Dataset Information

Dietary weight loss and exercise effects on insulin resistance in postmenopausal women.

ABSTRACT:

Background

Comprehensive lifestyle interventions are effective in preventing diabetes and restoring glucose regulation; however, the key stimulus for change has not been identified and effects in older individuals are not established. The aim of the study was to investigate the independent and combined effects of dietary weight loss and exercise on insulin sensitivity and restoration of normal fasting glucose in middle-aged and older women.

Design

Four-arm RCT, conducted between 2005 and 2009 and data analyzed in 2010.

Setting/participants

439 inactive, overweight/obese postmenopausal women.

Interventions

Women were assigned to: dietary weight loss (n=118); exercise (n=117); exercise+diet (n=117); or control (n=87). The diet intervention was a group-based reduced-calorie program with a 10% weight-loss goal. The exercise intervention was 45 min/day, 5 days/week of moderate-to-vigorous intensity aerobic activity.

Main outcome measures

12-month change in serum insulin, C-peptide, fasting glucose, and whole body insulin resistance (HOMA-IR).

Results

A significant improvement in HOMA-IR was detected in the diet (-24%, p<0.001) and exercise+ diet (-26%, p<0.001) groups but not in the exercise (-9%, p=0.22) group compared with controls (-2%); these effects were similar in middle-aged (50-60 years) and older women (aged 60-75 years). Among those with impaired fasting glucose (5.6-6.9 mmol/L) at baseline (n=143; 33%), the odds (95% CI) of regressing to normal fasting glucose after adjusting for weight loss and baseline levels were 2.5 (0.8, 8.4); 2.76 (0.8, 10.0); and 3.1 (1.0, 9.9) in the diet, exercise+diet, and exercise group, respectively, compared with controls.

Conclusions

Dietary weight loss, with or without exercise, significantly improved insulin resistance. Older women derived as much benefit as did the younger postmenopausal women.

Trial registration

This study is registered at Clinicaltrials.govNCT00470119.

SUBMITTER: Mason C

PROVIDER: S-EPMC3185302 | biostudies-literature | 2011 Oct

REPOSITORIES: biostudies-literature

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Publications

Dietary weight loss and exercise effects on insulin resistance in postmenopausal women.

Mason Caitlin C Foster-Schubert Karen E KE Imayama Ikuyo I Kong Angela A Xiao Liren L Bain Carolyn C Campbell Kristin L KL Wang Ching-Yun CY Duggan Catherine R CR Ulrich Cornelia M CM Alfano Catherine M CM Blackburn George L GL McTiernan Anne A

American journal of preventive medicine 20111001 4

<h4>Background</h4>Comprehensive lifestyle interventions are effective in preventing diabetes and restoring glucose regulation; however, the key stimulus for change has not been identified and effects in older individuals are not established. The aim of the study was to investigate the independent and combined effects of dietary weight loss and exercise on insulin sensitivity and restoration of normal fasting glucose in middle-aged and older women.<h4>Design</h4>Four-arm RCT, conducted between 2 ...[more]

PMID: 21961463

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Project description:Excess body weight and a sedentary lifestyle are associated with the development of several diseases, including cardiovascular disease, diabetes and cancer in women. One proposed mechanism linking obesity to chronic diseases is an alteration in adipose-derived adiponectin and leptin levels. We investigated the effects of 12-month reduced calorie, weight loss and exercise interventions on adiponectin and leptin concentrations.Overweight/obese postmenopausal women (n = 439) were randomized as follows: (i) a reduced calorie, weight-loss diet (diet; N = 118), (ii) moderate-to-vigorous intensity aerobic exercise (exercise; N = 117), (iii) a combination of a reduced calorie, weight-loss diet and moderate-to-vigorous intensity aerobic exercise (diet + exercise; N = 117), and (iv) control (N = 87). The reduced calorie diet had a 10% weight-loss goal. The exercise intervention consisted of 45 min of moderate-to-vigorous aerobic activity 5 days per week. Adiponectin and leptin levels were measured at baseline and after 12 months of intervention using a radioimmunoassay.Adiponectin increased by 9.5% in the diet group and 6.6% in the diet + exercise group (both P ? 0.0001 vs. control). Compared with controls, leptin decreased with all interventions (diet + exercise, -40.1%, P < 0.0001; diet, -27.1%, P < 0.0001; exercise, -12.7%, P = 0.005). The results were not influenced by the baseline body mass index (BMI). The degree of weight loss was inversely associated with concentrations of adiponectin (diet, P-trend = 0.0002; diet + exercise, P-trend = 0.0005) and directly associated with leptin (diet, P-trend < 0.0001; diet + exercise, P-trend < 0.0001).Weight loss through diet or diet + exercise increased adiponectin concentrations. Leptin concentrations decreased in all of the intervention groups, but the greatest reduction occurred with diet + exercise. Weight loss and exercise exerted some beneficial effects on chronic diseases via effects on adiponectin and leptin.

Project description:Intramyocellular lipids, including diacylglycerol (DAG) and ceramides, have been linked to insulin resistance. This randomised repeated-measures study examined the effects of diet-induced weight loss (DIWL) and aerobic exercise (EX) on insulin sensitivity and intramyocellular triacylglycerol (IMTG), DAG and ceramide.Sixteen overweight to obese adults (BMI 30.6?±?0.8; 67.2?±?4.0 years of age) with either impaired fasting glucose, or impaired glucose tolerance completed one of two lifestyle interventions: DIWL (n?=?8) or EX (n?=?8). Insulin sensitivity was determined using hyperinsulinaemic-euglycaemic clamps. Intramyocellular lipids were measured in muscle biopsies using histochemistry and tandem mass spectrometry.Insulin sensitivity was improved with DIWL (20.6?±?4.7%) and EX (19.2?±?12.9%). Body weight and body fat were decreased by both interventions, with greater decreases in DIWL compared with EX. Muscle glycogen, IMTG content and oxidative capacity were all significantly (p?<?0.05) decreased with DIWL and increased with EX. There were decreases in DAG with DIWL (-12.4?±?14.6%) and EX (-40.9?±?12.0%). Ceramide decreased with EX (-33.7?±?11.2%), but not with DIWL. Dihydroceramide was decreased with both interventions. Sphingosine was decreased only with EX. Changes in total DAG, total ceramides and other sphingolipids did not correlate with changes in glucose disposal. Stearoyl-coenzyme A desaturase 1 (SCD1) content was decreased with DIWL (-19.5?±?8.5%, p?<?0.05), but increased with EX (19.6?±?7.4%, p?<?0.05). Diacylglycerol acyltransferase 1 (DGAT1) was unchanged with the interventions.Diet-induced weight loss and exercise training both improved insulin resistance and decreased DAG, while only exercise decreased ceramides, despite the interventions having different effects on IMTG. These alterations may be mediated through differential changes in skeletal muscle capacity for oxidation and triacylglycerol synthesis.ClinicalTrials.gov NCT00766298.

Dataset Information

Dietary weight loss and exercise effects on insulin resistance in postmenopausal women.

Background

Design

Setting/participants

Interventions

Main outcome measures

Results

Conclusions

Trial registration

Publications

Dietary weight loss and exercise effects on insulin resistance in postmenopausal women.

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