AI infant death are identifiable using observational data.Methods-Vital records for infants born between 1990 and 1999 to AI women in a metropolitan area (n = 4,751) are linked with tract-level poverty data. A counterfactual framework, an explicit causal contrast study design, and propensity score matching methods are employed. For each comparison, we create exchangeable groups by matching infants with the same probability of exposure to poverty when one was exposed and the other was not.Results-Our results suggest that neighborhood poverty has little effect on AI infant death outcomes. Importantly, the study design makes transparent the challenge of identifying appropriate analytic comparison groups in studies of neighborhood poverty and health.Conclusions-Collecting additional data will likely not overcome the fact that AI with a high probability of living in poverty rarely reside in low poverty neighborhoods. Yet, some of them must if a meaningful counterfactual comparison is to be made and the effects of neighborhood poverty on AI infant death are to be identified.
MeSH KeywordsCausality; Confounding Factors (Epidemiology); Epidemiologic Research Design; Indians; North American; Infant Mortality High rates of infant mortality continue to characterize many American Indian (AI) communities, both on reservations and in urban areas throughout the United States (US). However, little is known about the etiology of urban AI infant mortality, including potential mechanisms of risk.Researchers have noted a number of individual-level risk factors for infant mortality in the general population. These are often associated with pregnancy complications and low birth Address for Reprints: Pamela Jo Johnson, MPH, PhD, State Health Access Data Assistance Center, School of Public Health, University of Minnesota, 2221 University Avenue, Suite 345, Minneapolis, MN 55414. Publisher's Disclaimer: This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final citable form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. weight, which are closely tied to neonatal mortality, death in the first 28 days after birth (1). Among AI, however, more infant deaths occur among average weight infants than for any other race group (2). Further, while two-thirds of infant deaths in the US occur in the neonatal period for all other race groups, nearly half of AI infant deaths still occur in the postneonatal (between 28 days and one year) period (2). Since postneonatal death has hist...