Targeting risk factors for type 2 diabetes in American Indian youth: the Tribal Turning Point pilot study.

BACKGROUND: American Indian (AI) youth are at high risk for type 2 diabetes. OBJECTIVES: To partner with Eastern Band of Cherokee Indians and Navajo Nation to develop a culturally sensitive behavioural intervention for youth (Tribal Turning Point; TTP) and assess feasibility in an 8-month randomized pilot study. METHODS: We enrolled 62 overweight/obese AI children (7-10 years) who participated with ≥1 parent/primary caregiver. Intervention participants (n = 29) attended 12 group classes and five individual sessions. Control participants (n = 33) attended three health and safety group sessions. We analysed group differences for changes in anthropometrics (BMI, BMI z-score, waist circumference), cardiometabolic (insulin, glucose, blood pressure) and behavioural (physical activity and dietary self-efficacy) outcomes. RESULTS: Study retention was 97%, and intervention group attendance averaged 84%. We observed significant treatment effects (p = 0.02) for BMI and BMI z-score: BMI increased in control (+1.0 kg m-2 , p < 0.001) but not intervention participants (+0.3 kg m-2 , p = 0.13); BMI z-score decreased in intervention (-0.17, p = 0.004) but not control participants (0.01, p = 0.82). There were no treatment effects for cardiometabolic or behavioural outcomes. CONCLUSIONS: We demonstrated that a behavioural intervention is feasible to deliver and improved obesity measures in AI youth. Future work should evaluate TTP for effectiveness, sustainability and long-term impact in expanded tribal settings.

Fetal overnutrition and offspring insulin resistance and ß-cell function: the Exploring Perinatal Outcomes among Children (EPOCH) study.

AIMS: To examine the associations of intrauterine exposure to maternal diabetes and obesity with offspring insulin resistance, ß-cell function and oral disposition index in a longitudinal observational study of ethnically diverse offspring. METHODS: A total of 445 offspring who were exposed (n=81) or not exposed (n=364) to maternal diabetes in utero completed two fasting blood measurements at mean (sd) ages of 10.5 (1.5) and 16.5 (1.2) years, respectively, and an oral glucose tolerance test at the second visit. We used linear mixed models and general linear univariate models to evaluate the associations of maternal diabetes and pre-pregnancy BMI with offspring outcomes. RESULTS: Maternal diabetes in utero predicted increased insulin resistance [18% higher updated homeostatic model assessment of insulin resistance (HOMA2-IR), P=0.01; 19% lower Matsuda index, P=0.01 and 9% greater updated homeostatic model assessment of ß-cell function (HOMA2-ß), P=0.04]. Each 5-kg/m2 increase in pre-pregnancy BMI predicted increased insulin resistance (11% greater HOMA2-IR, P<0.001; 10% lower Matsuda index, P<0.001; 6% greater HOMA2-ß, P<0.001). Similar results were obtained in a combined model with both exposures. After adjustment for offspring BMI, only maternal diabetes was associated with higher HOMA2-IR (ß=1.12, P=0.03) and lower Matsuda index (ß=0.83, P=0.01). Neither exposure was associated with early insulin response or oral disposition index. CONCLUSIONS: Intrauterine exposure to diabetes or obesity is associated with greater offspring insulin resistance than non-exposure, supporting the hypothesis that fetal overnutrition results in metabolic abnormalities during childhood and adolescence.

Vitamin D status and muscle function in children with neurofibromatosis type 1 (NF1).

OBJECTIVES: The aim of this cross-sectional study was to assess the vitamin D status and muscle function in children with NF1 compared with their unaffected siblings. METHODS: NF1 children between 5 and 18 years of age and who had at least one unaffected sibling were identified. Serum concentrations of 25-hydroxyvitamin D (25(OH)D), calcium, inorganic phosphate, alkaline phosphate, parathyroid hormone and 1,25-dihydroxyvitamin D were measured. The Leonardo Mechanography Ground Reaction Force Platform (GRFP) was used to measure EFI, jump power, force and height. RESULTS: There was no significant difference in 25(OH)D between NF1 subjects and unaffected siblings. Relative jump power and force were found to be significantly different. The adjusted means (95% confidence limits) of non-NF1 and NF1 children for relative jump power (W/kg), controlling for body mass and age, were 37.31 (34.14, 40.49) and 32.51 (29.34, 35.68), respectively (P=0.054); and force (N/kg), controlling for body mass, age and gender, were 25.79 (24.28, 27.30) and 21.12 (19.61, 22.63), respectively (P<0.0001). Jumping parameters were not related to serum 25(OH)D. CONCLUSIONS: There was no significant relationship between vitamin D status and NF1 status in children. NF1 children had significantly impaired jumping power and force, when compared to their unaffected siblings.