Muscle-strengthening activity and its association with insulin sensitivity.
ABSTRACT Muscle-strengthening activities (MSAs) may increase insulin sensitivity, thereby reducing the risk of diabetes. The purpose of this study was to assess the relationship between MSAs and insulin sensitivity among American adults.
We analyzed data on 4,504 adults without diabetes, aged 20-79 years, who participated in the National Health and Nutrition Examination Survey 1999-2004 and had information on MSAs. Self-reported frequency (times/week) of MSAs was grouped as low (<1), moderate (1-2.9), or high (>or=3). Insulin sensitivity was measured by the fasting quantitative insulin sensitivity check index x 100 (QUICKI).
After adjustment for age, race/ethnicity, physical activity other than MSAs, BMI, smoking, alcohol consumption, and daily total caloric intake, the mean values for QUICKI by low, moderate, and high MSA were 33.6, 33.9, and 34.2, respectively (P for linear trend = 0.008) for men and 34.2, 34.6, 34.6, respectively (P for linear trend = 0.009) for women. Mean fasting insulin (picomols per liter) concentrations were 75.0, 68.9, and 65.9, respectively (P for linear trend = 0.017) for men and 66.9, 63.3, 61.2, respectively (P for linear trend = 0.007) for women. There were no significant differences across MSA groups for fasting glucose among men or women.
MSA is independently associated with higher insulin sensitivity among U.S. adults. Efforts to increase MSA may be a realistic, feasible, and effective method of reducing insulin resistance among the U.S. population.
Article: Associations among 25-hydroxyvitamin D, diet quality, and metabolic disturbance differ by adiposity in adults in the United States.[show abstract] [hide abstract]
ABSTRACT: Recent evidence indicates that a higher plasma level of 25-hydroxyvitamin D [25(OH)D] is associated with lower adiposity and a reduced number of metabolic disturbances (MetD). We examined associations among dietary quality, 25(OH)D, percent body fat (%BF), and MetD, and a pathway linking them, across central obesity. This cross-sectional nationally representative study used extensive data from the National Health and Nutrition Examination Surveys of 2001-2004. U.S. adults aged at least 20 yr were stratified by central obesity (CO) status. Sample sizes ranged from 1943 (all MetD combined) to 7796 (each component). %BF was measured using dual-energy x-ray absorptiometry, and MetD was measured with individual continuous nonadiposity outcomes (e.g. fasting plasma glucose) and with a composite count index of binary MetD with prespecified cutoff points (Index I). A higher 25(OH)D was associated with better dietary quality, lower %BF, and lower number of MetD. These inverse 25(OH)D-%BF and 25(OH)D-MetD associations (i.e. fasting blood glucose, homeostatic model assessment of insulin resistance, C-reactive protein, and Index I) were significantly stronger among the CO+ group. Finally, the pathway linking the dairy component of the Healthy Eating Index (HEIdairy) to Index I through 25(OH)D and %BF indicated complete mediation among the CO- group, but HEIdairy and 25(OH)D had direct inverse associations with Index I among the CO+ group. Due to potential genetic differences between CO- and CO+ groups, empowering U.S. adults with central obesity to make related behavioral changes may be especially effective in improving their vitamin D status and metabolic profile.The Journal of clinical endocrinology and metabolism 05/2010; 95(8):3814-27. · 6.50 Impact Factor
Article: Serum antioxidant status is associated with metabolic syndrome among U.S. adults in recent national surveys.[show abstract] [hide abstract]
ABSTRACT: Potential antiinflammatory and antioxidant effects were recently ascribed to naturally occurring micronutrients. The extent and magnitudes of their differential effects on the metabolic syndrome (MetS) are still unknown. We examined the association between serum antioxidant status and MetS. NHANES 2001-2006 cross-sectional data among adults aged 20-85 y were analyzed (n = 3008-9099). MetS was defined with the National Cholesterol Education Program Adult Treatment Panel III (NCEP ATP III) and also by elevated homeostatic model assessment insulin resistance (HOMA-IR), C-reactive protein (CRP) and hyperuricemia. Serum antioxidants included retinol, retinyl esters, carotenoids [α-carotene, β-carotene (cis+trans), β-cryptoxanthin, lutein+zeaxanthin, total lycopene], vitamin E, and vitamin C. MetS (NCEP ATP III) prevalence in U.S. adults was 32.0% among men and 29.5% among women. Adults with MetS had consistently lower serum carotenoid concentrations compared with those without MetS, even after controlling for total cholesterol and TG among other potential confounders. Vitamin E had no significant relationship with MetS in the full multiple logistic regression model, whereas retinol+retinyl esters were inversely related to MetS among men only. The latter were also inversely related to elevated CRP and positively associated with hyperuricemia. Vitamin C exhibited a similar pattern to serum carotenoids with an inverse linear association with MetS (binary), HOMA-IR, and hyperuricemia. Future intervention studies of dietary and lifestyle change must be conducted to assess the utility of modifying serum antioxidant concentrations, especially carotenoids, given their suboptimal levels among U.S. adults with MetS, for the prevention of type 2 diabetes and various cardiovascular endpoints.Journal of Nutrition 03/2011; 141(5):903-13. · 3.92 Impact Factor
Article: The Correlations between Extremity Circumferences with Total and Regional Amounts of Skeletal Muscle and Muscle Strength in Obese Women with Type 2 Diabetes.[show abstract] [hide abstract]
ABSTRACT: Insulin resistance is related to central obesity and the amount of skeletal muscle. A simple and practical anthropometric marker for muscle mass is not known, although waist circumference (WC) is used as an indicator of abdominal obesity. The aims of this study were to investigate whether arm (AC) and thigh circumferences (TC) can be used as an indicator of muscle mass and if they are related to muscle strength. A total of 110 obese (body mass index [BMI]≥25 kg/m(2)) women with type 2 diabetes were enrolled, and WC, AC, and TC were measured. Abdominal visceral fat (AVF), subcutaneous fat (ASF), and total fat (ATF) were assessed by computed tomography, regional muscle (MM), and fat mass by dual-energy X-ray absorptiometry, muscle strength by one repetition maximum (1RM) of both extremities (chest and leg press) and insulin resistance by K(ITT). The mean age was 56.2±7.3 years, duration of diabetes was 4.2±4.4 years, and BMI was 27.2±2.8 kg/m(2). WC was correlated with ATF, AVF, and ASF (r=0.728, P<0.001; r=0.515, P<0.001; r=0.608, P<0.001, respectively). Arm MM was correlated with AC (r=0.500, P<0.001), and leg MM with TC (r=0.291, P=0.002). Upper 1RM was related to AC/WC ratio (r=0.359, P<0.001), and lower 1RM was to TC/WC ratio (r=0.286, P=0.003). Insulin resistance had significant relations with AVF, WC, and total MM (r=-0.262, P=0.008; r=-0.217, P=0.029; r=0.160, P=0.031, respectively). The muscle mass was related to extremity circumferences, and muscle strength was to extremity/waist circumference ratio in obese women with type 2 diabetes.Diabetes & metabolism journal 08/2011; 35(4):374-83.