[show abstract][hide abstract] ABSTRACT: The purpose of this study was to examine ethnic differences in the metabolic responses to a 16-week intervention designed to improve insulin sensitivity (SI), adiposity, and inflammation in obese African-American and Latino adolescents. A total of 100 participants (African Americans: n = 48, Latino: n = 52; age: 15.4 ± 1.1 years, BMI percentile: 97.3 ± 3.3) were randomly assigned to interventions: control (C; n = 30), nutrition (N; n = 39, 1×/week focused on decreasing sugar and increasing fiber intake), or nutrition + strength training (N+ST; n = 31, 2×/week). The following were measured at pre- and postintervention: strength, dietary intake, body composition (dual-energy X-ray absorptiometry/magnetic resonance imaging) and glucose/insulin indexes (oral glucose tolerance test (OGTT)/intravenous glucose tolerance test (IVGTT)) and inflammatory markers. Overall, N compared to C and N+ST reported significant improvements in SI (+16.5% vs. -32.3% vs. -6.9% respectively, P < 0.01) and disposition index (DI: +15.5% vs. -14.2% vs. -13.7% respectively, P < 0.01). N+ST compared to C and N reported significant reductions in hepatic fat fraction (HFF: -27.3% vs. -4.3% vs. 0% respectively, P < 0.01). Compared to N, N+ST reported reductions in plasminogen activator inhibitor-1 (PAI-1) (-38.3% vs. +1.0%, P < 0.01) and resistin (-18.7% vs. +11.3%, P = 0.02). There were no intervention effects for all other measures of adiposity or inflammation. Significant intervention by ethnicity interactions were found for African Americans in the N group who reported increases in total fat mass, 2-h glucose and glucose incremental areas under the curve (IAUC) compared to Latinos (P's < 0.05). These interventions yielded differential effects with N reporting favorable improvements in SI and DI and N+ST reporting marked reductions in HFF and inflammation. Both ethnic groups had significant improvements in metabolic health; however some improvements were not seen in African Americans.
[show abstract][hide abstract] ABSTRACT: To examine changes in insulin sensitivity (SI), compensatory acute insulin response (AIR), and β-cell function/disposition index (DI) across puberty in overweight Latino boys and girls.
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.
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.
In overweight Hispanic youth, compensatory changes in insulin secretion fails after Tanner stage 3 in both sexes, indicating β-cell deterioration during this critical period of development, thus increasing risk for type 2 diabetes.
The Journal of pediatrics 09/2010; 158(3):442-6. · 4.02 Impact Factor
[show abstract][hide abstract] ABSTRACT: Purpose: The objectives of this study were to examine 1) whether changes in total physical activity (PA; counts per minute, cpm) and time spent in moderate to vigorous PA (MVPA) are associated with changes in adiposity and 2) whether energy intake influences the relationship between changes in PA and changes in adiposity in overweight Hispanic adolescents.
Methods: Analysis included 38 overweight (body mass index, >85th percentile) Hispanic adolescents with complete pretest and posttest data on relevant variables after participating in a 16-wk intervention. The intervention treatment did not influence PA, so the sample was combined and the randomization group was adjusted for in the analysis. Body composition by dual-energy x-ray absorptiometry, 7-d PA by accelerometry, and dietary intake by 3-d diet records were assessed before and after intervention.
Results: Within individuals, the mean increase of PA (n = 19) and mean decrease of PA (n = 19) was approximately 105 cpm. A 100-cpm increase in total PA was associated with a decrease of 1.3 kg of fat mass and 0.8% body fat after adjusting for pretest adiposity, PA, age, sex, and treatment (P < 0.05). Controlling for energy intake modestly strengthened the relationships between total PA and fat mass and percent body fat. Changes in MVPA were not related to changes in adiposity after controlling for total PA (P > 0.05).
Conclusions: Increasing total PA by 28% (100 cpm) was associated with a decrease of 1.4 kg of fat mass and 1% body fat for 16 wk in overweight Hispanic adolescents independent of intervention group assignment. Increases in total PA, compared with MVPA, may be sufficient to improve body composition in overweight Hispanic adolescents.
Medicine & Science in Sports & Exercise 02/2010; 42(3):478-484. · 4.48 Impact Factor
[show abstract][hide abstract] ABSTRACT: We examined dietary fiber intake, food sources of dietary fiber, and relation of dietary fiber to body composition and metabolic parameters in college students with plausible dietary reports.
Students (18-24 y of age) provided data on anthropometry, fasting blood chemistries, and body composition (bioelectric impedance). Diet and physical activity were assessed with the Diet History Questionnaire and the International Physical Activity Questionnaire. Plausible dietary reporters were identified (+/-1 SD cutoffs for reported energy intake as a percentage of predicted energy requirement). Multiple regression analyses were conducted with the total (n = 298) and plausible (n = 123) samples, adjusting for age, race, sex, smoking status, physical activity, energy intake, and fat-free mass (where applicable).
Food sources of dietary fiber were similar in men and women. In the plausible sample compared with the total sample, dietary fiber was more strongly associated with fat mass (beta = -0.24, P < 0.001), percentage of body fat (beta = -0.23, P < 0.001), body mass index (beta = -0.11, P < 0.01), waist circumference (beta = -0.67, P < 0.05), and fasting insulin (beta = -0.15, P < 0.001). When the effect of sex was investigated, dietary fiber was inversely related to fasting insulin and fat mass in men and women and inversely related to percentage of body fat, body mass index, and waist circumference in men only (P < 0.05).
Inclusion of implausible dietary reports may result in spurious or weakened diet-health associations. Dietary fiber is negatively associated with fasting insulin levels in men and women and consistently associated with adiposity measurements in men.
[show abstract][hide abstract] ABSTRACT: Few randomized trials attempt to improve insulin sensitivity and associated metabolic risks in overweight Latino youth. The purpose of this study is to examine the effects of a modified carbohydrate nutrition program combined with strength training on insulin sensitivity, adiposity, and other type 2 diabetes risk factors in overweight Latino adolescents. In a 16-week randomized trial, 54 overweight Latino adolescents (15.5 +/- 1.0 years) were randomly assigned to: (i) Control (C; n = 16), (ii) Nutrition (N; n = 21), or (iii) Nutrition + Strength training (N+ST; n = 17). The N group received modified carbohydrate nutrition classes (once per week), while the N+ST received the same nutrition classes plus strength training (twice per week). The following were measured at pre- and postintervention: strength by 1-repetition maximum, dietary intake by 3-day records, body composition by dual-energy X-ray absorptiometry, glucose/insulin indices by oral glucose tolerance test (OGTT) and intravenous glucose tolerance test with minimal modeling. Across intervention group effects were tested using analysis of covariance with post hoc pairwise comparisons. A significant overall intervention effect was found for improvement in bench press (P < 0.001) and reductions in energy (P = 0.05), carbohydrate (P = 0.04) and fat intake (P = 0.03). There were no significant intervention effects on insulin sensitivity, body composition, or most glucose/insulin indices with the exception of glucose incremental area under the curve (IAUC) (P = 0.05), which decreased in the N and N+ST group by 18 and 6.3% compared to a 32% increase in the C group. In conclusion, this intense, culturally tailored intervention resulted in no significant intervention effects on measured risk factors with the exception of a beneficial effect on glycemic response to oral glucose.
[show abstract][hide abstract] ABSTRACT: To investigate the importance of a maternal and paternal family history of Type 2 diabetes and their combined association with plasma leptin and adiponectin levels in overweight Latino children with a family history of Type 2 diabetes (T2DM).
This cross-sectional study investigated the combined association of a maternal and paternal family history of T2DM with leptin and adiponectin in 175 overweight Latino children (age 11.1 +/- 1.7 years). All subjects had a family history of T2DM. Plasma adiponectin and leptin levels, body fat measured by dual-energy X-ray absorptiometry, Tanner stage, age and insulin sensitivity were assessed.
After adjustment for age, gestational diabetes, insulin sensitivity and body fat, a combined maternal and paternal family history of T2DM was associated with higher leptin concentrations (P = 0.004) compared with a maternal or paternal family history alone. This association was most pronounced at Tanner stage 1 (P for interaction family history x tanner stage = 0.022). The presence of a combined maternal and paternal family history of T2DM accounted for 4% (P = 0.003) of the variation in leptin concentrations. No such combined association was observed for adiponectin levels.
Maternal and paternal family history of T2DM may have an additive impact on leptin, but not on adiponectin levels independent of adiposity and insulin sensitivity in overweight Latino children. This may contribute to a further clinically relevant deterioration of metabolic health in this population.
Diabetic Medicine 10/2008; 25(9):1043-8. · 3.24 Impact Factor
[show abstract][hide abstract] ABSTRACT: To examine the associations between birth weight and BMI, and total body composition, in overweight Latino adolescents. Two hundred and forty-two overweight Latino children (baseline age = 11.1 +/- 1.7 years; BMI >or= 85th percentile) were measured annually for up to 6 years (2.6 +/- 1.4 observations/child, total 848 visits). Birth weight and history of gestational diabetes were obtained by parental interview. Visceral fat and subcutaneous abdominal fat were assessed by magnetic resonance imaging, while total body fat, total lean tissue mass (LTM), trunk fat, and lean tissue trunk mass were measured by dual-energy X-ray absorptiometry. BMI and BMI percentile were calculated using the Centers for Disease Control and Prevention age appropriate cutoffs. Longitudinal linear mixed effects (LME) modeling was used to evaluate the influence of birth weight on subsequent changes in body composition and distribution of fat across puberty. Birth weight significantly predicted BMI (P < 0.001), total trunk fat (P < 0.001), total trunk LTM (P < 0.001), total fat mass (FM) (P < 0.001), and total LTM (P < 0.001), but not subcutaneous (P = 0.534) or visceral fat (P = 0.593) at age 11 years. Longitudinally, as participants transitioned into puberty, birth weight did not significantly predict any of the body composition or fat distribution measures (P > 0.05). Birth weight is significantly associated with increased adiposity and LTM and negatively associated with trunk fat mass and trunk lean mass at baseline; however these relationships did not predict rate of change of any of the variables as the children progress through adolescence.
[show abstract][hide abstract] ABSTRACT: Little is known about the relationship between diet and metabolic health in Latino children, a population at increased risk for diabetes. The present study evaluates diet composition and the metabolic syndrome in a cross-sectional sample of 109 overweight Latino children aged 10 to 17 years with a family history of type 2 diabetes. Dietary intake was assessed by two 24-hour recalls. Associations between nutrients and features of the metabolic syndrome were examined using multiple linear regression and analysis of covariance. Log cholesterol intake was positively associated with log systolic blood pressure (beta=0.034, P=0.017) and log soluble dietary fiber intake was inversely associated with log waist circumference (beta=-0.069, P=0.036). Log soluble fiber intake was significantly higher in participants with 0 features compared to those with 3+ features of the metabolic syndrome (P=0.046), which translates to 5.2 g vs 4.1 g soluble fiber daily. No other significant associations were found between dietary variables and either the individual features of the metabolic syndrome or the clustering of metabolic syndrome components. Increases in soluble fiber through the daily consumption of fruits, vegetables, and beans may improve metabolic health in Latino children.
Journal of the American Dietetic Association 08/2008; 108(8):1355-9. · 3.80 Impact Factor
[show abstract][hide abstract] ABSTRACT: The aim of the study was to investigate the independent effects of leptin and adiponectin on insulin sensitivity as well as insulin secretion and beta-cell function in overweight Hispanic adolescents. Despite pubertal changes in hormone secretion, studies investigating the independent effect of both hormones on insulin sensitivity and beta-cell function in adolescents are lacking. In a cross-sectional study, 175 overweight Hispanic adolescent boys (n=101) and girls (n=74) with a family history of diabetes were recruited and insulin sensitivity (SI), acute insulin response to glucose (AIR), disposition index (DI), body composition, total serum adiponectin, and leptin were assessed. Over age, leptin significantly increased in girls but not in boys (p for age x gender interaction=0.005) while adiponectin was similar in boys and girls. Leptin was not correlated to adiponectin. Leptin (partial r=-0.180; p=0.019) and adiponectin (partial r=0.230; p=0.003) predicted SI independent of age, gender, body fat, lean body mass, and Tanner stage but together, they explained 5% of the unique variation in SI (p for R (2)-change<0.001). Leptin or adiponectin were not related to AIR or DI. With regard to SI, AIR, and DI, no significant gender, age, or Tanner stage interactions were observed suggesting similar effects of adiponectin and leptin among gender, age, and Tanner stages. Leptin and adiponectin were independently associated with SI, but not with insulin secretion or beta-cell function.
Hormone and Metabolic Research 06/2008; 40(10):708-12. · 2.15 Impact Factor
[show abstract][hide abstract] ABSTRACT: We have previously shown that cardiorespiratory fitness predicts increasing fat mass during growth in white and African-American youth, but limited data are available examining this issue in Hispanic youth. Study participants were 160 (53% boys) overweight (BMI>or=85th percentile for age and gender) Hispanic children (mean+/-s.d. age at baseline=11.2+/-1.7 years). Cardiorespiratory fitness, assessed by VO2max, was measured through a maximal effort treadmill test at baseline. Body composition through dual-energy X-ray absorptiometry and Tanner stage through clinical exam were measured at baseline and annually thereafter for up to 4 years. Linear mixed models were used to examine the gender-specific relationship between VO2max and increases in adiposity (change in fat mass independent of change in lean tissue mass) over 4 years. The analysis was adjusted for changes in Tanner stage, age, and lean tissue mass. In boys, higher VO2max at baseline was inversely associated with the rate of increase in adiposity (beta=-0.001, P=0.03); this effect translates to a 15% higher VO2max at baseline resulting in a 1.38 kg lower fat mass gain over 4 years. However, VO2max was not significantly associated with changes in fat mass in girls (beta=0.0002, P=0.31). In overweight Hispanic boys, greater cardiorespiratory fitness at baseline was protective against increasing adiposity. In girls however initial cardiorespiratory fitness was not significantly associated with longitudinal changes in adiposity. These results suggest that cardiorespiratory fitness may be an important determinant of changes in adiposity in overweight Hispanic boys but not in girls.
[show abstract][hide abstract] ABSTRACT: It has been suggested that young children regulate their daily energy intake very closely with highly stable day-to-day total energy intake. This hypothesis was developed on the basis of an experimental study of 15 children aged 26 to 62 months, which reported a within-subject coefficient of variation (CV) in daily energy intake of 10.4%. We tested the hypothesis that free-living energy intakes were highly stable on a day-to-day basis in a sample of free-living young children from Glasgow, Scotland. In 101 children (47 boys) aged 2.6-6.8 years, energy intake was measured using multiple-pass 24-hour recalls. Within-subject CV was 19.2% which was significantly higher than the 10.4% reported by Birch and colleagues (p<0.0001). In addition, we identified four other studies on free-living children with within-subject CV's ranging from 16.1-28.7%. This evidence indicates that young children show a wide intra-individual variation in day-to-day regulation of energy intake in a free-living environment.
Archives of Disease in Childhood 05/2008; · 3.05 Impact Factor
[show abstract][hide abstract] ABSTRACT: The purpose of this article was to examine metabolic risk factors for type 2 diabetes in children and adolescents as a function of maternal versus paternal family history of type 2 diabetes and to examine whether differences in these risk factors emerge during adolescent growth.
A total of 247 overweight Latino children (baseline age = 11.1 +/- 1.7 years) with a parental history of type 2 diabetes were followed annually for 5 years (2.2 +/- 1.2 observations/child) with measures of insulin sensitivity, acute insulin response to glucose, and disposition index. Longitudinal linear mixed-effects modeling was used to evaluate the influence of maternal versus paternal family history of type 2 diabetes on changes in diabetes risk factors over age.
Insulin sensitivity and the disposition index decreased over age (beta = -0.052 and beta = -0.033, P < 0 0.01). Acute insulin response to glucose and fasting and 2-h glucose increased (beta = 0.019, beta = 0.002, and beta = 0.003, P < 0.01). Declines in insulin sensitivity were significantly greater in participants whose maternal grandmothers had a history of type 2 diabetes (beta = -0.03, P = 0.03). Declines in the disposition index (beta = -0.02, P = 0.04) and increases in fasting glucose were significantly influenced by a maternal history of type 2 diabetes (beta = 0.60, P < 0.05).
Maternal but not paternal family history for diabetes may have a significant impact on insulin dynamics, becoming more pronounced during growth in overweight Latino adolescents. Further research is clearly warranted.
Diabetes care 11/2007; 30(10):2700-5. · 7.74 Impact Factor
[show abstract][hide abstract] ABSTRACT: Few studies have examined the relation between dietary carbohydrate quality, adiposity, and insulin dynamics in children.
The objective of the study was to determine which aspects of dietary carbohydrate, specifically dietary sugar, fiber, glycemic index, or glycemic load, are associated with adiposity and insulin dynamics in overweight Latino children.
We examined 120 overweight Latino children (10-17 y old) with a family history of type 2 diabetes. Dietary intake was determined by repeated 24-h diet recalls. Adiposity was assessed by using total-body dual-energy X-ray absorptiometry. Insulin dynamics [insulin sensitivity (SI), acute insulin response, and disposition index (an index of beta-cell function)] were measured by using a frequently sampled intravenous-glucose-tolerance test.
After adjustment for covariates, total sugar (g/d) was positively correlated with body mass index (BMI; in kg/m(2)), BMI z scores, and total fat mass (r = 0.20, r = 0.22, and r = 21, respectively; P < 0.05) and negatively correlated with SI and disposition index (r = -0.29 and r = -0.24, respectively; P < 0.05). Dietary fiber, glycemic index, and glycemic load were not significantly correlated with adiposity or insulin dynamics before or after control for covariates. Regression analyses showed that total sugar intake explained an additional 3.4%, 4.6%, and 2.4% of the variance in BMI, BMI z scores, and total fat mass, respectively, and an additional 5.6% and 4.8% of the variance in SI and disposition index (P < 0.05), respectively, after control for covariates.
In this cohort, total sugar intake, rather than glycemic index or glycemic load, was associated with higher adiposity measures, lower SI, and lower measures of insulin secretion.
American Journal of Clinical Nutrition 11/2007; 86(5):1331-8. · 6.50 Impact Factor
[show abstract][hide abstract] ABSTRACT: Adiponectin may be important in the pathogenesis of insulin resistance and the metabolic syndrome in youth.
The objective of the study was to determine the unique effect of adiponectin on the metabolic syndrome in overweight Latino youth.
Participants included 175 overweight children (aged 11.1 +/- 1.7 yr, body mass index percentile 97.3 +/- 2.9) with a family history of type 2 diabetes.
Metabolic syndrome was defined according to a pediatric adaptation of the Adult Treatment Panel III report and included dyslipidemia, abdominal obesity, elevated blood pressure, and prediabetes (impaired fasting glucose or impaired glucose tolerance from a 2-h oral glucose tolerance test). Body composition was estimated via dual-energy x-ray absorptiometry, insulin sensitivity was quantified by the frequently sampled iv glucose tolerance test, visceral fat was measured using magnetic resonance imaging, and adiponectin was determined in fasting serum.
In simple linear regression, adiponectin was significantly and inversely related to systolic blood pressure (P < 0.05), waist circumference (P < 0.001), triglycerides (P < 0.001), and 2-h glucose levels (P < 0.05) and positively related to high-density lipoprotein-cholesterol (P < 0.001). In multiple linear regression, adiponectin was significantly related to triglycerides (P < 0.01) and high-density lipoprotein-cholesterol (P < 0.01) independent of age, gender, Tanner stage, body composition, and insulin sensitivity. Analyses of covariance established that adiponectin levels were approximately 25% higher in healthy overweight youth, compared with those with the metabolic syndrome (12.5 +/- 3.5 vs. 9.4 +/- 2.8 microg/ml; P < 0.05). In multiple logistic regression, adiponectin was a significant independent predictor of the metabolic syndrome, even after adjustment for confounders including insulin sensitivity and visceral fat.
Hypoadiponectinemia is an independent biomarker of the metabolic syndrome, and thus, adiponectin may play a role in the pathophysiology of the disorder in overweight youth.
[show abstract][hide abstract] ABSTRACT: To determine whether breastfeeding is related to total adiposity, regional adiposity, and glucose and insulin dynamics in overweight Latino youth throughout puberty.
The relation between breastfeeding and diabetes risk was determined in 240 overweight (BMI > or =85th percentile) Latino children (aged 8-13 years) with a positive family history of type 2 diabetes. Children were examined at baseline (Tanner pubertal stage 1) and for 2 more years as they advanced in pubertal maturation. Children were divided into the following categories: never breastfed (n = 102), breastfed 0-5.99 months (n = 61), breastfed 6-11.99 months (n = 24), and breastfed > or =12 months (n = 53). Tanner pubertal stage was determined by physical examination. Visceral and subcutaneous abdominal fat were determined by magnetic resonance imagining, and total body fat, total lean tissue mass, and percent body fat were measured by dual-energy X-ray absorptiometry. Fasting and postchallenge glucose were assessed with a 2-h oral glucose tolerance test. Insulin sensitivity (SI), acute insulin response (AIR), and disposition index ([DI] an index of beta-cell function) were measured by frequently sampled intravenous glucose tolerance test and minimal modeling. Data were analyzed using linear mixed-effects modeling.
There were no significant effects of breastfeeding categories on adiposity (i.e., total fat mass, total lean tissue mass, percent body fat), fat distribution (visceral and subcutaneous abdominal fat), fasting glucose or 2-h glucose, or insulin dynamics (SI, AIR, and DI) at Tanner pubertal stage 1 or on changes in these variables over pubertal transitions in overweight Latino youth.
In this population of high-risk Latino youth, there were no significant protective effects of breastfeeding on adiposity or type 2 diabetes risk factors at Tanner pubertal stage 1 or across advances in maturation.
Diabetes care 04/2007; 30(4):784-9. · 7.74 Impact Factor
[show abstract][hide abstract] ABSTRACT: Tracking of total physical activity (PA), moderate to vigorous activity (MVPA), and sedentary behavior was assessed in 42 young children (mean age at baseline 3.8 years) over a 2-year period using the Actigraph accelerometer. Tracking was analyzed using Spearman rank correlations, percentage agreements, and kappa statistics. Spearman rank correlations were r = .35 (p = .002) for total PA, r = .37 (p = .002) for MVPA, and r = .35 (p = .002) for sedentary behavior. Percentage agreements for PA, MVPA, and sedentary behavior were 38, 41, and 26 respectively. Kappa statistics for PA, MVPA, and sedentary behavior ranged from poor to fair. Results suggest low levels of tracking of total physical activity, MVPA, and sedentary behavior in young Scottish children over a 2-year period.
[show abstract][hide abstract] ABSTRACT: Because leptin and adiponectin are counter-regulated in vivo and exert opposing effects on glucose metabolism, fat oxidation and insulin sensitivity, the ratio of leptin-to-adiponectin has been investigated as a potential atherogenic index, suggesting that the index is a better biomarker for atherosclerotic risk in obese Type 2 diabetic patients than either leptin or adiponectin alone. However, no information is available regarding the leptin-to-adiponectin ratio during adolescence in Hispanic adolescents. Therefore, the present study was designed to investigate the leptin-to-adiponectin ratio during growth and to establish whether the leptin-to-adiponectin ratio is a better predictor for insulin sensitivity compared to leptin and adiponectin alone in a regression model. From the age of 8 to 14, the leptin-to-adiponectin ratio increased from 2.0+/-0.8 to 5.8+/-2.2 in girls, with no significant change noted in boys (gender x age interaction p=0.007). In a multiple regression analysis, including both adiponectin and leptin as independent variables, leptin and adiponectin explained 5% of the variation in insulin sensitivity independent of gender, age, Tanner stage, total fat mass and lean body mass (p for R2-change <0.001). The leptin-to-adiponectin ratio also explained 5% of the variation in insulin sensitivity, after controlling for the same covariates (p for R2-change <0.001). These data indicate that the leptin-to-adiponectin ratio is not a better predictor of insulin sensitivity during growth than the additive effects of leptin and adiponectin levels.
Journal of endocrinological investigation 01/2007; 30(7):RC13-6. · 1.65 Impact Factor