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  • March 21, 2019
  • Pace, Nelson
    • Affiliation: Gillings School of Global Public Health, Department of Epidemiology
  • Birth defects are a leading cause of infant mortality in the U.S. accounting for 1 in every 5 infant deaths. Spina bifida, a serious though rare defect, is characterized by the protrusion of the spinal cord through a boney defect in the vertebral column. First-year mortality occurs among approximately 8% of infants with spina bifida, thirteen times higher than the national average risk of infant mortality for all U.S. births. Pre-pregnancy obesity (body mass index greater than or equal to 30 at the start of pregnancy) is common occurring in more than 1 in 5 pregnant women in the U.S. Furthermore, in the U.S., the average childbearing woman has a diet that is considered poor quality. Rates of childhood obesity have increased over the last few decades. We conducted a retrospective cohort study using data from the National Birth Defects Prevention Study linked to state death records to examine the role of pre-pregnancy body mass index and maternal dietary patterns on survival among infants born with spina bifida during the first-year of life. Overall first-year mortality risk among infants with spina bifida was 4.4% (95% CI: 3.52, 5.60%). Infants who had multiple co-occurring defects, were born very preterm, were one of multiples, had high-level spina bifida lesions, or had non-Hispanic Black mothers were at highest risk of infant mortality. Maternal pre-pregnancy underweight and obesity were associated with higher infant mortality risk (15.7% (95% CI: 7.20, 32.30%) and 5.8% (95% CI: 3.60, 9.35%), respectively) compared to normal weight mothers (2.2% (95% CI: 1.19, 4.18%)). Cox proportional hazards model adjusted for potential confounding by maternal age, education, race/ethnicity, and folic acid supplementation showed that underweight and obese mothers had greater hazard of infant mortality compared to normal weight mothers (HR: 4.5 (95% CI: 1.08, 16.72) and 2.6 (1.36, 8.02), respectively). Mothers that scored low (poorer diet quality) in both the Healthy Eating Index and the Diet Quality Index for Pregnancy had higher hazard of infant mortality compared to mothers with high (better diet quality) scores (HR: 1.4 (0.54, 4.33) and 2.4 (0.93, 5.78), respectively) though the estimates were imprecise. Our results support maternal pre-pregnancy body mass index as a modifiable factor that may be useful in efforts to improve infant survival. This study provides suggestive evidence that maternal pre-pregnancy diet is associated with infant survival among babies born with spina bifida. Nonetheless, adherence to dietary guidelines and healthy eating patterns have been associated with reduced risks of adverse pregnancy outcomes such as birth defects and improved maternal health.
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Rights statement
  • In Copyright
  • Olshan, Andrew
  • Siega-Riz, Anna Maria
  • Chescheir, Nancy
  • Cole, Stephen
  • Meyer, Robert
  • Doctor of Philosophy
Degree granting institution
  • University of North Carolina at Chapel Hill Graduate School
Graduation year
  • 2017

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