Discriminating glucose tolerance status by regions of interest of dual-energy X-ray absorptiometry. Clinical implications of body fat distribution

The association of metabolic syndrome and aging with cognition in Asian men

BACKGROUND

The present cross-sectional study examined the associations of individual metabolic factors and age with the short-term memory and perceptual capacity in 472 healthy Asian men.

METHODS

The symbol digit and digit span tests from the Swedish Performance Evaluation System were used to assess the perceptual capacity and memory cognitive domains. Linear regression with the stepwise method, and multivariate analyses of the General Linear Model with the Bonferroni correction for multiple comparisons were carried out with the SPSS 21.0 package.

RESULTS

High blood pressure and HDL were not significantly associated with either short-term memory or perceptual capacity. Age and glucose level were negatively associated but regular physical exercise was positively associated with perceptual capacity. On the other hand, high triglyceride level (TG) was positively associated but high waist/height ratio was negatively associated with short-term memory. When men without any component of the metabolic syndrome (MetS) were compared with men with one, two or three or more components of MetS, no significant differences in cognitive performance were noted.

CONCLUSION

Not all the metabolic factors were significantly associated with short-term memory or the perceptual capacity domains. Those that were did not show a sufficiently consistent pattern of association to support a role for MetS as a whole in cognitive decline with aging. It may not be meaningful to evaluate the association of MetS as a whole with cognition.

Regional fat distribution and cardiometabolic risk in healthy postmenopausal women

BACKGROUND

Regional fat distribution is an important determinant of cardiometabolic risk after menopause. The aim of the present study was to investigate the association between indices of fat distribution obtained by Dual-energy X-ray Absorptiometry (DXA) and representative cardiometabolic risk factors in a cohort of healthy postmenopausal women.

METHODS

In this cross-sectional study, cardiometabolic risk factors were correlated with a variety of central and peripheral fat depots obtained by DXA, in a total of 150 postmenopausal women, free of diabetes and cardiovascular disease (age 54 ± 7 years, BMI 29.6 ± 5.8 kg/m(2), mean ± 1 SD).

RESULTS

After adjusting for age and total adiposity, DXA-derived indices of central and peripheral fat distribution displayed opposite associations (positive versus negative) with the examined cardiometabolic risk factors. In multivariate regression analysis, thoracic fat mass % was an independent predictor of blood pressure, HOMA index and triglycerides, abdominal fat mass % was an independent predictor of high sensitivity C-reactive protein, and abdominal-to-gluteofemoral fat ratio was an independent predictor of high density lipoprotein cholesterol. An index of peripheral fat distribution, gluteofemoral fat mass %, proved to be the most important determinant of metabolic syndrome (Odds Ratio 0.76, 95% confidence intervals 0.67-0.87, p<0.001), independent of total and central adiposity.

CONCLUSION

DXA-derived indices of regional fat distribution such as thoracic, abdominal and gluteofemoral fat, correlate significantly with cardiometabolic risk factors in healthy postmenopausal women, and may serve as clinically useful tools for evaluating cardiometabolic risk after menopause.

The triglyceride content in skeletal muscle is associated with hepatic but not peripheral insulin resistance in elderly twins

CONTEXT AND OBJECTIVE

Total muscle triglyceride (MT) content has been associated with insulin resistance. We investigated the predictors and impact of MT on relevant metabolic parameters including peripheral and hepatic insulin resistance in elderly twins.

DESIGN AND PARTICIPANTS

Seventy-four elderly same-sex twins underwent hyperinsulinemic euglycemic clamps preceded by an iv glucose tolerance test. Aerobic capacity (VO2max) and body composition (dual-energy x-ray absorptiometry scan) were determined in all twins. A biopsy from the vastus lateralis muscle was excised in the fasting state. The muscle triacylglycerol content was analyzed by biochemical extraction from these biopsies.

RESULTS

The percentage of total body fat was the only independent predictor of MT content. After adjustment for trunk fat percentages and sex, MT level was significantly associated to fasting plasma levels of glucose and insulin as well as hepatic insulin resistance. However, the association was weakened after adjustment for total fat percentages. A 1 SD (34.5 mmol/kg dry weight) increase in MT content was associated with a 24% increase of hepatic insulin resistance. No association between MT content and peripheral insulin sensitivity was observed.

CONCLUSION

MT content is associated with hepatic but not peripheral insulin resistance in elderly twins. We speculate that MT content may reflect the general ectopic accumulation of triglycerides, including fat in the liver.

Independent and combined effects of exercise training and metformin on insulin sensitivity in individuals with prediabetes

OBJECTIVE

Physical activity or metformin enhances insulin sensitivity and opposes the progression from prediabetes to type 2 diabetes. The combination may be more effective because each treatment stimulates AMP-activated protein kinase activity in skeletal muscle. We evaluated the effects of exercise training plus metformin on insulin sensitivity in men and women with prediabetes, compared with each treatment alone.

RESEARCH DESIGN AND METHODS

For 12 weeks, men and women with prediabetes were assigned to the following groups: placebo (P), 2,000 mg/day metformin (M), exercise training with placebo (EP), or exercise training with metformin (EM) (n = 8 per group). Before and after the intervention, insulin sensitivity was measured by euglycemic hyperinsulinemic (80 mU/m(2)/min) clamp enriched with [6,6-(2)H]glucose. Changes due to intervention were compared across groups by repeated-measures ANOVA.

RESULTS

All three interventions increased insulin sensitivity (P < 0.05) relative to the control group. The mean rise was 25-30% higher after EP than after either EM or M, but this difference was not significant.

CONCLUSIONS

Insulin sensitivity was considerably higher after 12 weeks of exercise training and/or metformin in men and women with prediabetes. Subtle differences among condition means suggest that adding metformin blunted the full effect of exercise training.

Altered body composition in type 2 diabetes mellitus

OBJECTIVE

To identify differences in amount and distribution of fat and lean soft tissue in a cross-sectional study of subjects with and without type 2 diabetes and to determine whether any differences are affected by race/ethnicity or sex.

DESIGN AND METHODS

Overweight and obese (body mass index, BMI > or = 25 kg m(-2)) Black, White and Hispanic men (490) and women (825) with type 2 diabetes ((mean+/-s.d.) age 58.5+/-6.6; BMI 35.3+/-5.3) who had a baseline dual energy X-ray absorptiometry whole-body scan at the time of enrollment in the Look AHEAD clinical trial, and 242 healthy controls, 91 males and 151 females (age 55.3+/-8.6 years, BMI 30.7+/-4.2 kg m(-2)) who were participating in unrelated research and were scanned on the same densitometers.

RESULTS

Adjusted for gender, age, race, clinical site and body size, total fat mass was smaller in persons with type 2 diabetes than in controls (-1.4+/-0.3 (s.e.); 34.5 vs 35.8 kg, P<0.001) while trunk fat was larger (1.3+/-0.2 (s.e.); 19.9 vs 18.6 kg, P<0.001) and leg fat was smaller (-1.5+/-0.2 (s.e.); 10.7 vs 12.3 kg, P<0.001). The arms of subjects with type 2 diabetes did not have significantly less fat compared to controls. Adjusted trunk lean mass was larger in type 2 diabetes by 0.6 kg (28.4 vs 27.8 kg, P<0.001) while leg lean was smaller by 0.5 kg (18.1 vs 18.6 kg, P<0.001).

CONCLUSIONS

Type 2 diabetes is associated with less total fat, leg fat and leg lean mass and more truncal fat and lean mass than controls. The physiological processes producing these deviations in tissue distribution and their metabolic significance warrant further investigation.

Differential impact of aging and gender on lipid and lipoprotein profiles in a cohort of healthy Chinese Singaporeans

AIM

To evaluate the impact of age and gender on lipid and lipoprotein profiles and the burden of dyslipidemia in a cohort of healthy Chinese Singaporean.

METHODS

A total of 1 775 healthy Chinese, 536 men and 1 239 women aged between 30 and 70 years old were involved in the present study.

RESULTS

Gender differences in all lipid and lipoprotein levels were clearly evident. Singaporean Chinese men have significantly higher levels of total cholesterol (TC), triglyceride (TG), low density lipoprotein-cholesterol (LDL-C) and total cholesterol/high density lipoprotein-cholesterol (TC/HDL-C), and lower levels of HDL-C than women. Although lipid and lipoprotein levels in men did not change in the different age groups, those in women, especially TC, LDL-C and TC/HDL-C, were significantly higher in older women (> 50 years old) than corresponding levels in younger women (30-46 years old). Furthermore, TG was significantly correlated with lipids and lipoproteins differently in men and women. If 100 mg/dL of LDL-C were to be adopted as the therapeutic cut-off level, then the burden of care will be huge as approximately 90% of both Chinese men and women have LDL-C greater than 100 mg/dL.

CONCLUSION

In light of the findings of the present study, we suggest that preventive measures to promote the reduction in risk of coronary heart disease (CHD) must address the high proportion of men and women with high LDL-C, and that these measures should take into account both the gender and age factors. For men, reduction of high cholesterol must start early in life, whereas for women, steps must be taken earlier to mitigate the anticipated sharp increase in risk, especially after menopause.

Visceral obesity and hemostatic profile in patients with type 2 diabetes: the effect of gender and metabolic compensation

BACKGROUND

Type 2 diabetes (T2DM) patients are characterized by a very high risk of cardiovascular diseases. Among the factors that are responsible for this phenomenon are abdominal obesity and hemostatic abnormalities.

AIM OF THE STUDY

To examine the association of the markers of coagulation and fibrinolysis with the parameters of abdominal obesity and metabolic compensation in T2DM patients.

METHODS

46 T2DM patients participated in the study: 24 men (mean age 61.1 +/- 7.9 years) and 22 postmenopausal women (mean age 62.6 +/- 8.7 years). In each patient the content and distribution of fatty tissue was measured by a dual energy X-ray absorptiometry method (DEXA). The central abdominal fat/gynoid hip fat (CAF/GF) ratio was calculated. The following hemostatic parameters were measured: fibrinogen (Fb), factor VII (fVII), antithrombin III (ATIII), C protein (pC), tissue plasminogen activator inhibitor (PAI-1) and alpha 2 antiplasmin (alpha2 AP). In addition, the biochemical indices of metabolic compensation were measured: HbA1c, glucose levels and lipids.

RESULTS

Patients of both genders were divided according to median CAF/GF ratio. The activity of PAI-1 was significantly higher in women with CAF/GF ratio >or= 0.88 as compared to those with CAF/GF < 0.88 (2.64 +/- 1.28 vs. 1.61 +/- 0.27 U/ml, p < 0.05). The activity of ATIII was significantly lower in men with CAF/GF ratio >or= 1.17, as compared to those with CAF/GF < 1.17 (105.10 +/- 10.02 vs. 113.42 +/- 10.72 %, p < 0.05). There was a significant correlation between the CAF/GF ratio and the activity of PAI-1 in women (r = 0.30, p < 0.05). In addition, in men the CAF/GF ratio was negatively correlated with ATIII activity (r = -0.44, p < 0.05). Multiple stepwise regression analysis demonstrated independent association between the CAF/ GF ratio and the activity of PAI-1 (p < 0.001), and between the CAF/GF ratio and the activity of alpha2 AP (p < 0.01). There was an independent association between the concentration of HbA1c and the concentration of Fb (p < 0.001) and between triglycerides and the activity of fVII (p < 0.01).

CONCLUSIONS

The results of our study show that the patients with T2DM and with higher markers of abdominal obesity measured by DEXA show fibrinolysis impairment and thrombinogenesis elevation compared to those with lower abdominal obesity markers. Independent factors determining hypercoagulation also include metabolic control and lipids. Hemostatic disorders place subjects with diabetes and abdominal obesity at risk of developing vascular complications.

Are BMI and other anthropometric measures appropriate as indices for obesity? A study in an Asian population

We have examined the relationships between percentage of body fat (PBF) and risk factors for cardiovascular disease and insulin resistance and how good body mass index (BMI) and other anthropometric measures are as indices of obesity. High PBF levels were associated with increased risk of cardiovascular disease and insulin resistance. The World Health Organization BMI of 30 kg/m(2) for obesity has low sensitivity, 6.7% and 13.4% for men and women, respectively. For every obese man and woman identified, 6.7 and 1.76 times nonobese men and women, respectively, will be misclassified as obese. With the locally established BMI cutoff point for obesity of 27 kg/m(2) for men and 25 kg/m(2) for women, the sensitivity was improved to 46.7% and 60.8%, respectively. For every obese man and woman identified, 3.76 and 1.64 times nonobese men and women, respectively, will be misclassified as obese. None of the other anthropometric indices was better than the locally established BMIs. We showed that the BMIs for obesity for our local men and women are different. These BMIs were most precise among all indices studied. However, they still lead to high false-positive rates. For more effective management of the problem of obesity, we need to develop more precise, simple, and cost-effective methods for the measurement of PBF.

Managing aging men in Asia: a strategic approach

We have established a comprehensive diagnostic paradigm for the management of aging men which seeks to evaluate the various determinants of the aging process in five major health areas: cardio-health, bone health, sex health, general health and endocrine state. This paradigm appears to be useful for the management of the problem of aging in our local population. It could be used for the management of individuals as well as for population research. When combined with the establishment of evidence-based management modalities, it will provide a useful tool for the holistic management of aging in Asia.

Body composition in adolescent girls with type 1 diabetes

AIMS

To compare body composition in adolescent girls with Type 1 diabetes with healthy controls.

RESEARCH DESIGN AND METHODS

In this population-based study, body composition was examined, using dual-energy X-ray absorptiometry (DXA) and skinfold measurements, in 18 adolescent post-menarcheal females, 16-19 years of age, with Type 1 diabetes since childhood in comparison to age-matched healthy control subjects.

RESULTS

Body mass index was 2.7 kg/m2 higher in diabetic patients (26.3 +/- 2.6 vs. 23.6 +/- 3.8; P < 0.05). The overweight consisted almost entirely of increased fat mass, as evaluated by both skinfold measurements and DXA. Bone mineral density did not differ between the two groups. In diabetic females, the distribution of the fat mass was increased in the upper part of the body. The fat distribution, expressed as the abdominal-to-leg ratio, was significantly correlated to glycated haemoglobin (HbA1c) (r = 0.69; P < 0.005), daily dosage of insulin expressed per kilogram body weight (r = 0.78; P < 0.0005) and total cholesterol (r = 0.60; P < 0.001).

CONCLUSIONS

The observed overweight in adolescent females with Type 1 diabetes is explained by an increased fat mass. Abdominal fat accumulation was associated with poor glycaemic control, increased need for insulin and elevated blood lipids.

Iatrogenic lipodystrophy in HIV patients – the need for very-low-fat diets

In HIV patients, chronic treatment with protease inhibitors often precipitates a peripheral lipodystrophy associated with insulin resistance syndrome and premature coronary disease. In vitro studies demonstrate that these drugs can compromise the ability of adipocytes to store triglycerides; in vivo, peripheral subcutaneous adipocytes appear to be most affected, such that body fat often redistributes to visceral or truncal adipose stores. Dysfunction of peripheral subcutaneous adipocytes - ordinarily quite efficient for storing fat - can be expected to give rise to an excessive flux of free fatty acids (FFAs) following fatty meals; chronic overexposure of tissues to FFAs is a likely explanation for the insulin resistance syndrome associated with lipodystrophy. These considerations suggest that a very-low-fat diet - less than 15% fat calories - may ameliorate the cardiovascular risk associated with lipodystrophy; such diets are known to have a favorable effect on the insulin sensitivity of healthy subjects. Very-low-fat whole-food vegan diets are particularly recommendable in this context, as they may help to shrink visceral fat depots while markedly reducing LDL cholesterol. Appropriate adjunctive measures may include aerobic exercise training - beneficial both for insulin sensitivity and weight control - as well as administration of statins or policosanol, and of fibrates or fish oil, to decrease LDL and triglycerides, respectively. Despite perceptions to the contrary, very-low-fat diets can meet with good compliance in well-motivated subjects given appropriate instruction.

A paradox resolved: the postprandial model of insulin resistance explains why gynoid adiposity appears to be protective

Although an increased visceral adipose mass is clearly linked to insulin resistance syndrome and increased vascular risk, some studies suggest that the ratio of visceral to subcutaneous fat (gynoid or abdominal) is a better correlate of insulin resistance. For example, the utility of waist-to-hip ratio as a risk factor illustrates this principle--and suggests that gynoid obesity may somehow be protective. The postprandial model of insulin resistance--the hypothesis that excessive postprandial free, fatty acid (FFA) flux plays a key role in the genesis of the insulin resistance syndrome--may help to rationalize this seemingly paradoxical observation. A high proportion of this FFA flux is derived, not from adipocytes, but from meal-derived fatty acids that adipocytes fail to store following chylomicron breakdown; insulin-resistant adipocytes are notably inefficient in regard to FFA storage. Hypertrophied visceral adipocytes are poorly insulin sensitive, whereas gynoid adipocytes tend to be highly insulin sensitive. After a fatty meal, the lipoprotein lipase (LPL) activities associated with the various depots--visceral and subcutaneous adipocytes, as well as skeletal muscle--effectively compete to hydrolyze chylomicra. When circulating triglycerides are broken down by muscle or by insulin-sensitive subcutaneous adipocytes, the evolved fatty acids are apt to be stored immediately--whereas the fatty acids produced by chylomicron breakdown in the visceral depot are much more prone to escape to the circulation and contribute to high postprandial FFA flux. Thus, the LPL activity of gynoid adipocytes provides protection from the potentially adverse metabolic consequences of fatty meals--and a large mass of gynoid adipocytes presumably is a marker for high LPL activity in this depot. The ability of the postprandial model of insulin resistance to rationalize the seeming protection afforded by gynoid obesity constitutes evidence that this model has validity.

Detection of cardiovascular risk factors by indices of obesity obtained from anthropometry and dual-energy X-ray absorptiometry in Japanese individuals

OBJECTIVE

To determine the cut-off points of indices of obesity for detecting hypertension, dyslipidemia and diabetes mellitus in Japanese individuals.

DESIGN

Cross-sectional study.

SUBJECTS

A total of 2728 Japanese individuals (768 males and 1960 females, aged 20-79 y) who attended the Fukuoka Health Promotion Center, Japan for health check-up.

MEASUREMENTS

Body mass index (BMI), waist circumference (WC) and waist-hip ratio (WHR) were measured. Percentage fat mass (%FM), trunk fat mass (FM(trunk)) and trunk fat mass-leg fat mass ratio (FM(trunk)/FM(legs)) were obtained by dual-energy X-ray absorptiometry (DXA). Cardiovascular risk factors were determined by blood pressure, serum lipids, fasting blood glucose and hemoglobin A(1C).

RESULTS

The cut-off points of BMI, WC and WHR were around 23.5 kg/m(2), 84 cm and 0.9 for males, and 22.5 kg/m(2), 72 cm and 0.8 for females. The cut-off points of %FM, FM(trunk) and FM(trunk)/FM(legs) were around 24%, 8 kg and 1.6 for males, and 35%, 9 kg and 1.4 for females. WHR and FM(trunk)/FM(legs) most accurately detected the risk factors.

CONCLUSIONS

For Japanese individuals, the cut-off points for detecting cardiovascular risk factors are lower than the criteria by the World Health Organization. Indices of fat distribution detected the cardiovascular risk factors more accurately than those of overall adiposity. The accuracy of detecting the risk factors was comparable between the anthropometric indices and indices obtained by DXA.

Low body mass index but high percent body fat in Taiwanese subjects: implications of obesity cutoffs

OBJECTIVES

To compare the different correlations of body mass index (BMI) and percent body fat (BF%) with other ethnic groups and to evaluate the appropriateness of Asia-Pacific redefining obesity criteria in the Taiwanese population. The corresponding BF% to BMI cutoffs of overweight and obesity will also be studied.

DESIGN

A cross-sectional epidemiological survey.

SUBJECTS

A total of 509 male and 570 female Taiwanese subjects aged > or =20 y sampled by the systematic stratified clustering sampling method were analyzed.

MEASUREMENTS

BMI was obtained by body weight (kg) divided by squared body height (m(2)). The estimated BMI (BMIe) was deduced from the Caucasian-based four-compartment equation (4C). BF% measured by the methods of dual-energy X-ray absorptiometry (DXA) or Caucasian-based 4C were used and abbreviated as DXA-BF and 4C-BF, respectively.

RESULTS

The curvilinear relationship between age and BMI or DXA-BF was established. When compared by age-stratified groups, Taiwanese subjects had a higher BF% (4C-BF) in any given BMI than Caucasians. That is, the level of 4C-BF for BMI> or =25 kg/m(2) in Taiwanese subjects was similar to BMI> or =30 kg/m(2) in Caucasians. The BMIe values of 25 and 30 kg/m(2) were nearly equal to the BMIs of 23.6 and 25.3 kg/m(2) in males, and 22.7 and 24.8 kg/m(2) in females, respectively. The 4C-BF of 25% was nearly equal to a BMI of 26.2 kg/m(2) in males, and 35% was equal to a BMI of 24.4 kg/m(2) in females. Consequently, the DXA-BF cutoffs for BMIs of 23 and 25 kg/m(2) were compatible to 23 and 25% in males, and 35 and 38% in females, respectively.

CONCLUSION

It was demonstrated that Taiwanese subjects had a relatively lower BMI but a higher BF% than Caucasians. In general, the newly proposed Asia-Pacific BMI cutoffs for overweight (> or =23 kg/m(2)) and obesity (> or =25 kg/m(2)) may be acceptable to both male and female Taiwanese subjects. The corresponding BF% (DXA-BF) cutoffs for obesity would be 25% in male and 38% in female Taiwanese subjects, respectively.

Relationships of age, menopause and central obesity on cardiovascular disease risk factors in Chinese women

OBJECTIVE

To evaluate the inter-relationships of age- and menopause- related changes of general obesity and body fat distribution and their independent effects on cardiovascular risk factors.

DESIGN

Cross-sectional study.

SUBJECTS

One-hundred and thirty-six premenopausal and 193 postmenopausal Chinese women with body mass index (BMI) < 30 kg/m2.

MEASUREMENTS

Anthropometric surrogates of general obesity (BMI, total body fat percentage) and central obesity (waist-to-hip ratio, centrality index) were measured. Blood pressure, 75 g oral glucose tolerance test, glycosylated hemoglobin A1c and lipid profiles were also measured.

RESULTS

Significant correlation coefficients between age, general obesity, central obesity and cardiovascular disease risk factors were noted. Through the menopausal transition, the BMI and total body fat percentage were increased significantly. After adjustments for age and BMI, the postmenopausal women showed higher android fat percentage, centrality index, glycosylated hemoglobin A1c, serum concentrations of total cholesterol, low-density lipoprotein (LDL) cholesterol and atherogenic indices than the premenopausal women. In multiple stepwise regression models, age exerted independent effects on oral glucose tolerance test 2 h plasma glucose level, systolic and diastolic blood pressure, total cholesterol level, and LDL cholesterol. Menopause was an independent variable in relation to the changes of glycosylated hemoglobin A1c, total and LDL cholesterol levels, triglyceride levels and atherogenic indices. The centrality index was the major independent variable of all the cardiovascular disease risk factors, except total and LDL cholesterol level. However, the variation of total body fat percentage had no independent effect on any cardiovascular disease risk factors.

CONCLUSION

Through the aging and menopausal effects, women will increase total body fat content, favoring the central body fat distribution. Age, menopause and central obesity were all independent and significant factors to the cardiovascular disease risk factors in Chinese women.