No abstract

Irisin is a recently discovered myokine that increases adipocyte metabolism, induces further "browning" of white adipose tissue, and enhances glucose metabolism. No study has ever determined how an acute bout of exercise impacts immediate post-exercise irisin concentration using a meta-analytic approach. The purpose of this study is to determine the impact of an acute bout of exercise on the magnitude of post-exercise irisin concentration in adults using meta-analytic procedures. Searches were performed on PubMed, EMBASE, CINAHL, PEDro, SCOPUS, and SPORTDiscus databases. Effect summaries were obtained using random-effects models. Random-effects single and multiple meta-regressions were performed to determine relationships between, and potential confounding effects of, variables of interest. Ten articles were retained for the final meta-analysis, producing 21 study estimates. An acute bout of exercise was accompanied by a post-exercise average increase in irisin concentration of 15.0 (95% CI: 10.8%-19.3%). There was no significant relationship between post-exercise irisin concentration and age, intensity of aerobic exercise, or type of exercise training session (resistance vs aerobic training). Fitness level and body mass index were identified as significant predictive variables for post-exercise irisin concentration. However, a multiple meta-regression model identified fitness level as the single best predictor, with being fit (21.1%±2.2%) associated with a nearly twofold increase in post-exercise irisin concentration, compared with being unfit (11.8%±2.1%). Immediately following an acute bout of exercise, irisin concentration increases substantially in adults, with fitness level as an important modifier for the effect.

This cross-sectional study proposes two relative strength indexes in order to evaluate the risks of lower mobility in healthy older adults: 1) handgrip strength on body mass index and 2) quadriceps strength on body weight. Nine hundred and four men and women aged between 67-84 years old were tested for body composition, muscle strength and mobility function. Individuals in the lowest and middle tertiles of relative handgrip strength were respectively 2.2 (1.3-3.7) and 4.4 (2.6-7.6) more likely to have a lower mobility score. As for relative quadriceps strength, odd ratios for lowest and middle tertiles were respectively 2.8 (1.6-4.9) and 6.9 (3.9-12.1). Relative strength indexes, either using handgrip strength or quadriceps strength, are convenient to use in large scale studies and clinical practice.

The ID resulted in similar short- and long-term changes in body composition and metabolic profile compared with a CD. Most improvements occurred during the first 5 weeks of treatment in both interventions.

OBJECTIVE: The goal of this study was to assess the efficacy of an after-school, peer-led, healthy living program on adiposity, self-efficacy, and knowledge of healthy living behaviors in children living in a remote isolated First Nation. METHODS: A quasi-experimental trial with a parallel nonequivalent control arm was performed with 151 children in Garden Hill First Nation during the 2010–2011 and 2011–2012 school years. Fourth grade students were offered a 5-month, peer-led intervention facilitated by high school mentors between January and May of each school year; students in the control arm received standard curriculum. The main outcome measures were waist circumference (WC) and BMI z score. Secondary outcome measures included healthy living knowledge and self-efficacy. RESULTS: Fifty-one children (mean ± SD age: 9.7 ± 0.4 years; BMI z score: 1.46 ± 0.84) received the intervention, and 100 children were in the control arm. At baseline, WC (79.8 vs 83.9 cm), BMI z score (1.46 vs 1.48), and rates of overweight/obesity (75% vs 72%) did not differ between arms. After the intervention, the change in WC (adjusted treatment effect: –2.5 cm [95% confidence interval (CI): –4.1 to –0.90]; P = .002) and BMI z score (adjusted treatment effect: –0.09 [95% CI: –0.16 to –0.03]; P = .007) were significantly lower in the intervention arm compared to the control arm. The intervention arm also experienced improvements in knowledge of healthy dietary choices (2.25% [95% CI: –0.01 to 6.25]; P = .02). Self-efficacy was associated with the change in WC after the intervention (β = –7.9, P = .03). CONCLUSIONS: An after-school, peer-led, healthy living program attenuated weight gain and improved healthy living knowledge in children living in a remote isolated First Nation.

WHAT'S KNOWN ON THIS SUBJECT: Obesity is associated with cardiometabolic risk factors and chronic conditions, such as type 2 diabetes. However, a proportion of overweight and obese youth remain free from cardiometabolic risk factors and are considered metabolically healthy. WHAT THIS STUDY ADDS:This study provides insight into the determinants of cardiometabolic risk factors and the concept in health promotion of "fitness versus fatness." Hepatic lipid accumulation and not fitness level appears to drive cardiometabolic risk factor clustering among overweight and obese youth. abstract 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 genderspecific cut-points for fasting glucose, triglycerides, high-density lipoprotein cholesterol, systolic and diastolic blood pressure, and hepatic steatosis.RESULTS: Twenty-five percent of overweight and obese youth were classified as MHO. This phenotype was associated with lower BMI z-score (BMI z-score: 1.8 6 0.3 vs 2.1 6 0.4, P = .02) and waist circumference (99.7 6 13.2 vs 106.1 6 13.7 cm, P = .04) compared with non-MHO youth. When matched for fitness level and stratified by BMI z-score (1.6 6 0.3 vs 2.4 6 0.2), the prevalence of MHO was fourfold 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 0.40-0.80) or BMI z-score (odds ratio 0.59, 95% confidence interval 0.43-0.80). 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. Pediatrics 2013;132:e85-e92 Obesity is associated with a clustering of cardiometabolic risk factors, including hypertension, insulin resistance, inflammation, and dyslipidemia. 1 However, cardiometabolic risk factor clustering is not an obligatory consequence of obesity. In fact, 18% to 44% of obese individuals are free from cardiometabolic risk factors. 2,3 The absence of cardiometabolic risk factor clustering in obese individuals is associated with lower measures of adiposity, including lower total fat mass, 4 abdominal obesity, 5,6 visceral fat mass, 3,7,8 and the absence of ectopic lipid accumulation. 9 Surprisingly, little attention has been paid to the modifiable factors as determinants of this "Metabolically Healthy Overweight" (MHO) phenotype. 10,11 This is particularly important, as the identification of modifiable behaviors associa...

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.

Lifestyle intervention remains the cornerstone of management of type 2 diabetes mellitus (T2DM). However, adherence to physical activity (PA) recommendations and the impact of that adherence on cardiorespiratory fitness in this population have been poorly described. We sought to investigate adherence to PA recommendations and its association with cardiorespiratory fitness in a population of patients with T2DM. RESEARCH DESIGN AND METHODSA cross-sectional analysis of baseline data from a randomized clinical trial (NCT00424762) was performed. A total of 150 individuals with medically treated T2DM and atherosclerotic cardiovascular disease (ASCVD) or risk factors for ASCVD were recruited from outpatient clinics at a single academic medical center. All individuals underwent a graded maximal exercise treadmill test to exhaustion with breath-by-breath gas exchange analysis to determine VO 2peak . PA was estimated using a structured 7-Day Physical Activity Recall interview. RESULTSParticipants had a mean 6 SD age of 54.9 6 9.0 years; 41% were women, 40% were black, and 21% were Hispanic. The mean HbA 1c was 7.7 6 1.8% and the mean BMI, 34.5 6 7.2 kg/m 2 . A total of 72% had hypertension, 73% had hyperlipidemia, and 35% had prevalent ASCVD. The mean 6 SD reported daily PA was 34.3 6 4 kcal/kg, only 7% above a sedentary state; 47% of the cohort failed to achieve the minimum recommended PA. Mean 6 SD VO 2peak was 27.4 6 6.5 mL/kg fat-free mass/min (18.8 6 5.0 mL/kg/min). CONCLUSIONSOn average, patients with T2DM who have or are at risk for ASCVD report low levels of PA and have low measured cardiopulmonary fitness. This underscores the importance of continued efforts to close this therapeutic gap.Lifestyle interventions, including weight loss and physical activity (PA), are cornerstones in treating type 2 diabetes mellitus (T2DM) and preventing associated atherosclerotic cardiovascular disease (ASCVD)-related complications (1). Weight loss and PA have long been promoted as the first line of treatment to prevent many