Faculty Bibliography

BACKGROUND: The prevalence of obesity in U.S. has been rising at an alarming rate, particularly among Hispanic, African, and Asian minority groups. This trend is due in part to excessive calorie consumption and sedentary lifestyle. We sought to investigate whether parental origins influence eating behaviors in healthy urban middle school students. METHODS: A multiethnic/racial population of students (N = 182) enrolled in the ROAD (Reduce Obesity and Diabetes) Study, a school-based trial to assess clinical, behavioral, and biochemical risk factors for adiposity and its co-morbidities completed questionnaires regarding parental origins, length of US residency, and food behaviors and preferences. The primary behavioral questionnaire outcome variables were nutrition knowledge, attitude, intention and behavior, which were then related to anthropometric measures of waist circumference, BMI z-scores, and percent body fat. Two-way analysis of variance was used to evaluate the joint effects of number of parents born in the U.S. and ethnicity on food preference and knowledge score. The Tukey-Kramer method was used to compute pairwise comparisons to determine where differences lie. Analysis of covariance (ANCOVA) was used to analyze the joint effects of number of parents born in the US and student ethnicity, along with the interaction term, on each adiposity measure outcome. Pearson correlation coefficients were used to examine the relationships between maternal and paternal length of residency in the US with measures of adiposity, food preference and food knowledge. RESULTS: African Americans had significantly higher BMI, waist circumference and body fat percentage compared to other racial and ethnic groups. Neither ethnicity/race nor parental origins had an impact on nutrition behavior. Mothers' length of US residency positively correlated with students' nutrition knowledge, but not food attitude, intention or behavior. CONCLUSIONS: Adiposity measures in children differ according to ethnicity and race. In contrast, food behaviors in this middle school sample were not influenced by parental origins. Longer maternal US residency benefited offspring in terms of nutrition knowledge only. We suggest that interventions to prevent obesity begin in early childhood.

Nonclassic actions of vitamin D include potential regulation of immune function and glucose homeostasis. The bone-metabolism loop has recently been expanded to include osteocalcin, which appears to play a more direct role in pancreatic beta cell function and energy metabolism. We hypothesized that both vitamin D and osteocalcin would correlate negatively with indices of adiposity-related co-morbidity risk in periadolescents, varying by ethnic group. We analyzed anthropometric, metabolic and inflammatory markers from a multi-ethnic population of 106 school children 11-14 yrs of age studied as part of the ROAD (Reduce Obesity and Diabetes) consortium. As expected, 25-hydroxyvitamin D was inversely correlated with intact parathyroid hormone (iPTH); total (OCN) and uncarboxylated osteocalcin (uOCN) were directly correlated with each other. OCN, and uOCN concentrations correlated inversely with age. Vitamin D deficiency was most prevalent among East Asians (EA) and African Americans (AA). The highest lipid risk scores and HOMA-IR values (a measure of insulin resistance) were seen in the South Asian (SA) group. Overall, adiposity measures were inversely correlated with OCN and iPTH, whereas such relationships were not observed for vitamin D. Acute insulin response to glucose challenge correlated negatively with uOCN in all subjects, however, lipid risk score correlated negatively with uOCN only in Caucasians. The relationships between markers of calcium metabolism and body composition, glucose homeostasis, lipids, and inflammation all showed racial and ethnic differences. No consistent relationship was found between Vitamin D, and adiposity or glucose metabolism, rather vitamin D levels varied by race and ethnicity in this school-based group. These findings are consistent with the hypothesis that markers of calcium and bone metabolism may reflect risk for adiposity-related co-morbidities in children. (c) 2011 American Society for Bone and Mineral Research

OBJECTIVE: In adults, elevated levels of retinol binding protein 4 (RBP4) have been associated with biochemical markers of adiposity-related co-morbidities including insulin resistance, dyslipidemia, hypertension, and abdominal obesity. This study examined the relationship between RBP4 and risk factors for co-morbidities of adiposity in a population of ethnically diverse children in early- to mid-adolescence in the public school system of New York City. MATERIALS/METHODS: We analyzed anthropometric (body mass index, % body fat, waist circumference), metabolic (lipids, glucose), and inflammatory (TNF-alpha, interleukin-6, C-reactive protein, adiponectin) markers for adiposity-related co-morbidities and serum alanine aminotransferase (ALT) in 106 school children (65 males, 41 females) 11-15 years of age (mean +/- SD = 13.0 +/- 0.1 years) who were enrolled in the Reduce Obesity and Diabetes (ROAD) project. Insulin sensitivity was assessed by quantitative insulin sensitivity check index. Insulin secretory capacity was measured as acute insulin response and glucose disposal index. RESULTS: Serum RBP4 was significantly correlated directly with ALT, triglycerides, and triglyceride z-score, and inversely correlated with adiponectin. Correlations with ALT and adiponectin remained significant when corrected for % body fat, age, and gender. There were significant ethnic differences in the relationship of RBP4 to ALT, glucose disposal index and adiponectin. CONCLUSIONS: In early- to mid-adolescents, circulating concentrations of RBP4 are correlated with multiple risk factors for adiposity-related co-morbidities. The observation that many associations persisted when corrected for % body fat, suggests that RBP4 can be viewed as an independent marker of adiposity-related co-morbidity risk in children.

Short stature is characteristic of children with Prader-Willi syndrome (PWS). While previous studies have demonstrated acceleration of linear height velocity with growth hormone (GH) treatment, the long-term benefit on final adult height (AH) has not been reported. The objective of this study was to compare AH attained in PWS subjects with and without GH treatment. We reviewed the records of 21 children (aged 8.3 +/- 2.7 years) with PWS and confirmed GH deficiency that attained AH after receiving human GH treatment (0.25 +/- 0.06 mg/kg/week) for a period of 7.9 +/- 1.7 years. A group of 39 non-GH-treated adults with matched initial height standard deviation score (SDS) at age 6.8 +/- 1.3 years was used as control. In the GH-treated group the mean initial height and AH-SDS was -1.9 +/- 1.7 and -0.3 +/- 1.2 respectively (P < 0.0001), whereas the mean initial and AH-SDS in the control group was -1.9 +/- 1.3 and -3.1 +/- 1 respectively (P < 0.0001). Scoliosis was seen in 43% and 39% in the GH-treated and control group respectively. Premature adrenarche (PA) was noticed in 57% of GH-treated group. Six subjects in the control group but none of the GH-treated subjects developed type 2 diabetes mellitus. Our data show that administration of GH to children with PWS restores linear growth and final AH without significant adverse effects other than PA. Further studies will be necessary to determine related morbidity and mortality in individuals with PWS that reached final AH with or without GH treatment.