RESUMEN
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.
Asunto(s)
Tejido Adiposo , Composición Corporal , Tejido Adiposo/diagnóstico por imagen , Tejido Adiposo/patología , Calibración , Preescolar , Humanos , Lactante , Modelos Lineales , ObesidadRESUMEN
OBJECTIVE: To examine the impact of maternal gestational diabetes mellitus (GDM) status on longitudinal changes in adiposity and metabolic variables in overweight Latino offspring (from age 8-20 years) across puberty. STUDY DESIGN: This longitudinal cohort of 210 overweight Latino children was measured annually for a period of 3 ± 1 years for Tanner stage through physical examination, adiposity by dual-energy X-ray absorptiometry and magnetic resonance imaging, lipids, and glucose and insulin action via the oral glucose tolerance test and frequently sampled intravenous glucose tolerance test. Linear mixed-effects modeling estimated the impact of maternal GDM status on baseline and changes in adiposity and metabolic variables across puberty. RESULTS: In our cohort, 22% of offspring were from GDM pregnancies. At baseline, the GDM offspring were heavier at birth, more likely to have a family history of type 2 diabetes, and less likely to have been breastfed (for any duration). Compared with the non-GDM offspring, the GDM offspring had greater increases in total body fat (+6.5% vs +4.5%; P = .03) and steeper declines in acute insulin response (-39% vs -17%; P < .001) and disposition index (-57% vs -35%; P < .001) across Tanner stages, independent of ethnicity, sex, breastfeeding status, family history of diabetes, and baseline and changes in body composition. CONCLUSION: These findings confirm the elevated risk for excess adiposity and type 2 diabetes in GDM offspring, and further underscore the need for interventions targeting Latino GDM and their offspring.
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Diabetes Gestacional/fisiopatología , Absorciometría de Fotón/métodos , Adiposidad , Adolescente , Adulto , Glucemia/metabolismo , Niño , Estudios de Cohortes , Femenino , Prueba de Tolerancia a la Glucosa , Hispánicos o Latinos , Humanos , Insulina/metabolismo , Lípidos/química , Estudios Longitudinales , Imagen por Resonancia Magnética/métodos , Masculino , Embarazo , Efectos Tardíos de la Exposición Prenatal , PubertadAsunto(s)
Hígado Graso/etnología , Hígado Graso/etiología , Fructosa/efectos adversos , Predisposición Genética a la Enfermedad , Hispánicos o Latinos/genética , Edulcorantes/efectos adversos , Dieta/tendencias , Carbohidratos de la Dieta/efectos adversos , Humanos , Lipasa/genética , Proteínas de la Membrana/genética , México/epidemiología , Estados Unidos/epidemiologíaRESUMEN
OBJECTIVE: To evaluate how adolescents with or at risk for type 2 diabetes mellitus (T2DM) and their parent/guardians (parents) perceive adolescents' health-related quality of life. STUDY DESIGN: We interviewed overweight/obese, 12- to 18-year-old youth with T2DM, prediabetes, or insulin resistance and one parent from 5 US sites. Assessments included Pediatric Quality of Life Inventory (PedsQL), Health Utilities Index, family conflict, and diabetes burden. RESULTS: In 108 adolescents, diagnoses included 40.7% with T2DM, 25.0% with prediabetes, and 34.3% with insulin resistance. PedsQL summary score (SS) was higher in adolescents than parents (P=.02). Parents rated physical functioning lower than adolescents (P<.0001), but there were no differences in psychosocial health. Adolescent PedsQL SS did not differ with diagnosis, but was inversely associated with adolescent body mass index z-score (P=.0004) and family conflict (P<.0001) and associated with race/ethnicity (P<.0001). Number of adolescent co-morbidities (P=.007) and burden of diabetes care (P<.05) were inversely associated with parent PedsQL SS. There were no differences in the Health Utilities Index-Mark 3 multi-attribute utility score. CONCLUSIONS: Parents perceive their adolescents' physical functioning as more impaired than adolescents themselves. Contextual factors including severity of obesity, race/ethnicity, family conflict, and burden of diabetes care influence health-related quality of life. Family-based approaches to treatment and prevention of T2DM may benefit from increased attention to the biopsychosocial context.
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Diabetes Mellitus Tipo 2/psicología , Estado de Salud , Calidad de Vida , Medición de Riesgo/métodos , Adolescente , Adulto , Actitud Frente a la Salud , Niño , Diabetes Mellitus Tipo 2/epidemiología , Femenino , Humanos , Incidencia , Masculino , Pronóstico , Psicometría/métodos , Factores de Riesgo , Encuestas y Cuestionarios , Estados Unidos/epidemiologíaRESUMEN
OBJECTIVE: To examine whether a hemoglobin A1c (HbA1c)-identified prediabetic state (HbA1c ≥ 6.0%-6.4%) is associated with decreased insulin sensitivity (SI) and ß-cell dysfunction, known factors in the pathogenesis of type 2 diabetes, in an overweight pediatric population. STUDY DESIGN: A total of 206 healthy overweight Latino adolescents (124 males and 82 females; mean age, 13.1 ± 2.0 years) were divided into 2 groups: lower risk (n=179), with HbA1c <6.0%, and higher risk (n=27), with HbA1c 6.0%-6.4%. Measurements included HbA1c, oral glucose tolerance testing, fasting and 2-hour glucose and insulin, SI, acute insulin response, and disposition index (an index of ß-cell function) by the frequently sampled intravenous glucose tolerance test with minimal modeling. Body fat was determined by dual-energy X-ray absorptiometry. RESULTS: Compared with the lower risk group, the higher risk group had 21% lower SI (1.21 ± 0.06 vs 1.54 ± 0.13; P<.05), 30% lower acute insulin response (928 ± 102 vs 1342 ± 56; P<.01), and a 31% lower disposition index (1390 ± 146 vs 2023 ± 83; P=.001) after adjusting for age and total percent body fat. CONCLUSION: These data provide clear evidence of greater impairment of ß-cell function in overweight Latino children with HbA1c 6.0%-6.4%, and thereby support the adoption of the International Expert Committee's HbA1c-determined definition of high-risk state for overweight children at risk for type 2 diabetes.
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Diabetes Mellitus Tipo 2/diagnóstico , Hemoglobina Glucada/análisis , Células Secretoras de Insulina/metabolismo , Sobrepeso/sangre , Adolescente , Distribución por Edad , Índice de Masa Corporal , Cromatografía Líquida de Alta Presión/métodos , Estudios de Cohortes , Diabetes Mellitus Tipo 2/etnología , Femenino , Prueba de Tolerancia a la Glucosa , Hemoglobina Glucada/metabolismo , Hispánicos o Latinos/estadística & datos numéricos , Humanos , Incidencia , Resistencia a la Insulina/fisiología , Masculino , Sobrepeso/etnología , Valor Predictivo de las Pruebas , Estudios Prospectivos , Valores de Referencia , Medición de RiesgoRESUMEN
OBJECTIVE: To assess carotid artery intima-media thickness (CIMT) change over 2 years in overweight Latino adolescents and examine its relationship to cardiometabolic risk. STUDY DESIGN: Seventy-two healthy overweight male and female Latino adolescents (mean age, 14.5 ± 1.7 years; mean body mass index, 31.5 ± 6.9 kg/m(2)) were evaluated at baseline and 2 years later for CIMT by high-resolution B-mode ultrasound, the metabolic syndrome and its features, body composition by dual-energy x-ray absorptiometry and magnetic resonance imaging, glucose/insulin measures by fasting blood, and oral and intravenous glucose tolerance tests. RESULTS: Baseline CIMT did not differ from 2-year follow-up; however, 38 participants increased CIMT (0.017 ± 0.003 mm; +2.8%) and 34 decreased or remained the same (-0.019 ± 0.002 mm; -3.1%). ANCOVA analyses showed that participants with CIMT progression had higher baseline low-density lipoprotein (LDL)-cholesterol and total cholesterol (91.3 ± 3.4 and 150.3 ± 3.9 mg/dL) compared with those with CIMT non-progression (78.1 ± 3.6 and 135.6 ± 4.2 mg/dL, P < .05), independent of sex, baseline CIMT, age, and height. In multivariate regression, LDL-cholesterol was the sole predictor of CIMT progression, but the effect was small (odds of CIMT progression increased by 3% for each 1 mg/dL higher baseline LDL-cholesterol; 95% CI, 1.004 to 1.006, P = .03). CONCLUSIONS: These results indicate a high variability in the magnitude of CIMT change in growing overweight Latino youth and support the use of LDL-cholesterol to assess subclinical atherosclerosis risk in this population.
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Aterosclerosis/diagnóstico , Enfermedades Cardiovasculares/metabolismo , Túnica Íntima/patología , Túnica Media/patología , Adolescente , Aterosclerosis/epidemiología , Índice de Masa Corporal , HDL-Colesterol/metabolismo , LDL-Colesterol/metabolismo , Femenino , Hispánicos o Latinos , Humanos , Masculino , Sobrepeso , Riesgo , Factores de RiesgoRESUMEN
OBJECTIVE: To examine changes in insulin sensitivity (SI), compensatory acute insulin response (AIR), and ß-cell function/disposition index (DI) across puberty in overweight Latino boys and girls. STUDY DESIGN: Latino children (n = 253) were followed annually for up to 5 years. Longitudinal modeling was used to examine changes in SI, AIR, DI, and fasting and 2-hour glucose and insulin across Tanner stage. RESULTS: In boys, SI decreased in early puberty with a recovery by late puberty. The compensatory increase in AIR was appropriate in early maturation, but after Tanner stage 3, AIR declined by more than that predicted from the recovery in SI. For girls, SI decreased in early puberty and across all stages of maturation. In early maturation, there was an appropriate compensatory increase in AIR, but after Tanner stage 3, AIR decreased. Thus, DI deteriorated across puberty in boys and girls. CONCLUSIONS: In overweight Hispanic youth, compensatory changes in insulin secretion fails after Tanner stage 3 in both sexes, indicating ß-cell deterioration during this critical period of development, thus increasing risk for type 2 diabetes.
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Hispánicos o Latinos , Resistencia a la Insulina/etnología , Células Secretoras de Insulina/metabolismo , Insulina/metabolismo , Sobrepeso/etnología , Pubertad , Adolescente , Niño , Femenino , Humanos , Estudios Longitudinales , Los Angeles/epidemiología , Masculino , Sobrepeso/metabolismo , Análisis de Regresión , Factores SexualesRESUMEN
OBJECTIVE: To examine an association between persistent metabolic syndrome (MetS) and the risk for type 2 diabetes in overweight Hispanic children. STUDY DESIGN: A total of 73 subjects (mean age, 11.0 +/- 1.7 years) from a longitudinal study were classified as Never (negative for MetS at all 3 annual visits), Intermittent (positive for MetS at 1 or 2 visits), or Persistent (positive for MetS at all 3 visits). Measures included dual-energy x-ray absorptiometry, magnetic resonance imaging, the 2-hour oral glucose tolerance test, and the frequently sampled intravenous glucose tolerance test. RESULTS: The Persistent group had a faster rate of fat mass gain than the Never group (20% vs 15% gain of baseline value; P < .05 for time *group interaction [time = visit]). Independent of body composition, the Persistent group increased by 70% in insulin incremental area under the curve, whereas the other groups decreased (P < .05 for time *group interaction). Despite no time *group interactions for insulin sensitivity, acute insulin response, or disposition index, the Persistent group maintained 43% lower insulin sensitivity (P < .01) and by visit 2 had a 25% lower disposition index (P < .05) compared with the Never group. CONCLUSIONS: Patients with persistent MetS had accelerated fat gain, increased insulin response to oral glucose, and decreased sensitivity and beta cell function, indicators of progressively greater risk for type 2 diabetes.
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Diabetes Mellitus Tipo 2/etnología , Hispánicos o Latinos/estadística & datos numéricos , Síndrome Metabólico/etnología , Sobrepeso/complicaciones , Sobrepeso/etnología , Adiposidad , Glucemia/metabolismo , Niño , Femenino , Humanos , Resistencia a la Insulina/fisiología , Estudios Longitudinales , Masculino , Síndrome Metabólico/diagnóstico , Visita a Consultorio Médico , Sobrepeso/metabolismo , Factores de RiesgoAsunto(s)
Diabetes Mellitus Tipo 2/epidemiología , Adolescente , Niño , Femenino , Hispánicos o Latinos , Humanos , Los Angeles/epidemiología , Masculino , PrevalenciaRESUMEN
OBJECTIVE: To examine the prevalence of the metabolic syndrome in overweight Hispanic youth according to 3 published pediatric definitions. Furthermore, the relationship of each definition to directly measured insulin resistance was examined. STUDY DESIGN: We conducted a secondary data analysis of 218 overweight Hispanic youth with a family history of type 2 diabetes mellitus. The metabolic syndrome was defined as >/=3 of these criteria: elevated triglyceride level, low high-density lipoprotein cholesterol level, elevated blood pressure, abdominal obesity, and hyperglycemia. The cutoff points were derived from updated definitions of Cook et al,(1) Cruz et al,(2) and Weiss et al.(3) Insulin sensitivity was determined with the insulin-modified frequently sampled intravenous glucose tolerance test. RESULTS: Prevalence of the metabolic syndrome ranged from 25.7% to 39%, with moderate to substantial agreement between definitions (kappa = 0.52-0.70). Regardless of definition, an inverse relationship between metabolic risk and insulin sensitivity was noted such that children with the metabolic syndrome had 51% to 60% lower insulin sensitivity compared with children without any risk factors (P
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Resistencia a la Insulina , Síndrome Metabólico/complicaciones , Síndrome Metabólico/diagnóstico , Pediatría/normas , Adolescente , Composición Corporal , Índice de Masa Corporal , Niño , Complicaciones de la Diabetes/diagnóstico , Diabetes Mellitus Tipo 2/diagnóstico , Femenino , Hispánicos o Latinos , Humanos , Hiperglucemia/metabolismo , Insulina/metabolismo , Masculino , Síndrome Metabólico/etnología , Obesidad , SobrepesoRESUMEN
OBJECTIVE: Parental child-feeding practices are potentially significant determinants of body weight in youth. To date, research has focused on white middle class mother-child dyads. This study examines the longitudinal influences of child-feeding practices with time on total fat mass in white and African American boys and girls. STUDY DESIGN: Seventy-four white children (49 girls, 25 boys) and 47 African American children (25 girls, 22 boys; mean age at baseline, 11.0 years) and their mothers participated in this study. Child-feeding practices were measured with the Child Feeding Questionnaire. Total fat mass was measured by means of Dual energy X-ray absorptiometry on a yearly basis. The average follow-up period was 2.7 years. RESULTS: Pressure to eat and concern for the child's weight in white participants and restriction and concern for the child's weight in African American participants were significantly related to total fat mass at baseline. Concern for the child's weight was negatively related to the change of total fat mass with time in white participants. No longitudinal effects of child feeding practices on the change of total fat mass were found in African American participants. CONCLUSION: Parental concern for weight is a predictor of change in total fat mass with time in white children, but not African American children.
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Fenómenos Fisiológicos Nutricionales Infantiles , Conducta Alimentaria , Conocimientos, Actitudes y Práctica en Salud , Relaciones Madre-Hijo , Obesidad/prevención & control , Población Negra , Índice de Masa Corporal , Niño , Femenino , Conductas Relacionadas con la Salud , Humanos , Estudios Longitudinales , Masculino , Obesidad/etnología , Encuestas y Cuestionarios , Estados Unidos , Población BlancaRESUMEN
OBJECTIVE: To determine longitudinal changes in insulin sensitivity (SI), insulin secretion, and beta-cell function during puberty in white and black youth. STUDY DESIGN: The tolbutamide-modified frequently sampled intravenous glucose tolerance test and minimal modeling were used to measure SI, the acute insulin response to glucose (AIRg), and beta-cell function (disposition index, DI) in white (n = 46) and black (n = 46) children (mean [+/-SD] age at baseline = 10.2 +/- 1.7 years). Growth curve models (including 272 observations) with SI, AIRg, and DI regressed on Tanner stage were run after adjusting for covariates. RESULTS: After adjusting for covariates, growth curve models revealed that SI decreased and subsequently recovered by the end of puberty in whites and blacks (both p < .05), AIRg decreased linearly across Tanner stages in both races (both p < .001), and DI decreased across puberty in blacks (p = .001) but not in whites (p = .2). CONCLUSIONS: White and black youth exhibited transient insulin resistance and diminished AIRg during puberty. The progressive decline in DI among blacks versus whites may reflect a unique effect of puberty on beta-cell compensation in blacks. Future studies are needed to identify whether this difference contributes to the increased risk of type II diabetes in young blacks.