Are dual-energy X-ray absorptiometry regional estimates associated with visceral adipose tissue mass?

Increased strength and physical performance with eccentric training in women with impaired glucose tolerance: a pilot study

BACKGROUND

Menopause is associated with both a loss of muscle mass and a worsening of insulin sensitivity (IS). Although eccentric resistance exercise (ECC) can effectively improve muscle mass over time, a single bout of ECC can worsen IS. This study assessed the effect of repeated ECC on IS, muscle mass, and function in postmenopausal women with impaired glucose tolerance (IGT).

METHODS

Sixteen PM women (aged 56 years +/- 6.4) with IGT were randomly assigned to a 12-week, knee extensor ECC program (n = 10) or a nonexercise control group (CON) (n = 6). Participants underwent hyperinsulinemic-euglycemic clamps, dual-energy x-ray (DEXA) absorptiometry, quadriceps strength assessment, 6-minute walk (6MW) tests, and an assessment of steps taken per day before and after training.

RESULTS

ECC participants experienced greater increases in leg lean soft tissue mass (ECC, 0.41 kg; CON, -0.53 kg; p = 0.03), quadriceps strength (ECC, 9.3 kg force; CON, -2.9 kg force; p = 0.02), and 6MW distance (ECC, 56.4 meters; CON, 3.3 meters; p = 0.03) than CON participants and demonstrated a trend toward more steps taken per day posttraining (ECC, +1747 steps; CON, +339 steps; p = 0.10). IS was unchanged.

CONCLUSIONS

This novel exercise improves muscle mass and function without worsening IS in postmenopausal women with IGT. Because it can be performed at low levels of exertion and improves muscle mass and function without impairing IS, ECC should be used to ameliorate muscle loss in physically inactive postmenopausal women. The impact of longer-term ECC on IS should be investigated. Demonstrating that ECC does not worsen IS in this population is significant because it has promise to combat the muscle-mediated impairments common in aging women.

Body composition by dual-energy X-ray absorptiometry in women with previous pre-eclampsia or small-for-gestational-age offspring

OBJECTIVE

To investigate differences in body composition and fat distribution between women with previous pre-eclampsia or small-for-gestational-age (SGA) offspring and those with uncomplicated pregnancies.

DESIGN

Cohort study.

SETTING

Population-based study in a genetically isolated population in the southwest of the Netherlands.

POPULATION

Women after pregnancies complicated by pre-eclampsia (n=45), SGA offspring (n=53) and uncomplicated pregnancies (n=106).

METHODS

Women were compared for body composition and fat distribution variables, assessed by dual-energy X-ray absorptiometry (DXA) and anthropometrics at a mean follow-up time of 10.8 (SD +/- 5.9) years after pregnancy.

MAIN OUTCOME MEASURES

Total lean and fat mass, android fat mass, gynoid fat mass, android-to-gynoid fat ratio, waist and hip circumference, waist-to-hip ratio.

RESULTS

Women with previous pre-eclampsia compared with controls had higher mean total fat mass index (11.5 +/- 0.6 versus 9.7 +/- 0.4 kg/m(2); P = 0.03), lean mass index (15.8 +/- 0.3 versus 14.5 +/- 0.2 kg/m(2); P =0.001) and body mass index ([BMI]; 28.4 +/- 0.8 versus 25.4 +/- 0.5 kg/m(2); P = 0.005). Their waist circumferences (90.7 +/- 2.0 versus 78.5 +/- 1.3 cm; P < 0.001) and waist-to-hip ratios (0.86 +/- 0.01 versus 0.77 +/- 0.01; P < 0.001) were also higher as well as android fat mass (2.8 +/- 0.2 versus 2.1 +/- 0.1 kg; P = 0.01) and android-to-gynoid fat ratios (0.45 +/- 0.02 versus 0.39 +/- 0.01; P = 0.02). Mean total fat, lean and BMI was not significantly different between women with previous SGA offspring and controls, yet waist-to-hip ratios (0.83 +/- 0.01; P < 0.001) were higher. The observed differences in waist and hip circumference, waist-to-hip ratio and gynoid fat mass could not be attributed to differences in BMI.

CONCLUSION

Women with previous pre-eclampsia or SGA offspring pregnancies compared with those with uncomplicated pregnancies have a preferential fat accumulation in the abdominal over hip region, which may explain, at least partly, their increased cardiovascular risk.

The healthy eating index and youth healthy eating index are unique, nonredundant measures of diet quality among low-income, African American adolescents

Chronic disease is related to poor diet quality. The Healthy Eating Index (HEI) was developed to assess diet quality. The Youth HEI (YHEI) is an adaptation of the HEI for use with children and adolescents. The objectives were to compare HEI and YHEI scores among adolescents at risk for chronic disease and to compare associations between the scores and health indicators. This cross-sectional study included 2 low-income, urban African American adolescent samples (Challenge, n = 196; Three Generation, n = 121). HEI and YHEI scores were calculated from a FFQ and compared with BMI, body composition, and micronutrient, energy, and dietary intakes. YHEI scores were lower than HEI scores across both adolescent samples (Challenge, 48.94 +/- 9.31 vs. 62.83 +/- 11.75; Three Generation, 47.08 +/- 9.65 vs. 59.93 +/- 11.27; P < 0.001). Females (64.47 +/- 11.70) had higher HEI scores than males (61.15 +/- 11.61) (P < 0.05), but there was no gender difference in YHEI scores. HEI and YHEI scores were associated with higher micronutrient and total energy intakes (r = 0.19-0.76; P < 0.05). Higher percent body/abdominal fat was associated with lower HEI scores (r = -0.17 to -0.19; P < 0.05) but not with YHEI scores. BMI was not associated with either HEI or YHEI scores. In conclusion, many adolescents were consuming diets that placed them at risk for developing chronic disease. Although both the HEI and YHEI are useful in assessing diet quality, the HEI is inversely associated with body composition, a predictor of chronic disease, and accounts for gender differences in the Dietary Guidelines, whereas the YHEI discounts nutrient-poor, energy-dense foods.

Effects of novel capsinoid treatment on fatness and energy metabolism in humans: possible pharmacogenetic implications

BACKGROUND

Capsinoids from the Capsicum genus of plants are nonpungent capsaicin-related substances with effects on metabolism and body weight in animals.

OBJECTIVES

Our objectives were to explore the safety and efficacy of capsinoids taken orally (6 mg/d) for weight loss, fat loss, and change in metabolism and to examine whether candidate genes are predictors of capsinoid response.

DESIGN

This was a 12-wk, placebo-controlled, double-blind, randomized study. Eligibility criteria included a body mass index (BMI; in kg/m(2)) of 25-35. Body weight was measured, and dual-energy X-ray absorptiometry, indirect calorimetry (men only), and genotyping were conducted.

RESULTS

Forty women and 40 men with a mean (+/- SD) age of 42 +/- 8 y and BMI of 30.4 +/- 2.4 were randomly assigned to a capsinoid or placebo group. Capsinoids were well tolerated. Mean (+/- SD) weight change was 0.9 +/- 3.1 and 0.5 +/- 2.4 kg in the capsinoid and placebo groups, respectively (P = 0.86). There was no significant group difference in total change in adiposity, but abdominal adiposity decreased more (P = 0.049) in the capsinoid group (-1.11 +/- 1.83%) than in the placebo group (-0.18 +/- 1.94%), and this change correlated with the change in body weight (r = 0.46, P < 0.0001). Changes in resting energy expenditure did not differ significantly between groups, but fat oxidation was higher at the end of the study in the capsinoid group (least-squares mean difference: 21.0 mg/min; P = 0.06). Of 13 genetic variants tested, TRPV1 Val585Ile and UCP2 -866 G/A correlated significantly with change in abdominal adiposity.

CONCLUSIONS

Treatment with 6 mg/d capsinoids orally appeared to be safe and was associated with abdominal fat loss. Capsinoid ingestion was associated with an increase in fat oxidation that was nearly significant. We identified 2 common genetic variants that may be predictors of therapeutic response.

Abdominal and gynoid fat mass are associated with cardiovascular risk factors in men and women

CONTEXT

Abdominal obesity is an established risk factor for cardiovascular disease (CVD). However, the correlation of dual-energy x-ray absorptiometry (DEXA) measurements of regional fat mass with CVD risk factors has not been completely investigated.

OBJECTIVE

The aim of this study was to investigate the association of estimated regional fat mass, measured with DEXA and CVD risk factors.

DESIGN, SETTING, AND PARTICIPANTS

This was a cross-sectional study of 175 men and 417 women. DEXA measurements of regional fat mass were performed on all subjects, who subsequently participated in a community intervention program.

MAIN OUTCOME MEASURES

Outcome measures included impaired glucose tolerance, hypercholesterolemia, hypertriglyceridemia, and hypertension.

RESULTS

We began by assessing the associations of the adipose measures with the cardiovascular outcomes. After adjustment for confounders, a sd unit increase in abdominal fat mass was the strongest predictor of most cardiovascular variables in men [odds ratio (OR)=2.63-3.37; P<0.05], whereas the ratio of abdominal to gynoid fat mass was the strongest predictor in women (OR=1.48-2.19; P<0.05). Gynoid fat mass was positively associated with impaired glucose tolerance, hypertriglyceridemia, and hypertension in men (OR=2.07-2.15; P<0.05), whereas the ratio of gynoid to total fat mass showed a negative association with hypertriglyceridemia and hypertension (OR=0.42-0.62; P<0.005).

CONCLUSIONS

Abdominal fat mass is strongly independently associated with CVD risk factors in the present study. In contrast, gynoid fat mass was positively associated, whereas the ratio of gynoid to total fat mass was negatively associated with risk factors for CVD.

Comparison of dual-energy X-ray absorptiometry and magnetic resonance imaging-measured adipose tissue depots in HIV-infected and control subjects

BACKGROUND

Studies in persons without HIV infection have compared adipose tissue measured by dual-energy X-ray absorptiometry (DXA) and magnetic resonance imaging (MRI), but no such study has been conducted in HIV-infected (HIV+) subjects, who have a high prevalence of regional fat loss.

OBJECTIVE

We compared DXA- with MRI-measured trunk, leg, arm, and total fat in HIV+ and control subjects.

DESIGN

A cross-sectional analysis was conducted in 877 HIV+ subjects and 260 control subjects in FRAM (Study of Fat Redistribution and Metabolic Change in HIV Infection), stratified by sex and HIV status.

RESULTS

Univariate associations of DXA with MRI were strongest for total and trunk fat (r > or = 0.92) and slightly weaker for leg (r > or = 0.87) and arm (r > or = 0.71) fat. The average estimated limb fat was substantially greater for DXA than for MRI for HIV+ and control men and women (all P < 0.0001). Less of a difference was observed in trunk fat measured by DXA and MRI, but the difference was still statistically significant (P < 0.0001). Bland-Altman plots showed increasing differences and variability. Greater average limb fat in control and HIV+ subjects (both P < 0.0001) was associated with greater differences between DXA and MRI measurements. Because the control subjects had more limb fat than did the HIV+ subjects, greater amounts of fat were measured by DXA than by MRI when control subjects were compared with HIV+ subjects. More HIV+ subjects had leg fat in the bottom decile of the control subjects by DXA than by MRI (P < 0.0001).

CONCLUSIONS

Although DXA- and MRI-measured adipose tissue depots correlate strongly in HIV+ and control subjects, differences increase as average fat increases, particularly for limb fat. DXA may estimate a higher prevalence of peripheral lipoatrophy than does MRI in HIV+ subjects.

Centrally located body fat is related to appetitive hormones in healthy postmenopausal women

OBJECTIVE

Body composition and energy homeostasis are thought to affect the appetitive hormones: adiponectin, leptin, insulin, and ghrelin. This study examined whether centrally located fat and/or overall adiposity were related to these appetitive hormones in healthy postmenopausal women.

DESIGN

Overall and regional body composition was assessed by dual-energy X ray absorptiometry in relation to plasma adiponectin, serum leptin, serum insulin, and plasma ghrelin in 242 postmenopausal women.

RESULTS

Regression analyses revealed that the androidal-to-gynoidal fat mass ratio (18.0%), age (3.2%), and white blood cell count (1.8%) accounted for 28% of the variability in adiponectin (F=22.2; P<0.0001); androidal (waist+hip) fat mass (66.0%), androidal fat mass(2) (6.2%), whole-body lean mass (2.2%), and age (0.8%) accounted for 69% of the variability in leptin (F=102.5; P<0.0001). Regression analyses revealed that sagittal abdominal diameter (8.4%), glucose (5.4%), white blood cell count (2.6%), and dietary omega-3 fatty acids (2.0%) accounted for 32% of the variability in insulin (F=20.8; P<0.0001); waist circumference (12.7%), hip lean mass (2.0%), and white blood cell count (1.9%) accounted for 26% of the variability in ghrelin (F=20.7; P<0.0001). Our results indicated that centralized fat mass was the primary contributor to these appetitive hormones in healthy postmenopausal women.

CONCLUSION

Since central adiposity in postmenopausal women was related to appetitive hormones, minimizing weight gain during the menopausal transition may optimize appetitive hormones, thereby facilitating appetite control and weight maintenance.

Waist circumference, dual-energy X-ray absortiometrically measured abdominal adiposity, and computed tomographically derived intra-abdominal fat area on detecting metabolic risk factors in obese women

OBJECTIVES

We investigated which abdominal adiposity measurements, waist circumference (WC), dual-energy X-ray absorptiometry (DXA)-measured abdominal fat, and computed tomography (CT)-derived intra-abdominal fat areas (IAF), were the most predictive in identifying metabolic risk factors.

METHODS

Ninety-five Korean women (body mass index 27.5 +/- 3.2 kg/m(2), WC 90.2 +/- 6.8 cm, age 42 +/- 10.6 y) with abdominal obesity (WC > or = 80 cm) were examined in this study. Abdominal adiposity was assessed using DXA (absolute values and percentages of trunk and android fat, trunk-to-leg fat ratio, and android-to-gynoid fat ratio) and CT (IAF and ratio of IAF to subcutaneous abdominal fat [SAF]). Metabolic indicators were blood pressure, high-density lipoprotein cholesterol, triacylglycerol, fasting glucose, insulin, and high-sensitivity C-reactive protein. Metabolic syndrome (MS) was defined as the presence of at least two of the following: triacylglycerol level > or = 150 mg/dL, high-density lipoprotein cholesterol level <50 mg/dL, blood pressure > or = 130/85 mmHg, and/or fasting glucose level > or = 100 mg/dL.

RESULTS

The correlations between adiposity measurements and metabolic indicators were stronger in premenopausal compared with postmenopausal women. Areas under the curve for MS and all abdominal adiposity measurements (WC, DXA-measured abdominal fat, and CT-derived IAF) were significant. Areas under the curve were not significantly different among measurements. The sensitivity and specificity at the threshold value of each abdominal adiposity measurement to predict MS were 38-93% and 34-96%, respectively. Women with 1 SD higher abdominal adiposity were 1.6-3.4 times more likely to have MS.

CONCLUSION

No single abdominal adiposity measurement, i.e., WC, DXA-measured abdominal fat, and CT-assessed IAF, was a stronger predictor of metabolic risk factors than the other.

Effect of a conjugated linoleic acid and omega-3 fatty acid mixture on body composition and adiponectin

This study aimed to determine the effect of supplementation with conjugated linoleic acids (CLAs) plus n-3 long-chain polyunsaturated fatty acids (n-3 LC-PUFAs) on body composition, adiposity, and hormone levels in young and older, lean and obese men. Young (31.4+/-3.9 years) lean (BMI, 23.6+/-1.5 kg/m2; n=13) and obese (BMI, 32.4+/-1.9 kg/m2; n=12) and older (56.5+/-4.6 years) lean (BMI, 23.6+/-1.5 kg/m2; n=20) and obese (BMI, 32.0+/-1.6 kg/m2; n=14) men participated in a double-blind placebo-controlled, randomized crossover study. Subjects received either 6 g/day control fat or 3 g/day CLA (50:50 cis-9, trans-11:trans-10, cis-12) and 3 g/day n-3 LC-PUFA for 12 weeks with a 12-week wash-out period between crossovers. Body composition was assessed by dual-energy X-ray absorptiometry. Fasting adiponectin, leptin, glucose, and insulin concentrations were measured and insulin resistance estimated by homeostasis model assessment for insulin resistance (HOMA-IR). In the younger obese subjects, CLA plus n-3 LC-PUFA supplementation compared with control fat did not result in increased abdominal fat and raised both fat-free mass (2.4%) and adiponectin levels (12%). CLA plus n-3 LC-PUFA showed no significant effects on HOMA-IR in any group but did increase fasting glucose in older obese subjects. In summary, supplementation with CLA plus n-3 LC-PUFA prevents increased abdominal fat mass and raises fat-free mass and adiponectin levels in younger obese individuals without deleteriously affecting insulin sensitivity, whereas these parameters in young and older lean and older obese individuals were unaffected, apart from increased fasting glucose in older obese men.

Relationship of abdominal obesity measured by DXA and waist circumference with insulin sensitivity in Hispanic and non-Hispanic white individuals: the San Luis Valley Diabetes Study

BACKGROUND

To determine if dual-energy X-ray absorptiometry (DXA) measures of trunk fat, a user-defined abdominal region of interest (ROI) and waist circumference (WC) differ in their association with insulin sensitivity among Hispanics and non-Hispanic whites (NHW) or explain any ethnic differences in insulin sensitivity.

METHODS

A cross-sectional study of data collected (1997-98) as part of the longitudinal San Luis Valley Diabetes Study was utilized. There were 664 non-diabetic participants including 349 women (220 NHW, 139 Hispanic) and 305 men (197 NHW, 108 Hispanic), average age 63 years. Measurements included body mass index, WC and DXA measures of total and abdominal fat. Fasting glucose and insulin were used to estimate insulin sensitivity using the QUICKI index. A 2-h oral glucose tolerance test was used to classify participants with normal glucose tolerance (NGT) or impaired glucose tolerance (IGT).

RESULTS

Among women with NGT, Hispanics had lower insulin sensitivity, with DXA trunk fat explaining the most variance in QUICKI and 54% of the ethnic difference in QUICKI after adjusting for total body fat and lean mass. Among men with NGT, there were no differences between Hispanics and NHW in insulin sensitivity or any differences in the association of the abdominal fat measures with insulin sensitivity. Among men and women with IGT, the fat distribution variables explained little variance in QUICKI.

CONCLUSIONS

DXA measures of trunk fat provide additional information over WC and the DXA abdominal ROI measure about ethnic differences in insulin sensitivity between older Hispanic and NHW women with NGT.

The effects of a whole grain-enriched hypocaloric diet on cardiovascular disease risk factors in men and women with metabolic syndrome

BACKGROUND

Whole-grain foods are associated in observational studies with a lower body mass index and lower cardiovascular disease (CVD) risk. However, few clinical trials have tested whether incorporating whole grains into a hypocaloric diet increases weight loss and improves CVD risk factors.

OBJECTIVE

The aim of this study was to determine whether including whole-grain foods in a hypocaloric (reduced by 500 kcal/d) diet enhances weight loss and improves CVD risk factors.

DESIGN

Obese adults (25 M, 25 F) with metabolic syndrome were randomly assigned to receive dietary advice either to avoid whole-grain foods or to obtain all of their grain servings from whole grains for 12 wk. All participants were given the same dietary advice in other respects for weight loss.

RESULTS

Body weight, waist circumference, and percentage body fat decreased significantly (P<0.001) in both groups over the study period, but there was a significantly (P=0.03) greater decrease in percentage body fat in the abdominal region in the whole-grain group than in the refined-grain group. C-reactive protein (CRP) decreased 38% in the whole-grain group independent of weight loss but was unchanged in the refined-grain group (P=0.01 for group x time interaction). Total, LDL, and HDL cholesterol decreased in both diet groups (P<0.05). Dietary fiber and magnesium intakes increased in the whole-grain but not the refined-grain group (P=0.007 and P<0.001, respectively, for group x time interaction).

CONCLUSIONS

Both hypocaloric diets were effective means of improving CVD risk factors with moderate weight loss. There were significantly (P<0.05) greater decreases in CRP and percentage body fat in the abdominal region in participants consuming whole grains than in those consuming refined grains.

Birth weight is inversely associated with central adipose tissue in healthy children and adolescents

OBJECTIVE

Previous studies have explored the association between birth weight and excess childhood body fat, but few have used precise measures of body composition, leading to equivocal and sometimes contradictory results.

RESEARCH METHODS AND PROCEDURES

Subjects included 101 children who underwent DXA measurements between 1995 and 2000. Birth weight and gestational age were assessed using maternal recall. Multiple linear regression analysis was used to determine the relationship between birth weight and the following four outcome variables: total fat mass (FM), truncal fat mass (TrFM), percentage body fat (%BF), and TrFM adjusted for FM (TrFMadj), controlling for current weight and Tanner stage.

RESULTS

The mean age of the children studied was 12.9 +/- 2.4 years, and the mean birth weight reported by subjects' mothers was 3.3 +/- 0.5 kg. The FM and TrFM were 12.8 +/- 8.7 kg and 5.1 +/- 4.1 kg, respectively, and the mean %BF was 22.9 +/- 10.3%. Birth weight was a significant predictor of FM (p = 0.02) and %BF (p = 0.038). However, birth weight adjusted for gestational age (BWTadj) was a significant (p = 0.03) negative predictor of TrFMadj, independently of race, sex, Tanner stage, and current weight.

DISCUSSION

These results provide evidence that, even in childhood and adolescence, a higher birth weight is associated with higher FM and %BF, while a low birth weight is associated with TrFM, adjusted for FM.

Prediction of visceral fat area at the umbilicus level using fat mass of the trunk: The validity of bioelectrical impedance analysis

The aims of this study were to determine the validity of fat mass of the trunk as a predictor for visceral fat area at the umbilicus level and to develop equations to predict visceral fat mass at the umbilicus level using fat mass of the trunk measured by dual-energy X-ray absorptiometry (DXA) and bioelectrical impedance analysis (BIA). The participants were 121 normal Japanese adults (69 males, 52 females). Another 60 volunteer adults (34 males, 26 females) were recruited for examination of cross-validity. Altogether, 41 adults (15 males, 26 females) in the original group and 19 adults (7 males, 12 females) in the cross-validity group received BIA measurement. We measured fat mass by DXA and the BIA system, which was a single-frequency BIA with 8-point contact electrodes, and visceral fat area by computed tomography. We observed significant correlations for visceral fat area in waist circumference (0.56) and fat mass of the trunk measured by DXA (0.64). There was no significant difference in fat mass of the trunk between the DXA and BIA systems, but the BIA system tended to provide an underestimate compared with DXA. With combined fat mass of the trunk measured by DXA and waist circumference as predictors, visceral fat area was estimated by equation (1) (R = 0.87, R(2) = 0.76, standard error of the estimate = 20.9 cm(2)). When substituting fat mass of the trunk measured by BIA into equation (1), there was no significant difference in visceral fat area between the reference and predicted values. An equation using fat mass of the trunk measured by BIA (equation 2) was obtained (R = 0.89, R(2) = 0.78, standard error of the estimate = 20.7 cm(2)), but a systematic error was found for the males. There was cross-validity in both equations. In conclusion, fat mass of the trunk is an effective predictor for the visceral fat area at the umbilicus level. Fat mass of the trunk measured by BIA might be a valid method to predict visceral fat, although further studies with larger samples taking into account the extent and type of obesity are required.

Combined low-dose pioglitazone, flutamide, and metformin for women with androgen excess

CONTEXT AND OBJECTIVE

One of the treatments for hyperinsulinemic hyperandrogenism in nonobese women is combined androgen receptor blockade (with flutamide; Flu), insulin sensitization (with metformin; Met) plus an estroprogestagen contraceptive. We tested whether adding low-dose pioglitazone (Pio; 7.5 mg/d) confers more benefit.

SETTING

The study was conducted at a university hospital.

STUDY POPULATION AND DESIGN

This double-blind study enrolled 38 young women with hyperinsulinemic hyperandrogenism [mean body mass index (BMI) 24 kg/m(2)], all of whom started on Flu (62.5 mg/d) and Met (850 mg/d) plus a transdermal estroprogestagen, each for 21 of 28 d over 6 months. Patients were randomly assigned to receive, in addition, placebo (n=19) or Pio (n=19; 7.5 mg/d) for the same 21 of 28 d over 6 months.

MAIN OUTCOMES

BMI, waist to hip ratio, hirsutism score, fasting endocrine-metabolic markers, body composition, abdominal fat (visceral vs. sc), and carotid intima-media thickness were measured at study start and after 6 months.

RESULTS

PioFluMet reduced intima-media thickness more than FluMet and lowered glucose, IGF-I, and C-reactive protein more as well as the ratio of low-density lipoprotein to high-density lipoprotein cholesterol and the ratio of neutrophils to lymphocytes. PioFluMet treatment was followed by a leaner body composition and a loss of visceral fat (both P < 0.001). In the total group, the changes included not only decreases in waist to hip ratio, hirsutism score, and testosterone (all P < 0.001) but also minor drops in alanine aminotransferase, aspartate aminotransferase, gamma-glutamyl transpeptidase, and lactate dehydrogenase (all P < 0.005), indicating absence of hepatotoxicity; BMI remained unchanged. Clinical side effects were not detected.

CONCLUSION

In this proof-of-concept study, addition of Pio to FluMet plus an estroprogestagen led to improvements in the endocrine-metabolic condition, in low-grade inflammation, in total and visceral adiposity, and in markers of cardiovascular health.

Truncal fat in relation to total body fat: influences of age, sex, ethnicity and fatness

OBJECTIVE

To investigate the influence of age, sex, ethnicity and total fatness on central obesity in four ethnic populations.

DESIGN

Cross-sectional analysis of study subjects enrolled from 1993 to 2005.

SUBJECTS

A multi-ethnic (Caucasian (CA), African-American (AA), Hispanic-American (HA) and Asian (As)) convenience sample of 604 men and 1192 women (aged 18-96 years, body mass index 15.93-45.80 kg/m(2)).

MEASUREMENTS

Total body fat (TBF) and truncal fat were measured by dual-energy X-ray absorptiometry. General linear regression models were used to test for independent associations with log(10)-transformed truncal fat.

RESULTS

For all ethnicities, men had a lower percent body fat and more truncal fat than women. Log(10-)transformed truncal fat increased with TBF approximately as a square root function. At older ages, there was a greater amount of truncal fat in CA, HA and As men (approximately 0.20-0.25 kg/decade) with the effect more pronounced in AA men ( approximately 0.33 kg/decade). For women, the increment of truncal fat per decade was reduced in CA and AA women (approximately 0.07 kg) compared with As and HA women (approximately 0.33 kg). Adjusted for mean values of covariates in our sample, AA had less truncal fat than As.

CONCLUSION

The accumulation of truncal fat is strongly related to age, ethnicity and total fatness in both men and women.

Association between body composition and blood pressure in a contemporary cohort of 9-year-old children

Elevated blood pressure (BP) in children is an early risk factor for cardiovascular disease and is positively associated with body mass index (BMI). However, BMI does not distinguish between fat and lean masses, and the relationship of BP in children to different elements of body composition is not well established. BP, BMI and body composition were measured in 6863 children enrolled in the Avon Longitudinal Study of Parents and Children. Fat mass, lean mass and trunk fat were assessed using dual-energy X-ray absorptiometry. After full adjustment for confounders, total body fat and BMI were positively associated with systolic blood pressure (SBP) (beta=3.29, 95% confidence interval CI 3.02, 3.57 mm Hg/standard deviation (s.d.) and beta=3.97, 95% CI 3.73, 4.21 mm Hg/s.d., respectively) and diastolic blood pressure (DBP) (beta=1.26, 95% CI 1.05, 1.46 mm Hg/s.d. and beta=1.37, 95% CI 1.19, 1.54 mm Hg/s.d., respectively). SBP was also positively associated with lean mass (beta=3.38, 95% CI 2.95, 3.81 mm Hg/s.d.), and weakly associated with trunk fat (beta=1.42, 95% CI -0.06, 2.90 mm Hg/s.d., independent of total fat mass), which was robust in girls only. The association between lean mass and SBP remained even after accounting for fat mass. SBP in 9-year-old children is independently associated with fat mass and lean mass and, to a lesser extent, trunk fat in girls. In this analysis, because both fat and lean masses are associated with BP, BMI predicts BP at least as well as these components of body composition.

Substrate-energy metabolism and metabolic risk factors for cardiovascular disease in relation to fetal growth and adult body composition

The effect of fetal programming on intermediary metabolism is uncertain. Therefore, we examined whether fetal programming affects oxidative and nonoxidative macronutrient metabolism and the prevalence of the metabolic syndrome in adult life. Healthy older men, aged 64-72 years, with either a lower birth weight (LBW, <or=25th %ile; n = 16) or higher birth weight (HBW, >or=75th %ile; n = 13) had measurements of 1) net oxidative metabolism using indirect calorimetry before and for 6 h after a mixed meal (3,720 kJ) and 2) postprandial oxidation of exogenous [13C]palmitic acid. Body composition was measured using dual-energy X-ray absorptiometry. After adjustment for current weight and height, the LBW group had a lower resting energy expenditure (REE) in the preprandial (4.01 vs. 4.54 kJ/min, P = 0.015) and postprandial state (4.60 vs. 5.20 kJ/min, P = 0.004), and less fat-free mass than the HBW group. The BW category was a significant, independent, and better predictor of REE than weight plus height. There were no significant differences between groups in net oxidative and nonoxidative macronutrient (protein, fat, carbohydrate) metabolism (or of exogenous [13C]palmitate) or in the prevalence of the metabolic syndrome, which was present almost twice as commonly in the LBW than in the HBW group. The study suggests that fetal programming affects both pre- and postprandial EE in older life by mechanisms that are at least partly related to the mass of the fat-free body. BW was found to be a significant predictor of REE that was independent of adult weight plus height.

Adipose tissue lipin expression levels distinguish HIV patients with and without lipodystrophy

OBJECTIVE

Lipodystrophy is the major complication of antiretroviral therapy in HIV-infected patients. Its pathophysiology is not well understood, but has been linked to antiadipogenic effects of antiretroviral drugs. Lipin represents a newly characterized protein that is critical for adipocyte differentiation, and lipin deficiency leads to lipodystrophy in the mouse. The objective of this study was to determine whether altered lipin gene expression is associated with HIV lipodystrophy in humans.

DESIGN

We measured lipin mRNA levels in subcutaneous abdominal and femoral-gluteal adipose tissue biopsies from HIV-infected patients with or without lipodystrophy, and in healthy controls. Real-time reverse transcription-PCR was performed to quantitate total lipin expression levels, and expression of two lipin isoforms (lipin-alpha and -beta) that are generated by alternative mRNA splicing.

RESULTS

As predicted from studies with mice, lipin mRNA levels were correlated with limb fat mass in HIV patients, with lower lipin levels in patients with lipodystrophy than those without lipodystrophy. Unexpectedly, however, this was explained by an increase in lipin-beta expression in HIV patients without lipodystrophy compared to patients with lipodystrophy and control subjects. In addition, lipin expression levels were inversely correlated with adipose tissue expression of inflammatory cytokines interleukin (IL)-6, IL-8 and IL-18, which typically increase in HIV-associated lipoatrophy.

CONCLUSIONS

Elevated lipin expression levels are associated both with the maintenance of greater fat mass and lower cytokine expression in HIV-infected patients. Based on the demonstrated role for lipin in promoting lipogenic gene expression, these observations raise the possibility that variations in lipin levels may contribute to variations in adipose tissue mass and function that distinguish HIV patients with and without lipodystrophy.

Influence of extracurricular sport activities on body composition and physical fitness in boys: a 3-year longitudinal study

OBJECTIVE

To analyse the effect of extracurricular physical activities on fat mass accumulation and physical fitness during growth in early pubertal males.

DESIGN

Longitudinal study.

SUBJECTS

A total of 42 male children (9.4+/-1.4 years, Tanner I-II and 12.7+/-1.5 years, Tanner III-IV, before and after the 3.3 years follow-up, respectively), randomly sampled from the population of Gran Canaria (Spain), 26 of them physically active (PA, at least 3 h per week during 3 years) and 16 non-physically active (non-PA).

MEASUREMENTS

Body composition (dual-energy X-ray absorptiometry), anthropometrics (body circumferences and skinfolds) and physical fitness variables (dynamic and isometric force, anaerobic capacity and maximal aerobic power) were determined in all subjects.

RESULTS

Both groups had comparable body sizes at the start and the end of the study. Body mass index increased with growth more in the PA than in the non-PA group (P<0.05). However, fat mass accumulation with growth was lower in the PA than in the non-PA (P<0.05). There was a positive relationship between the increment of total and trunkal fat mass, especially in non-active children (r2=0.93). In contrast, there was an inverse relationship between the total lean mass growth and the accumulation of total and regional fat mass (r=-0.37 to -0.41, all P<0.05). Physical fitness was maintained in the PA, while it worsened in the non-PA children.

CONCLUSIONS

Without any dietary intervention, children who regularly participate in at least 3 h per week of sports activities are more protected against total and regional fat mass accumulation. They also increase their total lean and bone mass to a greater extent than children who do not participate in extracurricular sport activities. In addition, PA children maintain their physical fitness during growth, while it deteriorates in the non-PA children.

Weight, fat mass, and central distribution of fat increase when women use depot-medroxyprogesterone acetate for contraception

OBJECTIVE

To compare longitudinal changes in weight, body fat, and ratio of central to peripheral fat mass among first-time depot-medroxyprogesterone acetate (DMPA) users to women using no hormonal contraception, and to evaluate user characteristics associated with that change.

DESIGN

Prospective longitudinal study.

SUBJECTS

Healthy women, aged 18-35 y, using DMPA for contraception (n=178) and women using no hormonal contraception (n=145).

MEASUREMENTS

Weight, body fat, and the central distribution of fat, measured at 3-month intervals for 30 months, by electronic scale and dual-energy X-ray absorptiometry (DEXA). The ratio of central to peripheral distribution of body fat was computed by dividing the body fat in the conventional DEXA trunk region of interest (ROI) by the ROI's that encompass the arms, hips and legs.

RESULTS

Women using DMPA had a significantly greater increase in all measures of fatness than women using no hormonal method of contraception (P<0.03). The observed weight of DMPA users increased from a mean of 69.4 kg (s.d.=16.9) at baseline to 75.5 kg (s.d.=25.0) at 30 months; an increase of 6.1 kg (8.8.%). Fat mass increased from a mean of 25.3 kg (s.d.=12.6 kg) at baseline to 31.4 kg (s.d.=17.8); an increase of 6.1 kg (23.6%) in DMPA users. The ratio of central to peripheral fat mass in DMPA users changed from 0.95 (s.d.=0.155) at baseline to 1.01(s.d.=0.198) at 30 months. In contrast, weight, fat mass and the ratio of central to peripheral fat mass of control participants remained virtually unchanged over the same time period. Women with higher baseline physical activity levels had a smaller increase in body fat (P=0.003) and the fat ratio (P=0.03), but not weight (P=0.48). No other user characteristics including, smoking, past oral contraceptive use or previous pregnancies predicted change in level of fatness.

CONCLUSIONS

This study has demonstrated a change in body composition toward greater fatness and toward a central redistribution of fat among DMPA users as compared to controls and provides important information to be used when counseling women regarding contraceptive methods. Given the potential long-term implication of these changes, further study is recommended to determine whether the gains in fatness are reversed following DMPA discontinuation and to examine the role of progestins in the development and maintenance of obesity.

Fetal programming of body composition: relation between birth weight and body composition measured with dual-energy X-ray absorptiometry and anthropometric methods in older Englishmen

BACKGROUND

Reduced fetal growth is associated with differences in body composition in adult life that may predispose to cardiovascular disease and diabetes. Most published data are based on simple anthropometric measures, which incompletely describe body composition.

OBJECTIVE

The objective was to assess body composition and fat distribution by using dual-energy X-ray absorptiometry (DXA).

DESIGN

This was a case-control study of 64-72-y-old white men (n = 32) with a low (mean: 2.76 kg) or high (mean: 4.23 kg) birth weight.

RESULTS

Compared with the high-birth-weight group, after adjustment for weight and height, the low-birth-weight group had a higher percentage body fat (29.31% compared with 25.33%; P = 0.029) and fat mass (P = 0.039) but a lower fat-free soft tissue (56.32 compared with 59.22 kg; P = 0.024), muscle mass (27.25 compared with 29.22 kg; P = 0.022), and muscle-to-fat ratio. Low birth weight was also associated with a higher trunk-to-limb fat ratio after control for total fat mass (1.42 compared with 1.16; P = 0.005) or percentage body fat (P = 0.041). The same body mass index predicted a greater percentage body fat (P = 0.019) in the low- than in the high-birth-weight group, and the same ratio of trunk-to-limb skinfold thickness (or waist-to-hip ratio) predicted a higher trunk-to-limb fat ratio (P < 0.01).

CONCLUSION

Lifelong differences in adult body composition and fat distribution between the low- and high-birth-weight groups are consistent with programming in early life. The use of BMI to predict percentage body fat and the use of the trunk-to-limb skinfold thickness ratio (and waist-to-hip ratio) to predict the trunk-to-limb fat ratio measured by DXA can be misleading when low- and high-birth-weight groups are compared.

A placebo-controlled, dose-ranging study of a growth hormone releasing factor in HIV-infected patients with abdominal fat accumulation

OBJECTIVE

To investigate the effects of TH9507, a novel growth hormone releasing factor, on abdominal fat accumulation, metabolic and safety parameters in HIV-infected patients with central fat accumulation.

DESIGN AND METHODS

Randomized, double-blind, placebo-controlled trial enrolling 61 HIV-infected patients with increased waist circumference and waist-to-hip ratio. Participants were randomized to placebo or 1 or 2 mg TH9507 subcutaneously, once daily for 12 weeks. The primary outcome was change in abdominal fat, assessed by dual energy X-ray absorptiometry and cross-sectional computerized tomography scan. Secondary endpoints included change in insulin-like growth factor-I (IGF-I), metabolic, quality of life, and safety parameters.

RESULTS

TH9507 resulted in dose-related physiological increases in IGF-I (P < 0.01 for 1 mg (+48%) and 2 mg (+65%) versus placebo). Trunk fat decreased in the 2 mg group versus placebo (0.8, -4.6 and -9.2%; placebo, 1 and 2 mg, respectively, P = 0.014 for 2 mg versus placebo), without significant change in limb fat. Visceral fat (VAT) decreased most in the 2 mg group (-5.4, -3.6 and -15.7%; placebo, 1 and 2 mg, respectively) but this change was not significant versus placebo. Subcutaneous fat (SAT) was preserved and did not change between or within groups. Lean body mass and the ratio of VAT to SAT improved significantly in both treatment groups versus placebo. Triglyceride and the cholesterol to high-density lipoprotein ratio decreased significantly in the 2 mg group versus placebo. Treatment was generally well tolerated without changes in glucose.

CONCLUSIONS

TH9507 reduced truncal fat, improved the lipid profile and did not increase glucose levels in HIV-infected patients with central fat accumulation. TH9507 may be a beneficial treatment strategy in this population, but longer-term studies with more patients are needed to determine effects on VAT, treatment durability, and safety.

Calcium-fortified beverage supplementation on body composition in postmenopausal women

BACKGROUND

We investigated the effects of a calcium-fortified beverage supplemented over 12 months on body composition in postmenopausal women (n = 37, age = 48-75 y).

METHODS

Body composition (total-body percent fat, %FatTB; abdominal percent fat, %FatAB) was measured with dual energy x-ray absorptiometry. After baseline assessments, subjects were randomly assigned to a free-living control group (CTL) or the supplement group (1,125 mg Ca++/d, CAL). Dietary intake was assessed with 3-day diet records taken at baseline and 12 months (POST). Physical activity was measured using the Yale Physical Activity Survey.

RESULTS

At 12 months, the dietary calcium to protein ratio in the CAL group (32.3 +/- 15.6 mg/g) was greater than the CTL group (15.2 +/- 7.5 mg/g). There were no differences from baseline to POST between groups for changes in body weight (CAL = 0.1 +/- 3.0 kg; CTL = 0.0 +/- 2.9 kg), %FatTB (CAL = 0.0 +/- 2.4%; CTL = 0.5 +/- 5.4%), %FatAB (CAL = -0.4 +/- 8.7%; CTL = 0.6 +/- 8.7%), or fat mass (CAL = 1.3 +/- 2.6 kg; CTL = 1.3 +/- 2.7 kg).

CONCLUSION

These results indicate that increasing the calcium to protein ratio over two-fold by consuming a calcium-fortified beverage for 12 months did not decrease body weight, body fat, or abdominal fat composition in postmenopausal women.

Relationships between insulin sensitivity and measures of body fat in asymptomatic men and women

OBJECTIVE

To assess whether measures of body fat by DXA scanning can improve prediction of insulin sensitivity (S(I)) beyond what is possible with traditional measures, such as BMI, waist circumference, and waist-to-hip ratio (WHR).

RESEARCH METHODS AND PROCEDURES

Frequently sampled intravenous glucose tolerance tests were performed in 256 asymptomatic non-Hispanic white subjects from Rochester, MN (age 19-60 years; 123 men and 133 women) to determine the S(I) index by Bergman's minimal model technique. Height, weight, and waist and hip circumferences were measured for calculation of BMI and WHR; DXA was used to determine fat in the head, upper body, abdomen, and lower body. Linear regression was used to assess their relationships with S(I) after sex stratification and adjustment for age.

RESULTS

After controlling for age, increases in traditional and DXA measures of fat were consistently associated with smaller declines in S(I) among women than among men. In men, after controlling for age, all of the predictive information of S(I) was provided by waist circumference (additional R2 = 0.39, p < 0.001); none of the DXA measures improved the ability to predict S(I). In women, after adjustment for age, BMI, and WHR, the only DXA measure that improved the prediction of S(I) was percentage head fat (additional R2 = 0.03, p < 0.001).

DISCUSSION

Equivalent increases in most measures of body fat had lesser impact on S(I) in women than in men. In both sexes, the predictive information provided by DXA measures is approximately equal to, but not additive to, that provided by simpler, traditional measures.

Measuring body composition in overweight individuals by dual energy x-ray absorptiometry

Background

Dual energy x-ray absorptiometry (DXA) is widely used for body composition measurements in normal-weight and overweight/obese individuals. The limitations of bone densitometers have been frequently addressed. However, the possible errors in assessing body composition in overweight individuals due to incorrect positioning or limitations of DXA to accurately assess both bone mineral density and body composition in obese individuals have not received much attention and are the focus of this report.

Discussion

We discuss proper ways of measuring overweight individuals and point to some studies where that might not have been the case. It appears that currently, the most prudent approach to assess body composition of large individuals who cannot fit under the scanning area would be to estimate regional fat, namely the regions of thigh and/or abdomen. Additionally, using two-half body scans, although time consuming, may provide a relatively accurate measurement of total body fat, however, more studies using this technique are needed to validate it.

Summary

Researchers using bone densitometers for body composition measurements need to have an understanding of its limitations in overweight individuals and address them appropriately when interpreting their results. Studies on accuracy and precision in measurements of both bone and soft tissue composition in overweight individuals using available densitometers are needed.

Favourable association of leg fat with cardiovascular risk factors

OBJECTIVES

To assess the association of trunk and leg fat mass (FM) and leg lean tissue mass (LTM) with conventional cardiovascular risk factors.

DESIGN

Cross-sectional study.

SETTING AND SUBJECTS

We studied 1249 men and 3007 women (age 20-79 years) who attended a research institute for a health checkup between October 1995 and February 2004.

MAIN OUTCOME MEASURES

Body mass index, waist circumference (WC), hip circumference (HC), systolic and diastolic blood pressure, total cholesterol, HDL cholesterol, triglycerides, glucose and haemoglobin A(1C) were measured. Trunk FM, leg FM and leg LTM were obtained by dual-energy X-ray absorptiometry. We evaluated the associations between the indices for regional body composition and cardiovascular risk factors, which included hypertension, hypercholesterolaemia, hypo-HDL cholesterolaemia, hypertriglyceridaemia, dyslipidaemia and diabetes mellitus.

RESULTS

Increase in WC and HC respectively showed increase and decrease in odds ratios of cardiovascular risk factors. Increase in trunk FM by 1 kg significantly increased the risk of the cardiovascular risk factors with the odds ratios ranging between 1.11 and 1.45. Increase in leg FM by 1 kg significantly decreased the risk with the odds ratios ranging between 0.52 and 0.90, except for the nonsignificant results for hypercholesterolaemia and hypo-HDL cholesterolaemia in men. Odds ratios of 1 kg increase in leg LTM were only significant for dyslipidaemia in men and hypercholesterolaemia in women (both 0.93).

CONCLUSIONS

WC and HC showed opposite and independent associations with cardiovascular risk factors. The favourable association of HC was mainly attributable to that of leg FM.

Visceral and central abdominal fat and anthropometry in relation to diabetes in Asian Indians

OBJECTIVE

The objective of the study was to examine body fat distribution using computed tomography (CT), dual-energy X-ray absorptiometry (DEXA), and anthropometry in relation to type 2 diabetes in urban Asian Indians.

RESEARCH DESIGN AND METHODS

This is a case-control study of 82 type 2 diabetic and 82 age- and sex-matched nondiabetic subjects from the Chennai Urban Rural Epidemiology Study, an ongoing epidemiological study in southern India. Visceral, subcutaneous, and total abdominal fat were measured using CT, while DEXA was used to measure central abdominal and total body fat. Anthropometric measures included BMI, waist circumference, sagittal abdominal diameter (SAD), and waist-to-hip ratio.

RESULTS

Visceral and central abdominal fat showed a strong correlation with each other (P <0.0001), and kappa analysis revealed a fairly good agreement between tertiles of visceral and central abdominal fat (kappa=0.44, P <0.0001). Diabetic subjects had significantly higher visceral (P=0.005) and central abdominal (P=0.011) fat compared with nondiabetic subjects. Waist circumference and SAD showed a strong correlation with visceral (P <0.01) and central abdominal (P <0.0001) fat in both diabetic and nondiabetic subjects. Logistic regression analysis revealed visceral (odds ratio [OR] 1.011, P=0.004) and central abdominal (OR 1.001, P=0.013) fat to be associated with diabetes, even after adjusting for age and sex.

CONCLUSIONS

Visceral and central abdominal fat showed a strong association with type 2 diabetes. Both measures correlated well with each other and with waist circumference and SAD in diabetic and nondiabetic urban Asian Indians.

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.

Increased abdominal-to-peripheral fat distribution contributes to altered autonomic-circulatory control with human aging

Autonomic nervous system (ANS) control of the circulation is altered with aging in adult humans. Similar changes are observed in obesity, particularly abdominal obesity. To determine whether age-associated differences in ANS-circulatory function can be partially explained by increased body fatness, we examined ANS function and three expressions of adiposity (total body fat, abdominal body fat, and abdominal-to-peripheral body fat distribution; dual-energy X-ray absorptiometry) in 43 healthy men: 27 young (25 ± 1 yr) and 16 older (65 ± 1). ANS functions assessed included 1) autonomic support of arterial blood pressure (BP; radial artery catheter), i.e., the reduction in BP during versus before acute ganglionic blockade (GB; intravenous trimethaphan); 2) baroreflex buffering, i.e., the increase in systolic BP with continuous incremental and bolus infusions of phenylephrine during versus before GB; 3) cardiovagal baroreflex sensitivity (Oxford technique); and 4) heart rate variability (time- and frequency-domain analyses). Covarying for abdominal-to-peripheral fat distribution reduced or abolished age-related differences in ANS support of BP, cardiovagal baroreflex sensitivity, and heart rate variability but did not affect age-related differences in baroreflex buffering. Covarying for abdominal and total fat had small selective or no effects on age-associated differences in autonomic-circulatory control. Abdominal-to-peripheral fat distribution explains a significant portion of the variance in a number of autonomic-circulatory functions attributable to aging. Therefore, the development of this fat pattern may contribute to several changes in ANS-cardiovascular function observed with aging. These results may help explain how changes in body fat distribution with advancing age are linked to impairments in circulatory control.

Adiposity contributes to differences in left ventricular structure and diastolic function with age in healthy men

We sought to examine the influence of adiposity in age-associated changes in the left ventricle (LV) in a cohort of 113 healthy men, aged 20-79 yr, by measuring LV structure and diastolic function (echocardiography), whole body composition, and regional adiposity (dual energy x-ray absorptiometry). Aging was associated with increased levels of adiposity, greater wall thickness to chamber radius ratio, LV concentric remodeling, and reduced LV diastolic function (all P < 0.05). Bivariate correlation analysis showed that mean LV wall thickness, a concentric LV morphology, and diastolic function were related to adiposity (r = -0.63 to 0.51; all P < 0.05). The relation between age and both mean LV wall thickness and concentric remodeling was reduced after controlling for percentage total body fat (by 38% and 54%, respectively), percentage abdominal fat (by 42% and 62%), and the abdominal/thigh fat ratio (by 35% and 46%). The diastolic function-age relation was reduced after controlling for percentage total body fat (by 35%), percentage abdominal fat (by 39%), and the abdominal/thigh fat ratio (by 29%). There were no apparent differences in the contribution of percentage total body fat, percentage abdominal fat, or abdominal/thigh fat to the association between age and LV structure/diastolic function. We conclude that increasing adiposity contributes to the LV remodeling/reduced diastolic function that occurs with aging in healthy men.

Evaluation of body composition: practical guidelines

The measurement of body composition in the truest sense allows for the estimation of body tissues, organs, and their distributions in living persons without inflicting harm. It is important to recognize that there is no single measurement method that is error-free. Furthermore, bias can be introduced if a measurement method makes assumptions related to body composition proportions and characteristics that are inaccurate across different populations. Some methodologic concerns include hydration of fat-free body mass changes with age and differences across ethnic groups [73]; the density of fat-free body mass changes with age and differences between men and women [74, 75]; total body potassium decreases with age [73] and fatness [76] and differences between African Americans and Caucasians [77]; the mass of skeletal muscle differences across race group [63]; and VAT differences across sex [78] and race [67, 79, 80] groups, independent of total adiposity. These between-group differences influence the absolute accuracy of methods for estimating fatness or FFM that involve the two-compartment model approach. The clinical significance of the body compartment to be measured should be determined before a measurement method is selected, because the more advanced techniques are less accessible and more costly.