ABSTRACT
OBJECTIVE: The objective of this study was to examine associations between umbilical cord mitochondrial DNA copy number (mtDNAcn) and adiposity across childhood. METHODS: In a prospective birth cohort of Dominican and African American children from New York City, New York (1998-2006), mtDNAcn was measured in cord blood. Children (N = 336) were evaluated for their height, weight, and bioimpedance at age 5, 7, 9, and 11 years. We used linear mixed-effects models to assess associations of mtDNAcn tertiles in cord blood with child BMI, BMI z scores, fat mass index, and body fat percentage. Latent class growth models and interactions between mtDNAcn and child age or child age2 were used to assess associations between age and adiposity trajectories. RESULTS: BMI was, on average, 1.5 kg/m2 higher (95% CI: 0.58, 2.5) in individuals with mtDNAcn in the low- compared with the middle-mtDNAcn tertile. Results were similar for BMI z score, fat mass index, and body fat percentage. Moreover, children in the low-mtDNAcn group had increased odds of being in an "increasing" or "high-stable" adiposity class. CONCLUSIONS: Lower mtDNAcn at birth may predict greater childhood adiposity, highlighting the potential key role of perinatal mitochondrial function in adiposity during development.
Subject(s)
Adiposity , Body Mass Index , DNA Copy Number Variations , DNA, Mitochondrial , Fetal Blood , Pediatric Obesity , Humans , DNA, Mitochondrial/blood , DNA, Mitochondrial/genetics , Fetal Blood/metabolism , Fetal Blood/chemistry , Adiposity/genetics , Female , Male , Child , Child, Preschool , Prospective Studies , Pediatric Obesity/genetics , Pediatric Obesity/blood , New York City , Black or African American/genetics , Birth Cohort , Dominican RepublicABSTRACT
OBJECTIVES: To develop and validate a prediction model for fat mass in infants ≤12 kg using easily accessible measurements such as weight and length. STUDY DESIGN: We used data from a pooled cohort of 359 infants age 1-24 months and weighing 3-12 kg from 3 studies across Southern California and New York City. The training data set (75% of the cohort) included 269 infants and the testing data set (25% of the cohort) included 90 infants age 1-24 months. Quantitative magnetic resonance was used as the standard measure for fat mass. We used multivariable linear regression analysis, with backwards selection of predictor variables and fractional polynomials for nonlinear relationships to predict infant fat mass (from which lean mass can be estimated by subtracting resulting estimates from total mass) in the training data set. We used 5-fold cross-validation to examine overfitting and generalizability of the model's predictive performance. Finally, we tested the adjusted model on the testing data set. RESULTS: The final model included weight, length, sex, and age, and had high predictive ability for fat mass with good calibration of observed and predicted values in the training data set (optimism-adjusted R2: 92.1%). Performance on the test dataset showed promising generalizability (adjusted R2: 85.4%). The mean difference between observed and predicted values in the testing dataset was 0.015 kg (-0.043 to -0.072 kg; 0.7% of the mean). CONCLUSIONS: Our model accurately predicted infant fat mass and could be used to improve the accuracy of assessments of infant body composition for effective early identification, surveillance, prevention, and management of obesity and future chronic disease risk.
Subject(s)
Adipose Tissue , Body Composition , Adipose Tissue/diagnostic imaging , Adipose Tissue/pathology , Calibration , Child, Preschool , Humans , Infant , Linear Models , ObesityABSTRACT
Gestational weight gain (GWG) is potentially modifiable and is associated with infant size and body composition; however, long-term effects on childhood obesity have not been reported among multi-ethnic urban populations. We examined the association between GWG and child anthropometric measures and body composition at 7 years [waist circumference (WC), body mass index z-score (BMIZ), obesity (BMIZ ≥95%ile) and bioelectrical impedance analysis estimates of percentage body fat (%fat)] in African-American and Dominican dyads (n = 323) in the Columbia Center for Children's Environmental Health prospective birth cohort study from 1998 to 2013. Linear and logistic regression evaluated associations between excessive GWG [>Institute of Medicine (IOM) 2009 guidelines] and outcomes, adjusting for pre-pregnancy BMI and covariates. Pre-pregnancy BMI (mean ± standard deviation, all such values) and total GWG were 25.8 ± 6.2 kg m(-2) (45% overweight/obese) and 16.4 ± 7.9 kg (64% > IOM guidelines), respectively. Excessive GWG was associated with higher BMIZ {0.44 [95% confidence interval (CI): 0.2, 0.7], P < 0.001}, WC [ß: 2.9 cm (95% CI: 1.1, 4.6), P = 0.002], %fat at 7 years [ß: 2.2% (95% CI: 1.0, 3.5), P = 0.001)] and obesity [odds ratio: 2.93 (95% CI: 1.5, 5.8), P = 0.002]. Pre-pregnancy BMI was positively associated with child size, adiposity and obesity (all P < 0.05). Excessive GWG was highly prevalent and was associated with child obesity, greater percentage body fat and abdominal adiposity. Strategies to support healthy GWG are warranted to promote healthy growth and prevent childhood obesity.
Subject(s)
Adiposity , Body Size , Health Promotion , Overweight/ethnology , Pediatric Obesity/ethnology , Weight Gain , Black or African American , Birth Weight , Body Composition , Body Mass Index , Child , Dominican Republic/ethnology , Female , Follow-Up Studies , Hispanic or Latino , Humans , Linear Models , Logistic Models , Male , New York/epidemiology , Pregnancy , Prevalence , Prospective Studies , Risk Factors , Waist CircumferenceABSTRACT
BACKGROUND: Excessive gestational weight gain (GWG) is associated with postpartum weight retention (PPWR) and abdominal adiposity, but long-term effects are understudied in low-income and minority populations at high risk of obesity and associated sequelae. OBJECTIVE: We examined associations between GWG and long-term PPWR and adiposity in a prospective cohort of African American and Dominican mothers in the Bronx and Northern Manhattan. DESIGN: Women (n = 302) were enrolled during pregnancy and were followed for 7 y postpartum. Linear regression was used to relate excessive GWG [greater than 2009 Institute of Medicine (IOM) guidelines] to outcomes [percentage body fat and long-term PPWR (change in weight from prepregnancy to 7 y postpartum)], adjusting for covariates and included an interaction term between prepregnancy body mass index (BMI; in kg/m(2)) and GWG. RESULTS: Mean ± SD prepregnancy BMI and total GWG were 25.6 ± 5.8 (42% of women had BMI ≥25) and 16.6 ± 7.8 kg (64% of women had total GWG greater than IOM guidelines), respectively. Associations between GWG and long-term PPWR and the percentage body fat varied by prepregnancy BMI (P-interaction ≤ 0.06); excessive GWG was associated with a higher percentage body fat and greater long-term PPWR in mothers with lower prepregnancy BMI. To illustrate the interaction, a predicted covariate-adjusted model, which was used to derive estimates for the percentage body fat and PPWR associated with excessive GWG, was estimated for 2 prepregnancy BMI examples. For a woman with prepregnancy BMI of 22, excessive GWG was associated with 3.0% higher body fat (P < 0.001) and a 5.6-kg higher PPWR (P < 0.001); however, for a woman with a prepregnancy BMI of 30, excessive GWG was associated with 0.58% higher body fat (P = 0.55) and 2.06 kg PPWR (P = 0.24). CONCLUSIONS: Long-term adiposity and PPWR in low-income African American and Dominican mothers were predicted by interacting effects of prepregnancy BMI and excessive GWG. The provision of support for mothers to begin pregnancy at a healthy weight and to gain weight appropriately during pregnancy may have important lasting implications for weight-related health in this population. This study was registered at clinicaltrials.gov as NCT00043498.