Aging is associated with an increased accumulation of abdominal fat, glucose intolerance, and insulin resistance. We tested the hypothesis that diet-induced weight loss would reduce the abdominal distribution of fat and improve glucose tolerance and insulin action in a group of obese middle-aged and older men with normal or impaired glucose tolerance (IGT). Oral glucose tolerance tests (OGTTs) were performed at baseline and after 9 months of diet-induced weight loss in 35 men (mean age, 60 +/- 8 years). Fifteen men of comparable age and degree of obesity who did not participate in the weight loss intervention served as controls. Subjects lost 9.0 +/- 2.0 kg (mean +/- SD) body weight (P < .001), resulting in a 19% reduction in percent body fat (30.0 +/- 4.0% to 24.0% +/- 4.0%, P < .001), an 8% reduction in waist circumference (104.0 +/- 7.0 to 96.0 +/- 7.0 cm, P < .001), and a 2% reduction in waist to hip ratio [WHR] (0.97 +/- 0.06 to 0.95 +/- 0.06, P < .01). Weight loss improved glucose tolerance: nine men with IGT at baseline reverted to normal glucose tolerance following the intervention. Glucose area during the OGTT was significantly reduced after weight loss (-22.0%, P < .001), while it increased in control subjects (+32%, P < .004). In multiple regression analysis, the improvement in glucose area following weight loss in these 35 men was attributed to the reduction in waist circumference (P < .01) and baseline glucose area (P < .05).(ABSTRACT TRUNCATED AT 250 WORDS)

Abdomen↗

PubMed1995

Body fatness and waist circumference are independent predictors of the age-associated increase in fasting insulin levels in healthy men and women.

OBJECTIVE: Elevated levels of fasting insulin increase the risk for coronary artery disease. In this study, we considered the independent contributions of age, total body fatness, abdominal fat distribution, peak aerobic capacity, leisure time physical activity, dietary intake, and fasting glucose levels to the age-associated increase in fasting insulin levels in healthy men and women. DESIGN: A cross-sectional analysis. SUBJECTS: A total of 427 healthy men and 293 healthy women age 18 to 90 years. MEASUREMENTS: Plasma glucose and insulin levels were measured in the fasted state and subjects were characterized for body fatness from underwater weighting, abdominal fat distribution from the waist circumference, peak VO2 from a treadmill test to exhaustion, leisure time physical activity from a structured interview and dietary intake from a 3-day food diary. The independent predictors of fasting insulin levels were determined by stepwise multiple regression analysis. RESULTS: Fasting insulin concentrations increased with age in both men (0.09 +/- 0.02 pmol/yr, unadjusted slope +/- SEE) and women (0.14 +/- 0.03 pmol/yr). In men, the major independent predictors of fasting insulin levels were percent body fat (r2 = 28%, P < 0.001) and waist circumference (r2 = 3% P < 0.001). Age, glucose concentration, and peak VO2 were small (1% each), but independent contributors to the variance in insulin levels. In women, the waist circumference (r2 = 18%, P < 0.001) and the fasting glucose concentration (r2 = 7%, P < 0.001) were the independent correlates of fasting insulin concentrations. CONCLUSIONS: Our data suggest that total adiposity and central body fat distribution are significant determinants of the increase in fasting insulin levels, whereas age, dietary intake, and levels of aerobic fitness and physical activity appear to be less important contributors to the variation in fasting insulin concentrations in healthy men and women.

Adolescent↗

PubMed1994

Risk factors for exercise-induced silent myocardial ischemia in healthy volunteers.

This study determined the risk factors for exercise-induced silent ischemia (SI) in 281 apparently healthy volunteers aged 40 to 87 years and compared their risk factor profiles with those of 132 patients with overt coronary artery disease (CAD). SI (concordant exercise-induced asymptomatic ST-segment depression on electrocardiography and perfusion defects on tomographic thallium-201 scintigraphy) was detected in 37 of 225 men (16%), versus 2 of 56 women (4%, p < 0.05). The prevalence of SI increased with age from 6% in men aged < 55 years to 18% in men aged 55 to 70 years, and to 25% in men aged > 70 years (p < 0.001). Compared with the 118 men with concordant normal exercise electrocardiogram and thallium scan (normals), men with SI were older (p < 0.001), and had a higher waist-to-hip ratio (p < 0.005), higher plasma triglyceride levels (p < 0.001), and lower high-density lipoprotein (HDL) cholesterol levels (p < 0.001). In stepwise logistic regression analysis, age, waist-to-hip ratio, and HDL levels were independent predictors of SI in men. Compared with 108 men with overt CAD, men with SI were younger (67 +/- 2 vs 73 +/- 1 years, p < 0.001) but had similar plasma lipids and waist-to-hip ratio. Thus, older age, male gender, abdominal obesity, and reduced HDL levels--all well-established risk factors for overt CAD--were risk factors for exercise-induced SI in these asymptomatic volunteers.

Age Factors↗

PubMedDate not supplied

Robert Graves and the origins of Irish medical journalism.

Explore the source record for details and available documents.

Endocrinology↗

PubMedDate not supplied

The role of obesity and cardiovascular fitness in the impaired glucose tolerance of aging.

The prevalence of impaired glucose tolerance (IGT) increases with aging. Although some data suggest that age is independently associated with IGT, other studies suggest that age-associated changes in body composition and reduced cardiovascular fitness are responsible for the development of IGT. We, therefore, examined the relationship of age, total and regional adiposity, and level of fitness (VO2max) to the presence of IGT in 155 healthy, nondiabetic, nonsmoking, older community dwelling men. Sixty-two of 155 men (40%) had IGT, while 93 men (60%) had normal glucose tolerance (WHO criteria). The subjects with IGT were of similar age (61.0 +/- 1.0 vs. 59.0 +/- 0.7 years, p = 0.49) and had the same maximal aerobic capacity, (VO2max) (42.0 +/- 1.0 vs. 44.0 +/- 0.8 mL/kg ffm/min, p = 0.42), but had a higher waist to hip ratio (WHR) (0.98 +/- 0.01 vs. 0.96 +/- 0.01, p = 0.005) and percent body fat (30.0 +/- 0.4 vs. 26.0 +/- 0.6, p = 0.004) than the men with normal glucose tolerance. In univariate analysis, the 2-h glucose level correlated positively with percent body fat (r = 0.30, p = 0.0002), WHR (0.24, p = 0.002), and age (r = 0.17, p = 0.03) and negatively with VO2max (r = -0.23, p = 0.005). In both multiple logistic and linear regression analyses, percent body fat was the only independent predictor of IGT (p = 0.002). These results suggest that the age-associated increase in total adiposity is a major contributor to the development of IGT in middle-aged and older men. Thus, lifestyle modifications that reduce body fat should reduce the risk for IGT and the development of noninsulin-dependent diabetes mellitus in the elderly.

Aged↗

PubMedDate not supplied

Physiological predictors of increasing total and central adiposity in aging men and women.

BACKGROUND: Increasing levels of total and central body fat with advancing age contribute to the development of cardiovascular and metabolic disease. We examined gender-related differences and physiological predictors of the rate of increase in total and central body fat in men and women. METHODS: We studied 427 healthy men (age range, 17 to 90 years) and 293 women (age range, 18 to 88 years). We measured body fatness by hydrostatic weighing, central adiposity from the waist circumference, peak volume of oxygen utilization (VO2) from a treadmill test, leisure time physical activity (LTA) from a questionnaire, resting metabolic rate and respiratory quotient from indirect calorimetry, and energy intake from 3-day food diaries. RESULTS: Fat mass increased with age, and the rate was greater in women (r = .61; slope = 0.25 kg/y; P < .01) than in men (r = .43; slope = 0.16 kg/y; P < .01). Increasing fat mass in men and women was most strongly associated with declines in peak VO2 and LTA. Controlling for these variables reduced the increase in fat mass from 17% to 3% per decade in men and from 26% to 5% per decade in women. The increase in waist circumference with age was also greater in women (r = .53; slope = 0.28 cm/y) than in men (r = .39; slope = 0.18 cm/y; P < .01). Increasing waist circumference with age in men and women was most strongly associated with declines in LTA and peak VO2, respectively. Control for these variables reduced the age-related increase in waist circumference from 2% to 1% per decade in men and from 4% to 1% per decade in women. We observed no independent contribution of resting metabolic rate, respiratory quotient, menopause status, energy, or macronutrient intake to the age-related increase in fat mass and waist circumference. CONCLUSIONS: Our findings suggest that (1) the age-related increase in fat mass and waist circumference is greater in women than in men and (2) the physiological characteristics that reflect a decline in physical activity-related energy expenditure, rather than resting energy expenditure, are important predictors of the increases in total and central fatness. Lifestyle changes that increase the level of physical activity may be advantageous in blunting age-related increases in total and central body fatness.

Adipose Tissue↗