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Biomedical subjects

Steven B Heymsfield

Publications and source records attributed to Steven B Heymsfield.

At least 55 records · Page 3Linked to original sources

Combination of BMI and Waist Circumference for Identifying Cardiovascular Risk Factors in Whites.

OBJECTIVE: BMI (kilograms per meters squared) and waist circumference (WC) (measured in centimeters) are each associated with the risk of developing cardiovascular disease (CVD). Therefore, a combination of the two may be more effective in identifying subjects at risk than either alone. The present study sought to identify the combination of BMI and WC that has the strongest association with CVD risk factors in whites. RESEARCH METHODS AND PROCEDURES: Subjects were 8712 white men and women from the Third National Health and Nutrition Examination Survey. The optimal combination of BMI and WC was developed using logistic regression models with BMI and WC as predictors and CVD risk factors as outcomes. The combined measure of BMI and WC using current cut-off points was also examined. Sensitivity, specificity, and receiver operating characteristics curves were compared between the combined measures and BMI alone. RESULTS: For white men, the optimal combination of BMI and WC for identifying CVD risk factors was 0.68 x BMI + 0.32 x WC. This combination generated a score that better estimated the odds of having CVD risk factors than either alone. For white women, WC alone largely determined the likelihood of having CVD risks. The combination of BMI and WC using current cut-off points may provide an improved measure of CVD risk. Combined measures showed a higher sensitivity or a shorter distance in receiver operating characteristic curves in the identification of CVD risk factors. DISCUSSION: Combined measures of BMI and WC may provide a higher overall test performance for CVD risk factors and may be useful in some ethnic groups as an improved means of screening subjects for further evaluation in the clinical setting.

Body Constitution↗

A new hand-held indirect calorimeter to measure postprandial energy expenditure.

OBJECTIVE: To verify the accuracy of a new hand-held metabolic rate measuring device (MedGem) in quantifying postprandial energy expenditure (PP EE). MedGem measurements were compared to measurements obtained with a conventional indirect calorimeter (Delta-Trac). RESEARCH METHODS AND PROCEDURES: The resting metabolic rate of 15 healthy subjects was measured for 20 minutes using Delta-Trac followed by a 10-minute measurement period using MedGem. EE was again measured for 7 hours after consumption of a 2510-kJ breakfast. Measurements were read from the Delta-Trac for the initial 50 minutes of each hour followed by a single reading from the MedGem after 5 to 10 minutes of measurement. Measured EE was calculated as the average of the total measurement period for Delta-Trac and for eight readings using MedGem; PP EE was calculated as the average of all measurements obtained after breakfast consumption. RESULTS: There was no difference in resting metabolic rate between the two methods (6455.1 +/- 417.6 vs. 6468.5 +/- 337.2 kJ/d for Delta-Trac and MedGem, respectively). Measured EE and PP EE values with Delta-Trac (7019.1 +/- 400.8 and 7099.8 +/- 399.2 kJ/d, respectively) and MedGem (6775.6 +/- 372.0 and 6819.5 +/- 379.9 kJ/d, respectively) were not significantly different. There was no bias detected in any of the measurements made with MedGem compared with those of Delta-Trac. DISCUSSION: The new hand-held EE measuring device can accurately track PP EE relative to a conventional indirect calorimetry system and, therefore, provides a new opportunity to assess PP EE in research settings and large-scale trials.

Adult↗

Body-composition differences between African American and white women: relation to resting energy requirements.

BACKGROUND: Body composition differs between African American (AA) and white women, and the resting metabolic rate (RMR) is likely to be lower in AA women than in white women. OBJECTIVE: We tested 2 hypotheses: that AA women have a greater proportion of low-metabolic-rate skeletal muscle (SM) and bone than do white women and that between-race musculoskeletal differences are a function of body weight. DESIGN: Hypothesis 1 was tested by comparing SM, bone, adipose tissue, and high-metabolic-rate residual mass across 22 pairs of matched AA and white women. Magnetic resonance imaging and dual-energy X-ray absorptiometry were used to partition weight into 4 components, and RMR was both calculated from tissue-organ mass and measured. Hypothesis 2 was evaluated by measuring SM, bone, fat, and residual mass in 521 AA and white women with the use of dual-energy X-ray absorptiometry alone. RESULTS: Hypothesis 1: AA women had greater SM ( +/- SD group difference: 1.52 +/- 2.48 kg; P < 0.01) and musculoskeletal mass (1.72 +/- 2.66 kg; P < 0.01) than did white women. RMR calculated from body composition and measured RMR did not differ; RMR estimated by both approaches tended to be lower (approximately 160 kJ/d) in AA women than in white women. Hypothesis 2: SM was significantly correlated with weight, height, age, and race x weight interaction; greater SM in the AA women was a function of body weight. CONCLUSIONS: Lower RMRs in AA women than in white women are related to corresponding differences in the proportions of heat-producing tissues and organs, and these race-related body-composition differences increase as a function of body weight.

Adipose Tissue↗

Familial aggregation of energy intake in children.

BACKGROUND: Uncompensated overnutrition promotes obesity, but the controls of children's eating behavior are poorly understood. Insights may be achieved by testing whether the eating patterns of children are associated with demographic variables or whether they aggregate among family members. OBJECTIVE: We tested whether children's total energy intake and macronutrient intake and their ability to compensate for earlier energy intake were associated with sociodemographic variables and anthropometric indexes. We also tested whether these behavioral traits aggregate among siblings. DESIGN: Thirty-two sibling pairs aged 3-7 y consumed a multi-item lunch preceded by a low-energy (12.55 kJ) or high-energy (627.60 kJ) preload drink. Mixed-models regression tested the associations between children's energy intake, demographic variables, and anthropometric measures. An intraclass correlation coefficient quantified the family correlation of the measures of children's eating. RESULTS: Children consumed significantly more total energy after consuming the low-energy preload ( +/- SD: 2237.39 +/- 1176.45 kJ) than after consuming the high-energy preload (1601.18 +/- 930.65 kJ). Compensation ability was unrelated to the children's age, sex, or ethnicity. Total energy and macronutrient intake, but not compensation propensity, were associated among siblings. CONCLUSIONS: The familial association of total energy and macronutrient intakes, independent of anthropometric measures, suggests genetic or home environmental influences specific to these behaviors. Short-term energy compensation, although very accurate within this sample, showed no significant familial correlation.

Appetite Regulation↗

Visceral adipose tissue: relations between single-slice areas and total volume.

BACKGROUND: Visceral adipose tissue (VAT), which is linked with the metabolic consequences of obesity, is usually characterized by measuring VAT area at the L4-L5 vertebral interspace. However, the location of the slice with the strongest relation to VAT volume is not established. OBJECTIVE: We sought to investigate the relations between cross-sectional VAT areas at different anatomic locations and VAT volume in a large, diverse sample of healthy subjects. DESIGN: VAT volume was derived from slice areas taken at 5-cm intervals from magnetic resonance images in 121 healthy men [x +/- SD age: 41.9 +/- 15.8 y; body mass index (BMI; in kg/m(2)): 26.0 +/- 3.2; VAT: 2.7 +/- 1.8 L] and 198 healthy women (age: 48.1 +/- 18.7 y; BMI: 27.0 +/- 5.4; VAT: 1.7 +/- 1.2 L). Regression models were developed to identify the best single slice for estimating VAT volume. RESULTS: The VAT area 10 cm above L4-L5 (A(+10)) in men (R(2) = 0.932, P < 0.001) and 5 cm above L4-L5 (A(+5)) in women (R(2) = 0.945, P < 0.001) had the highest correlation with abdominal VAT. R(2) increased by only 3.8% in men and 0.5% in women with adjustment for age, race, scanning position, BMI, and waist circumference. Studies using A(+10) in men and A(+5) in women will require 14% and 9% fewer subjects, respectively, than those using slices at L4-L5 and will have equivalent power. CONCLUSION: Measurement of slice areas at A(+10) in men and A(+5) in women provides greater power for the detection of VAT volume differences than does measurement at L4-L5.

Abdomen↗

Relation between whole-body and regional measures of human skeletal muscle.

BACKGROUND: It is unknown whether regional measures of skeletal muscle (SM) in the thigh and abdomen accurately reflect whole-body SM mass. OBJECTIVE: We aimed to determine whether thigh and abdominal SM measures reflect whole-body SM mass and, if so, which region is a stronger marker. DESIGN: Whole-body and regional measures of SM were obtained by magnetic resonance imaging in a sample of 387 white men and women. RESULTS: The regional SM measures, whether obtained by using a single image (midthigh or L4-L5 level) or a series of 7 consecutive images covering 31 cm (thigh or abdomen), were strongly correlated with whole-body SM (P < 0.001). Independent of sex, the thigh SM measures derived from a single image (men: R(2) = 0.77, SEE = 6.5%; women: R(2) = 0.79, SEE = 7.4%) or a series of 7 consecutive images (men: R(2) = 0.84, SEE = 5.4%; women: R(2) = 0.90, SEE = 5.1%) were stronger correlates of whole-body SM with smaller SEE values than were the abdominal SM measures (P < 0.01). However, SM in the abdomen was also a strong marker of whole-body SM, whether determined from a single image at the L4-L5 level (men: R(2) = 0.63, SEE = 8.2%; women: R(2) = 0.58, SEE = 10.4%) or from a series of images across the abdomen (men: R(2) = 0.77, SEE = 6.5%; women: R(2) = 0.70, SEE = 8.7%). CONCLUSION: Although thigh measures of SM are better predictors of whole-body SM, a single image within the abdomen routinely used to estimate abdominal fat may also be a useful marker of whole-body SM.

Abdomen↗

Dual-energy x-ray absorptiometry-measured lean soft tissue mass: differing relation to body cell mass across the adult life span.

Lean soft tissue (LST) measured by dual-energy X-ray absorptiometry (DEXA) is used as a metabolic measure in aging research despite evidence of extracellular fluid expansion and a corresponding reduction in body cell mass (BCM) in older participants. We investigated the hypothesis that the fraction of LST as BCM is smaller with greater age. Men and women (n = 2043) had DEXA and 40K-counting for body potassium and BCM measured on the same day. Both BCM and LST were lower with greater age but the relative lowering was larger for BCM. A multiple linear regression model was fitted with BCM/LST as the dependent variable, and age, sex, and interaction terms as independent variables. Men had a mean BCM/LST greater (p < .001) than women; quadratic and cubic age terms were also significant or approached significance. Thus, the fraction of LST as BCM is smaller in older adults, a finding that has implications for the interpretation of DEXA results.

Absorptiometry, Photon↗

Effect of calcium supplementation on weight and fat loss in women.

Data suggest that a diet deficient in calcium is associated with higher body weight and that augmenting calcium intake may reduce weight and fat gain or enhance loss. Our aim was to determine whether calcium supplementation during a weight loss intervention affects body fat or weight loss. Data were combined from three separate 25-wk randomized, double blind, placebo-controlled trials of 1000 mg/d calcium supplementation in 100 premenopausal and postmenopausal women. The primary outcome measures were change in body weight and fat mass adjusted for baseline values. There were no significant differences in body weight or fat mass change between the placebo and the calcium-supplemented groups in the pooled analysis (adjusted mean +/- SE; body weight, placebo -6.2 +/- 0.7 vs. Ca -7.0 +/- 0.7 kg; fat mass, placebo -4.5 +/- 0.6 vs. Ca -5.5 +/- 0.6 kg), and no significant interactions of calcium supplementation with menopausal/diet status. Analysis as separate trials also found no significant differences between the placebo and the calcium groups. Calcium supplementation did not significantly affect amount of weight or fat lost by women counseled to follow a moderately restricted diet for 25 wk. Nevertheless, the magnitude and direction of the differences for group means are consistent with a hypothesized small effect.

Adipose Tissue↗

Pencil-beam vs fan-beam dual-energy X-ray absorptiometry comparisons across four systems: body composition and bone mineral.

We compared bone mineral density (BMD) and body fat percentage (%fat) between two pencil-beam (Lunar DPX and DPX-L) and two fan-beam (Lunar Prodigy, Hologic Delphi A) dual-energy X-ray absorptiometry (DXA) systems. We examined these values in the total-body, spine, femur, and forearm scans in 78 healthy adults across these four DXA systems. BMD and %fat values were highly correlated among the four instruments. DPX-L gave the lowest mean %fat and Prodigy gave the highest mean %fat for both sexes. The means were system dependent for %fat estimates across the four DXA machines. There was a significant difference detected in BMD estimates across manufacturers, with the Delphi A providing systematically lower values than the Lunar systems in the whole body, spine, and femur sites but higher values than the Lunar systems in the forearm. The present study results show that both %fat and bone mineral estimates between pencil-beam and fan-beam systems are highly correlated, but vary by system. Significant differences exist between the instruments, especially between different manufacturers, and most of the comparisons are sex dependent. We conclude that longitudinal studies should always be evaluated on the same system when possible, and translation models should be used to assess cross-instrument differences.

Absorptiometry, Photon↗

Measurement of percentage of body fat in 411 children and adolescents: a comparison of dual-energy X-ray absorptiometry with a four-compartment model.

OBJECTIVE: Pediatricians are encountering body composition information more frequently, with percentage of body fat (%BF) measurement receiving particular attention as a result of the obesity epidemic. One confounding issue is that different methods may yield different %BF results in the same person. The objective of this study was to compare dual-energy X-ray absorptiometry (DXA) with the criterion 4-compartment model (4-CM) for measurement of %BF in a large pediatric cohort and to assist pediatricians in appropriate interpretation of body composition information by recognizing differences between techniques. METHODS: Height, weight, anthropometrics, body density by underwater weighing, total body water by deuterium dilution, and bone mineral content and %BF by DXA (Lunar DPX/DPX-L) were measured in 411 healthy subjects, aged 6 to 18 years. Values for %BF by 4-CM and DXA were compared using regression analysis. RESULTS: The mean +/- standard deviation values for %BF by DXA (22.73% +/- 11.23%) and by 4-CM (21.72% +/- 9.42%) were different, but there was a strong relationship between the 2 methods (R2 = 0.85). DXA underestimated %BF in subjects with lower %BF and overestimated it in those with higher %BF. The relationship between the 2 methods was not affected by gender, age, ethnicity, pubertal stage, height, weight, or body mass index. The standard error of the estimate was 3.66%. CONCLUSION: This analysis demonstrates a predictable relationship between DXA and 4-CM for %BF measurement. Because of its ease of use, consistent relationship with 4-CM, and availability, we propose that DXA has the capacity for clinical application including prediction of metabolic abnormalities associated with excess %BF in pediatrics.

Absorptiometry, Photon↗

Metabolic syndrome in normal-weight Americans: new definition of the metabolically obese, normal-weight individual.

OBJECTIVE: To determine the prevalence rates and likelihood of the metabolic syndrome and its individual components in normal-weight and slightly overweight individuals (BMI 18.5-26.9 kg/m(2)). RESEARCH DESIGN AND METHODS: There were a total of 7,602 adult participants of the Third National Health and Nutrition Examination Survey, a nationally representative cross-sectional survey. Prevalence and odds ratios (ORs) of the metabolic syndrome, defined according to National Cholesterol Education Program Adult Treatment Panel III criteria, were computed according to 2.0- to 2.5-unit increments in BMI. RESULTS: Depending on ethnicity and sex, the prevalence of the metabolic syndrome increased in a graded fashion from 0.9-3.0% at BMI 18.5-20.9 kg/m(2) to 9.6-22.5% at BMI 25.0-26.9 kg/m(2). Compared with men with BMI 18.5-20.9 kg/m(2), the odds for the metabolic syndrome were 4.13 (95% CI 1.57-10.87) for men with BMI 21-22.9 kg/m(2), 5.35 (2.41-11.86) for men with BMI 23-24.9 kg/m(2), and 9.08 (4.23-19.52) for men with BMI 25-26.9 kg/m(2) after controlling for age, ethnicity, education, income, physical activity, smoking status, and alcohol and total fat, saturated fat, carbohydrate, and fiber intakes. The corresponding ORs in women were 4.34 (2.08-9.07), 7.77 (3.95-15.26), and 17.34 (9.29-32.38). CONCLUSIONS: Individuals in the upper normal-weight and slightly overweight BMI range have a relatively high prevalence and are at increased risk of having the metabolic syndrome. Therefore, screening in individuals with normal or slightly elevated BMI is important in the prevention of diabetes and cardiovascular disease.

Adult↗

Results of soy-based meal replacement formula on weight, anthropometry, serum lipids & blood pressure during a 40-week clinical weight loss trial.

BACKGROUND: To evaluate the intermediate-term health outcomes associated with a soy-based meal replacement, and to compare the weight loss efficacy of two distinct patterns of caloric restriction. METHODS: Ninety overweight/obese (28 < BMI < or = 41 kg/m2) adults received a single session of dietary counseling and were randomized to either 12 weeks at 1200 kcal/day, 16 weeks at 1500 kcal/d and 12 weeks at 1800 kcal/d (i.e., the 12/15/18 diet group), or 28 weeks at 1500 kcal/d and 12 weeks at 1800 kcal/d (i.e., the 15/18 diet group). Weight, body fat, waist circumference, blood pressure and serum lipid concentrations were measured at 4-week intervals throughout the 40-week trial. RESULTS: Subjects in both treatments showed statistically significant improvements in outcomes. A regression model for weight change suggests that subjects with larger baseline weights tended to lose more weight and subjects in the 12/15/18 group tended to experience, on average, an additional 0.9 kg of weight loss compared with subjects in the 15/18 group. CONCLUSION: Both treatments using the soy-based meal replacement program were associated with significant and comparable weight loss and improvements on selected health variables.

Clinical Trial↗

Transgenic complementation of leptin receptor deficiency. II. Increased leptin receptor transgene dose effects on obesity/diabetes and fertility/lactation in lepr-db/db mice.

We have generated mice that are homozygous for a leptin receptor transgene that is expressed exclusively in neurons (NSE-LEPR-B). We had previously shown that this transgene in the hemizygous state is effective in ameliorating almost all aspects of leptin receptor deficiency. Now, we show that the transgene, in the homozygous state, almost fully corrects the excess adiposity of LEPR-deficient (db/db) mice. Body composition analyses indicate that the transgene is able to restrain the massive increase in adiposity observed in LEPR-deficient mice. Examination of hypothalamic agouti gene-related peptide and proopiomelanocortin mRNA shows normalization of these leptin-regulated transcripts. Interestingly, despite normalization of circulating leptin concentrations by the transgene in the fed state, transgenic db3J/db mice did not show fasting-induced reductions of circulating leptin. Increased adiposity of the transgenic db/db mice at 4 wk of age, immediately postweaning, suggests that the transgene is less effective in correcting the preferential fat deposition caused by LEPR deficiency. We noted that the morphology of brown adipose tissue is nearly normal, concordant with the cold tolerance conferred by the transgene. Aspects of the diabetes phenotype are also corrected: glucose and insulin concentrations are nearly normal, and islet hyperplasia is greatly diminished. The transgene also corrects the infertility of db/db females and confers the ability to lactate sufficiently to nurse normal-sized litters. Finally, the slightly increased adiposity and mild insulin resistance of transgenic db/db dams were not a contributory factor to the increased fat content of transgenic db/db male progeny.

Adaptation, Physiological↗

Body cell mass: model development and validation at the cellular level of body composition.

Existing models to estimate the metabolically active body cell mass (BCM) component in vivo remain incompletely developed. The classic Moore model is based on an assumed BCM potassium content of 120 mmol/kg. Our objectives were to develop an improved total body potassium (TBK)-independent BCM prediction model on the basis of an earlier model (Cohn SH, Vaswani AN, Yasumura S, Yuen K, and Ellis KJ. J Lab Clin Med 105: 305-311, 1985), to apply this improved model in subjects to explore the sex and age dependence of the TBK/BCM ratio, to develop a new TBK/BCM model on the basis of physiological associations between TBK and total body water (TBW) at the cellular level of body composition, and to fit this new model with available reference data. Subjects were 112 healthy adults who had the following components measured: TBW by 2H2O or 3H2O, extracellular water by NaBr, total body nitrogen by in vivo neutron activation, bone mineral by dual-energy X-ray absorptiometry, and TBK by whole body counting. Human reference data were collected from earlier published reports. The improved Cohn model-derived TBK/BCM ratio was (mean +/- SD) 109.0 +/- 10.9 mmol/kg and was not significantly related to sex and age. A simplified version of the new TBK-TBW model provided a TBK/BCM ratio almost identical (109.1 mmol/kg) to that derived by the improved Cohn model. The TBK-BCM prediction formula derived from the improved and new models [BCM (kg) = 1/109 x TBK (mmol); or BCM = 0.0092 x TBK] gives BCM estimates approximately 11% higher than the classic Moore model (BCM = 0.0083 x TBK) formulated on rough tissue composition estimates. The present analyses provide a physiologically based, improved, and validated TBK-BCM prediction formula that should prove useful in body composition and metabolism research.

Adult↗

Recombinant variant of ciliary neurotrophic factor for weight loss in obese adults: a randomized, dose-ranging study.

CONTEXT: Obese individuals tend to resist the weight-regulating effects of exogenously administered leptin. A genetically engineered recombinant human variant ciliary neurotrophic factor (rhvCNTF) that signals through leptinlike pathways in the hypothalamus has been shown to bypass leptin resistance in animal models of obesity. OBJECTIVE: To identify a safe and well-tolerated dose of rhvCNTF that causes weight loss in obese adults. DESIGN, SETTING, AND PATIENTS: Twelve-week, double-blind, randomized, parallel-group, dose-ranging, multicenter clinical trial conducted at 2 university obesity clinics and at 5 independent clinical research clinics from March 2000 to August 2001, and including 173 nondiabetic obese adults, 82.6% of whom were women, with a mean (SD) body mass index of 41.1 (4.1). INTERVENTIONS: Patients were randomly assigned to receive daily for 12 weeks subcutaneous injections of placebo (n = 32) or 0.3 microg/kg (n = 32), 1.0 microg/kg (n = 38), or 2.0 microg/kg (n = 33) of rhvCNTF. Another group received 1.0 microg/kg for 8 weeks and placebo for 4 weeks (n = 38), but they were not included in the primary analysis. All participants received instructions for a reduced-calorie diet (World Health Organization formula minus 500 kcal/d). MAIN OUTCOME MEASURES: Change in weight during the 12-week double-blind treatment period and proportion of patients who achieved a weight loss of at least 5%. RESULTS: Of the 173 randomized patients, 123 (71%) completed the double-blind dosing period. Mean (SEM) changes in kilograms from baseline body weights were 0.1 (0.6) for placebo and -1.5 (0.6) for the 0.3, -4.1 (0.6) for the 1.0, and -3.4 (0.7) for the 2.0 microg/kg of rhvCNTF dosage groups (P<.001, test for trend). Two patients (8.7%) in the placebo and 2 (8.3%) in the 0.3- microg/kg, 8 (29.6%) in the 1.0- microg/kg, and 5 (26%) in the 2.0- microg/kg treatment groups achieved a weight loss of at least 5%. Recombinant human variant CNTF was generally well tolerated although adverse events occurred in 75% of patients receiving placebo and 78% to 93% of patients receiving rhvCNTF, in a dose-related fashion, with mild injection site reactions as the most frequently reported adverse event. CONCLUSIONS: In this initial, dose-ranging, 12-week study, treatment with rhvCNTF resulted in more weight loss than placebo. These preliminary findings require confirmation in large prospective clinical trials.

Adult↗

The metabolic syndrome: prevalence and associated risk factor findings in the US population from the Third National Health and Nutrition Examination Survey, 1988-1994.

BACKGROUND: The metabolic syndrome is an important cluster of coronary heart disease risk factors with common insulin resistance. The extent to which the metabolic syndrome is associated with demographic and potentially modifiable lifestyle factors in the US population is unknown. METHODS: Metabolic syndrome-associated factors and prevalence, as defined by Adult Treatment Panel III criteria, were evaluated in a representative US sample of 3305 black, 3477 Mexican American, and 5581 white men and nonpregnant or lactating women aged 20 years and older who participated in the cross-sectional Third National Health and Nutrition Examination Survey. RESULTS: The metabolic syndrome was present in 22.8% and 22.6% of US men and women, respectively (P =.86). The age-specific prevalence was highest in Mexican Americans and lowest in blacks of both sexes. Ethnic differences persisted even after adjusting for age, body mass index, and socioeconomic status. The metabolic syndrome was present in 4.6%, 22.4%, and 59.6% of normal-weight, overweight, and obese men, respectively, and a similar distribution was observed in women. Older age, postmenopausal status, Mexican American ethnicity, higher body mass index, current smoking, low household income, high carbohydrate intake, no alcohol consumption, and physical inactivity were associated with increased odds of the metabolic syndrome. CONCLUSIONS: The metabolic syndrome is present in more than 20% of the US adult population; varies substantially by ethnicity even after adjusting for body mass index, age, socioeconomic status, and other predictor variables; and is associated with several potentially modifiable lifestyle factors. Identification and clinical management of this high-risk group is an important aspect of coronary heart disease prevention.

Adult↗

Relationships in men of sex hormones, insulin, adiposity, and risk factors for myocardial infarction.

That sex hormones, insulin, and obesity all correlate with the constellation of risk factors for myocardial infarction (MI) that has come to be known as "syndrome X," the "insulin-resistance syndrome," or the "metabolic syndrome" suggests that any one or more of them could underlie and link the risk factors to form the constellation. That sex hormones, insulin, and obesity also correlate with each other complicates their identification as an underlying link. To compare the likelihood of each being a link, we measured and determined the interrelationships of sex hormones, insulin, adiposity variables, and risk factors for MI in 80 apparently healthy men. Of the adiposity variables, visceral adipose tissue (VAT) correlated more strongly with the risk factors for MI than did body mass index (BMI), total adipose tissue (TAT), subcutaneous adipose tissue (SCAT), waist-to-hip ratio (WHR), and waist circumference (W). Controlling for VAT eliminated all of the other adiposity correlations that had been significant. VAT, therefore, was used as the measure of adiposity for further data analysis. VAT correlated more strongly with risk factors for MI than did sex hormones and insulin, and most of the correlations of sex hormones and insulin with risk factors for MI lost statistical significance after controlling for VAT. Testosterone and the ratio of estradiol-to-testosterone (E/T) correlated with insulin; on controlling for VAT, only the E/T-insulin correlation remained significant (r =.38, P <.001) and on multiple linear regression analysis, insulin was associated with estradiol (P =.01) and testosterone (P =.04) independently of VAT and age. In conclusion, (1) VAT in men may largely explain the correlations of sex hormones, insulin, and obesity with the risk factors for MI measured, (2) VAT may be the principal factor in men, independently of other measures of adiposity, that links risk factors for MI to form the constellation, and (3) estradiol may play a more important role in the sex hormone-insulin relationship in men than has generally been considered.

Adipose Tissue↗