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International Journal of Pediatrics
Volume 2013 (2013), Article ID 191472, 7 pages
http://dx.doi.org/10.1155/2013/191472
Clinical Study

Maternal BMI, IGF-I Levels, and Birth Weight in African American and White Infants

1Department of Obstetrics and Gynecology and Program of Cancer Detection, Prevention and Control, Duke University School of Medicine, Durham, NC 27710, USA
2Division of Maternal-Fetal Medicine, Department of Obstetrics and Gynecology, Duke University School of Medicine, Durham, NC 27710, USA
3Division of Gynecologic Oncology, Department of Obstetrics and Gynecology, Duke University School of Medicine, Durham, NC 27710, USA
4Division of Maternal Fetal Medicine, Department Obstetrics and Gynecology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
5Department of Obstetrics and Gynecology, Duke University School of Medicine, Durham, NC 27710, USA
6Duke University School of Medicine, Durham, NC 27710, USA
7Department of Community and Family Medicine and Program of Cancer Detection, Prevention and Control, Duke University Medical Center, Durham, NC 27710, USA
8Department of Epidemiology, The University of Texas at Austin, Austin, TX 78712, USA
9Department of Nutrition Sciences and UAB Comprehensive Cancer Center, University of Alabama at Birmingham, Birmingham, AL 35294, USA
10Carolina Cord Blood Bank, Duke University Medical Center, Durham, NC 27710, USA
11Department of Radiation Oncology, Duke University Medical Center, Durham, NC 27710, USA
12Division of Epidemiology, Department of Obstetrics and Gynecology, Duke University School of Medicine, Durham, NC 27710, USA

Received 18 January 2013; Revised 9 May 2013; Accepted 9 May 2013

Academic Editor: Steven M. Donn

Copyright © 2013 Adriana C. Vidal et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

At birth, elevated IGF-I levels have been linked to birth weight extremes; high birth weight and low birth weight are risk factors for adult-onset chronic diseases including obesity, cardiovascular disease, and type 2 diabetes. We examined associations between plasma IGF-I levels and birth weight among infants born to African American and White obese and nonobese women. Prepregnancy weight and height were assessed among 251 pregnant women and anthropometric measurements of full term infants (≥37 weeks of gestation) were taken at birth. Circulating IGF-I was measured by ELISA in umbilical cord blood plasma. Linear regression models were utilized to examine associations between birth weight and high IGF-I, using the bottom two tertiles as referents. Compared with infants with lower IGF-I levels (≤3rd tertile), those with higher IGF-I levels (>3rd tertile) were 130 g heavier at birth, ( , , ), after adjusting for gender, race/ethnicity, gestational age, delivery route, maternal BMI and smoking. Stratified analyses suggested that these associations are more pronounced in infants born to African American women and women with BMI ≥30 kg/m2; the cross product term for IGF-I and maternal BMI was statistically significant ( ). Our findings suggest that the association between IGF-I levels and birth weight depends more on maternal obesity than African American race/ethnicity.