Faculty Bibliography

BACKGROUND: Current validated neonatal body composition methods are limited/impractical for use outside of a clinical setting because they are labor intensive, time consuming, and require expensive equipment. The purpose of this study was to develop an anthropometric model to estimate neonatal fat mass (kg) using an air displacement plethysmography (PEA POD(R) Infant Body Composition System) as the criterion. METHODS: A total of 128 healthy term infants, 60 females and 68 males, from a multiethnic cohort were included in the analyses. Gender, race/ethnicity, gestational age, age (in days), anthropometric measurements of weight, length, abdominal circumference, skin-fold thicknesses (triceps, biceps, sub scapular, and thigh), and body composition by PEA POD(R) were collected within 1-3 days of birth. Backward stepwise linear regression was used to determine the model that best predicted neonatal fat mass. RESULTS: The statistical model that best predicted neonatal fat mass (kg) was: -0.012 -0.064*gender + 0.024*day of measurement post-delivery -0.150*weight (kg) + 0.055*weight (kg)2 + 0.046*ethnicity + 0.020*sum of three skin-fold thicknesses (triceps, sub scapular, and thigh); R2 = 0.81, MSE = 0.08 kg. CONCLUSIONS: Our anthropometric model explained 81% of the variance in neonatal fat mass. Future studies with a greater variety of neonatal anthropometric measurements may provide equations that explain more of the variance.

PURPOSE: Previous studies suggest that hair products containing endocrine disrupting chemicals could alter puberty. We evaluated the association between childhood hair product use and age at menarche in a racially diverse study population. METHODS: We recruited 300 African-American, African-Caribbean, Hispanic, and white women from the New York City metropolitan area who were between 18-77 years of age. Data were collected retrospectively on hair oil, lotion, leave-in conditioner, perm, and other types of hair products used before age 13. Recalled age at menarche ranged from 8 to 19 years. We used multivariable binomial regression to evaluate the association between hair product use and age at menarche (<12 vs. >/=12), adjusting for potential confounders. RESULTS: African-Americans were more likely to use hair products and reached menarche earlier than other racial/ethnic groups. Women reporting childhood hair oil use had a risk ratio of 1.4 (95% confidence interval [CI]: 1.1-1.9) for earlier menarche, adjusting for race/ethnicity and year of birth. Hair perm users had an increased risk for earlier menarche (adjusted risk ratio = 1.4, 95% CI: 1.1-1.8). Other types of hair products assessed in this study were not associated with earlier menarche. CONCLUSIONS: Childhood hair oil and perm use were associated with earlier menarche. If replicated, these results suggest that hair product use may be important to measure in evaluating earlier age at menarche.

OBJECTIVE: To determine whether pre-pregnancy body mass index (BMI) and gestational weight gain (GWG) influence infant postnatal growth. STUDY DESIGN: Participants were from the Pregnancy, Infection, and Nutrition study, a prospective pregnancy cohort. Term infants with weight or length measurements at approximately 6 months were included (n = 363). Multivariable regression estimated associations for weight-for-age (WAZ), length-for-age (LAZ), and weight-for-length z-scores (WLZ) and rapid infant weight gain with categorical maternal exposures defined with the 2009 Institute of Medicine recommendations. RESULTS: Pre-pregnancy overweight and obesity were associated with higher WAZ (linear regression coefficient [beta], 0.32; 95% CI, 0.04-0.61) and WLZ (beta, 0.39; 95% CI, 0.02-0.76), respectively. Pre-pregnancy BMI was not associated with LAZ. Excessive GWG was associated with higher WAZ (beta, 0.39; 95% CI, 0.15-0.62) and LAZ (beta, 0.34; 95% CI, 0.12-0.56). Excessive GWG >/= 200% of recommended amount was associated with higher WAZ (beta, 0.68; 95% CI, 0.28-1.07), LAZ (beta, 0.45; 95% CI, 0.06-0.83), and WLZ (beta, 0.43; 95% CI, 0.04-0.82). Risk of rapid weight gain increased across maternal exposure categories; however, none of the estimates were significant. CONCLUSIONS: Pre-pregnancy BMI and GWG are modifiable intrauterine exposures that influence infant postnatal anthropometric outcomes. Further investigation with infant body composition measurements is warranted.

OBJECTIVE: The objective of the study was to determine the association between child BMI at age 3 years and maternal glucose concentration among women without pre-existing diabetes or a gestational diabetes mellitus (GDM) diagnosis. RESEARCH DESIGN AND METHODS: Data are from the Pregnancy Infection and Nutrition and Postpartum studies and include 263 mother-child pairs. Measured weights and heights at 3 years were used to calculate age- and sex-specific BMI z scores and percentiles. Multivariable linear regression models were used to examine associations of continuous BMI z scores with maternal glucose concentration. Modified Poisson regression estimated risk ratios of child overweight/obesity (BMI >/= 85th percentile). RESULTS: The mean (SD) maternal glucose concentration and prepregnancy BMI were 103.8 (23.7) mg/dL and 24.3 (5.9) kg/m(2), respectively. At 3 years, the mean (SD) child BMI z score was 0.29 (0.99), 20.9% were overweight/obese and 5.3% were obese. In the adjusted model, when compared with glucose concentration <100 mg/dL, a concentration >/= 130 mg/dL was associated with significantly higher child BMI z score at 3 years (estimated z score difference of 0.39 [95% CI: 0.03-0.75]). With the use of the same reference category, a concentration >/= 130 mg/dL was associated with an approximate twofold greater risk of child overweight/obesity (adjusted risk ratio 2.34 [95% CI: 1.25-4.38]). CONCLUSIONS: Fetal exposure to high maternal glucose concentration in the absence of pre-existing diabetes or GDM may contribute to the development of overweight/obesity in the offspring, independent of maternal prepregnancy BMI.

In May 2009, the Institute of Medicine (IOM) introduced revised gestational weight gain guidelines that were based on balancing the benefits and risks of weight gain for both the mother and child's health. This article provides an overview of these new recommendations, explaining the key changes made from the previous 1990 IOM recommendations. The important role of health care providers of pregnant women in the implementation of the new recommendations is detailed, and specific guidance for troubleshooting issues that may be encountered when helping women achieve appropriate gestational weight gains is provided.

Postpartum weight retention plays an important role in the pathway leading to obesity among women of childbearing age. The objective of this study was to examine predictors of moderate (1-10 pounds) and high (>10 pounds) postpartum weight retention using data from a prospective pregnancy cohort that followed women into the postpartum period; n = 688 and 550 women at 3 and 12 months, respectively. Analysis included descriptive statistics and predictive modeling using log-binomial techniques. The average weight retained at 3 and 12 months postpartum in this population was 9.4 lb (s.d. = 11.4) and 5.7 lb (s.d. = 13.2), respectively. At 3 months postpartum, prepregnancy weight, gestational weight gain, and hours slept during the night were associated with moderate or high weight retention, whereas having an infant hospitalized after going home and scoring in the upper 75th percentile of the Eating Attitudes Test (EAT) were associated only with high weight retention. At 12 months postpartum, prepregnancy weight, gestational weight gain, and maternal education were associated with moderate weight retention; and gestational weight gain, maternal age, race, employment status, and having an infant hospitalized at birth were associated with high weight retention. The results of this study illustrate the importance of prepregnancy weight and gestational weight gain in predicting postpartum weight retention. Furthermore, given the lack of successful intervention studies that exist to date to help women lose weight in the postpartum period, the results of this study may help to inform future interventions that focus on such aspects as hours of sleep, dealing with stress associated with a hospitalized infant, and nonclinical eating disorder symptomatology.

This systematic review focuses on outcomes of gestational weight gain, specifically birthweight, fetal growth, and postpartum weight retention, for singleton pregnancies with respect to the 1990 Institute of Medicine weight gain recommendations. A total of 35 studies met the inclusion criteria and were reviewed. There was strong evidence to support associations between excessive gestational weight gain and increased birthweight and fetal growth (large for gestational age) as well as inadequate gestational weight gain and decreased birthweight and fetal growth (small for gestational age). There was moderate evidence to support the association between excessive gestational weight gain and postpartum weight retention. Clear clinical recommendations based on this review are challenging because of several limitations in the literature. Improvements in future research include the use of consistent definitions of gestational weight gain and outcomes of interest, assessment of confounders, and better collection of weight and weight gain data.