Mandy B. Belfort

Weight Status in the First 6 Months of Life and Obesity at 3 Years of Age

OBJECTIVE. The goal was to examine the associations of weight-for-length at birth and at 6 months with obesity at 3 years of age. METHODS. We studied 559 children in Project Viva, an ongoing, prospective, cohort study of pregnant women and their children. We measured length and weight at birth, 6 months, and 3 years. Our main exposures were weight-for-length z score at birth adjusted for gestational age and weight-for-length z score at 6 months adjusted for weight-for-length z score at birth. We used multivariate regression analyses to predict the independent effects of birth weight-for-length z score and, separately, 6-month weight-for-length z score on BMI z score, the sum of subscapular and triceps skinfold thicknesses, and obesity (BMI for age and gender of ≥95th percentile) at age 3. RESULTS. Mean weights at birth, 6 months, and 3 years were 3.55, 8.15, and 15.67 kg, respectively. Corresponding lengths were 49.9, 66.9, and 97.4 cm. At 3 years, 48 children (9%) were obese. After adjustment for confounding variables and birth weight-for-length z score, each increment in 6-month weight-for-length z score was associated with higher BMI z scores, higher sums of subscapular and triceps skinfold thicknesses, and increased odds of obesity at age 3. The predicted obesity prevalence among children in the highest quartiles of both birth and 6-month weight-for-length z scores was 40%, compared with 1% for children in the lowest quartiles of both. Whereas birth weight-for-length z scores were associated with higher BMI z scores, the magnitude of effect was smaller than that of weight-for-length z scores at 6 months. CONCLUSIONS. More-rapid increases in weight for length in the first 6 months of life were associated with sharply increased risk of obesity at 3 years of age. Changes in weight status in infancy may influence risk of later obesity more than weight status at birth.

Associations of Gestational Weight Gain With Short- and Longer-term Maternal and Child Health Outcomes

The authors investigated the rate of gestational weight gain associated with the lowest combined risk of 5 short- and longer-term maternal and child health outcomes for 2,012 mother-child pairs recruited in 1999-2002 into Project Viva, a prebirth cohort study in Massachusetts. Within each maternal prepregnancy body mass index (BMI, kg/m(2)) stratum, they performed a logistic regression analysis predicting all 5 outcomes, from which they determined the rate of gain at which average predicted prevalence of the adverse outcomes was the lowest. The mean rate of total gestational weight gain was 0.39 kg/week (standard deviation, 0.14). The prevalence of small for gestational age was 6%, large for gestational age was 14%, preterm delivery was 7%, substantial postpartum weight retention was 16%, and child obesity was 10%. The lowest predicted outcome prevalence occurred with a 0.28-kg/week gain for women whose BMI was 18.5-24.9, a 0.03-kg/week loss for a BMI of 25.0-29.9, and a 0.19-kg/week loss for a BMI of >or=30.0 kg/m(2)--the lowest observed weight changes in overweight and obese women. For normal-weight and overweight women, lowest-risk gains varied modestly with adjustment for maternal characteristics and with different outcome weightings. For obese women, the lowest-risk weight change was weight loss in all models. Recommendations for gestational weight gain for obese women should be revised.

Cohort Profile: Project Viva

We established Project Viva to examine prenatal diet and other factors in relation to maternal and child health. We recruited pregnant women at their initial prenatal visit in eastern Massachusetts between 1999 and 2002. Exclusion criteria included multiple gestation, inability to answer questions in English, gestational age ≥22 weeks at recruitment and plans to move away before delivery. We completed in-person visits with mothers during pregnancy in the late first (median 9.9 weeks of gestation) and second (median 27.9 weeks) trimesters. We saw mothers and children in the hospital during the delivery admission and during infancy (median age 6.3 months), early childhood (median 3.2 years) and mid-childhood (median 7.7 years). We collected information from mothers via interviews and questionnaires, performed anthropometric and neurodevelopmental assessments and collected biosamples. We have collected additional information from medical records and from mailed questionnaires sent annually to mothers between in-person visits and to children beginning at age 9 years. From 2341 eligible women, there were 2128 live births; 1279 mother-child pairs provided data at the mid-childhood visit. Primary study outcomes include pregnancy outcomes, maternal mental and cardiometabolic health and child neurodevelopment, asthma/atopy and obesity/cardiometabolic health. Investigators interested in learning more about how to obtain Project Viva data can contact Project_Viva@hphc.org.

Preterm Infant Linear Growth and Adiposity Gain: Trade-Offs for Later Weight Status and Intelligence Quotient

OBJECTIVE To examine trade-offs between cognitive outcome and overweight/obesity in preterm-born infants at school age and young adulthood in relation to weight gain and linear growth during infancy. STUDY DESIGN We studied 945 participants in the Infant Health and Development Program, an 8-center study of preterm (≤37 weeks gestational age), low birth weight (≤2500 g) infants from birth to age 18 years. Adjusting for maternal and child factors in logistic regression, we estimated the odds of overweight/obesity (body mass index [BMI] ≥85th percentile at age 8 or ≥25 kg/m(2) at age 18) and in separate models, low IQ (<85) per z-score changes in infant length and BMI from term to 4 months, from 4 to 12 months, and from 12 to 18 months. RESULTS More rapid linear growth from term to 4 months was associated with lower odds of IQ <85 at age 8 years (OR, 0.82; 95% CI, 0.70-0.96), but higher odds of overweight/obesity (OR, 1.27; 95% CI, 1.05-1.53). More rapid BMI gain in all 3 infant time intervals was also associated with higher odds of overweight/obesity, and BMI gain from 4-12 months was associated with lower odds of IQ <85 at age 8. Results at age 18 were similar. CONCLUSION In these preterm, low birth weight infants born in the 1980s, faster linear growth soon after term was associated with better cognition, but also with a greater risk of overweight/obesity at age 8 years and 18 years. BMI gain over the entire 18 months after term was associated with later risk of overweight/obesity, with less evidence of a benefit for IQ.

Pasteurized Human Donor Milk Use among US Level 3 Neonatal Intensive Care Units

Background: Pasteurized human donor milk (DM) is recommended by the World Health Organization and American Academy of Pediatrics for preterm infants when mother’s own milk is unavailable, yet the extent and predictors of use and criteria for use in US neonatal intensive care units (NICUs) are unknown. Objective: This study aimed to evaluate current DM use in US level 3 NICUs and predictors and criteria of use. Methods: We sent mail surveys to 302 US level 3 NICU directors. We used multivariable logistic regression to analyze predictors of DM use. Results: Survey response rate was 60%, and 76 of 182 (42%) directors reported DM use. Among DM users, 30% have used DM < 2 years and 55% for 2 to 5 years. Among nonusers, 63% were uncertain of turnaround time when ordering DM, 36% were unclear what guidelines milk banks followed, and 31% were unsure of parent receptiveness. In multivariate analyses, > 800 annual admissions (odds ratio [OR], 4.11; 95% confidence interval [CI], 1.43-11.82; reference ≤ 400 admissions) and location in the Midwest (OR, 3.02; 95% CI, 1.17-7.76) and West (OR, 6.33; 95% CI, 2.28-15.57; reference Northeast) were positively associated with DM use; safety-net hospitals (> 75% Medicaid insurance) were negatively associated (OR, 0.35; 95% CI, 0.14-0.89). Conclusion: Pasteurized human donor milk use is rapidly emerging among US level 3 NICUs. Larger NICUs and those in the West and Midwest were more likely to use DM, while safety-net hospitals were less likely to use DM. Lack of knowledge by medical directors of accessibility, safety, and parental receptiveness may be barriers to DM use.

Gestational Glucose Tolerance and Cord Blood Leptin Levels Predict Slower Weight Gain in Early Infancy

OBJECTIVE To determine the extent to which known prenatal and perinatal predictors of childhood obesity also predict weight gain in early infancy. STUDY DESIGN We studied 690 infants participating in the prospective cohort Project Viva. We measured length and weight at birth and at 6 months. Using multivariable linear regression, we examined relationships of selected maternal and infant factors with change in weight-for-length z-score (WFL-z) from 0 to 6 months. RESULTS Mean (standard deviation) change in WFL-z from 0 to 6 months was 0.23 (1.11), which translates to 4500 grams gained from birth to 6 months of life in an infant with average birth weight and length. After adjustment for confounding variables and birth weight-for-gestational age z-score (-0.28 [95% confidence interval, -0.37, -0.19] per unit), cord blood leptin (-0.40 [95%confidence interval, -0.61, -0.19] per 10 ng/mL), and gestational diabetes -0.50 [95%confidence interval, -0.88, -0.11] versus normal glucose tolerance)were each associated with slower gain in WFL-z from 0 to 6 months. CONCLUSIONS Higher neonatal leptin and gestational diabetes predicted slower weight gain in the first 6 months of life. The hormonal milieu of the intrauterine environment may determine growth patterns in early infancy and thus later obesity.

Infant growth and child cognition at 3 years of age.

BACKGROUND. Infancy is a critical period for brain development. Few studies have examined the extent to which infant weight gain is associated with later neurodevelopmental outcomes in healthy populations. OBJECTIVE. The purpose of this work was to examine associations of infant weight gain from birth to 6 months with child cognitive and visual-motor skills at 3 years of age. PATIENTS AND METHODS. We studied 872 participants in Project Viva, an ongoing prospective, longitudinal, prebirth cohort. We abstracted birth weight from the medical chart and weighed infants at 6 months of age. We used the 2000 Centers for Disease Control and Prevention growth charts to derive weight-for-age z scores. Our primary predictor was infant weight gain, defined as the weight-for-age z score at 6 months adjusted for the weight-for-age z score at birth. At 3 years of age, we measured child cognition with the Peabody Picture Vocabulary Test III and visual-motor skills with the Wide Range Assessment of Visual Motor Abilities. RESULTS. Mean Peabody Picture Vocabulary Test III score was 104.2, and mean Wide Range Assessment of Visual Motor Abilities test score was 102.8. Mean birth weight z score was 0.21, and mean 6-month weight z score was 0.39. In multiple linear regression adjusted for child age, gender, gestational age, breastfeeding duration, primary language, and race/ethnicity; maternal age, parity, smoking status, and cognition; and parental education and income level, we found no association of infant weight gain with child Peabody Picture Vocabulary Test III score (−0.4 points per z score weight gain increment, 95% confidence interval −1.3, 0.6) or total Wide Range Assessment of Visual Motor Abilities standard score (−0.4 points, 95% confidence interval −1.2, 0.5). CONCLUSIONS. Slower infant weight gain was not associated with poorer neurodevelopmental outcomes in healthy, term-born 3-year-old children. These results should aid in determining optimal growth patterns in infants to balance risks and benefits of health outcomes through the life course.

Low Iodine Content in the Diets of Hospitalized Preterm Infants

CONTEXT Iodine is critical for normal thyroid hormone synthesis and brain development during infancy, and preterm infants are particularly vulnerable to the effects of both iodine deficiency and excess. Use of iodine-containing skin antiseptics in intensive care nurseries has declined substantially in recent years, but whether the current dietary iodine intake meets the requirement for hospitalized preterm infants is unknown. OBJECTIVE The aim of the study was to measure the iodine content of enteral and parenteral nutrition products commonly used for hospitalized preterm infants and estimate the daily iodine intake for a hypothetical 1-kg infant. METHODS We used mass spectrometry to measure the iodine concentration of seven preterm infant formulas, 10 samples of pooled donor human milk, two human milk fortifiers (HMF) and other enteral supplements, and a parenteral amino acid solution and soy-based lipid emulsion. We calculated the iodine provided by typical diets based on 150 ml/kg · d of formula, donor human milk with or without HMF, and parenteral nutrition. RESULTS Preterm formula provided 16.4-28.5 μg/d of iodine, whereas unfortified donor human milk provided only 5.0-17.6 μg/d. Adding two servings (six packets) of Similac HMF to human milk increased iodine intake by 11.7 μg/d, whereas adding two servings of Enfamil HMF increased iodine intake by only 0.9 μg/d. The other enteral supplements contained almost no iodine, nor did a parenteral nutrition-based diet. CONCLUSIONS Typical enteral diets for hospitalized preterm infants, particularly those based on donor human milk, provide less than the recommended 30 μg/d of iodine, and parenteral nutrition provides almost no iodine. Additional iodine fortification should be considered.

Early Weight Gain, Linear Growth, and Mid-Childhood Blood Pressure A Prospective Study in Project Viva

In recent years, the prevalence of hypertension and prehypertension increased markedly among children and adolescents, highlighting the importance of identifying determinants of elevated blood pressure early in life. Low birth weight and rapid early childhood weight gain are associated with higher future blood pressure. However, few studies have examined the timing of postnatal weight gain in relation to later blood pressure, and little is known regarding the contribution of linear growth. We studied 957 participants in Project Viva, an ongoing US prebirth cohort. We examined the relations of gains in body mass index z-score and length/height z-score during 4 early life age intervals (birth to 6 months, 6 months to 1 year, 1 to 2 years, and 2 to 3 years) with blood pressure during mid-childhood (6–10 years) and evaluated whether these relations differed by birth size. After accounting for confounders, each additional z-score gain in body mass index during birth to 6 months and 2 to 3 years was associated with 0.81 (0.15, 1.46) and 1.61 (0.33, 2.89) mm Hg higher systolic blood pressure, respectively. Length/height gain was unrelated to mid-childhood blood pressure, and there was no evidence of effect modification by birth size for body mass index or length/height z-score gain. Our findings suggest that more rapid gain in body mass index during the first 6 postnatal months and in the preschool years may lead to higher systolic blood pressure in mid-childhood, regardless of size at birth. Strategies to reduce accrual of excess adiposity during early life may reduce mid-childhood blood pressure, which may also impact adult blood pressure and cardiovascular health.

Maternal iron intake and iron status during pregnancy and child blood pressure at age 3 years

BACKGROUND Animal data suggest that maternal iron deficiency during pregnancy leads to lower birth weight and sustained blood pressure elevation in the offspring. In humans, iron deficiency during pregnancy is common and is associated with adverse birth outcomes such as low birth weight. Data are lacking, however, regarding the effects of maternal iron intake and iron status during pregnancy on offspring blood pressure. Our aim was to examine the extent to which lower maternal iron intake, haemoglobin level and mean cell volume (MCV) during pregnancy are associated with higher child systolic blood pressure (SBP) at age 3 years. METHODS We studied 1167 participants in Project Viva, a longitudinal cohort study of pregnant women and their children. We estimated first and second trimester maternal iron intake from food frequency questionnaires. We used an electronic laboratory database to identify haemoglobin and MCV levels in pregnancy. We measured child BP up to five times with a Dinamap and used mixed-effects regression models in our analysis. RESULTS Mean (SD) child SBP at 3 years was 92.0 (9.9) mmHg. Adjusting for confounders, for each 10 mg increase in first trimester iron intake, child SBP was not lower, but was in fact 0.4 mmHg higher (95% CI 0.1, 0.7). For second trimester iron intake, and for first or second trimester haemoglobin and MCV levels, we did not find any appreciable association with 3 year SBP. CONCLUSIONS In contrast to animal studies, we did not find that lower maternal iron status during pregnancy was associated with higher offspring BP.