Interindividual variation in cardiometabolic health outcomes following 6 months of endurance training in youth at risk of type 2 diabetes mellitus.

This study determined the interindividual variation in the cardiometabolic response to 6 months of moderate or vigorous intensity exercise training (ET) among youth at risk for type 2 diabetes mellitus. Youth were randomized to moderate intensity ET (45-55% heart rate reserve; n = 31), vigorous intensity ET (70-85% heart rate reserve; n = 37), or control (n = 36). Only those attending ≥70% of ET sessions were included. Cardiometabolic measures included insulin sensitivity, hepatic triglyceride content, visceral adipose area, and cardiorespiratory fitness. The contribution of ET to interindividual variation was determined using the standard deviation of individual responses (SDIR) and considered meaningful if the SDIR surpassed the smallest worthwhile difference (SWD), calculated as 0.2 × the standard deviation of the control group baseline values. ET meaningfully contributed to the interindividual variation among changes in peak oxygen uptake following moderate (SDIR: 2.04) and vigorous (SDIR: 3.43) ET (SWD: 1.17 mL·kg fat free mass-1·min-1), body fat percentage and hepatic triglyceride content following moderate-intensity ET (SDIR: 1.64, SWD: 1.05%; SDIR: 10.08, SWD: 1.06%, respectively), and visceral fat mass following vigorous ET (SDIR: 11.06, SWD: 7.13 cm2). Variation in the changes in insulin sensitivity were not influenced by ET. The contribution of ET to interindividual variation appears to be influenced by the desired outcome and prescribed intensity. Trial registration at ClinicalTrials.gov (identifier no.: NCT00755547). Novelty: The contribution of exercise to interindividual variation following training depends on the outcome and exercise intensity. Increasing exercise intensity does not systematically reduce non-response among youth at risk for type 2 diabetes.

Fitness is a determinant of the metabolic response to endurance training in adolescents at risk of type 2 diabetes mellitus.

OBJECTIVE: The purpose of this prospective cohort study was to determine whether changes in cardiorespiratory fitness are associated with the metabolic response to endurance training in adolescents at risk of type 2 diabetes mellitus (T2DM). METHODS: Seventy-three overweight and obese adolescents completed a 6-month endurance exercise intervention. Total fat mass, trunk fat mass, visceral adipose tissue, and liver fat were assessed with dual energy X-ray absorptiometry and magnetic resonance imaging spectroscopy. RESULTS: The change in cardiorespiratory fitness with training was independently associated with reductions in BMI z-score (ß = -0.09; P = 0.006), total fat mass (ß = -1.40; P = 0.007), trunk fat mass (ß = -0.70; P = 0.01), and liver fat (ß = -1.80; P = 0.053). Adolescents within the highest tertile of change in fitness were 4.67 (95% CI: 1.15-13.73; P = 0.03), 11.90 (95% CI: 2.37-59.77; P = 0.002), and 6.21 (95% CI: 1.14-33.99; P = 0.035) times more likely to experience decreases in body weight, BMI, and liver fat compared with adolescents in the lowest tertile. CONCLUSIONS: The changes in adiposity and hepatic triglyceride content in response to endurance training are significantly related to the increase in cardiorespiratory fitness in adolescents at risk of T2DM.

The blood pressure response to exercise in youth with impaired glucose tolerance and type 2 diabetes.

Type 2 diabetes is associated with hypertension and an increased risk of cardiovascular disease. In adults, blood pressure (BP) responses to exercise are predictive of these complications. To determine if the hemodynamic response to exercise is exaggerated in youth with dysglycemia (DG) compared with normoglycemic overweight/ obese (OB) and healthy weight (HW) controls a cross-sectional comparison of BP and heart rate (HR) responses to graded exercise to exhaustion in participants was performed. DG and OB youth were matched for age, BMI z-score, height and sex. Systolic (SBP) and diastolic BP (DBP) were measured every 2 min, and HR was measured every 1 min. SBP was higher in OB and DG compared with HW youth at rest (p < .001). Despite working at lower relative workloads compared with HW, the BP response was elevated during exercise in OB and DG. For similar HR and oxygen consumption rates, BP responses to exercise were slightly higher in OB and DG compared with HW. OB and DG youth both display elevated resting and exercise BP relative to HW peers. Obesity may play a greater role than dysglycemia in the exaggerated BP response to exercise in youth.

Dietary determinants of hepatic steatosis and visceral adiposity in overweight and obese youth at risk of type 2 diabetes.

BACKGROUND: Dietary determinants of hepatic steatosis, an important precursor for nonalcoholic fatty liver disease, are undefined. OBJECTIVE: We explored the roles of sugar and fat intake as determinants of hepatic steatosis and visceral obesity in overweight adolescents at risk of type 2 diabetes. DESIGN: This was a cross-sectional study of dietary patterns and adipose tissue distribution in 74 overweight adolescents (aged: 15.4 ± 1.8 y; body mass index z score: 2.2 ± 0.4). Main outcome measures were hepatic steatosis (≥5.5% fat:water) measured by magnetic resonance spectroscopy and visceral obesity (visceral-to-subcutaneous adipose tissue ratio ≥0.25) measured by magnetic resonance imaging. Main exposure variables were dietary intake and habits assessed by the Harvard Youth Adolescent Food Frequency Questionnaire. RESULTS: Hepatic steatosis and visceral obesity were evident in 43% and 44% of the sample, respectively. Fried food consumption was more common in adolescents with hepatic steatosis than in adolescents without hepatic steatosis (41% compared with 18%; P = 0.04). Total fat intake (ß = 0.51, P = 0.03) and the consumption of >35% of daily energy intake from fat (OR: 11.8; 95% CI: 1.6, 86.6; P = 0.02) were both positively associated with hepatic steatosis. Available carbohydrate (ß = 0.54, P = 0.02) and the frequent consumption of soda were positively associated with visceral obesity (OR: 6.4; 95% CI: 1.2, 34.0; P = 0.03). Daily fiber intake was associated with reduced odds of visceral obesity (OR: 0.82; 95% CI: 0.68, 0.98; P = 0.02) but not hepatic steatosis. CONCLUSION: Hepatic steatosis is associated with a greater intake of fat and fried foods, whereas visceral obesity is associated with increased consumption of sugar and reduced consumption of fiber in overweight and obese adolescents at risk of type 2 diabetes.

Cardiorespiratory fitness and adiposity in metabolically healthy overweight and obese youth.

OBJECTIVE: Controversy exists surrounding the contribution of fitness and adiposity as determinants of the Metabolically Healthy Overweight(MHO) phenotype in youth. This study investigated the independent contribution of cardiorespiratory fitness and adiposity to the MHO phenotype among overweight and obese youth. METHODS: This cross-sectional study included 108 overweight and obese youth classified as MHO (no cardiometabolic risk factors) or non-MHO (≥1 cardiometabolic risk factor), based on age- and gender specific cut-points for fasting glucose, triglycerides, high-density lipoprotein cholesterol, systolic and diastolic blood pressure, and hepaticsteatosis. RESULTS: Twenty-five percent of overweight and obese youth were classified as MHO. This phenotype was associated with lower BMIz-score (BMI z-score: 1.8 ± 0.3 vs 2.1 ± 0.4, P = .02) and waist circumference (99.7 ± 13.2 vs 106.1 ± 13.7 cm, P = .04) compared with non-MHO youth. When matched for fitness level and stratified by BMI z-score (1.6 ± 0.3 vs 2.4 ± 0.2), the prevalence of MHO was four fold higher in the low BMI z-score group (27% vs 7%; P = .03).Multiple logistic regression analyses revealed that the best predictor of MHO was the absence of hepatic steatosis even after adjusting for waist circumference (odds ratio 0.57, 95% confidence interval 0.40­0.80) or BMI z-score (odds ratio 0.59, 95% confidence interval 0.43­0.80). CONCLUSIONS: The MHO phenotype was present in 25% of overweight and obese youth and is strongly associated with lower levels of adiposity,and the absence of hepatic steatosis, but not with cardiorespiratory fitness.

Metabolic consequences of hepatic steatosis in overweight and obese adolescents.

OBJECTIVE: To test the hypothesis that hepatic steatosis is associated with risk factors for type 2 diabetes in overweight and obese youth, mediated by cardiorespiratory fitness. RESEARCH DESIGN AND METHODS: This was a cross-sectional study comparing insulin sensitivity between 30 overweight and obese adolescents with hepatic steatosis, 68 overweight and obese adolescents without hepatic steatosis, and 11 healthy weight adolescents without hepatic steatosis. Cardiorespiratory fitness was determined by a graded maximal exercise test on a cycle ergometer. Secondary outcomes included presence of metabolic syndrome and glucose response to a 75-g oral glucose challenge. RESULTS: The presence of hepatic steatosis was associated with 55% lower insulin sensitivity (P = 0.02) and a twofold greater prevalence of metabolic syndrome (P = 0.001). Differences in insulin sensitivity (3.5 vs. 4.5 mU ⋅ kg(-1) ⋅ min(-1), P = 0.03), prevalence of metabolic syndrome (48 vs. 20%, P = 0.03), and glucose area under the curve (816 vs. 710, P = 0.04) remained between groups after matching for age, sex, and visceral fat. The association between hepatic steatosis and insulin sensitivity (ß = -0.24, t = -2.29, P < 0.025), metabolic syndrome (ß = -0.54, t = -5.8, P < 0.001), and glucose area under the curve (ß = 0.33, t = 3.3, P < 0.001) was independent of visceral and whole-body adiposity. Cardiorespiratory fitness was not associated with hepatic steatosis, insulin sensitivity, or presence of metabolic syndrome. CONCLUSIONS: Hepatic steatosis is associated with type 2 diabetes risk factors independent of cardiorespiratory fitness, whole-body adiposity, and visceral fat mass.

Hepatic steatosis and low cardiorespiratory fitness in youth with type 2 diabetes.

The purpose of this study was to examine the association between cardiorespiratory fitness, ectopic triglyceride accumulation, and insulin sensitivity among youth with and without type 2 diabetes. Subjects included 137 youth ages 13-18 years including 27 with type 2 diabetes, 97 overweight normoglycemic controls, and 13 healthy weight normoglycemic controls. The primary outcome measure was cardiorespiratory fitness defined as peak oxygen uptake indexed to fat free mass. Secondary outcomes included liver and muscle triglyceride content determined by (1)H-magnetic resonance spectroscopy and insulin sensitivity determined by frequently sampled intravenous glucose tolerance test. Despite similar measures of adiposity, peak oxygen uptake was 11% lower (38.9 ± 7.9 vs. 43.9 ± 6.1 ml/kgFFM/min, P = 0.002) and hepatic triglyceride content was nearly threefold higher (14.4 vs. 5.7%, P = 0.001) in youth with type 2 diabetes relative to overweight controls. In all 137 youth, cardiorespiratory fitness was negatively associated with hepatic triglyceride content (r = -0.22, P = 0.02) and positively associated with insulin sensitivity (r = 0.29, P = 0.002) independent of total body and visceral fat mass. Hepatic triglyceride content was also negatively associated with insulin sensitivity (r = -0.35, P < 0.001), independent of adiposity, sex, age, and peak oxygen uptake. This study demonstrated that low cardiorespiratory fitness and elevated hepatic triglyceride content are features of type 2 diabetes in youth. Furthermore, cardiorespiratory fitness and hepatic triglyceride are associated with insulin sensitivity in youth. Taken together, these data suggest that cardiorespiratory fitness and hepatic steatosis are potential clinical biomarkers for type 2 diabetes among youth.

The impact of community workshops on improving early childhood oral health knowledge.

PURPOSE: The purpose of this study was to evaluate the effectiveness of community workshops designed to equip participants with early childhood oral health (ECOH) knowledge and early childhood caries (ECC) prevention. METHODS: Convenience sample of individuals working with infants and preschool children attending an ECOH training workshop completed a questionnaire before the workshop. One month later, participants completed a follow-up questionnaire. A P-value