Area-level risk factors for adverse birth outcomes: trends in urban and rural settings

Abstract

BackgroundSignificant and persistent racial and income disparities in birth outcomes exist in the US. The analyses in this manuscript examine whether adverse birth outcome time trends and associations between area-level variables and adverse birth outcomes differ by urban–rural status.MethodsAlabama births records were merged with ZIP code-level census measures of race, poverty, and rurality. B-splines were used to determine long-term preterm birth (PTB) and low birth weight (LBW) trends by rurality. Logistic regression models were used to examine differences in the relationships between ZIP code-level percent poverty or percent African-American with either PTB or LBW. Interactions with rurality were examined.ResultsPopulation dense areas had higher adverse birth outcome rates compared to other regions. For LBW, the disparity between population dense and other regions increased during the 1991–2005 time period, and the magnitude of the disparity was maintained through 2010. Overall PTB and LBW rates have decreased since 2006, except within isolated rural regions. The addition of individual-level socioeconomic or race risk factors greatly attenuated these geographical disparities, but isolated rural regions maintained increased odds of adverse birth outcomes. ZIP code-level percent poverty and percent African American both had significant relationships with adverse birth outcomes. Poverty associations remained significant in the most population-dense regions when models were adjusted for individual-level risk factors.ConclusionsPopulation dense urban areas have heightened rates of adverse birth outcomes. High-poverty African American areas have higher odds of adverse birth outcomes in urban versus rural regions. These results suggest there are urban-specific social or environmental factors increasing risk for adverse birth outcomes in underserved communities. On the other hand, trends in PTBs and LBWs suggest interventions that have decreased adverse birth outcomes elsewhere may not be reaching isolated rural areas.

Epidemiologic Factors and Urogenital Infections Associated With Preterm Birth in a Midwestern U.S. Population

“…Significant epidemiologic differences were found between the four sites, and when the sites were combined, univariable analysis of demographic risk factors supported recent literature (19). Fifty percent of births at < 35 weeks occurred in the large urban site, and 55% of all preterm births occurred in the Black and other minority groups, primarily at the large urban site.…”

Preterm birth and its associations with residence and ambient vehicular traffic exposure

“…14,15,17,28–30 Consistent with a potential causal relationship, a reduction in exposure to air pollution caused by increased use of public transport resulted in fewer cases of PTB. 27,31 The reduced odds for PTB in neighborhoods with high traffic density (inner loop) that we found in our study is of noted interest, given the finding of these prior studies. Our observations are consistent insomuch as time spent in traffic during peak commuter hours, and not residence per se, has been found to determine the individual exposure to traffic-related air pollution.…”

“…Our findings demonstrating increased odds for delivering early preterm in the suburban (outer loop) and urban areas (middle loop) of Harris County support other investigators’ observations in similar settings. 31,33 …”

Modulation of prenatal stress via docosahexaenoic acid supplementation: implications for child mental health

“…18 This is especially true for African American women living in urban lowincome environments. 22 Greater exposure to psychosocial stress during the prenatal period has been hypothesized to be a primary mechanism by which poverty confers risk for physical and mental health disorders to the offspring. 67,68 This is a viable hypothesis given the data on the impact of race and poverty on the functioning of the HPA axis and stress reactivity.…”

“…21 African American women living in dense, urban areas with high levels of poverty appear to have the highest risk for adverse birth outcomes. 22 Adequate prenatal nutrition is a critical component of subsequent healthy growth and development, and brain development is particularly sensitive to adequate proteins and lipids. 23,24 There are several reviews on the importance of n-3 fatty acids for offspring cognition and vision [25][26][27] and on the role of fatty acid status and supplementation in the etiology and treatment of physical and mental disorders across the lifespan.…”