Waist To Hip Girth Ratio Research Articles

Cortisol levels and measures of body composition in middle‐aged and older men

Similarities in the symptomatic expressions of excess adiposity and hypercortisolaemic conditions suggest that elevated glucocorticoid exposure may influence the pathogenesis of obesity. Circulating cortisol levels are not typically elevated in obese subjects, but data from large prospective samples are rare. We undertook an analysis to determine both cross-sectional and longitudinal associations between body composition and serum cortisol concentrations in a randomly chosen group of 999 community-dwelling men, aged 40-79 years. Data were obtained from the two follow-up waves of the Massachusetts Male Ageing Study (T2: 1995-97; T3: 2002-04). Partial correlation and multivariate regression analyses were used to estimate cross-sectional (T2) and longitudinal associations between serum cortisol concentrations and a range of measures of subjects' body composition, including weight, body mass index (BMI), waist circumference (WC), waist-to-hip girth ratio (WHR), and percentage body fat (measured by bioelectrical impedance at T3); similar analyses were conducted to assess the association between change (T2 to T3) in serum cortisol and simultaneous change in body composition parameters. We observed weak negative associations between cortisol concentrations and all body composition parameters, with the exception of percentage body fat. Longitudinal results demonstrated similar relationships but associations were of lesser magnitude. T2 cortisol concentrations were not associated with change in body composition over time, whereas T2 body size was positively associated with longitudinal changes in cortisol concentrations, providing limited evidence that weight change drives changes in cortisol concentrations, rather than vice versa. Results were unchanged when age and other covariate effects were controlled. Circulating cortisol concentrations are somewhat lower in obese than in nonobese community-dwelling men. There is some evidence that excess adiposity presages increases in cortisol concentrations, rather than the reverse. However, this observation should be greeted with caution, as age-related weight loss - and not gain - was associated with simultaneous increases in serum cortisol concentrations.

Cadaver studies and their impact on the understanding of human adiposity

The skinfold thickness is a much-used measurement for monitoring adiposity in a wide range of medical, health, occupational and sport science disciplines. Misconceptions abound, however, in its use, particularly that of purportedly predicting body ‘fat’ as opposed to ‘adipose tissue’. To obtain data to investigate body composition and the extent to which anthropometry can be justifiably used to predict whole-body adiposity, an extensive dissection study was undertaken on 34 cadavers. In addition, to pre-empt questions on the applicability of cadaver data to living subjects, 40 elderly in vivo subjects of the same age range were compared with the cadaver population. No significant macro-morphological differences were found between males or females in the morbid and in vivo groups. Significant findings affect our previous understanding of the predictability of whole-body ‘fat’. Skinfold compressibility was by no means constant; skin thickness varied with location in both sexes, females having thinner skin than males; there were significant sex differences in adipose tissue patterning. An identical thickness of adipose tissue did not necessarily contain the same concentrations of fat. Despite this variability, a relationship was demonstrated between aggregate skinfold measures and subcutaneous adipose tissue mass (as opposed to subcutaneous fat), this relationship being more evident in men. A strong relationship was found between subcutaneous adiposity and whole-body adiposity, and between direct skinfold depth measures and whole-body adiposity. The amount of visceral adipose tissue was the same in men and women, but in the men this represented a greater proportion of their total body adiposity. Further, the use of waist-to-hip girth ratio (WHR) was identified as an important predictor of health risk. These findings demonstrate that it is not sustainable to introduce a non-quantifiable error by transforming anthropometric values (skinfolds) into predictions of percentage body fat. If subcutaneous adiposity can be predicted, then an excellent indication of overall adiposity could be obtained. Currently, skinfold measurement can yield a reasonable indication of comparative subcutaneous adiposity (better in men than in women). In neither gender is this prediction completely reliable due to both inter- and intra-individual differences in the skinfold measurement procedure.

Factors associated with circulating levels of insulin-like growth factor-I and insulin-like growth factor binding protein-3 in 740 women at risk for breast cancer

Prospective studies have shown an association between elevated plasma levels of insulin-like growth factor-I (IGF-I) and/or decreased levels of its major circulating carrier protein insulin-like growth factor binding protein-3 (IGFBP-3) and increased risk of major cancers. Identifying the factors which affect these biomarkers is of particular interest as subjects at increased risk could benefit from lifestyle changes, and/or chemoprevention intervention. We evaluated the association between constitutional, hormonal and clinical factors and IGF-I and IGFBP-3 in 740 women, including 376 unaffected women and 364 women with intraepithelial neoplasia (IEN) or early invasive breast cancer enrolled in breast cancer chemoprevention trials, conducted at a single institution. Age, body mass index (BMI), height, waist to hip girth ratio (WHR), parity, menopausal status, age at menarche, number of affected first degree relatives, number of biopsies and breast cancer status were considered in the analysis. Women with early breast cancer had 21% higher IGF-I levels (p = 0.033) and 19% higher IGF-I/IGFBP-3 molar ratio (p = 0.047) than unaffected women. In unaffected women, age was negatively associated with IGF-I (p = 0.002) and IGF-I/IGFBP-3 (p = 0.001), while age at menarche was negatively associated with IGFBP-3 levels (p = 0.043). In women with IEN or early breast cancer, IGF-I levels were negatively associated with age (p < 0.001), and positively associated with prior biopsies for benign disease (p = 0.013), while age, parity and menopausal status were significant predictors of IGF-I/IGFBP-3 molar ratio. We conclude that circulating IGF-I levels are higher in women with prior breast cancer compared to unaffected women, and that IGF-I and/or IGFBP-3 levels are influenced by age and by reproductive and hormonal factors. These findings support their putative role as breast cancer risk biomarker.

Bone mineral density and adipose tissue distribution in young women: relationship to smoking status.

Interrelationships between anthropometric variables and bone mineral density (BMD) may allow simple and inexpensive identification of those at risk for low bone density and osteoporosis. Risk appraisal is particularly important in young women, as lifestyle modifications may slow the rate of bone loss through adulthood and decrease the risk of osteoporosis later in life. Though weight, height and body mass index are frequently assessed in relation to bone, adipose tissue distribution has rarely been considered. Smoking is associated with low bone density and abdominally localized adipose tissue. The relationship between smoking, adipose tissue distribution and BMD in women has not been examined. Regional and whole-body BMD were assessed by dual-energy X-ray absorptiometry, and adipose tissue distribution using the anthropometric indicator, waist-to-hip girth ratio (WHR), in 52 women (25 smokers, and 27 nonsmokers) aged 20-35 years. There were significant (p < 0.05) positive correlations between WHR and BMD for smokers and nonsmokers separately (r = 0.44-0.57), and for the sample overall (r = 0.30-0.51). Most relationships remained significant after adjustment for weight. Smokers did not differ significantly from nonsmokers in relationships between WHR and BMD. The results indicate a positive relationship between BMD and abdominal relative to gluteal-femoral adiposity. This relationship is independent of smoking status. The biological determinants underlying a relationship between BMD and WHR require consideration before inferences regarding BMD can reasonably be considered on the basis of WHR.

Body measurements, estrogen availability and the risk of human breast cancer: a case-control study.

Recent studies on lifestyle-related mechanisms involved in cardiovascular risk offer important clues for a better understanding of breast-cancer epidemiology. Central body-fat distribution promoted by an affluent dietary intake and a sedentary lifestyle over many years is related to elevated serum triglycerides and free fatty acids, with lower levels of sex-hormone-binding globulin (SHBG). The resulting greater availability of estradiol not bound to SHBG could help to explain the high breast-cancer incidence in Western industrialized countries. We conducted a case-control study comparing 225 women aged 38 to 75 years with operable (stage I or II) breast cancer and 441 women of the same age having no breast cancer who participated in a population-based breast-cancer screening program. Body fatness, as measured by body mass index (BMI), fat distribution as measured by waist-to-hip girth ratio (WHR), body height, serum lipids, SHBG and the available fraction of estradiol were analyzed in a conditional logistic regression, together with family history for breast cancer, reproductive history and smoking. Post-menopausal cases showed no difference in body fatness (BMI), but a significant preponderance of central adiposity (WHR). In contrast, pre-menopausal cases were significantly leaner, but had a similar body-fat distribution as compared with controls. In all women, WHR, and less strongly BMI, was positively correlated with serum levels of triglycerides and available estradiol fractions. An independent, positive linear correlation between body height and relative risk (RR) was observed. Moreover, a significant correlation between SHBG and menarcheal age was seen in cases, but not in controls. These data support our hypothesis that lifestyle relates to breast-cancer risk by metabolic-endocrine mechanisms which modulate the availability of individual sex-steroid concentrations in plasma. The findings of height as a risk factor and adult SHBG levels being correlated with menarcheal age suggest that lifestyle factors promoting breast-cancer development already act around puberty. The leanness of pre-menopausal cases awaits further explanation.

The Influence of Regional Adiposity on Atherogenic Risk Factors in Men and Women with Type 2 Diabetes

To determine firstly whether body fat distribution could predict the presence of atherogenic risk factors better than overall adiposity in Type 2 diabetes, and secondly whether sex differences in these risk factors could be explained by sex differences in fat distribution, waist-to-hip girth ratio (WHR), serum lipids, lipoproteins, apolipoproteins, plasma lipolytic activity, and blood pressure were assessed in 47 patients with Type 2 diabetes, 21 women matched for age, body mass index (BMI) and blood glucose control with 26 men. The men had higher WHR (0.95 (range 0.83-1.07) vs 0.82 (0.74-0.94), p less than 0.001), lower HDL-cholesterol (1.03 +/- 0.05 vs 1.38 +/- 0.06 mmol l-1, p less than 0.001) and apolipoprotein A1 (1.40 +/- 0.06 vs 1.76 +/- 0.06 gl-1, p less than 0.001) concentrations, and higher hepatic lipase activities (16.2 (6.4-38.0) vs 8.6 (2.3-23.1) mmol h-1 l-1, p less than 0.01). In both men and women, BMI and WHR were positively related to serum triglyceride, insulin and C-peptide concentrations. In women, HDL-cholesterol was negatively related to BMI (r = -0.45, p less than 0.05) but only possibly related to WHR (r = -0.33, NS). In men, by contrast, WHR was related negatively to HDL-cholesterol (r = -0.60, p less than 0.005), HDL2-cholesterol (r = -0.43, p less than 0.05), and apolipoprotein A1 (r = -0.70, p less than 0.001) and positively to hepatic lipase activity (r = 0.65, p less than 0.001), whereas the same relationships with BMI were not significant.(ABSTRACT TRUNCATED AT 250 WORDS)

Intra-abdominal fat is associated with decreased insulin sensitivity in healthy young men

To distinguish the relative role of intra-abdominal and subcutaneous abdominal fat in metabolic aberrations in upper body fat localization, we measured the relationship between regional fat distribution and insulin sensitivity in nine young men (28.6 ± 0.7 years; body mass index [BMI], 24.7 ± 1.3 kg/m 2). Regional fat distribution was measured by anthropometric measurement and computed tomography (CT). Insulin sensitivity was measured by euglycemic hyperinsulinemic glucose clamp. Insulin sensitivity, expressed as the ratio of rate of glucose utilization to the mean plasma insulin concentration during the second hour of glucose clamp ( M I ) was negatively correlated with BMI ( r = −.91, P < .001), waist to hip girth ratio (WHR) ( r = −.80, P < .01), subcutaneous abdominal fat area ( r = −.90, P < .001), and intra-abdominal fat area ( r = −.88, P < .01). Stepwise forward regression analysis showed that in addition to BMI, intra-abdominal fat area was a significant correlate of decrease in insulin sensitivity. These findings suggest that intra-abdominal fat play an important role in decreasing insulin sensitivity, even in healthy young men.

Characterization of Obese Women with Reduced Sex Hormone-Binding Globulin Concentrations

Factors influencing sex-hormone binding globulin (SHBG) concentrations in obesity are poorly understood. Preliminary observations suggest that dietary lipids may be involved and there are data confirming a direct inhibiting effect of insulin. Since only some obese subjects show lowered SHBG levels, we performed this study with the aim of defining obese women with low SHBG (LSO) (2 SD above normal values) in comparison with those presenting normal globulin concentrations (NSO). These groups were selected from a larger group of obese women with a history of normal menses and aged less than 40 years. An age-matched group of normal weight healthy women served as controls. Both LSO and NSO had similar body mass index and percentage body fat, but the waist to hip girth ratio (WHR), an index of body fat distribution, was significantly higher in LSO (0.88 +/- 0.04) than in NSO (0.81 +/- 0.09; P less than 0.05). Gonadotropin and androgen concentrations were similar in both groups, whereas estrone (E1) levels were higher in LSO (32.8 +/- 15.8 pg/ml) than in NSO (19.4 +/- 6.2 pg/ml; P less than 0.05; controls: 23.5 +/- 7.8 pg/ml; P less than 0.05). Moreover, compared to NSO, LSO women had significantly higher glucose-stimulated insulin and C-peptide levels. Partial regression analysis revealed significant correlation coefficients between SHBG, stimulated insulin values (r = -0.38; P less than 0.05) and WHR (r = 0.40; P less than 0.005). Therefore, compared to NSO, LSO women have distinctive clinical and endocrine characteristics, namely more pronounced hyperinsulinemia, higher E1 concentrations and a central type body fat distribution.

Alterations in low-density lipoproteins in subjects with abdominal adiposity

Abdominal adiposity, as indexed by the waist to hip girth ratio (WHR), has been associated with increased risk and incidence of coronary heart disease (CHD). The purpose of this study was to determine if this enhanced risk is related to alterations in the structure of low density lipoproteins (LDL). LDL were isolated from nine nonobese men with an average WHR of 1.046 and nine nonobese men with a WHR of 0.94, who were matched on age (45.6 ± 2.7 v 47.7 ± 2.3 mean ± SEM) percent body fat (26.5 ± 0.5 v 26.1 ± 0.9), and body mass index (27.3 ± 0.6 v 26.3 ± 0.6). The average molecular weight of LDL from the subjects with a high WHR was lower than that of subjects with low WHR (2.70 v 3.02 × 10 6 d), the average hydrated density higher (1.050 v 1.040 g/mL), and the mobility (R f) on 2% to 16% polyacrylamide gradient gel electrophoresis higher. Subfractionation by equilibrium density ultracentrifugation showed that the LDL of subjects with a high WHR was predominantly in the heavy density range (1.038 to 1.048 g/mL) compared with the LDL of subjects with low WHR, which was in the lighter density range (1.030 to 1.040 g/mL). Chemical analysis of the subfractions showed that the peak density fractions of LDL of subjects with a high WHR had a lower cholesterol to protein ratio than the peak density fractions of LDL of subjects with low WHR. Electron microscopy of these peak density fractions showed that LDL of subjects with high WHR was smaller than that of subjects with low WHR. These characteristics of LDL of subjects with abdominal adiposity closely resemble the properties of LDL of patients with documented CHD. It is concluded that the increased risk of CHD associated with abdominal adiposity may be due in part to the alterations in LDL characteristics, and that these alterations in LDL are independent of the degree of obesity.

Relationships of plasma estradiol, testosterone, and sex hormone-binding globulin with lipoproteins, apolipoproteins, and high density lipoprotein subfractions in men.

Plasma estradiol, testosterone, and sex hormone-binding globulin (SHBG) were studied in relation to plasma lipoproteins, high density lipoprotein (HDL) subfractions, and apolipoproteins in 73 healthy but sedentary middle-aged men. Among potentially confounding variables, a strong positive association was found between estradiol levels and cigarette use, while testosterone and SHBG correlated negatively with percent body fat and alcohol intake. After adjustment for smoking, percent body fat, and alcohol, plasma estradiol levels correlated negatively with total cholesterol and low density lipoprotein cholesterol, and testosterone levels correlated positively with apolipoprotein B, while SHBG levels correlated positively with HDL2 mass and apolipoprotein A-I. SHBG was also strongly associated with the waist to hip girth ratio (WHR). Adjustment for WHR eliminated the significant associations of SHBG with triglycerides, HDL2 mass, and apolipoprotein A-I. SHBG levels and WHR may reflect tissue sensitivity and the impact of exposure to fluctuating levels of sex hormones for a period of days, or longer. These variables may provide more insight into the role of sex hormones in lipoprotein metabolism than do single samples of circulating hormones. It is also suggested that long term effects of sex hormones on adipose tissue distribution may at least partially underlie sex-related differences in lipoprotein metabolism.

Relationship of androgenic activity to splanchnic insulin metabolism and peripheral glucose utilization in premenopausal women.

The importance of androgenic activity in mediating the effects of obesity and body fat topography on splanchnic insulin metabolism and peripheral insulin sensitivity was studied in 19 nonhirsute premenopausal women with a wide range of ideal body weight [percent ideal body weight (% IBW), 78-202%] and body fat distribution pattern [waist to hip girth ratio (WHR), 0.67-0.91]. Turnover kinetics of peripheral plasma C-peptide and insulin were measured, and estimates of pancreatic insulin production (PIP) and the hepatic extraction fraction (HEF) were calculated. The peripheral insulin sensitivity index (M/I) was determined during an euglycemic insulin clamp study. Androgenic activity was assessed by estimating the plasma level of sex hormone-binding globulin (SHBG) and percentage of free testosterone (% FT). After iv glucose stimulation, PIP ranged from 40-254 mU/min X m2 and correlated highly with % IBW (r = 0.78; P less than 0.01). Insulin HEF ranged from 5-69% of the pancreatic production and was inversely proportional to WHR (r = -0.60; P less than 0.01). Increasing WHR also correlated with the diminution in M/I (r = -0.47; P less than 0.05), which, in turn, correlated with the decline in the HEF of insulin (r = 0.60; P less than 0.01). Since PIP, HEF, and M/I correlated with SHBG and % FT, and since the degree of androgenic activity correlated with % IBW and WHR, partial regression analysis was performed. After adjusting for the effects of SHBG and % FT, the relationship between % IBW and PIP remained unaltered, whereas the correlation between WHR and HEF or M/I and their relationship to each other were either markedly reduced or became insignificant. Thus, in premenopausal women, the increase in pancreatic insulin production with increasing weight is independent of the degree of androgenic activity. On the other hand, the decline in hepatic insulin extraction and diminution in peripheral insulin sensitivity with upper body fat localization are in part mediated by increased androgenic activity. This association may account for the pronounced hyperinsulinemia and insulin resistance characteristic of this form of obesity.

Splanchnic insulin metabolism in obesity. Influence of body fat distribution.

The effects of obesity and body fat distribution on splanchnic insulin metabolism and the relationship to peripheral insulin sensitivity were assessed in 6 nonobese and 16 obese premenopausal women. When compared with the nonobese women, obese women had significantly greater prehepatic production and portal vein levels of insulin both basally and following glucose stimulation. This increase correlated with the degree of adiposity but not with waist-to-hip girth ratio (WHR). WHR, however, correlated inversely with the hepatic extraction fraction and directly with the posthepatic delivery of insulin. The latter correlated with the degree of peripheral insulinemia. The decline in hepatic insulin extraction with increasing WHR also correlated with the accompanying diminution in peripheral insulin sensitivity. Increasing adiposity is thus associated with insulin hypersecretion. The pronounced hyperinsulinemia of upper body fat localization, however, is due to an additional defect in hepatic insulin extraction. This defect is closely allied with the decline in peripheral insulin sensitivity.