Effect of menopausal status on insulin-stimulated glucose disposal: comparison of middle-aged premenopausal and early postmenopausal women

OBJECTIVE: Studies in animal models suggest that ovarian hormone deficiency is associated with the development of insulin resistance. In women, ovarian hormone levels are dramatically reduced after the menopause transition. However, the effect of the menopause transition on insulin sensitivity is unclear. Thus, we examined the effect of menopausal status on insulin sensitivity. RESEARCH DESIGN AND METHODS: Insulin-stimulated glucose disposal was measured in 43 middle-aged premenopausal women (47 +/- 3 years of age) during the luteal phase of the menstrual cycle and 40 early postmenopausal women (51 +/- 4 years; time since menopause, 21 +/- 13 months) using the hyperinsulinemic-euglycemic clamp technique. Body composition was measured by dual-energy X-ray absorptiometry and abdominal fat distribution by computed tomography RESULTS: No difference in fat-free mass (FFM) was found between groups. Total body (P < 0.01), subcutaneous abdominal (P < 0.05), and intra-abdominal (P < 0.01) adiposity were greater in postmenopausal women compared with premenopausal women. No differences in insulin-stimulated glucose disposal were found between premenopausal and postmenopausal women on an absolute basis (pre, 436 +/- 130 vs. post, 446 +/- 120 mg/min), when expressed relative to FFM (pre, 10.7 +/- 3.0 vs. post, 11.5 +/- 3.6 mg x kg(-1) FFM x min(-1)) or when statistically adjusted for FFM (pre, 436 +/- 125 vs. post, 445 +/- 126 mg/min). CONCLUSIONS: These results suggest that menopausal status does not affect insulin sensitivity, as measured by the hyperinsulinemic-euglycemic clamp technique.     

Decreased insulin activation of glycogen synthase in skeletal muscles in young nonobese Caucasian first-degree relatives of patients with non-insulin-dependent diabetes mellitus.

Insulin resistance in non-insulin-dependent diabetes is associated with a defective insulin activation of the enzyme glycogen synthase in skeletal muscles. To investigate whether this may be a primary defect, we studied 20 young (25 +/- 1 yr) Caucasian first-degree relatives (children) of patients with non-insulin-dependent diabetes, and 20 matched controls without a family history of diabetes. Relatives and controls had a normal oral glucose tolerance, and were studied by means of the euglycemic hyperinsulinemic clamp technique, which included performance of indirect calorimetry and muscle biopsies. Insulin-stimulated glucose disposal was decreased in the relatives (9.2 +/- 0.6 vs 11.5 +/- 0.5 mg/kg fat-free mass per (FFM) min, P less than 0.02), and was due to a decreased rate of insulin-stimulated nonoxidative glucose metabolism (5.0 +/- 0.5 vs 7.5 +/- 0.4 mg/kg fat-free mass per min, P less than 0.001). The insulin-stimulated, fractional glycogen synthase activity (0.1/10 mmol liter glucose-6-phosphate) was decreased in the relatives (46.9 +/- 2.3 vs 56.4 +/- 3.2%, P less than 0.01), and there was a significant correlation between insulin-stimulated, fractional glycogen synthase activity and nonoxidative glucose metabolism in relatives (r = 0.76, P less than 0.001) and controls (r = 0.63, P less than 0.01). Furthermore, the insulin-stimulated increase in muscle glycogen content over basal values was lower in the relatives (13 +/- 25 vs 46 +/- 9 mmol/kg dry wt, P = 0.05). We conclude that the defect in insulin activation of muscle glycogen synthase may be a primary, possibly genetically determined, defect that contributes to the development of non-insulin-dependent diabetes.     

Anthropometry,bioelectrical impedance and dual-energy X-ray absorptiometry in the assessment of body composition in elderly Finnish women

In this study, the bioelectrical impedance analysis (BIA), skinfold thickness measurement (STM) and dual-energy X-ray absorptiometry (DXA), as a reference method, were compared with each other in the assessment of body composition in elderly (62-72-year-old) Finnish women (n=93). BIA had better agreement with DXA in the assessment of fat free mass (FFM, R2=0.70, Sres=2.1) and fat mass (FM, R2=0.93, Sres=2.3) than the STM (FFM, R2=0.62, Sres=2.4; FM, R2=0.89,Sres=2.8). There was quite a large variation in the estimates when different BIA prediction equations were used. The equation developed in this study, FFM (kg)=-128.06 + 1.85 x BMI-0.63 x weight + 1.07 x height - 0.03 x resistance +10.0 x waist-hip ratio, yielded a small and unbiased error (0.5 +/- 1.6 kg), with a small residual standard deviation (R2=0.83, Sres=1.6). However, error associated with the estimate of FM was positively related to the degree of FM. BIA(Heitmann) equation yielded unbiased estimates of both FFM and FM (FFM, R2=0.77, Sres=1.8; FM, R2=0.95, Sres=1.9). Both the STM and BIA (manufacturer's equation) resulted in error which was statistically significant and positively correlated with FFM and FM. These results indicate that BIA prediction equations, chosen with care, can improve the performance of equations based upon anthropometric measurements alone in the assessment of body composition in elderly women.     

High-intensity resistance training improves glycemic control in older patients with type 2 diabetes

OBJECTIVE: To examine the effect of high-intensity progressive resistance training combined with moderate weight loss on glycemic control and body composition in older patients with type 2 diabetes. RESEARCH DESIGN AND METHODS: Sedentary, overweight men and women with type 2 diabetes, aged 60-80 years (n = 36), were randomized to high-intensity progressive resistance training plus moderate weight loss (RT & WL group) or moderate weight loss plus a control program (WL group). Clinical and laboratory measurements were assessed at 0, 3, and 6 months. RESULTS: HbA(1c) fell significantly more in RT & WL than WL at 3 months (0.6 +/- 0.7 vs. 0.07 +/- 0.8%, P < 0.05) and 6 months (1.2 +/- 1.0 vs. 0.4 +/- 0.8%, P < 0.05). Similar reductions in body weight (RT & WL 2.5 +/- 2.9 vs. WL 3.1 +/- 2.1 kg) and fat mass (RT & WL 2.4 +/- 2.7 vs. WL 2.7 +/- 2.5 kg) were observed after 6 months. In contrast, lean body mass (LBM) increased in the RT & WL group (0.5 +/- 1.1 kg) and decreased in the WL group (0.4 +/- 1.0) after 6 months (P < 0.05). There were no between-group differences for fasting glucose, insulin, serum lipids and lipoproteins, or resting blood pressure. CONCLUSIONS: High-intensity progressive resistance training, in combination with moderate weight loss, was effective in improving glycemic control in older patients with type 2 diabetes. Additional benefits of improved muscular strength and LBM identify high-intensity resistance training as a feasible and effective component in the management program for older patients with type 2 diabetes.     

Resistance training volume, energy balance and weight management: rationale and design of a 9 month trial

The increased prevalence of obesity and the lack of treatment success both argue for the design and evaluation of strategies to prevent the development of overweight and obesity. To date, the role of resistance training (RT) in this regard is largely unexplored. RT may be effective for weight management as a result of increased fat-free mass (FFM), which may result in increased resting metabolic rate and increased physical activity energy expenditure. However, the literature relative to the efficacy of RT protocols recommended for healthy adults to alter the aforementioned parameters is inconsistent or inadequately evaluated. We will conduct a 9 month randomized controlled efficacy trial to compare changes in body composition (fat mass, FFM, % body fat) and energy balance in response to 2 volumes of RT (1 vs. 3 sets vs. non-exercise control) both at the completion of training (9 months) and 1 year later (body composition). This investigation will be conducted in a sample of healthy, normal and overweight, sedentary, young adult men and women; a group at high risk for development of overweight and obesity. Our results will provide information relative to the minimum volume of RT that may be associated with body weight/fat gain which may inform the development of guidelines for RT to prevent weight gain or to alter body composition.     

Resting energy expenditure and body mass changes in women during adjuvant chemotherapy for breast cancer

Weight gain is a commonly reported side effect of adjuvant chemotherapy. A change in resting energy expenditure during treatment has been a suggested mechanism for weight gain. We prospectively measured resting energy expenditure, weight change, and body composition (dual-energy x-ray absorptiometry) in 10 women undergoing adjuvant chemotherapy for breast cancer. There was no change in resting energy expenditure across cycles of chemotherapy (P =.78) or from baseline to the end of treatment (1,189.68 +/- 80.27 vs 1,205.76 +/- 56.71 kcal/d; P =.74). Overall, participants did not gain weight across treatment. However, there was an overall trend toward weight gain (66.3 +/- 5.1 vs 68.2 +/- 5.0 kg; P =.09), and participants did show an increase in total fat mass (24.2 +/- 3.8 vs 26.5 +/- 3.2 kg; P =.04), whereas muscle mass remained the same. Although no change in resting energy expenditure was seen, the observed increase in total fat mass is consistent with a decrease in physical activity level commonly reported with adjuvant chemotherapy treatment of breast cancer, and these body composition changes may have important health implications for survivors.     

Overexpression of Glut4 protein in muscle increases basal and insulin-stimulated whole body glucose disposal in conscious mice.

The effect of increased Glut4 protein expression in muscle and fat on the whole body glucose metabolism has been evaluated by the euglycemic hyperinsulinemic clamp technique in conscious mice. Fed and fasting plasma glucose concentrations were 172 +/- 7 and 78 +/- 7 mg/dl, respectively, in transgenic mice, and were significantly lower than that of nontransgenic littermates (208 +/- 5 mg/dl in fed; 102 +/- 5 mg/dl in fasting state). Plasma lactate concentrations were higher in transgenic mice, (6.5 +/- 0.7 mM in the fed and 5.8 +/- 1.0 mM in fasting state) compared with that of non-transgenic littermates (4.7 +/- 0.3 mM in the fed and 4.2 +/- 0.5 mM in fasting state). In the fed state, the rate of whole body glucose disposal was 70% higher in transgenic mice in the basal state, 81 and 54% higher during submaximal and maximal insulin stimulation. In the fasting state, insulin-stimulated whole body glucose disposal was also higher in the transgenic mice. Hepatic glucose production after an overnight fast was 24.8 +/- 0.7 mg/kg per min in transgenic mice, and 25.4 +/- 2.7 mg/kg per min in nontransgenic mice. Our data demonstrate that overexpression of Glut4 protein in muscle increases basal as well as insulin-stimulated whole body glucose disposal. These results suggest that skeletal muscle glucose transport is rate-limiting for whole body glucose disposal and that the Glut4 protein is a potential target for pharmacological or genetic manipulation for treatment of patients with non-insulin-dependent diabetes mellitus.     

Independent effects of obesity and insulin resistance on postprandial thermogenesis in men.

The putative blunted thermogenesis in obesity may be related to insulin resistance, but insulin sensitivity and obesity are potentially confounding factors. To determine the independent effects of obesity and insulin resistance on the thermic effect of food, at rest and after exercise, lean and obese men were matched at two levels of insulin sensitivity determined by insulin-stimulated glucose disposal (milligrams per kilogram fat-free mass [FFM] per minute) during the euglycemic, hyperinsulinemic (40 mU/m2.min) clamp: 5.4 mg/kg FFM for the lean and obese groups with low insulin sensitivity, and 8.1 mg/kg FFM for the groups with high insulin sensitivity. The two lean groups were matched for percent fat (approximately 15 +/- 1% fat), as were the two obese groups (approximately 33 +/- 2% fat). Energy expenditure was measured for 3 h in the fasting state and for 3 h after a 720-kcal mixed meal, each at rest and immediately after 1 h of cycling at 100 W. The thermic effect of food (TEF) was calculated as the postprandial minus fasting energy expenditure (kcal/3 h) during rest and after exercise. During rest, TEF was blunted by both obesity (24 +/- 5 and 34 +/- 6 kcal/3 h for obese groups with low and high insulin sensitivity vs. 56 +/- 6 and 74 +/- 6 kcal/3 h for the lean groups with low and high insulin sensitivity; P less than 0.01 lean vs. obese) and insulin resistance (insulin-resistant less than insulin-sensitive, at both levels of obesity; P less than 0.01). After exercise, TEF was also impaired in the obese (47 +/- 6 and 44 +/- 5 kcal/3 h for the insulin-resistant and -sensitive groups) and in the lean insulin-resistant (55 +/- 5 kcal/3 h), compared with the lean insulin-sensitive men (71 +/- 3 kcal/3 h), P less than 0.01. Compared with rest, TEF after exercise was improved, but not normalized, in both obese groups (P less than 0.05), but unchanged in the lean groups. These results suggest that both insulin resistance and obesity are independently associated with impaired TEF at rest, but the responsiveness of thermogenesis to exercise before a meal is related to the obese state and not independently to insulin resistance per se.     

Resistance training improves muscle function and body composition in patients with hyperthyroidism

OBJECTIVE: To evaluate the effect of resistance training on skeletal muscle performance and body composition in patients with medically treated hyperthyroidism. DESIGN: Nonrandomized controlled trial. SETTING: Large public tertiary hospital. PARTICIPANTS: Sixteen sedentary patients with recent clinical diagnosis and laboratory confirmation of hyperthyroidism (7 men, 9 women; age, 38+/-11 y; weight, 58.4+/-2.6 kg; height, 1.6+/-0.3m) were assigned to the control group (medical therapy; n=9) or training group (medical therapy associated with resistance training; n=7). An age- and sex-matched healthy group served as controls (3 men, 5 women; age, 40+/-3 y; weight, 68.4+/-4.3 kg; height, 1.6+/-0.3m). INTERVENTION: Resistance training twice a week for 16 weeks. MAIN OUTCOME MEASURES: Peak muscular strength (by dynamometry and 1 repetition maximum method) and endurance (30% of peak force) for 7 movements and anthropometric measurements. RESULTS: The hyperthyroid patients as a group had lower baseline overall strength values when compared with healthy subjects (200.3+/-16.0 kg vs 274.9+/-21.8 kg, respectively; P=.006). Overall absolute increases in strength (49 kg vs 91 kg, P<.05) and endurance (78.5x10(2)kg/s vs 176.9x10(2)kg/s, P<.05) were higher in the training group compared with the control group. Body weight increased in both groups, but the sum of muscular circumference increased only in the training group (training group, 92.6+/-3.3 cm vs 97.1+/-3.8 cm; control group, 94.6+/-2.2 cm vs 94.4+/-2.1cm; P<.05), with no change in the sum of skinfolds. CONCLUSIONS: Resistance training accelerates the recovery of skeletal muscle function and promotes weight gain based on muscle mass improvement in patients with medically treated hyperthyroidism.     

成年人身高与去脂组织重的关系

目的研究成年人去脂组织重(fat-free mass,FFM)与身高之间的关系,并建立预测FFM的简单方程.方法对955名健康成年人进行人体测量和生物电阻抗测量,按BMI分为肥胖组和非肥胖组,按年龄分别45岁以下组和45岁以上组,分析FFM与年龄和肥胖的关系.根据FFM是身高的异速生长指数的模型关系,进行非线性回归,建立指数曲线回归方程.结果18～45岁健康成年人的身高为(1.65±0.07)m,体质量为(62.03±10.69)kg,体脂质量(11.28±6.75)kg,体脂含量(17.91±8.67)%,去脂组织含量(82.02±8.87)%,BMI(22.85±2.99)kg/m2,而46～74岁健康成年人的相应指标为(1.62±0.08)m,体质量为(66.08±10.21)kg,体脂质量(14.56±6.44)kg,体脂含量(22.09±9.23)%,去脂组织含量(77.58±10.07)%,BMI(25.19±2.95)kg/m2,差异有显著性意义(P＜0.05);18～45岁与46～74岁的健康人的FFM分别为(50.93±10.23),(51.53±10.07)kg,差异无显著性意义(P＞0.05);健康成年人的FFM并不随年龄增加;非肥胖组与肥胖组的FFM也是相对不变的.预测男性FFM的适宜方程为FFM(kg)=24.98×身高1.68,预测女性FFM的适宜方程为FFM(kg)=22.84×身高1.42.结论以身高为变量能估计出正常成年人FFM的近似值.     

Lowering of LDL cholesterol rather than moderate weight loss improves endothelium-dependent vasodilatation in obese women with previous gestational diabetes

OBJECTIVE: Effects of weight loss on vascular function are unknown. We compared, in the face of similar weight loss over 3-6 months, effects of orlistat (120 mg t.i.d., n = 23) and placebo (n = 24) on in vivo endothelial function in a high-risk group of obese (BMI 32.1 +/- 0.4 kg/m(2)) premenopausal nondiabetic women with a history of gestational diabetes. RESEARCH DESIGN AND METHODS: Forearm blood flow responses to intra-arterial infusions of acetylcholine (ACh) and sodium nitroprusside (SNP), body composition, and serum lipids were determined before and after weight loss. RESULTS: Weight loss averaged 7.3 +/- 0.2 kg (8.3 +/- 0.1%) and 7.4 +/- 0.2 kg (8.2 +/- 0.1%) of initial body weight in the orlistat and placebo groups, respectively. Forearm and body compositions changed similarly in both groups. Responses to ACh increased by 41% to the low dose (5.9 +/- 0.6 vs. 8.3 +/- 0.3 for flow in the experimental/control arm, P < 0.01) and by 33% to the high dose (7.6 +/- 0.8 vs. 10.1 +/- 0.6, P < 0.001) in the orlistat group, but they remained unchanged in the placebo group. The blood flow responses to SNP did not differ significantly between the groups. LDL cholesterol decreased significantly in the orlistat group from 3.5 +/- 0.2 to 3.0 +/- 0.1 mmol/l (P < 0.01) but remained unchanged in the placebo group. Within the orlistat group, the decrease in LDL cholesterol correlated significantly with the improvement in the blood flow response to ACh (r = -0.44, P < 0.05). CONCLUSIONS: Orlistat but not moderate (8%) weight loss per se improves endothelial function in women with previous gestational diabetes. This improvement is associated with a lowering of LDL cholesterol by orlistat.     

Influence of fluid status on techniques used to assess body composition in peritoneal dialysis patients.

OBJECTIVE: A reliable assessment of nutritional state in peritoneal dialysis (PD) patients is of great importance. Nevertheless, techniques used to assess body composition in patients on PD may be affected by abnormalities in fluid status. The primary aim of the present study was to compare different techniques used to evaluate body composition and to assess the influence of fluid status on the assessment of body composition. The secondary aim was to assess the relevance of handgrip muscle strength in the nutritional evaluation of the patient. METHODS: In 40 PD patients, dual-energy x-ray absorptiometry (DEXA), multifrequency bioimpedance analysis (MF-BIA), and anthropometry were compared with respect to the evaluation of body composition [fat mass and lean body mass (LBM; by DEXA), and fat-free mass (FFM; by MF-BIA, anthropometry]. The influence of fluid status on the measurement of LBM/FFM by the various techniques was assessed by their relation to left ventricular end-diastolic diameter (LVEDD), assessed by echocardiography, and by estimating the ratio between extracellular water (ECW) and total body water (TBW), assessed by bromide and deuterium dilution, with LBM (DEXA). The relevance of handgrip muscle strength as a nutritional parameter was assessed by its relation to LBM and other nutritional parameters. RESULTS: Despite highly significant correlations, wide limits of agreement between the various techniques were present with respect to assessment of body composition (expressed as % body weight) and were most pronounced for anthropometry: LBM (DEXA) - FFM (MF-BIA) = 3.4% +/- 12.2%; LBM (DEXA) - FFM (anthropometry) = -5.7% +/- 7.8%; fat mass (DEXA - MF-BIA) = -4.2% +/- 7.9%; fat mass (DEXA - anthropometry) = 2.9% +/- 7.2%. The ratio between ECW and LBM (DEXA) was 0.36 +/- 0.08 L/kg (range 0.25 - 0.67 L/kg), and the ratio between TBW and LBM was 0.75 +/- 0.06 L/kg (range 0.63 - 0.86 L/kg), which shows the variability in hydration state of LBM/FFM between individual patients. LBM/FFM measured by all three techniques was significantly related to LVEDD, suggesting an important influence of hydration state on this parameter. Handgrip muscle strength was significantly related to LBM/FFM, as measured by all three techniques, but not to other nutritional parameters. CONCLUSION: Wide limits of agreement were found between various techniques used to assess body composition in PD patients. The assessment of body composition was strongly influenced by hydration state.The handgrip test is related to body composition, but not to other nutritional parameters.     

Hormone replacement therapy, insulin sensitivity, and abdominal obesity in postmenopausal women.

OBJECTIVE: The purpose of this study was to determine whether insulin sensitivity differs between postmenopausal women taking estradiol, women on estrogen plus progesterone hormone replacement therapy (HRT), and women not on HRT and whether differences are explained by the differences in total and/or abdominal adiposity and fat deposition in the muscle. RESEARCH DESIGN AND METHODS: We studied 28 obese, sedentary postmenopausal Caucasian women. Women taking oral estrogen (n = 6) were matched for age (57 +/- 3 vs. 58 +/- 2 years), weight (87.9 +/- 6.0 vs. 83.0 +/- 3.9 kg), and BMI (33.9 +/- 1.7 vs. 33.9 +/- 1.9 kg/m(2)) with women not on HRT (n = 6). Eight women taking oral estrogen plus progesterone were matched with eight different women not on HRT for age (59 +/- 2 vs. 60 +/- 2 years), weight (82.8 +/- 3.7 vs. 83.7 +/- 4.1 kg), and BMI (30.7 +/- 1.0 vs. 29.9 +/- 1.3 kg/m(2)). RESULTS: VO(2max) (maximal aerobic capacity), percentage of fat, total body fat mass, and fat-free mass (FFM) were similar between groups. Visceral fat, subcutaneous abdominal fat, sagittal diameter, and mid-thigh low-density lean tissue (intramuscular fat) did not differ by hormone status. Basal carbohydrate and fat utilization was not different among groups. Fasting plasma glucose and insulin did not differ by hormone use. Glucose utilization (M) was measured during the last 30 min of a 3-h hyperinsulinemic-euglycemic clamp (40 mU. m(2). min(-1)). Postmenopausal women taking oral estrogen had a 31% lower M than women not on HRT (42.7 +/- 4.0 vs. 61.7 +/- 4.7 micromol. kg(FFM). min(-1), P < 0.05). M was 26% lower in women taking estrogen plus progesterone (44.0 +/- 3.5 vs. 59.7 +/- 6.2 micromol. kg(FFM). min(-1), P < 0.05) than women not on HRT. M/I, the amount of glucose metabolized per unit of plasma insulin (I), an index of insulin sensitivity, was 36% lower in women taking estrogen compared with matched women not on HRT (P < 0.05) and 28% lower in women taking estrogen plus progesterone compared with matched women not on HRT (P < 0.05). CONCLUSIONS: Postmenopausal women taking oral estrogen or those taking a combination of estrogen and HRT are more insulin-resistant than women not on HRT, even when women are of comparable total and abdominal adiposity.     

Effects of body fat distribution on regional lipolysis in obesity.

To determine the contribution of the major body fat depots to systemic free fatty acid (FFA) availability, palmitate ([1-14C]-palmitate) release was measured from leg (lower body) and non-leg (upper body) fat in eight upper body obese (UB Ob), six lower body obese (LB Ob), and six nonobese (Non Ob) age-matched premenopausal women in the overnight postabsorptive state. Splanchnic palmitate release was determined in 16 of these subjects. Results: total palmitate release was greater in UB Ob (P less than 0.005) than LB Ob or Non Ob women (161 +/- 16 vs. 111 +/- 9 vs. 92 +/- 9 mumol/min, respectively). Despite increased leg fat mass in obese women, leg palmitate release was similar in each group. Therefore, leg fat palmitate release was greater in Non Ob women than LB Ob (P less than 0.01) or UB Ob (P = 0.06) women (3.7 +/- 0.3 vs. 2.4 +/- 0.2 vs. 2.7 +/- 0.2 mumol.kg fat-1.min-1, respectively). Upper body fat palmitate release was less (P less than 0.01) in LB Ob than Non Ob or UB Ob women (3.0 +/- 0.4 vs. 5.0 +/- 0.3 vs. 4.9 +/- 0.4 mumol.kg fat-1.min-1, respectively). Splanchnic palmitate release accounted for 20-32% of upper body fat palmitate release in each group (P = NS between groups). Leg fat palmitate release was significantly less than upper body fat palmitate release. We conclude that the major difference in resting FFA metabolism between UB Ob and LB Ob women is the ability of the later to down-regulate upper body fat lipolysis to maintain normal FFA availability.     

Preventing sarcopenic obesity among breast cancer patients who receive adjuvant chemotherapy: results of a feasibility study

PURPOSE: Weight gain is a common side effect of adjuvant chemotherapy for breast cancer - a side effect that decreases quality of life and also may decrease both disease-free and overall survival. This weight gain also is unique, since patients lose lean body mass while they gain weight. These body composition changes become apparent within six months of diagnosis. METHODS: We explored whether a clinic-based exercise program, which promoted a specialized program of strength training, aerobic activity and a healthful (相似文献   

Intact insulin stimulation of skeletal muscle blood flow, its heterogeneity and redistribution, but not of glucose uptake in non-insulin-dependent diabetes mellitus.

We tested the hypothesis that defects in insulin stimulation of skeletal muscle blood flow, flow dispersion, and coupling between flow and glucose uptake contribute to insulin resistance of glucose uptake in non-insulin-dependent diabetes mellitus (NIDDM). We used positron emission tomography combined with [15O]H2O and [18F]-2-deoxy--glucose and a Bayesian iterative reconstruction algorithm to quantitate mean muscle blood flow, flow heterogeneity, and their relationship to glucose uptake under normoglycemic hyperinsulinemic conditions in 10 men with NIDDM (HbA1c 8.1+/-0.5%, age 43+/-2 yr, BMI 27.3+/-0.7 kg/m2) and in 7 matched normal men. In patients with NIDDM, rates of whole body (35+/-3 vs. 44+/-3 micromol/kg body weight.min, P < 0.05) and femoral muscle (71+/-6 vs. 96+/-7 micromol/kg muscle.min, P < 0.02) glucose uptake were significantly decreased. Insulin increased mean muscle blood flow similarly in both groups, from 1.9+/-0.3 to 2.8+/-0.4 ml/100 g muscle.min in the patients with NIDDM, P < 0.01, and from 2.3+/-0.3 to 3.0+/-0.3 ml/100 g muscle.min in the normal subjects, P < 0.02. Pixel-by-pixel analysis of flow images revealed marked spatial heterogeneity of blood flow. In both groups, insulin increased absolute but not relative dispersion of flow, and insulin-stimulated but not basal blood flow colocalized with glucose uptake. These data provide the first evidence for physiological flow heterogeneity in human skeletal muscle, and demonstrate that insulin increases absolute but not relative dispersion of flow. Furthermore, insulin redirects flow to areas where it stimulates glucose uptake. In patients with NIDDM, these novel actions of insulin are intact, implying that muscle insulin resistance can be attributed to impaired cellular glucose uptake.     

Impact of age, anthropometric data and body composition on calcaneal bone characteristics, as measured by quantitative ultrasound (QUS) in an older German population

The impact of fat-free mass (FFM), fat mass (FM), body mass index (BMI), body mass and body height on calcaneal bone characteristics as measured with quantitative ultrasound (QUS) was investigated in 137 women and 85 men aged 62-92 years, considering age, smoking, waist-to-hip ratio (WHR) and physical activity level (PAL). In regression analyses using various models, in women, age was a negative predictor of speed of sound (SOS), broadband ultrasound attenuation (BUA) and stiffness index (SI) and smoking was a negative predictor of SOS; positive predictors of SOS, BUA, and SI were BMI, body mass and FFM. In men, smoking was a negative predictor and BMI, body mass and FFM were positive predictors of BUA and SI. In both sexes, PAL, body height, WHR and FM had no effect on QUS parameters. The influence of BMI on calcaneal bone characteristics in elderly people depends on FFM rather than on FM.     

Thermic effect of infused glucose and insulin in man. Decreased response with increased insulin resistance in obesity and noninsulin-dependent diabetes mellitus.

The thermic effect of infused glucose and insulin was measured by combining the hyperinsulinemic euglycemic clamp technique with indirect calorimetry, in 10 normal weight volunteers (group I), 7 obese subjects with normal glucose tolerance (group II), and 13 obese subjects with abnormal glucose tolerance or noninsulin-dependent diabetes mellitus before (group IIIa) and after weight loss of 10.8 +/- 0.4 kg (group IIIb). During hyperinsulinemia (760-1,100 pmol/liter), total glucose disposal from combined endogenous production and glucose infusion was 545 +/- 49, 441 +/- 70, 233 +/- 35, 231 +/- 31 mg/min and energy expenditure changed by + 0.476 +/- 0.080, +0.293 +/- 0.095, -0.114 +/- 0.063, and +0.135 +/- 0.082 kJ/min in group I, II, IIIa, and IIIb, respectively. The increased energy expenditure correlated with glucose storage (measured cost of processing the glucose: 1.33 kJ/g). In group IIIa there was no increase in energy expenditure in response to glucose and insulin infusions. After therapy (group IIIb) there was a significant recovery (P less than 0.05) of the thermic effect of infused glucose although total glucose disposal was unchanged. It is proposed that the recovered thermic effect of infused insulin/glucose is due to the different contributions of gluconeogenesis in the fasting state and during the glucose clamp before and after weight loss. In addition we hypothesize that some of the lower thermic effect of food reported in obese noninsulin-dependent diabetics may be explained by decreased energy expenditure due to a greater suppression of hepatic gluconeogenesis as well as by lower storage rate.     

Single- and multi-frequency bioelectrical impedance analyses to analyse body composition in maintenance haemodialysis patients: comparison with dual-energy x-ray absorptiometry

The aim of this study was to evaluate the adequacy of single-frequency (sf-BIA) and multi-frequency bioelectrical impedance analyses (mf-BIA), in comparison with dual-energy x-ray absorptiometry (DXA), to evaluate body composition in maintenance haemodialysis (MHD) patients. Body composition of 27 adult MHD patients (9 f, 18 m), BMI 17.5-34.4 kg m(-2), was examined with DXA and BIA, with two different sf-BIA and 1 mf-BIA analysers. Biochemical markers of nutritional status and adequacy of dialytic treatment were also determined. Fat mass (FM) estimated by the different BIA analysers was found to be slightly but significantly higher than FM measured by DXA. In contrast, fat-free mass (FFM) obtained with BIA was found to be slightly but significantly lower than FFM DXA. No significant differences were found between LBM-DXA (that is FFM-DXA minus bone mass) and the different FFM BIA. The lowest mean prediction error versus DXA values was found with sf1BIA. In any case, a close correlation was found between all BIA values and DXA values, particularly for FFM. Furthermore, FFM and LBM results were significantly correlated with serum creatinine, which in MHD patients is an indicator of muscle mass. These results indicate that BIA can be used to evaluate body composition in MHD patients.     

A randomized controlled trial of resistance exercise training to improve glycemic control in older adults with type 2 diabetes

OBJECTIVE: To determine the efficacy of high-intensity progressive resistance training (PRT) on glycemic control in older adults with type 2 diabetes. RESEARCH DESIGN AND METHODS: We performed a 16-week randomized controlled trial in 62 Latino older adults (40 women and 22 men; mean +/- SE age 66 +/- 8 years) with type 2 diabetes randomly assigned to supervised PRT or a control group. Glycemic control, metabolic syndrome abnormalities, body composition, and muscle glycogen stores were determined before and after the intervention. RESULTS: Sixteen weeks of PRT (three times per week) resulted in reduced plasma glycosylated hemoglobin levels (from 8.7 +/- 0.3 to 7.6 +/- 0.2%), increased muscle glycogen stores (from 60.3 +/- 3.9 to 79.1 +/- 5.0 mmol glucose/kg muscle), and reduced the dose of prescribed diabetes medication in 72% of exercisers compared with the control group, P = 0.004-0.05. Control subjects showed no change in glycosylated hemoglobin, a reduction in muscle glycogen (from 61.4 +/- 7.7 to 47.2 +/- 6.7 mmol glucose/kg muscle), and a 42% increase in diabetes medications. PRT subjects versus control subjects also increased lean mass (+1.2 +/- 0.2 vs. -0.1 +/- 0.1 kg), reduced systolic blood pressure (-9.7 +/- 1.6 vs. +7.7 +/- 1.9 mmHg), and decreased trunk fat mass (-0.7 +/- 0.1 vs. +0.8 +/- 0.1 kg; P = 0.01-0.05). CONCLUSIONS: PRT as an adjunct to standard of care is feasible and effective in improving glycemic control and some of the abnormalities associated with the metabolic syndrome among high-risk older adults with type 2 diabetes.