Assessment of Global Coronary Heart Disease Risk in Overweight and Obese African‐American Women

Objective : To examine, with the use of national guidelines, coronary heart disease (CHD) risk with increasing BMI for primary prevention in urban African‐American women. Research Methods and Procedures : Participants were recruited for CHD risk factor screening from 20 churches as part of a larger study of nutrition and fitness (Project Joy). All participants had a demographic, smoking and medical history assessment, and the following measurements were taken: weight, height, waist circumference, blood pressure, lipid levels, and glucose. Three methods of defining risk, the Framingham Point Scoring System, a count of risk factors, and the presence of the multiple metabolic syndrome, based on the National Cholesterol Education Program Adult Treatment Panel III Report and BMI classes established by the Clinical Guidelines, were used. Results : A total of 396 women were eligible. Participants were 40 to 80 years of age and had marked excess prevalence of overweight and obesity (84%); 55% were obese. There was a linear increase in risk factors as BMI increased. Lipids did not differ significantly among BMI classifications. Seventeen percent of women had multiple metabolic syndrome. Eight percent and 16% of women in the normal and overweight BMI classes, respectively, had two or more modifiable risk factors. There was no difference in number of modifiable risk factors among the obese classes. The Framingham Point Scoring System assigned a <10% risk of a hard CHD event in 10 years to 97% of the women. Discussion : National risk assessment guidelines for primary prevention of CHD may not be adequate for overweight and obese urban African‐American women and require further study.     

Plasma Leptin Response to an Epinephrine Infusion in Lean and Obese Women

Objective: Because leptin production by adipose tissue is under hormonal control, we examined the impact of epinephrine administration on plasma leptin concentrations. Research Methods and Procedures: We measured plasma leptin, insulin, and free fatty acid (FFA) responses after a 60-minute epinephrine infusion (0.010 μg/kg fat free mass/min) followed by a 30-minute recovery period (no infusion) in a group of 11 lean (mean body mass index ± SD: 22.6 ± 1.1 kg/m²) and 15 obese (30.0 ± 1.3 kg/m²) premenopausal women. Leptin, insulin, and FFA levels were measured in plasma before (−15 and 0 minutes) and at every 30 minutes over the 90-minute period. Results: In both lean and obese individuals, plasma leptin was significantly reduced by epinephrine (p < 0.0001). Body fat mass was associated with fasting leptin levels (r = 0.64, p < 0.0005) as well as with the decrease in leptinemia (r = −0.51, p < 0.01) produced by epinephrine administration. Furthermore, we noted a large range of leptin response to epinephrine among our subjects, especially in obese women (from −12 to −570 ng/mL per 60 minutes). However, there was no association between postepinephrine leptin and FFA levels (r = −0.14, p = 0.55). Discussion: Results of this study indicate that leptin levels decrease after epinephrine administration in both lean and obese premenopausal women. However, the heterogeneity in the response of leptin to catecholamines suggests potential alterations of the leptin axis that may contribute to generate a positive energy balance and, thus, may favor weight gain in some obese individuals.     

Severely Obese Have Greater LPS‐stimulated TNF‐α Production Than Normal Weight African‐American Women

Obesity is associated with an increase in chronic, low‐grade inflammation which has been implicated in the development of type 2 diabetes mellitus and cardiovascular disease. The purpose of this study was to determine whether obesity was associated with an elevation of whole blood lipopolysaccharide (LPS)‐stimulated tumor necrosis factor‐α (TNF‐α) production. African‐American women were recruited from a larger study and assigned to one of five groups based on BMI: normal weight (NORM; BMI 20–25, n = 7), overweight (OVER; BMI 25–30, n = 12), class 1 obese (OB1; BMI 30–35, n = 19), class 2 obese (OB2; BMI 35–40, n = 10), or class 3 obese (OB3; BMI >40, n = 17). Body composition was determined via a whole body dual‐energy X‐ray absorptiometry (DXA) scan. Venous blood samples were collected following an overnight fast (>8 h), and stimulated with five doses of LPS (Salmonella enteriditis): 80, 40, 20, 10, and 5 µg/ml for 24 h in a 37 °C, 5% CO₂ incubator. Following stimulation, TNF‐α was measured using enzyme‐linked immunosorbent assay. OB3 produced 365% more TNF‐α than NORM at an LPS dose of 20 µg/ml (P < 0.05). When maximal TNF‐α production was assessed regardless of LPS dose, OB3 produced 230% more than NORM and OVER produced 190% more than NW (P = 0.001). Total and trunk fat mass and BMI were significantly correlated with maximal TNF‐α production and LPS = 20 µg/ml. Our findings are consistent with previous reports suggesting a relationship between increased adiposity and inflammatory marker production. This is one of the first studies to focus on African‐American women, who have higher rates of obesity.     

Energy Expenditure and Adiposity in Nigerian and African‐American Women

Objective: Obesity is a prevalent condition in industrialized societies and is increasing around the world. We sought to assess the relative importance of resting energy expenditure (REE) and activity EE (AEE) in two populations with different rates of obesity. Methods and Procedures: Women of African descent between 18 and 59 years of age were recruited from rural Nigeria and from metropolitan Chicago. Total EE (TEE) was measured using the doubly labeled water (DLW) technique and REE by indirect calorimetry; AEE was calculated as the difference between TEE and the sum of REE plus a factor for the thermic effect of food. In the analyses all EE parameters were adjusted for body size using a regression method. Comparisons were made between the groups and associations between EE and adiposity examined. Results: A total of 149 Nigerian and 172 African‐American women completed the protocol. All body size measurements were lower in the Nigerian women. Adjusted TEE and REE were higher in the Nigerian cohort but adjusted AEE did not differ significantly. Adjustment for parity, seasonality, and recent illness did not modify mean AEE or adiposity. In neither cohort was there a meaningful association between measures of AEE and adiposity. Discussion: In these cohorts of women from very different environments, AEE did not differ significantly nor was it associated cross‐sectionally with adiposity. If generalizable, these findings suggest that reduction in AEE may have less of a role in the development of obesity than anticipated. The possibility remains that variation in type and duration of activity plays a role not captured by total AEE.     

Self‐Efficacy as a Predictor of Weight Change in African‐American Women

Objective: Although self‐efficacy has received increasing attention for its role in weight loss, there is less research examining this relationship in minority samples. The purpose of this study was to determine whether self‐efficacy for weight loss was predictive of weight change in a sample of African‐American women. Research Methods and Procedures: Subjects were 106 overweight or obese, low‐income African‐American women participating in a weight management intervention that involved either personalized monthly sessions with their primary care physician or standard care. Weight and self‐efficacy for weight loss were assessed at baseline and at the end of the 6‐month treatment. Results: For subjects in the personalized intervention, baseline self‐efficacy was predictive of subsequent weight change, such that higher levels of self‐efficacy before treatment were associated with less weight loss. In contrast, improvements in self‐efficacy during treatment were associated with greater weight loss for the personalized intervention group. Discussion: Results suggest high self‐efficacy for weight loss before treatment may be detrimental to success, whereas treatments that improve participants’ self‐efficacy may result in greater weight loss. High pretreatment self‐efficacy may be indicative of overconfidence or lack of experience with the difficulties associated with weight loss efforts. Whereas replication is needed, our results suggest that self‐efficacy is an important variable to consider when implementing weight loss interventions.     

Apolipoprotein A‐II Polymorphism and Visceral Adiposity in African‐American and White Women

To determine the association between the ?265 T to C substitution in the apolipoprotein A‐II (APOA‐II) gene and levels of visceral adipose tissue (VAT) in a group of premenopausal African‐American and white women, we genotyped 237 women (115 African‐American and 122 white) for this polymorphism. Body composition was assessed by DXA, and VAT was determined from a single computed tomography scan. In addition to VAT, we examined the association between the polymorphism and other phenotypes (total body fat, total abdominal adipose tissue, and subcutaneous abdominal adipose tissue). The mutant C allele in the APOA‐II gene was less frequent in African‐American compared with white women, 23% vs. 36%, respectively (p < 0.01). VAT was significantly higher in carriers of the C allele compared with noncarriers after adjustment for total body fat (p < 0.05). When separate analyses by ethnic group were conducted, the association between the polymorphism and VAT was observed in white (p < 0.05) but not African‐American (p = 0.57) women. There was no association between the polymorphism and the other phenotypes. These results indicate a significant association between the T265C APOA‐II polymorphism and levels of VAT in premenopausal women. This association is present in white but not African‐American women.     

Insulin Sensitivity in African‐American and White Women: Association With Inflammation

Whether the contribution of inflammation to risk for chronic metabolic disease differs with ethnicity is not known. The objective of this study was to determine: (i) whether ethnic differences exist in markers of inflammation and (ii) whether lower insulin sensitivity among African Americans vs. whites is due to greater inflammatory status. Subjects were African‐American (n = 108) and white (n = 105) women, BMI 27–30 kg/m². Insulin sensitivity was assessed with intravenous glucose tolerance test and minimal modeling; fat distribution with computed tomography; body composition with dual‐energy X‐ray absorptiometry; markers of inflammation (tumor necrosis factor (TNF)‐α, soluble tumor necrosis factor receptor (sTNFR)‐1, sTNFR‐2, C‐reactive protein (CRP), and interleukin (IL)‐6) with enzyme‐linked immunosorbent assay (ELISA). Whites had greater intra‐abdominal adipose tissue (IAAT), insulin sensitivity, and concentrations of TNF‐α, sTNFR‐1, and sTNFR‐2 than African Americans. Greater TNF‐α in whites vs. African Americans was attributed to greater IAAT in whites. Among whites, but not African Americans, CRP was independently and inversely associated with insulin sensitivity, after adjusting for IAAT (r = ?0.29 P < 0.05, and r = ?0.13 P = 0.53, respectively). Insulin sensitivity remained lower in African Americans after adjusting for CRP (P < 0.001). In conclusion, greater IAAT among whites may be associated with greater inflammation. Insulin sensitivity was lower among African Americans, independent of obesity, fat distribution, and inflammation.     

Fasting Plasma Glucose (FPG) and the Risk of Impaired Glucose Tolerance in Obese Children and Adolescents

A timely diagnosis of impaired glucose tolerance (IGT) is desirable in obesity. The oral glucose tolerance test (OGTT), the gold standard to diagnose this condition, may not be realistically performed in all patients due to discomfort, labor, and cost. The aim of this study was to assess whether one or more biochemical indexes measured in fasting conditions could be used to identify obese children at risk of IGT. A cohort of 563 white obese children and adolescents (M/F: 315/248; aged 4–17 years) was recruited and underwent anthropometric evaluation and OGTT. Anthropometric parameters, fasting plasma glucose (FPG), fasting serum insulin (FSI), and homeostasis model assessment of insulin resistance (HOMA_IR) were tested in pursuit of a possible threshold to be used as a predictor of IGT. Thirty‐seven children (6.9%) had IGT and one child (0.1%) had type 2 diabetes (T2D). FPG, FSI, and HOMA_IR were all significantly higher in children with IGT than in children without IGT. Receiver‐operating characteristic (ROC) curve analyses run for gender and puberty‐adjusted FPG, FSI, and HOMA_IR were all significant: area under the curve (95% confidence interval) equaled 0.68 (0.59–0.76), 0.66 (0.56–0.76), and 0.68 (0.59–0.78), respectively. The three parameters did not show significantly different sensitivity/specificity in the pooled population or in the gender/puberty subgroups. Thresholds varied among gender/puberty subgroups for FSI and HOMA_IR, but not for FPG, which showed a fixed threshold of 86 mg/dl. A gender/puberty independent cutoff of FPG may be considered a screening tool to narrow clinical indication to OGTT in obese white children and adolescents.     

Physical Activity and Reduced Intra‐abdominal Fat in Midlife African‐American and White Women

The purpose of our study was to determine whether self‐reported physical activity (PA), including recreational, household, and exercise activities, is associated with intra‐abdominal fat (IAF) in community‐dwelling white and black midlife women. We performed a cross‐sectional study of 369 women from the Chicago site of the Study of Women's Health Across the Nation (SWAN) ancillary study, the SWAN Fat Patterning Study. PA level was the independent variable, and IAF, assessed by computerized tomography (CT) scan, was the dependent variable. Measures were obtained at SWAN Fat Patterning Baseline visit between August 2002 and December 2005. Linear regression models explored the association between PA and IAF. The first model included IAF as the outcome and total score PA as the main predictor, adjusting for total percent fat mass, age, and ethnicity. The second model included education, parity, sex hormone–binding globulin (SHBG) level, and depressive symptoms, measured by Center for Epidemiological Studies‐Depression (CES‐D) scale. Each 1‐point higher total PA score was associated with a 4.0 cm² lower amount of IAF (P = 0.004), independent of total percent fat mass, age, ethnicity, SHBG level, educational level, CES‐D, and parity. Associations did not differ between white and black women. This study demonstrates a significant negative association between PA and IAF independent of multiple covariates in midlife women. Our findings suggest that motivating white and black women to increase PA during midlife may lessen IAF, which may have a positive impact on subsequent development of diabetes and cardiovascular disease.     

Fat Distribution,Aerobic Fitness,Blood Lipids,and Insulin Sensitivity in African‐American and European‐American Women

The purpose of this study was to determine independent relationships of intra‐abdominal adipose tissue (IAAT), leg fat, and aerobic fitness with blood lipids and insulin sensitivity (S_i) in European‐American (EA) and African‐American (AA) premenopausal women. Ninety‐three EA and ninety‐four AA with BMI between 27 and 30 kg/m² had IAAT by computed tomography, total fat and leg fat by dual‐energy X‐ray absorptiometry, aerobic fitness by a graded exercise test, African admixture (AFADM) by ancestry informative markers, blood lipids by the Ektachem DT system, and S_i by glucose tolerance test. Independent of age, aerobic fitness, AFADM, and leg fat, IAAT was positively related to low‐density lipoprotein–cholesterol (LDL‐C), cholesterol‐high‐density lipoprotein (HDL) ratio, triglycerides (TGs), and fasting insulin (standardized β varying 0.16–0.34) and negatively related to HDL‐cholesterol (HDL‐C) and S_i (standardized β ?0.15 and ?0.25, respectively). In contrast, independent of age, aerobic fitness, AFADM, and IAAT, leg fat was negatively related to total cholesterol, LDL‐C, cholesterol‐HDL ratio, TGs, and fasting insulin (standardized β varying ?0.15 to ?0.21) and positively related to HDL‐C and S_i (standardized β 0.16 and 0.23). Age was not independently related to worsening of any blood lipid but was related to increased S_i (standardized β for S_i 0.25, insulin ?0.31). With the exception of total cholesterol and LDL‐C, aerobic fitness was independently related to worsened blood lipid profile and increased S_i (standardized β varying 0.17 to ?0.21). Maintenance of favorable fat distribution and aerobic fitness may be important strategies for healthy aging, at least in premenopausal EA and AA women.     

Associations of Free Fatty Acids With Insulin Secretion and Action Among African‐American and European‐American Girls and Women

Ethnic differences in insulin secretion and action between African Americans (AAs) and European Americans (EAs) may influence mobilization of free fatty acids (FFAs). We tested the hypotheses that FFA concentrations would be associated with measures of insulin secretion and action before and during a glucose challenge test. Subjects were 48 prepubertal girls, 60 premenopausal women, and 46 postmenopausal women. Fasting insulin (insulin₀), the acute insulin response to glucose (AIR_g), the insulin sensitivity index (S_I), basal and nadir FFA (FFA₀, FFA_nadir), and nadir time (TIME_nadir) were determined during an intravenous glucose tolerance test (IVGTT). Stepwise multiple linear regression (MLR) analysis was conducted to identify associations of FFA₀, FFA_nadir, and TIME_nadir with ethnicity, age group, insulin measures, indexes of body composition from dual‐energy X‐ray absorptiometry, and measures of fat distribution from computed tomography scan. In this population, insulin₀ and AIR_g were higher among AAs vs. EAs, whereas S_I was lower, independent of age group. MLR analyses indicated that FFA₀ was best predicted by lean tissue mass (LTM), leg fat mass, ethnicity (lower in AAs), S_I, and insulin₀. FFA_nadir was best predicted by FFA₀, age group, and intra‐abdominal adipose tissue (IAAT). TIME_nadir was best predicted by leg fat mass, AIR_g, and S_I. In conclusion, indexes of insulin secretion and action were associated with FFA dynamics in healthy girls and women. Lower FFA₀ among AAs was independent of insulin₀ and S_I. Whether lower FFA₀ is associated with substrate oxidation or risk for obesity remains to be determined.     

A Prospective Study of the Effect of Childbearing on Weight Gain in African‐American Women

Objective: To prospectively assess the influence of bearing a first, second, or later child on weight gain among African‐American women in the context of other risk factors. Research Methods and Procedures: Data were obtained in a prospective follow‐up study of African‐American women from across the U.S. who are participants in the Black Women's Health Study. Postal questionnaires were used to collect baseline data in 1995 and follow‐up data in 1997 and 1999. Parous and nulliparous women (11, 196) (21 to 39 years old at baseline), of whom 1230 had a singleton birth during follow‐up, are the subjects of the present analyses. We assessed change in BMI (kilograms per meter squared) in relation to childbearing during 4 years of follow‐up, with use of multivariable linear regression to control for important risk factors. Results: During 4 years of follow‐up, the BMI of participants increased by an average of 1.6 kg/m², equivalent to a weight gain of ～4.4 kg. Women who had a child during follow‐up gained more weight than women who remained nulliparous, and those who had a first child gained more than those who had a second or later child. The weight gain associated with childbearing increased with increasing baseline BMI and was appreciable among heavier women. For example, among women with a baseline index of 36, the increase in BMI for women who bore a first child was 1.1 kg/m² more than that of nulliparous women, equivalent to a difference in weight gain of ～3.0 kg. Discussion: Childbearing is an important contributor to weight gain among African‐American women.     

Lower Serum Adiponectin Levels in African‐American Boys

Objective: To examine adiponectin, an adipocyte‐secreted hormone with anti‐inflammatory and insulin‐sensitizing effects, in relation to race or gender in younger subjects. Research Methods and Procedures: The relationship of adiponectin, quantitated by radioimmunoassay, to anthropometric and metabolic factors (fasting insulin, glucose, and leptin) and reproductive hormones was examined in 46 healthy African Americans (25 girls/21 boys) and 40 whites (20 girls/20 boys) ranging in age from 12 to 21 years. Results: There was no statistical difference in BMI or in BMI percentile among the four groups. Sums of skinfolds, but not skinfold percentile, were significantly lower in boys than girls (p = 0.001 and p = 0.896, respectively), whereas there was no difference between racial groups. Leptin was significantly greater in girls (p = 0.0002). There was no difference in fasting serum glucose, insulin, or homeostasis model assessment score among any of the groups. There was a significant negative univariate relationship between serum adiponectin and both BMI and BMI percentile for the entire group (p = 0.006 and p = 0.005). In a multivariate model, BMI percentile (p = 0.005) and the interaction between race and gender (p = 0.026) were significant predictors of serum adiponectin. In this model, African‐American boys had the lowest serum adiponectin level, 37% less than white boys, who had the highest adiponectin levels. Discussion: Serum adiponectin levels are reduced in young obese subjects (African Americans and whites) and are lower in African‐American boys than white boys. A lower adiponectin level in African‐American boys may predispose this group to a greater risk of diabetes and cardiovascular disease.     

Plasma Adiponectin Levels in High Risk African‐Americans with Normal Glucose Tolerance,Impaired Glucose Tolerance,and Type 2 Diabetes**

Objective: We studied plasma adiponectin, insulin sensitivity, and insulin secretion before and after oral glucose challenge in normal glucose tolerant, impaired glucose tolerant, and type 2 diabetic first degree relatives of African‐American patients with type 2 diabetes. Research Methods and Procedures: We studied 19 subjects with normal glucose tolerance (NGT), 8 with impaired glucose tolerance (IGT), and 14 with type 2 diabetes. Serum glucose, insulin, C‐peptide, and plasma adiponectin levels were measured before and 2 hours after oral glucose tolerance test. Homeostasis model assessment‐insulin resistance index (HOMA‐IR) and HOMA‐β cell function were calculated in each subject using HOMA. We empirically defined insulin sensitivity as HOMA‐IR < 2.68 and insulin resistance as HOMA‐IR > 2.68. Results: Subjects with IGT and type 2 diabetes were more insulin resistant (as assessed by HOMA‐IR) when compared with NGT subjects. Mean plasma fasting adiponectin levels were significantly lower in the type 2 diabetes group when compared with NGT and IGT groups. Plasma adiponectin levels were 2‐fold greater (11.09 ± 4.98 vs. 6.42 ± 3.3811 μg/mL) in insulin‐sensitive (HOMA‐IR, 1.74 ± 0.65) than in insulin‐resistant (HOMA‐IR, 5.12 ± 2.14) NGT subjects. Mean plasma adiponectin levels were significantly lower in the glucose tolerant, insulin‐resistant subjects than in the insulin sensitive NGT subjects and were comparable with those of the patients with newly diagnosed type 2 diabetes. We found significant inverse relationships of adiponectin with HOMA‐IR (r = ?0.502, p = 0.046) and with HOMA‐β cell function (r = ?0.498, p = 0.042) but not with the percentage body fat (r = ?0.368, p = 0.063), serum glucose, BMI, age, and glycosylated hemoglobin A1C (%A1C). Discussion: In summary, we found that plasma adiponectin levels were significantly lower in insulin‐resistant, non‐diabetic first degree relatives of African‐American patients with type 2 diabetes and in those with newly diagnosed type 2 diabetes. We conclude that a decreased plasma adiponectin and insulin resistance coexist in a genetically prone subset of first degree African‐American relatives before development of IGT and type 2 diabetes.     

Effect of Glucose Tolerance Status on PAI‐1 Plasma Levels in Overweight and Obese Subjects

Objective: The aim of our study was to examine whether plasminogen activator inhibitor‐1 (PAI‐1) plasma levels varied as a function of differences in glucose tolerance status independently of body fatness, body‐fat distribution, and insulin sensitivity. Research Methods and Procedures: Plasma PAI‐1 antigen levels, along with insulin resistance [measured by homeostatic model assessment (HOMA_IR)], central fat accumulation, body composition, blood pressure, and fasting concentrations of glucose, insulin, and lipids, were measured in 229 overweight and obese [body mass index (BMI) ≥25 kg/m²) subjects with normal glucose tolerance (NGT) and in 44 age‐ and BMI‐matched subjects with impaired glucose tolerance (IGT). Results: Plasma PAI‐1 antigen levels were significantly higher in IGT than in NGT subjects. Log PAI‐1 was positively correlated with BMI, HOMA_IR, and log insulin, and inversely associated with high‐density lipoprotein‐cholesterol both in IGT and in NGT individuals. On the other hand, log PAI‐1 was positively correlated with waist circumference, fat mass (FM), fat‐free mass, systolic and diastolic blood pressure, and log triglycerides only in the NGT group. After multivariate analyses, the strongest determinants of PAI‐1 levels were BMI, FM, waist circumference, and high‐density lipoprotein cholesterol in the NGT group and only HOMA_IR in the IGT cohort. Discussion: This study demonstrates that PAI‐1 concentrations are higher in IGT than in NGT subjects. Furthermore, we suggest that the influences of total adiposity, central fat, and insulin resistance, main determinants of PAI‐1 concentrations, are different according to the degree of glucose tolerance.     

BMI and Cervical Cancer Screening among White,African‐American,and Hispanic Women in the United States

Objectives: We examined cervical cancer screening by BMI in white, African‐American, and Hispanic women and explored women's reasons for not undergoing screening. Research Methods and Procedures: We used logistic regression to examine Pap testing in the preceding 3 years across BMI groups for white (n = 6419), African‐American (n = 1715), and Hispanic women (n = 1859) age 18 to 75 years who responded to the 2000 National Health Interview Survey. We used bivariable analyses to describe women's reasons for not undergoing testing and examined whether unscreened women received physician recommendations for screening. Results: Of 12, 170 women, 50% were normal weight, 26% were overweight, and 21% were obese. The proportion who reported Pap testing in the last 3 years was 86% in whites, 88% in African Americans, and 78% in Hispanics. After adjustment for sociodemographics, health care access, and illness burden, severely obese white women (BMI = 40+ kg/m²) were significantly less likely to undergo Pap testing (relative risk, 0.92; 95% CI, 0.83 to 0.99) compared with normal weight women. BMI was not associated with screening in African Americans or Hispanics. A higher proportion of obese white women than normal weight women cited putting off the test or embarrassment or discomfort as the primary reason for not undergoing screening. Among the unscreened, obese women were as likely as normal weight women to receive a physician recommendation to undergo screening. Discussion: Disparities in cervical cancer screening by body weight persist for white women with severe obesity. Disparities were not explained by differences in the rate of physician recommendations for screening, but obese white women may be more likely to delay screening or to find screening painful, uncomfortable, or embarrassing than normal weight white women. Efforts to increase screening among obese women should address women's reservations about screening.     

Ethnic Differences in Visceral Adipose Tissue and Type 2 Diabetes: Filipino,African‐American,and White Women

Objective: To compare ethnic differences in visceral adipose tissue (VAT), assessed by computed tomography, and type 2 diabetes risk among 55‐ to 80‐year‐old Filipino, African‐American, and white women without known cardiovascular disease. Research Methods and Procedures: Subjects were participants in the Rancho Bernardo Study (n = 196), the Filipino Women's Health Study (n = 181), and the Health Assessment Study of African‐American Women (n = 193). Glucose and anthropometric measurements were assessed between 1995 and 2002. Results: African‐American women had significantly higher age‐adjusted BMI (29.7 kg/m²) and waist girth (88.1 cm) compared with Filipino (BMI, 25.5 kg/m²; waist girth, 81.9 cm) or white (BMI: 26.0 kg/m²; waist girth: 80.7 cm) women. However, VAT was significantly higher among Filipino (69.1 cm³) compared with white (62.3 cm³; p = 0.037) or African‐American (57.5 cm³, p < 0.001) women. VAT correlated better with BMI (r = 0.69) and waist (r = 0.77) in whites, compared with Filipino (r = 0.42; r = 0.59) or African‐American (r = 0.50; r = 0.56) women. Age‐adjusted type 2 diabetes prevalence was significantly higher in Filipinas (32.1%) than in white (5.8%) or African‐American (12.1%) women. Filipinas had higher type 2 diabetes risk compared with African Americans [adjusted odds ratio, 2.30; 95% confidence interval (CI), 1.09 to 4.86] or whites (adjusted odds ratio, 7.51; 95% CI, 2.51 to 22.5) after adjusting for age, VAT, exercise, education, and alcohol intake. Discussion: VAT was highest among Filipinas despite similar BMI and waist circumference as whites. BMI and waist circumference were weaker estimates of VAT in Filipino and African‐American women than in whites. Type 2 diabetes prevalence was highest among Filipino women at every level of VAT, but VAT did not explain their elevated type 2 diabetes risk.     

Association of FTO Gene Variants With Adiposity in African‐American Adolescents

The prevalence of obesity continues to increase significantly, with the largest rise in the African‐American adolescents. Genetic contributions to obesity are being identified with the advent of genome‐wide association studies (GWAS). Specifically, variants of the fat mass and obesity associated (FTO) gene have been associated with obesity in populations of European descent. The studies in African Americans have been inconclusive. To further evaluate the association of the FTO gene and adiposity in African Americans, we genotyped 47 single‐nucleotide polymorphisms (SNPs), including seven SNPs previously reported to be significant in the literature in a cohort consisting of 561 non‐Hispanic white and 497 African‐American individuals. Analysis of our data showed 17 SNPs to be associated with BMI Z‐score (BMI‐Z) in our study population. The strongest association was found in the African Americans. The most significant SNP was rs8057044, which was associated with BMI‐Z in the African Americans (P = 0.00054). SNP rs9939609 was found to be significant in the non‐Hispanic white population (P = 0.028). Our data confirm the association between FTO and adiposity suggesting that FTO is a childhood obesity susceptibility gene. Our data also identify a novel SNP of the FTO gene (rs8057044) that is associated with measures of adiposity in the African‐American population.     

Baseline Correlates of Insulin Resistance in Inner City High‐BMI African‐American Children

To characterize the influence of diet‐, physical activity–, and self‐esteem‐related factors on insulin resistance in 8–10‐year‐old African‐American (AA) children with BMI greater than the 85th percentile who were screened to participate in a community‐based type 2 diabetes mellitus (T2DM) prevention trial. In 165 subjects, fasting glucose‐ and insulin‐derived values for homeostasis model assessment of insulin resistance (HOMA‐IR) assessed insulin resistance. Body fatness was calculated following bioelectrical impedance analysis, and fitness was measured using laps from a 20‐m shuttle run. Child questionnaires assessed physical activity, dietary habits, and self‐esteem. Pubertal staging was assessed using serum levels of sex hormones. Parent questionnaires assessed family demographics, family health, and family food and physical activity habits. Girls had significantly higher percent body fat but similar anthropometric measures compared with boys, whereas boys spent more time in high‐intensity activities than girls. Scores for self‐perceived behavior were higher for girls than for boys; and girls desired a more slender body. Girls had significantly higher insulin resistance (HOMA‐IR), compared with boys (P < 0.01). Adjusting for age, sex, pubertal stage, socioeconomic index (SE index), and family history of diabetes, multivariate regression analysis showed that children with higher waist circumference (WC) (P < 0.001) and lower Harter's scholastic competence (SC) scale (P = 0.044) had higher insulin resistance. WC and selected self‐esteem parameters predicted insulin resistance in high‐BMI AA children. The risk of T2DM may be reduced in these children by targeting these factors.     

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.