Comparison of Overall Obesity and Body Fat Distribution in Predicting Risk of Mortality

Results of studies comparing overall obesity and abdominal adiposity or body fat distribution with risk of mortality have varied considerably. We compared the relative importance and joint association of overall obesity and body fat distribution in predicting risk of mortality. Participants included 5,799 men and 6,429 women aged 30–102 years enrolled in the third National Health and Nutrition Examination Survey who completed a baseline health examination during 1988–1994. During a 12‐year follow‐up (102,172 person‐years), 1,188 men and 925 women died. In multivariable‐adjusted analyses, waist‐to‐thigh ratio (WTR) in both sexes (P_trend <0.01 for both) and waist‐to‐hip ratio (WHR) in women (P_trend 0.001) were positively associated with mortality in middle‐aged adults (30–64 years), while BMI and waist circumference (WC) exhibited U‐ or J‐shaped associations. Risk of mortality increased with a higher WHR and WTR among normal weight (BMI 18.5–24.9 kg/m²) and obese (BMI ≥30.0 kg/m²) adults. In older adults (65–102 years), a higher BMI in both sexes (P_trend <0.05) and WC in men (P_trend 0.001) were associated with increased survival, while remaining measures of body fat distribution exhibited either no association or an inverse relation with mortality. In conclusion, ratio measures of body fat distribution are strongly and positively associated with mortality and offer additional prognostic information beyond BMI and WC in middle‐aged adults. A higher BMI in both sexes and WC in men were associated with increased survival in older adults, while a higher WHR or WTR either decreased or did not influence risk of death.     

Genetic and Environmental Influences on Body‐Fat Measures among African‐American Twins

Objective: To investigate the genetic and environmental influences on body‐fat measures including waist circumference (WC), waist‐to‐hip ratio (WHR), and body mass index (BMI) among African‐American men and women. Research Methods and Procedures: Measurements were taken as part of the Carolina African American Twin Study of Aging. This sample currently comprises 146 same‐sex African‐American twins with an average age of 50 years (range, 22 to 88 years). This analysis included 26 monozygotic and 29 dizygotic men and 45 monozygotic and 46 dizygotic women. Maximum likelihood quantitative genetic analysis was used. Results: In men, additive genetic effects accounted for 77% of the variance in WC, 59% in WHR, and 89% in BMI. In women, additive genetic effects accounted for 76% of the variance in WC, 56% in WHR, and 73% in BMI. The remaining variance in both men and women was attributed to unique environmental effects (WC, 21%; WHR, 36%; BMI, 11% in men and WC, 22%; WHR, 38%; BMI, 27% in women) and age (WC, 2%; WHR, 5% in men and WC, 2%; WHR, 6% in women). When BMI was controlled in the analysis of WC and WHR, it accounted for a portion of the genetic and environmental variance in WHR and over one‐half of the genetic and environmental variance in WC. Discussion: There are both genetic and environmental influences on WC, WHR, and BMI, and independent of BMI, there are genetic and environmental effects on WC and WHR among both genders. The results from this African‐American twin sample are similar to findings among white twin samples.     

Relationships among body composition measures in community-dwelling older women

Objective: To examine whether simple anthropometric measures provide a good estimate of total and visceral fat in 146 community‐dwelling, older white women (mean age, 74.0 ± 4.1 years). Research Methods and Procedures: Total body fat and visceral fat were measured using electron beam computed tomography (EBT). Anthropometric parameters (height, weight, BMI, sagittal diameter, and waist circumference) were measured using standard techniques. Total percentage body fat was assessed using DXA. Spearman correlations were used to examine the association between the measures. Linear regression, controlling for age, was used to examine the associations between the anthropometric parameters and total and visceral body fat measured by EBT. Results: Correlations among body composition measures ranged from ρ = 0.46 to 0.93 (p < 0.0001). EBT total fat was strongly correlated with both DXA estimates of total percentage fat (ρ = 0.86) and BMI (ρ = 0.89). Separate linear regression models indicated that BMI, waist circumference, sagittal diameter, and DXA total percentage fat were each independently related to EBT total fat. BMI had the strongest linear relationship, explaining 80% of the model variance (p < 0.0001). Linear regression indicated that BMI, waist circumference, and sagittal diameter were each independently related to EBT visceral fat, with BMI and sagittal diameter explaining ～53% of the model variance (p < 0.0001). Discussion: The use of simple anthropometric measures such as BMI, sagittal diameter, and waist circumference may be an appropriate alternative for more expensive techniques when assessing total fat but should be used with caution when estimating visceral body fat.     

Associations of Fat Distribution and Obesity with Hypertension in a Bi‐ethnic Population: The ARIC Study

Objective: To examine associations of hypertension with obesity and fat distribution among African American and white men and women. Research Methods and Procedures: The analysis sample included 15,063 African American and white men and women between the ages of 45 and 64 years who were participants in the 1987 through 1989 examination of the Atherosclerosis Risk in Communities Study (ARIC). Odds ratios and adjusted prevalences of hypertension were calculated across sexspecific quintiles of body mass index (BMI), waist‐to‐hip ratio (WHR), waist circumference, and waist‐to‐height ratio (waist/height) and adjusted for age, research center, smoking, education, physical activity, alcohol consumption, hormone replacement therapy, and menopausal status. Results: The prevalence of hypertension was higher among African Americans than whites. In the lowest quintile of BMI, 41% of African American women and 43% of African American men had hypertension compared with 14% of white women and 19% of white men. Elevated BMI, WHR, waist circumference, and waist/height were associated with increased odds of hypertension in African American and white men and women. In women, but not in men, there were significant interactions between ethnicity and the anthropometric variables studied here. The direction of the interaction indicated larger odds ratios for hypertension with increasing levels of anthropometric indices in white compared with African American women. Discussion: Obesity and abdominal fat preponderance were associated with increased prevalence of hypertension in African American and white men and women. Associations were similar among African American and white men, but obesity and fat patterning were less strongly associated with hypertension in African American than in white women.     

Predicting Incident Diabetes in Jamaica: The Role of Anthropometry

Objective: To evaluate the performance of the body mass index (BMI), waist circumference, waist‐to‐hip ratio (WHR), and waist‐to‐height ratio (WHTR) in predicting incident diabetes in Jamaica. Research Methods and Procedures: A cohort of 728 nondiabetic adults (290 men and 438 women), ages 25 to 74 years and residents of Spanish Town, Jamaica, were followed for a mean of 4 years. Participants had fasting and 2‐hour postchallenge glucose concentrations measured at baseline and follow‐up. Results: There were 51 cases of incident diabetes (17 men and 34 women). All indices were independent predictors of diabetes, and none was clearly superior. The area under the receiver operating characteristics curves (95% confidence interval) for BMI was 0.74 (0.59 to 0.88) for men and 0.62 (0.51 to 0.72) for women. For waist circumference, these values were 0.78 (0.65 to 0.91) in men and 0.61 (0.50 to 0.71) in women. Similar results were obtained for WHR and WHTR. “Optimal” cut‐off points for BMI were 24.8 kg/m² (men) and 29.3 kg/m² (women). For waist circumference, these were 88 cm and 84.5 cm for men and women, respectively. Corresponding values for WHR were 0.87 and 0.80 and for WHTR were 0.51 and 0.54, respectively. Discussion: Cut‐off points for waist circumference and WHR were similar to those proposed in developed countries for women but lower in men. Waist circumference could be useful in health promotion as an alternative to BMI.     

The Body Adiposity Index (Hip Circumference ÷ Height1.5) Is Not a More Accurate Measure of Adiposity Than Is BMI,Waist Circumference,or Hip Circumference

Based on cross‐sectional analyses, it was suggested that hip circumference divided by height^1.5 ?18 (the body adiposity index (BAI)), could directly estimate percent body fat without the need for further correction for sex or age. We compared the prediction of percent body fat, as assessed by dual‐energy X‐ray absorptiometry (PBF_DXA), by BAI, BMI, and circumference (waist and hip) measurements among 1,151 adults who had a total body scan by DXA and circumference measurements from 1993 through 2005. After accounting for sex, we found that PBF_DXA was related similarly to BAI, BMI, waist circumference, and hip circumference. In general, BAI underestimated PBF_DXA among men (2.5%) and overestimated PBF_DXA among women (4%), but the magnitudes of these biases varied with the level of body fatness. The addition of covariates and quadratic terms for the body size measures in regression models substantially improved the prediction of PBF_DXA, but none of the models based on BAI could more accurately predict PBF_DXA than could those based on BMI or circumferences. We conclude that the use of BAI as an indicator of adiposity is likely to produce biased estimates of percent body fat, with the errors varying by sex and level of body fatness. Although regression models that account for the nonlinear association, as well as the influence of sex, age, and race, can yield more accurate estimates of PBF_DXA, estimates based on BAI are not more accurate than those based on BMI, waist circumference, or hip circumference.     

BMI and waist circumference as indicators of health among Samoan women

Objective: High rates of obesity and chronic disease make establishment of effective indicators of risk for chronic disease important. The objective was to examine adequacy of anthropometric cut‐off points as indicators of risk for chronic disease among Samoan women in Hawaii. Research Methods and Procedures: A cross‐sectional survey of 55 Samoan women 18 to 28 years of age that included blood lipids, cholesterol, and glucose (including after a 2‐hour oral glucose test); anthropometry (weight, height, waist circumference); and DXA of body composition. Results: Using the Centers for Disease Control and Prevention (CDC)/World Health Organization (WHO) cut‐off points for BMI, 22% of women were overweight and 58% were obese. Cholesterol, lipid, and glucose values were all linearly related to DXA body fat, BMI, and waist circumference. BMI and waist circumference at WHO/NIH cut‐off points predicted levels of blood lipids and glucose that indicate elevated risk for disease. Discussion: WHO/NIH cut‐off points for BMI and waist circumference reflect risk indicators of chronic disease among young Samoan women in Hawaii.     

Do Leptin Levels Predict Weight Gain?—A 5-Year Follow-Up Study in Mauritius

Objective : To investigate whether relative baseline leptin levels predict long-term changes in adiposity and/or its distribution. Research Methods and Procedures : In a longitudinal study of 2888 nondiabetic Mauritians aged 25 years to 74 years who participated in population-based surveys in 1987 and 1992, changes in body mass index (BMI), waist/hip ratio (WHR), and waist circumference were compared between “hyperleptinemic,” “normoleptinemic,” and “hypoleptinemic” groups. “Relative leptin levels” were calculated as standardized residuals from the regression of log₁₀ leptin on baseline BMI to provide a leptin measure independent of BMI. Analyses were performed within each sex. A linear regression model was used to assess the effect of standardized residuals on changes in BMI, WHR, and waist circumference, independent of baseline BMI, age, fasting insulin, and ethnicity. Results : After adjusting for age and baseline BMI by analysis of covariance, there was no difference in changes in BMI, WHR, or waist circumference between men with low, normal, or high relative leptin levels. Among women, there was a significant difference in ΔWHR across leptin groups, such that the largest increase occurred in the “normal” leptin group. For both men and women, the linear regression models explained ?10% of variation in dependent variables, and the only significant independent variables were age, BMI, and being of Chinese origin, compared with Indian origin. Discussion : These findings do not support a role for leptin concentration in predicting weight gain or changes in fat distribution in adults over a 5-year period.     

A Prospective Study of Adiposity and All‐Cause Mortality: The Malmö Diet and Cancer Study

Objective: This study aims to examine the association between various measures of adiposity and all‐cause mortality in Swedish middle‐aged and older men and women and, additionally, to describe the influences of age and sex on these associations. Research Methods and Procedures: A prospective analysis was performed in a cohort of 10,902 men and 16,814 women ages 45 to 73 years who participated in the Malmö Diet and Cancer Study in Sweden. Baseline examinations took place between 1991 and 1996, and 982 deaths were documented during an average follow‐up of 5.7 years. All‐cause mortality was related to the following variables measured at baseline: body mass index (BMI), percentage of body fat, lean body mass (LBM), and waist‐to‐hip ratio (WHR), with adjustment for age and selected covariates. Body composition data were derived from bioelectrical impedance analysis. Results: The association between percentage of body fat and mortality was modified by age, particularly in women. For instance, fatness was associated with excess mortality in the younger women but with reduced mortality in the older women. Weaker associations were seen for BMI than for percentage of body fat in both sexes. Placement in the top quintiles of waist‐to‐hip ratio, independent of overall body fat, was a stronger predictor of mortality in women than in men. The observed associations could not be explained by bias from early death or antecedent disease. Discussion: The findings reveal sex and age differences for the effects of adiposity and WHR on mortality and indicate the importance of considering direct measures of adiposity, as opposed to BMI, when describing obesity‐related mortality risks.     

Larger Thigh and Hip Circumferences Are Associated with Better Glucose Tolerance: The Hoorn Study

Objective: A higher waist‐to‐hip ratio, which can be due to a higher waist circumference, a lower hip circumference, or both, is associated with higher glucose levels and incident diabetes. A lower hip circumference could reflect either lower fat mass or lower muscle mass. Muscle mass might be better reflected by thigh circumference. The aim of this study was to investigate the contributions of thigh and hip circumferences, independent of waist circumference, to measures of glucose metabolism. Research Methods and Procedures: For this cross‐sectional study we used baseline data from the Hoorn Study, a population‐based cohort study of glucose tolerance among 2484 men and women aged 50 to 75. Glucose tolerance was assessed by a 75‐g oral glucose tolerance test; hemoglobin A_1c and fasting insulin were also measured. Anthropometric measurements included body mass index (BMI) and waist, hip, and thigh circumferences. Results: Stratified analyses and multiple linear regression showed that after adjustment for age, BMI, and waist circumference, thigh circumference was negatively associated with markers of glucose metabolism in women, but not in men. Standardized β values in women were ?0.164 for fasting, ?0.206 for post‐load glucose, ?0.190 for hemoglobin A_1c (all p < 0.001), and ?0.065 for natural log insulin levels (p = 0.061). Hip circumference was negatively associated with markers of glucose metabolism in both sexes (standardized betas ranging from ?0.093 to ?0.296, p < 0.05) except for insulin in men. Waist circumference was positively associated with glucose metabolism. Discussion: Thigh circumference in women and hip circumference in both sexes are negatively associated with markers of glucose metabolism independently of the waist circumference, BMI, and age. Both fat and muscle tissues may contribute to these associations.     

Obesity in South Africa: The South African Demographic and Health Survey

Objectives: To ascertain the anthropometric profile and determinants of obesity in South Africans who participated in the Demographic and Health Survey in 1998. Research Methods and Procedures: A sample of 13,089 men and women (age, ≥15 years) were randomly selected and then stratified by province and urban and nonurban areas. Height, weight, mid-upper arm circumference, and waist and hip circumference were measured. Body mass index (BMI) was used as an indicator of obesity, and the waist/hip ratio (WHR) was used as an indicator of abdominal obesity. Multivariate regression identified sociodemographic predictors of BMI and waist circumference in the data. Results: Mean BMI values for men and women were 22.9 kg/m² and 27.1 kg/m², respectively. For men, 29.2% were overweight or obese (≥25 kg/m²) and 9.2% had abdominal obesity (WHR ≥1.0), whereas 56.6% of women were overweight or obese and 42% had abdominal obesity (WHR >0.85). Underweight (BMI <18.5 kg/m²) was found in 12.2% of men and 5.6% of women. For men, 19% of the variation of BMI and 34% of the variation in waist circumference could be explained by age, level of education, population group, and area of residence. For women, these variables explained 16% of the variation of BMI and 24% of the variation in waist circumference. Obesity increased with age, and higher levels of obesity were found in urban African women. Discussion: Overnutrition is prevalent among adult South Africans, particularly women. Determinants of overnutrition include age, level of education, ethnicity, and area of residence.     

Body fat measured by a near-infrared interactance device as a predictor of cardiovascular events: the FINRISK'92 cohort

We evaluated how body fat percentage, measured by a portable near-infrared interactance (NIR) device predicts cardiovascular (CVD), coronary heart disease (CHD), and ischemic stroke events in a prospective population-based survey. The study population consisted of 2,842 men and 3,196 women, who participated in the FINRISK'92 survey. Obesity was assessed with BMI, waist circumference, and waist-to-hip ratio (WHR) and body fat percentage measured with an NIR. Mean length of follow-up was 9 years and 3 months. In Cox proportional hazards regression analyses for men, BMI, waist circumference, and WHR as well as body fat percentage were predictors of a CVD event when adjusted for age and for major risk factors. Hazard ratio (HR) per 1 s.d. was 1.27 (95% confidence interval: 1.10-1.48) for body fat percentage, 1.30 (1.16-1.46) for BMI, and 1.31 (1.16-1.50) for waist circumference. Among women, the body fat lost its predictive power in a fully adjusted model. Body fat percentage, BMI, waist circumference, and WHR were predictors of a CHD event both among men and women, whereas body fat percentage did not predict ischemic stroke among either gender. We observed that body fat percentage measured by an NIR device was a significant predictor of CVD and CHD events among men and women, but in our population-based survey, it did not provide any additional predictive power over and above the simpler measures, such as BMI or WHR.     

Validation of DXA Body Composition Estimates in Obese Men and Women

The aim of this study was to determine the accuracy of dual‐energy X‐ray absorptiometry (DXA)‐derived percentage fat estimates in obese adults by using four‐compartment (4C) values as criterion measures. Differences between methods were also investigated in relation to the influence of fat‐free mass (FFM) hydration and various anthropometric measurements. Six women and eight men (age 22–54 years, BMI 28.7–39.9 kg/m², 4C percent body fat (%BF) 31.3–52.6%) had relative body fat (%BF) determined via DXA and a 4C method that incorporated measures of body density (BD), total body water (TBW), and bone mineral mass (BMM) via underwater weighing, deuterium dilution, and DXA, respectively. Anthropometric measurements were also undertaken: height, waist and gluteal girth, and anterior‐posterior (A‐P) chest depth. Values for both methods were significantly correlated (r² = 0.894) and no significant difference (P = 0.57) was detected between the means (DXA = 41.1%BF, 4C = 41.5%BF). The slope and intercept for the regression line were not significantly different (P > 0.05) from 1 and 0, respectively. Although both methods were significantly correlated, intraindividual differences between the methods were sizable (4C‐DXA, range = ?3.04 to 4.01%BF) and significantly correlated with tissue thickness (chest depth) or most surrogates of tissue thickness (body mass, BMI, waist girth) but not FFM hydration and gluteal girth. DXA provided cross‐sectional %BF data for obese adults without bias. However, individual data are associated with large prediction errors (±4.2%BF). This error appears to be associated with tissue thickness indicating that the DXA device used may not be able to accurately account for beam hardening in obese cohorts.     

Usefulness of Anthropometry and DXA in Predicting Intra‐abdominal Fat in Obese Men and Women

Objective: To investigate the usefulness of anthropometry and DXA in predicting intra‐abdominal fat (IAF) in obese men and women. Research Methods and Procedures: Observational, cross sectional study of 22 women and 18 men with a body mass index of 30 or above. IAF from 20 cm above and 10 cm below the L4 to L5 intervertebral disc was measured by magnetic resonance imaging (MRI) as a reference method. Central abdominal fat was measured from the upper border of L2 to the lower border of L4 by DXA. Waist and hip circumferences were also measured. Results: In obese women DXA, waist circumference and waist‐hip ratio were equally well correlated with IAF (r = 0.74, 0.75, and 0.70, respectively). In obese men DXA was moderately correlated with IAF measured by MRI (r = 0.46), whereas waist circumference and waist‐hip ratio were not significantly correlated with IAF. Discussion: The prediction of IAF in obese subjects was highly dependent on sex more than in non‐obese persons. Anthropometry and DXA were equally useful in obese women, whereas anthropometry had no predictive power and DXA was the only acceptable predictor of IAF in obese men.     

Bioelectrical impedance underestimates total and truncal fatness in abdominally obese women

Objective: To compare estimates of total and truncal fatness from eight‐electrode bioelectrical impedance analysis equipment (BIA₈) with those from DXA in centrally obese women. The secondary aim was to examine BMI and waist circumference (WC) as proxy measures for percentage total body fat (%TBF) and truncal body fat percentage (tr%BF). Research Methods and Procedures: This was a cross‐sectional study of 136 women (age, 48.1 ± 7.7 years; BMI, 30.4 ± 2.9 kg/m²; %TBF_DXA, 46.0 ± 3.7%; WC, 104 ± 8 cm). Fatness was measured by DXA and Tanita BC‐418 equipment (Tanita Corp., Tokyo, Japan). Agreement among methods was assessed by Bland‐Altman plots, and regression analysis was used to evaluate anthropometric measures as proxies for total and abdominal fatness. Results: The percentage of overweight subjects was 41.9%, whereas 55.9% of the subjects were obese, as defined by BMI, and all subjects had a WC exceeding the World Health Organization cut‐off point for abdominal obesity. Compared with DXA, the BIA₈ equipment significantly underestimated total %BF (?5.0; ?3.6 to ?8.5 [mean; 95% confidence interval]), fat mass (?3.6; ?3.9 to ?3.2), and tr%BF (?8.5; ?9.1 to ?7.9). The discrepancies between the methods increased with increasing adiposity for both %TBF and tr%BF (both p < 0.001). Variation in BMI explained 28% of the variation in %TBF_DXA and 51% of %TBF_BIA8. Using WC as a proxy for truncal adiposity, it explained only 18% of tr%BF_DXA variance and 27% of tr%BF_BIA8 variance. The corresponding figures for truncal fat mass were 49% and 35%, respectively. No significant age effects were observed in any of the regressions. Discussion: BIA₈ underestimated both total and truncal fatness, compared with DXA, with higher dispersion for tr%BF than %TBF. The discrepancies increased with degree of adiposity, suggesting that the accuracy of BIA is negatively affected by obesity.     

Improved Prediction of Body Fat by Measuring Skinfold Thickness,Circumferences, and Bone Breadths

Objective: To develop improved predictive regression equations for body fat content derived from common anthropometric measurements. Research Methods and Procedures: 117 healthy German subjects, 46 men and 71 women, 26 to 67 years of age, from two different studies were assigned to a validation and a cross‐validation group. Common anthropometric measurements and body composition by DXA were obtained. Equations using anthropometric measurements predicting body fat mass (BFM) with DXA as a reference method were developed using regression models. Results: The final best predictive sex‐specific equations combining skinfold thicknesses (SF), circumferences, and bone breadth measurements were as follows: BFM_New (kg) for men = ?40.750 + [(0.397 × waist circumference) + [6.568 × (log triceps SF + log subscapular SF + log abdominal SF)]] and BFM_New (kg) for women = ?75.231 + [(0.512 × hip circumference) + [8.889 × (log chin SF + log triceps SF + log subscapular SF)] + (1.905 × knee breadth)]. The estimates of BFM from both validation and cross‐validation had an excellent correlation, showed excellent correspondence to the DXA estimates, and showed a negligible tendency to underestimate percent body fat in subjects with higher BFM compared with equations using a two‐compartment (Durnin and Womersley) or a four‐compartment (Peterson) model as the reference method. Discussion: Combining skinfold thicknesses with circumference and/or bone breadth measures provide a more precise prediction of percent body fat in comparison with established SF equations. Our equations are recommended for use in clinical or epidemiological settings in populations with similar ethnic background.     

Obesity Is Associated With Altered Lung Function Independently of Physical Activity and Fitness

Measures of obesity, especially central adiposity, have been associated with reduced lung function. However, previous studies may have been affected by confounding by physical activity and fitness. This study aimed to examine the relationship among body fatness, fat distribution, and lung function, adjusted for physical activity energy expenditure (PAEE) and aerobic fitness (VO₂max), in a cohort of British white adults with a family history of type 2 diabetes. A total of 320 adults (mean age 40.4 ± 6.0 years) attended for anthropometric and VO₂max testing, and had ambulatory heart rate monitoring for 4 days to determine PAEE. Spirometry was used to measure forced expiratory volume in 1 s (FEV₁) and forced vital capacity (FVC). The tests were repeated 12 months later, and a cross‐sectional analysis using linear regression with repeated measures was performed. Measures of obesity (BMI, waist circumference (WC), fat mass (FM), body fat percentage (BF%)) were associated with lower lung function in men and women (P < 0.01), while waist‐to‐hip ratio (WHR) was associated with lower lung function in men only (P < 0.001). Associations remained after adjusting for age, smoking status, height, PAEE, and VO₂max. The estimated difference in mean FEV₁ and FVC per unit increase in the exposure measures were consistently stronger in men compared to women (P for interaction <0.001). Obesity is inversely associated with lung function in adults, but central fat distribution appears to have a stronger relationship with respiratory mechanics in men than in women. These associations were independent of the degree of physical activity and aerobic fitness in this cohort.     

The Use of Anthropometric and Dual-Energy X-ray Absorptiometry (DXA) Measures to Estimate Total Abdominal and Abdominal Visceral Fat in Men and Women

CLASEY, JODY L., CLAUDE BOUCHARD, C. DAVID TEATES, JILL E. RIBLETT, MICHAEL O. THORNER, MARK L. HARTMAN, AND ARTHUR WELTMAN. the use of anthropometric and dual-energy X-ray absorptiometry (DXA) measures to estimate total abdominal and abdominal visceral fat in men and women. Obes Res. Objective: A single-slice computed tomography (CT) scan provides a criterion measure of total abdominal fat (TAF) and abdominal visceral fat (AVF), but this procedure is often prohibitive due to radiation exposure, cost, and accessibility. In the present study, the utility of anthropometric measures and estimates of trunk and abdominal fat mass by dual-energy X-ray absorptiometry (DXA) to predict CT measures of TAF and AVF (cross-sectional area, cm²) was assessed. Research Methods and Procedures: CT measures of abdominal fat (at the level of the L4-L5 inter-vertebral space), DXA scans, and anthropometric measures were obtained in 76 Caucasian adults ages 20–80 years. Results: Results demonstrated that abdominal sagittal diameter measured by anthropometry is an excellent predictor of sagittal diameter measured from a CT image (r = 0. 88 and 0. 94; Total Error [TE]=4. 1 and 3. 1 cm, for men and women, respectively). In both men and women, waist circumference and abdominal sagittal diameter were the anthropometric measures most strongly associated with TAF (r = 0. 87 to 0. 93; Standard Error of Estimate (SEE) = 60. 7 to 75. 4 cm²) and AVF (r = 0. 84 to 0. 93; SEE = 0. 7 to 30. 0 cm²). The least predictive anthropometric measure of TAF or AVF was the commonly used waist-to-hip ratio (WHR). DXA estimates of trunk and abdominal fat mass were strongly associated with TAF (r =. 94 to 0. 97; SEE = 36. 9 to 50. 9 cm²) and AVF (r = 0. 86 to 0. 90; SEE = 4. 9 to 27. 7 cm²). Discussion: The present results suggest that waist circumference and/or abdominal sagittal diameter are better predictors of TAF and AVF than the more commonly used WHR. DXA trunk fat and abdominal fat appear to be slightly better predictors of TAF but not AVF compared to these anthropometric measures. Thus DXA does not offer a significant advantage over anthropometry for estimation of AVF.     

Abdominal Obesity and Expression of Familial Combined Hyperlipidemia

Objective: To investigate the role of abdominal and body obesity on the prevalence of hyperlipidemia, in particular, hypertriglyceridemia, hypercholesterolemia, and high apolipoprotein B levels, in familial combined hyperlipidemia (FCHL) relatives and their spouses. Research Methods and Procedures: In FCHL relatives (n = 618) and spouses (n = 297), prevalence data of hyperlipidemia and high apolipoprotein B levels and their age and gender‐corrected odds ratios (ORs) were calculated for sex‐adjusted categories of waist‐to‐hip ratio (WHR), waist circumference, and BMI. Results: Increments of BMI, waist circumference, and WHR increased the frequency of hyperlipidemia. In the whole study population (relatives and spouses combined), frequency of hypertriglyceridemia showed a significant interaction only between WHR categories and FCHL. This was studied further after stratification of relatives by multivariable logistic regression analyses corrected for age and gender. Predominant expression of hypertriglyceridemia was observed with higher categories of WHR in FCHL relatives (prevalence up to 57.6%, OR 8.48 in highest vs. lowest WHR category, p < 0.001) but not in spouses (up to 32.9%, OR 1.05 in highest vs. lowest WHR category, not significant). Discussion: Both in spouses and FCHL relatives, increments in BMI and waist circumference increased the prevalence of hyperlipidemia. Specifically, in FCHL relatives, WHR was the most informative determinant of the expression of hyperlipidemia, in particular, hypertriglyceridemia. The data indicate that FCHL develops against a background of abdominal obesity.     

Higher insulin, triglycerides, and blood pressure with greater trunk fat in Tanner 1 Chinese

Objective: The aims of this study were to investigate the body fat distribution pattern in prepubertal Chinese children and to investigate the relationship between central fat distribution and specific biomarkers of cardiovascular disease. Research Methods and Procedures: The study was conducted in an urban Mainland Chinese (Jinan, Shandong) sample of children using a cross‐sectional design. Pubertal status was determined by Tanner criteria. Measurements included weight, height, waist circumference, DXA measures of total body fat and trunk fat; fasting serum measures of glucose, insulin, triglyceride, cholesterol, high‐density lipoprotein‐cholesterol; and systolic and diastolic blood pressure. Multiple regression models were developed with the biomarkers of cardiovascular risk factor as the dependent variables, and adjustments were made for significant covariates, including sex, age, height, weight, waist circumference, total body fat, trunk fat, and interactions. Results: A total of 247 healthy prepubertal subjects were studied. After co‐varying for age, weight, height, and extremity fat (the sum of arm fat and leg fat), girls had greater trunk fat than boys (p < 0.0001, R² for model = 0.95). Insulin and triglyceride were positively related to central fat measured by DXA‐trunk fat (p < 0.05) but not related to the waist circumference. In the blood pressure model, waist circumference was a significant predictor of both systolic blood pressure and diastolic blood pressure, while DXA‐trunk fat was associated with diastolic blood pressure only. Significant interactions between sex and trunk fat, and sex and total fat, were found in relation to diastolic blood pressure. Discussion: In prepubertal Chinese children, greater trunk fat was significantly associated with higher insulin and triglyceride in boys and girls and was associated with higher diastolic blood pressure in boys only.