Body-fat distribution and responsiveness of the pituitary-adrenal axis to corticotropin-releasing-hormone stimulation in sedentary and exercising women

Relationship between functional capacity and health-related quality of life of patients with type-2 diabetes

AIMS

Physical function is a determinant of survival in chronic diseases, however, little is known about functional capacity (FC) and self-reported health status of patients with type-2 diabetes (T2D). This study investigated the relationship between FC and health related quality of life (HRQoL) of patients with T2D.

MATERIALS AND METHODS

This cross-sectional survey recruited 150 patients with T2D from a Nigerian university teaching hospital using purposive sampling technique. Socio-demographic and physical characteristics were assessed. FC and HRQoL including physical and mental health component summary (PCS and MCS) were assessed using the six minute walk test (6MWT) and Short-Form (SF-12) questionnaire respectively. Maximum oxygen consumption (VO₂ max) was estimated, pre and post 6MWT cardiovascular parameters and fasting blood glucose (FBG) were assessed. Data were analyzed using descriptive and inferential statistics. Alpha level was set at p<0.05.

RESULTS

There were 83(55.3%) women, means of age and FBG of participants were 64.2±8.7years and 7.4±2.4mmol/L respectively. The means of 6-min walk distance (6-MWD) and estimated VO₂ max were 341.55±41.82m and 9.2±0.7mL/kg/min respectively. Significant differences were found between pre and post HR (t=-44.71; p=0.001), SBP (t=-38.38; p=0.001) and DBP (t=-38.58; p=0.001) following 6MWT. The means of PCS and MCS of HRQoL were 48.67±5.51 and 58.39±2.86 respectively. There were significant correlations between FC and each of PCS (r=0.678; p=0.001) and MCS (r=0.211; p=0.009).

CONCLUSION

Patients with T2D demonstrated low functional capacity and reduced HRQoL. Significant relationship exists between FC and physical and mental component summary of HRQoL. Exercise intervention to improve FC and HRQoL were recommended.

Hypothalamic-pituitary-adrenal (HPA) axis functioning in relation to body fat distribution

OBJECTIVE

To relate hypothalamic-pituitary-adrenal (HPA) axis functioning and HPA feedback functioning to body fat distribution in normal weight to obese subjects.

PATIENTS

91 men and 103 women [age 18-45 years, BMI 19-35 kg/m(2), waist-to-hip ratio (WHR) 0.6-1.1].

MEASUREMENTS

Anthropometry, body composition using hydrodensitometry and deuterium dilution method, cortisol variability by measuring 5-h cortisol concentrations, HPA axis feedback functioning using a dexamethasone suppression test, and HPA axis functioning under a challenged condition consisting of a standardized high-intensity test with ingestion of 4 mg dexamethasone.

RESULTS

In men, an inverse relationship was observed between 5-h cortisol exposure (nmol/ml) and fat mass index (FMI) (kg/m(2)) (r = -0.55, P < 0.001). In women, relationships were observed between 5-h cortisol exposure (nmol/ml.min) and WHR (r = -0.49, P < 0.001), maximal workload (r = 0.32, P < 0.001) as well as oral contraceptive use (r = 0.38, P < 0.001). Similarly, in men, an inverse relationship was observed between negative feedback expressed as baseline concentrations minus post dexamethasone cortisol concentrations (nmol/ml) and FMI (r = -0.53, P < 0.001). In women, relationships were observed between negative feedback expressed as baseline concentrations minus post dexamethasone cortisol concentrations (nmol/ml) and WHR (r = -0.43, P < 0.001), maximal workload (r = 0.30, P < 0.001) as well as oral contraceptive use (r = 0.43, P < 0.001) in women. Moreover, an inverse relationship was observed between HPA axis functioning in a challenged condition expressed as percentage increase of cortisol concentrations after standardized high-intensity test with ingestion of 4 mg dexamethasone (%) and waist circumference (r = -0.21, P < 0.10) in men and WHR (r = -0.21, P < 0.05) in women. In men, strong positive relationships were observed between FMI and waist circumference (r = 0.85, P < 0.001), as well as waist-to-hip ratio (r = 0.70, P < 0.001).

CONCLUSION

Disturbance of HPA axis functioning under basal and challenged conditions is related to visceral fat accumulation.

The influence of physical activity on abdominal fat: a systematic review of the literature

The relationship between excess abdominal adipose tissue, metabolic and cardiovascular health risk has stimulated interest in the efficacy of physical activity in specifically perturbing this adipose depot. The evolution of imaging techniques has enabled more direct measurement of changes in abdominal and visceral fat. The purpose of this summary was to systematically review the relationship between physical activity and abdominal fat.

METHODS

Database searches were performed on MEDLINE, CINAHL, SPORT DISCUS and PUBMED, from 1985 to 2005 with keywords "exercise", "abdominal fat" and "visceral fat".

RESULTS

Nineteen randomized controlled trials (RCTs) and eight non-randomized controlled trials were selected. In RCTs using imaging techniques to measure change in abdominal fat in overweight or obese subjects, seven out of 10 studies (including three trials with type 2 diabetics) reported significant reductions compared with controls. Reductions in visceral and total abdominal fat may occur in the absence of changes in body mass and waist circumference. Waist-to-hip ratio is not a sensitive measure of change in regional adiposity in exercise studies. No studies fulfil the Consolidated Standards of Reporting Trials (CONSORT) statement's criteria for the highest quality of randomized trial; however, many studies were in progress or published before the opportunity to comply with these recommendations. Therefore, limited evidence from a number of studies suggests a beneficial influence of physical activity on reduction in abdominal and visceral fat in overweight and obese subjects when imaging techniques are used to quantify changes in abdominal adiposity. More rigorous studies are needed to confirm these observations.

A case-control study evaluating the association of purposeful physical activity, body fat distribution, and steroid hormones on premenopausal breast cancer risk

The objective of this case-control study was to investigate the relationship between purposeful physical activity, body fat distribution, body mass index, and steroid hormones. These factors are known to be implicated in modulating breast cancer risk in premenopausal women. A total of 112 newly diagnosed, premenopausal breast cancer patients and 106 age-matched premenopausal disease-free controls were admitted to the study. Information regarding personal, medical, hormonal, and reproductive history, smoking and alcohol use, physical activity history, and anthropometric measurements was obtained. Serum samples for steroid hormone assays were collected and analyzed. Disease-free premenopausal controls had a significantly higher physical activity index (PAI) (p</=0.05), however, significantly higher weight (p</=0.05), body mass index (BMI) (p=0.01), waist (p</=0.005) and hip (p</=0.05) circumferences, waist:hip ratios (p</=0.05), and serum total estradiol levels (p<0.0005) were observed in cancer cases. The final model using stepwise logistic regression analysis indicates that the variables that significantly predicted breast cancer risk were waist:hip ratio (odds ratio [OR]=1.11, p</=0.005) and serum total estradiol levels (OR=1.03, p</=0.0001). Our study provides some evidence that purposeful physical activity may reduce upper body fat distribution associated with adult weight gain. This may be a result of alterations in the steroid hormone pathway, such as reduced estradiol levels. This demonstrates the potential mechanism through which increased physical activity can reduce the risk for breast cancer in premenopausal women.

Critical study of common conditions of storage of glucocorticoids and catecholamines in 24-h urine collected during resting and exercising conditions

BACKGROUND

Except immediate freezing of the samples, no practical method has been validated for preservation of glucocorticoids and catecholamines in 24-h urine collection. Furthermore, the influence of urine storage at bladder temperature during periods of different lengths and the effect of prior exercise on preservation of these hormones in the bladder have not been investigated until now.

METHODS

Ten healthy volunteers collected their urine both after a resting and after an exercise session. Urine was aliquoted into tubes which were stored during 24 h in the presence or in the absence of preservatives and at different temperatures. Two samples were stored either 3 or 9 h at 37 degrees C (bladder temperature) without additive.

RESULTS AND CONCLUSIONS

When collecting 24-h urine samples for glucocorticoids determination, sample can be stored at room temperature during the 24-h collection period without compromising glucocorticoids preservation. When collecting 24-h urine samples for catecholamines determination, samples have to be chilled without preservative during the whole of the collection period. If the samples have to be stored at room temperature, HCl should be used. Moreover, we report for the first time that catecholamines can be degraded in the bladder and therefore that subjects should urinate every 3 h during either a resting or an exercising day.

Battling insulin resistance in elderly obese people with type 2 diabetes: bring on the heavy weights

Exercise improves insulin resistance and has beneficial effects in preventing and treating type 2 diabetes. However, aerobic exercise is hindered in many type 2 diabetic patients because of advancing age, obesity, and other comorbid conditions. Weight lifting or progressive resistance training (PRT) offers a safe and effective exercise alternative for these people. PRT promotes favorable energy balance and reduced visceral fat deposition through enhanced basal metabolism and activity levels while counteracting age- and disease-related muscle wasting. PRT improves insulin sensitivity and glycemic control; increases muscle mass, strength, and endurance; and has positive effects on bone density, osteoarthritic symptoms, mobility impairment, self-efficacy, hypertension, and lipid profiles. PRT also alleviates symptoms of anxiety, depression, and insomnia in individuals with clinical depression and improves exercise tolerance in individuals with cardiac ischemic disease and congestive heart failure; all of these aspects are relevant to the care of diabetic elders. Moreover, PRT is safe and well accepted in many complex patient populations, including very frail elderly individuals and those with cardiovascular disease. The greater feasibility of using PRT over aerobic exercise in elderly obese type 2 diabetic individuals because of concomitant cardiovascular, arthritic, and other disease provides a solid rationale for investigating the global benefits of PRT in the management of diabetes.

Basal metabolic rate in anorexia nervosa: relation to body composition and leptin concentrations

BACKGROUND

Leptin is thought to represent a peripheral signal involved in the regulation of energy balance. Its action has been studied in animals and obese subjects. Little is known about leptin's role during negative energy balance.

OBJECTIVE

The objective was to evaluate the relation between energy turnover, body composition, and plasma leptin concentrations in anorexia nervosa (AN).

DESIGN

Sixteen weight-stable women with AN were compared with 22 control subjects and 14 rehabilitated AN patients (R-AN). Basal metabolic rate (BMR) was measured by indirect calorimetry; fat-free mass (FFM) and fat mass (FM) were calculated according to a 4-compartment model. Plasma leptin was determined by radioimmunoassay.

RESULTS

The BMR of AN patients (2.73 +/- 0.37 kJ/min) was significantly lower than that of control subjects (3.45 +/- 0.34 kJ/min) (P < 0.001), even after adjustment for FFM (2.92 +/- 0.33 kJ/min in AN patients and 3.30 +/- 0.26 kJ/min in control subjects; P < 0.004). Plasma leptin concentrations in AN patients were 76% lower than in control subjects, even after body fat was controlled for. In R-AN patients, BMR was not significantly different from that of control subjects and leptin concentrations were generally close to normal. Plasma leptin concentrations correlated significantly with FM (r(2) = 0.53, P < 0.0000) and BMR, even after adjustment for FFM (r(2) = 0.21, P < 0.0003).

CONCLUSIONS

BMR and plasma leptin concentrations are depressed in patients with AN; this is not explained by body-composition changes. The relation between leptin and BMR suggests that leptin plays a role in the energy sparing response to exposure to chronic energy deficiency. The return of BMR to normal and the significant increase in leptin concentrations in R-AN patients suggests a full reversibility of this adaptation mechanism.