Age, sex, ethnicity, body composition, and resting energy expenditure of obese African American and white children and adolescents

BACKGROUND: African Americans may have a lower resting energy expenditure (REE) than do whites, although the data are limited for obese children and adolescents and for boys. Differences in bone density and trunk lean body mass may account for some of these measured differences in REE. OBJECTIVE: We assessed the REE and body composition of obese African American and white children and adolescents. DESIGN: Obese, 5-17-y-old children and adolescents were evaluated (n = 203). Body composition was assessed by dual-energy X-ray absorptiometry. REE was measured by open-circuit calorimetry. African American and white children were compared. The relation between REE and the independent variables (age, sex, ethnic group, fat mass, and fat-free mass or lean tissue mass) was assessed. RESULTS: Of those evaluated, 66% were girls and 34% were African American. Age, sex, pubertal status, and body composition did not differ significantly by ethnic group. All the independent variables were significantly associated with REE. Using lean tissue mass to account for differences in bone density did not significantly alter the results. REE decreased with age and was lower in the girls than in the boys and in the African Americans than in the whites. When trunk fat-free mass was included in the model in place of whole-body fat-free mass, the ethnic difference in REE decreased. CONCLUSIONS: Adjustment for trunk lean tissue mass partially explains the lower REE of obese African American children and adolescents. The lower relative REE of older obese children suggests the importance of early intervention in the prevention of childhood obesity. The lower REE of girls and of African Americans may contribute to the difficulty in weight management in these groups.     

Racial differences in energy expenditure and aerobic fitness in premenopausal women

BACKGROUND: Aerobic fitness, or maximal oxygen uptake (f1.gif" BORDER="0">O(2)max), and energy expenditure (EE) may be lower in African Americans than in whites. OBJECTIVE: The objective of this study was to compare sleeping EE (SEE), resting EE (REE), free-living total EE (TEE), and f1.gif" BORDER="0">O(2)max in African American and white women after adjustment for body composition and free-living activity-related energy expenditure (AEE). DESIGN: Eighteen African American and 17 white premenopausal women were matched for weight, percentage body fat, and age. SEE and REE were measured in a room calorimeter and f1.gif" BORDER="0">O(2)max was measured on a treadmill. Fat-free mass (FFM) and fat mass (FM) (4-compartment model), AEE (doubly labeled water and SEE), and regional lean tissue (dual-energy X-ray absorptiometry) were used as adjustment variables in SEE, REE, TEE, and f1.gif" BORDER="0">O(2)max comparisons. RESULTS: The African American women had significantly more limb lean tissue and significantly less trunk lean tissue than did the white women. The African American women also had significantly lower SEE (6.9%), REE (7.5%), TEE (9.6%), and f1.gif" BORDER="0">O(2)max (13.4%) than did the white women. Racial differences persisted after adjustment for f1.gif" BORDER="0">O(2)max, AEE, FFM, and limb lean tissue but disappeared after adjustment for trunk lean tissue. The f1.gif" BORDER="0">O(2)max difference was independent of all body-composition variables and of AEE. CONCLUSIONS: African American women had lower aerobic fitness than did white women, independent of differences in lean tissue or AEE. Diminished racial differences in SEE, REE, and TEE after adjustment for trunk lean tissue suggest that low EE in African American women is mediated by low volumes of metabolically active organ mass.     

Fat-free mass can be utilized to assess resting energy expenditure for male athletes of different body size

The fat-free mass (FFM) of athletes is typically large, and thus the FFM is often utilized to estimate their resting energy expenditure (REE). While the proportional contribution of organ-tissues to the total influence of FFM on REE is known for untrained individuals and female athletes, the extent to which this is valid for male athletes is unclear. The purpose of this study was to clarify the contribution of the components of FFM to REE in male athletes. Fifty-seven male athletes participated in this study. REE was assessed by indirect calorimetry and body composition by dual X-ray absorptiometry. The athletes were equally divided into three groups based on FFM: Small (S), Medium (M), and Large (L). When measured REE (REEm) was compared with REE estimated (REEe) based on the four organ-tissue compartments with set metabolic rates, REEm and REEe had a strong association (r=0.76, p<0.001). In addition, the absolute value of total REE became larger in accordance with body size (S: 1,643±144, M: 1,865±140, and L: 2,060±156 kcal/d) accompanied by increases in mass of all four organ-tissue compartments as body size increased. The consistency of REE/FFM in male athletes in spite of the difference in body size can be explained by the steadiness among the three groups of the relative contribution of each organ-tissue compartment to the FFM. Based on these results, the FFM is the major determinant of REE regardless of body size in male athletes.     

Influence of leptin on changes in body fat during growth in African American and white children

OBJECTIVE: The aim of this study was to determine whether initial levels or temporal changes in fasting leptin were associated with longitudinal changes in body-fat mass in children. RESEARCH METHODS AND PROCEDURES: The study group consisted of 85 children (42 white and 43 African American) with a mean initial age of 8.1 +/- 0.1 years. The children had between three and six annual visits for repeated measurements of body composition by DXA and fasting leptin level. Fat mass and fasting leptin level were not normally distributed and were log-transformed. Data were analyzed using SAS Proc mixed growth models, with log fat as the dependent variable. RESULTS: Initial leptin level was a significant predictor of the change in fat mass over time (p < 0.0001), with high initial leptin levels resulting in increased fat gain, independent of initial fat levels. This relationship remained significant when the data were analyzed separately by race (whites, p < 0.0001; African Americans, p = 0.008). The relationship between the initial level of leptin and the change in fat mass was not modified by race, sex, or Tanner Stage. The rate of change in leptin during the study was significantly related to the rate of change in fat mass in African Americans (p = 0.008) but not in whites (p = 0.490). DISCUSSION: In conclusion, high fasting leptin level at the start of the study was significantly associated with increasing fat mass in this cohort, indicating that the children may be developing resistance to the effects of leptin.     

Racial/ethnic disparities in adult preventive dental care use

Using the Behavioral Model of Health Services Utilization, this study examines whether adult preventive dental care utilization differs by ethnicity/race. Logistic regression results find that controlling only for predisposing characteristics (gender, age, education, and health status), African Americans, Mexican Americans, and Other race/ethnicity are less likely than whites to utilize dental services. However, the effects are no longer significant when enabling resource variables are included in the model (income level, insurance, census region, and metropolitan statistical area). Interactions between race/ethnicity and insurance status show that privately insured racial/ethnic minority groups do not differ from privately insured whites in their utilization of dental services. Similarly, the preventive dental care utilization of publicly insured African Americans and Other Hispanics does not differ significantly from privately insured whites. However, publicly insured whites, Mexican Americans, and individuals of Other race/ethnicity have significantly lower odds of utilizing dental services relative to whites with private insurance.     

Larger amounts of visceral adipose tissue in Asian Americans.

OBJECTIVE: Excess visceral adipose tissue (VAT) is recognized as an important risk factor for the development of coronary heart disease and type 2 diabetes. Several studies have reported less VAT in African Americans compared with whites. As little is known about the levels of VAT in Asians, we compared whole-body VAT in Asian Americans with European Americans. RESEARCH METHODS AND PROCEDURES: VAT was measured using whole-body multislice magnetic resonance imaging in 54 women (18 Asian Americans, 36 European Americans) and 53 men (19 Asian Americans, 34 European Americans) with body mass index (measured in kilograms per square meter) < 30. Data were analyzed by multiple regression modeling. RESULTS: Asian American women had higher log-transformed VAT compared with European American women (p < 0.05), after adjusting for age and total body fat. There was a significant age by race interaction such that race differences in VAT were most evident over the age of 30 years. No differences in VAT could be detected between Asian American and European American men, even after adjusting for potential covariates, including total adiposity. DISCUSSION: These data are the first to demonstrate higher amounts of VAT in healthy Asian Americans, a finding that suggests normative VAT values or standards derived from whites may not be applicable to Asians.     

Racial differences in insulin secretion and sensitivity in prepubertal children: role of physical fitness and physical activity

OBJECTIVE: To investigate in prepubertal children whether physical fitness and/or physical activity are: 1) associated with insulin secretion and sensitivity and 2) account for racial differences in insulin secretion and sensitivity. RESEARCH METHODS AND PROCEDURES: Subjects included 34 African American and 34 white nondiabetic children aged 5 to 11 years. Data were divided into two sets according to the availability of VO2max and physical activity data. Body composition was measured by dual-energy X-ray absorptiometry. Subcutaneous abdominal adipose tissue and intra-abdominal adipose tissue were examined by computed tomography. Insulin sensitivity (S1) and acute insulin response (AIR) were determined by a frequently sampled intravenous glucose tolerance test. An all-out, progressive treadmill exercise test was used for measuring VO2max. Physical activity data were collected by questionnaire. RESULTS: African American children had lower SI and higher AIR than white children, after adjusting for total body fat mass. African Americans reported higher levels of physical activity (hours/wk) than whites, but had a lower VO2max. In multiple linear regression analysis, hours/wk of activity and hours/wk of vigorous activity, but not moderate activity, were independently related to SI and AIR after adjusting for race, total body fat mass or fat distribution, and total lean tissue mass. VO2max was not related to AIR, and was inversely related to SI, after adjusting for body composition. Race remained significantly associated with both SI and AIR, even after adjusting for body composition, fat distribution, and hours/wk of activity or hours/wk of vigorous activity. DISCUSSION: In summary, overall physical activity and, especially, vigorous activity were associated with insulin secretion and sensitivity. However, neither physical activity nor VO2max explained the racial difference in insulin secretion (higher in African Americans) and sensitivity (lower in African Americans). Thus, racial (African American to white) differences in aspects of insulin action seem to be due to factors other than body composition, fat distribution, cardiovascular fitness, and amount of physical activity.     

Circulating phylloquinone concentrations of adults in the United States differ according to race and ethnicity

Differences in micronutrient status are reported to contribute to racial and ethnic differences in chronic diseases. Diseases related to vitamin K are reported to differ by race and ethnicity, but it is unclear if circulating vitamin K concentrations similarly differ. We examined racial and ethnic differences in serum phylloquionone (K1) in the Multiethnic Study of Atherosclerosis (MESA) (mean ± SD age = 62 ± 10 y; 52% female; 262 white, 180 African American, 169 Hispanic, 93 Chinese American). Overall, 25% had serum K1 <0.1 nmol/L (the lower limit of detection). The prevalence of low serum K1 was 4% in Chinese Americans compared with 24% of whites, 29% of African Americans, and 33% of Hispanics. Compared with whites, Chinese Americans were significantly less likely to have serum K1 <0.1 nmol/L [OR (95% CI): 0.23 (0.09-0.23), adjusted for serum TG, K1 intake, age, sex, BMI, smoking, total cholesterol, site, season, and lipid-lowering medication use]. African Americans and Hispanics had similar odds to whites for having serum K1 <0.1 nmol/L [OR(95% CI): 1.30 (0.79-2.15) and 1.19 (0.66-2.15), respectively; fully adjusted]. In participants with detectable concentrations (n = 523), (natural log) serum K1 was higher in the Chinese Americans compared with whites, African Americans, and Hispanics (geometric mean ± SEM = 2.2 ± 0.1 nmol/L vs. 1.2 ± 0.1 nmol/L, 1.5 ± 0.1 nmol/L, and 1.1 ± 0.1 nmol/L, respectively, adjusted for serum TG, K1 intake, and additional covariates; all P < 0.001). These findings suggest circulating K1 differs by race and ethnicity in U.S. adults, especially among those of Chinese American descent, which merits consideration in the design and interpretation of future population-based and clinical studies of vitamin K and related diseases.     

Larger mass of high-metabolic-rate organs does not explain higher resting energy expenditure in children

BACKGROUND: Children have a high resting energy expenditure (REE) relative to their body weight. The decline in REE during growth may be due to changes in body composition or to changes in the metabolic rate of individual organs and tissues. OBJECTIVES: The goals were to quantify body-composition components in children at the organ-tissue level in vivo and to determine whether the observed masses 1) account for the elevated REE in children and 2) account, when combined with specific organ-tissue metabolic constants, for children's REE. DESIGN: This was a cross-sectional evaluation of 15 children (aged 9.3 +/- 1.7 y) and 13 young adults (aged 26.0 +/- 1.8 y) with body mass indexes (in kg/m(2)) < 30. Magnetic resonance imaging-derived in vivo measures of brain, liver, kidney, heart, skeletal muscle, and adipose tissue were acquired. REE was measured by indirect calorimetry (REE(m)). Previously published organ-tissue metabolic rate constants were used to calculate whole-body REE (REE(c)). RESULTS: The proportion of adipose-tissue-free mass as liver (3.7 +/- 0.5% compared with 3.1 +/- 0.5%; P < 0.01) and brain (6.2 +/- 1.2% compared with 3.3 +/- 0.9%; P < 0.001) was significantly greater in children than in young adults. The addition of brain and liver mass significantly improved the model but did not eliminate the role of age. REE(c) with published metabolic coefficients underestimated REE(m) (REE(c) = 3869 +/- 615 kJ/d; REE(m) = 5119 +/- 769 kJ/d; P < 0.001) in children. CONCLUSION: The decline in REE during growth is likely due to both a decrease in the proportion of some of the more metabolically active organs and tissues and changes in the metabolic rate of individual organs and tissues.     

Sex differences in resting energy expenditure and their relation to insulin resistance in children (EarlyBird 13)

BACKGROUND: Insulin resistance is believed to be the process underlying type 2 diabetes and premature cardiovascular disease. We have established that a relation between body mass and insulin resistance calculated by homeostasis model assessment (HOMA-IR) exists by 5 y of age in contemporary UK children. Resting energy expenditure (REE) is variable among individuals and is one of many factors controlling body mass. OBJECTIVE: The objective was to investigate the relations between REE, body mass, and HOMA-IR in young children. DESIGN: EarlyBird is a nonintervention prospective cohort study of 307 healthy 5-y-olds that asks the question: Which children develop insulin resistance and why? REE by indirect calorimetry and HOMA-IR were measured in addition to total body mass, fat-free mass (FFM) by bioimpedance, body mass index (BMI; in kg/m(2)), and skinfold thickness when the mean age of the cohort was 5.9 +/- 0.2 y. RESULTS: Whereas the BMI of the boys was lower than that of the girls (x +/- SD: boys, 15.9 +/- 1.9; girls, 16.5 +/- 1.9; P = 0.03), their REE was higher by 6% (x +/- SD: 4724 +/- 615 compared with 4469 +/- 531 kJ/d; P = 0.002). This difference persisted after adjustment for FFM and other anthropometric variables (P = 0.04). In boys, there was a weak, although significant, inverse correlation between REE and HOMA-IR, independent of fat mass and FFM (boys: r = -0.21, P = 0.03; girls: r = 0.12, P = 0.34). CONCLUSION: There is a sex difference in REE at 6 y of age that cannot be explained by body composition. The difference appears to be intrinsic, and its contribution to sex differences in adiposity and HOMA-IR in children merits further exploration.     

Resting Energy Expenditure and Related Factors in 6- to 9-Year-Old Southern African Children of Diverse Population Groups

Lower resting energy expenditure (REE) may partially explain the disproportionate prevalence of overweight/obesity among black African women. As no previous studies have investigated the REE of Southern African (South. Afr.) children, we aimed to determine, by sex and population group, the REE of 6- to 9-year-old urban school children. In a cross-sectional study with quota sampling, REE was measured with indirect calorimetry (IC). Confounders considered were: body composition (BC) (fat-free mass (FFM), FFM index, fat mass (FM), FM index), assessed using multifrequency bioelectrical impedance analysis, and physical activity (PA) measured with a pedometer. Multivariate regression was used to calculate REE adjusted for phenotypes (BC, z-scores of weight-for-age, height-for-age, body mass index-for-age) and PA. Sex and population differences in REE were determined with two-way ANOVA. Ninety-four healthy children (59.6% girls; 52.1% black) with similar socioeconomic status and PA opportunities participated. Despite BC variations, sex differences in REE were not significant (41 kcal/day; P = 0.375). The REE of black participants was lower than of white (146 kcal/day; P = 0.002). When adjusted for FFM and HFA z-score, the differences in REE declined but remained clinically meaningful at 91 kcal/day (P = 0.039) and 82 kcal/day (P = 0.108), respectively. We recommend the development of population-specific REE prediction equations for South. Afr. children.     

Social context as an explanation for race disparities in hypertension: findings from the Exploring Health Disparities in Integrated Communities (EHDIC) Study

Disparities in hypertension between African Americans and non-Hispanic whites have been well-documented, yet an explanation for this persistent disparity remains elusive. Since African Americans and non-Hispanic white Americans tend to live in very different social environments, it is not known whether race disparities in hypertension would persist if non-Hispanic whites and African Americans were exposed to similar social environments. We compared data from the Exploring Health Disparities in Integrated Communities-SWB (EHDIC-SWB) Study with the National Health and Nutrition Examination Survey (NHANES) 1999-2004 to determine if race disparities in hypertension in the USA were attenuated in EHDIC-SWB, which is based in a racially integrated community without race differences in income. Hypertension was defined as systolic blood pressure (BP) > or = 140 mmHg (millimeters of mercury) and/or diastolic BP > or = 90 mmHg or respondent's report of taking antihypertensive medications. Of the 1408 study participants, 835 (59.3%) were African American, 628 (44.6%) were men, and the mean age was 40.6 years. After adjustment for potential confounders, various analytic models from EHDIC-SWB and NHANES 1999-2004 data, we found the race odds ratio was between 29.0% and 34% smaller in the EHDIC-SWB sample. We conclude that social and environmental exposures explained a substantial proportion of the race difference in hypertension.     

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

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

Comparability of resting energy expenditure in Nigerians and U.S. blacks

OBJECTIVE: To determine the influence of environmental factors on resting energy expenditure (REE) and its relationship to adiposity in two populations of West African origin, Nigerians and U.S. blacks. RESEARCH METHODS AND PROCEDURES: REE and body composition were measured in a cross-sectional sample of 89 Nigerian adults (39 women and 50 men), and 181 U.S. black adults (117 women and 65 men). Both groups represent randomly selected population samples. REE was measured by indirect calorimetry after an overnight fast in both sites using the same instrument. Body composition was estimated using bioelectrical impedance analysis (BIA) in 72 Nigerians and 156 U.S. participants. Multivariate regression analysis was used to determine the significant predictors of REE. The analyses were repeated in a set of 17 Nigerians and 28 U.S. blacks in whom body composition was measured using deuterium dilution. RESULTS: U.S. black adults were significantly heavier and had both more fat-free mass (FFM) and body fat than Nigerians. FFM was the only significant determinant of REE in both population groups, whether body composition was measured using BIA or deuterium dilution. The relationship between REE and body composition did not differ by site. There was no relationship between REE and adiposity. DISCUSSION: Differences in current environmental settings did not impact REE. The differences observed in mean levels of body fat between Nigerians and U.S. blacks were not the result of differences in REE adjusted for body composition.     

The Role of Social Context in Racial Disparities in Self-Rated Health

Race disparities in self-rated health in the USA are well-documented, such that African Americans rate their health more poorly than whites. However, after adjusting for health status, socioeconomic status (SES), and health behaviors, residual race differences are observed. This suggests the importance of unmeasured variables. Because African Americans and whites tend to live in differing social contexts, it is possible that accounting for social and environmental conditions may reduce racial disparities in self-rated health. Differences in self-rated health among whites and African Americans were assessed in a low-income, urban integrated community (Exploring Health Disparities in Integrated Communities (EHDIC)) and compared with a national sample (National Health Interview Survey (NHIS)). Controlling for demographics, SES, health insurance, status, and behaviors, African Americans in NHIS had higher odds of reporting fair or poor health (odds ratio [OR] = 1.40, 95% confidence interval [CI] = 1.18–1.66) than whites. In EHDIC, there was no race difference in self-rated health (OR = 0.83, 95% CI = 0.63–1.11). These results demonstrate the importance of social context in understanding race disparities in self-rated health.     

The Contribution of Social and Environmental Factors to Race Differences in Dental Services Use

Dental services use is a public health issue that varies by race. African Americans are less likely than whites to make use of these services. While several explanations exist, little is known about the role of segregation in understanding this race difference. Most research does not account for the confounding of race, socioeconomic status, and segregation. Using cross-sectional data from the Exploring Health Disparities in Integrated Communities Study, we examined the relationship between race and dental services use. Our primary outcome of interest was dental services use within 2 years. Our main independent variable was self-identified race. Of the 1408 study participants, 59.3 % were African American. More African Americans used dental services within 2 years than whites. After adjusting for age, gender, marital status, income, education, insurance, self-rated health, and number of comorbidities, African Americans had greater odds of having used services (odds ratio = 1.48, 95 % confidence interval 1.16, 1.89) within 2 years. Within this low-income racially integrated sample, African Americans participated in dental services more than whites. Place of living is an important factor to consider when seeking to understand race differences in dental service use.     

The relationship between lipids/lipoproteins and atherosclerosis in African Americans and whites: the Atherosclerosis Risk in Communities Study

PURPOSE: The relationships between lipids/lipoproteins and atherosclerosis were determined in African Americans and whites to assess the consistency of the relationship between these two groups. Differences could suggest varying biological, environmental, or life-style cofactors influencing development of atherosclerosis. METHODS: In the Atherosclerosis Risk in Communities Study, 2966 African Americans and 9399 whites had determinations of LDL, HDL, HDL2, and HDL3 cholesterol, triglycerides, apolipoprotein A1 and B, and lipoprotein (a). Carotid intimal-medial thickening (IMT) was measured using B-mode ultrasound imaging. RESULTS: The associations, using linear regression, between carotid IMT and LDL cholesterol, HDL cholesterol, and other lipid measurements were significantly weaker in African Americans than whites. Averaging men and women, a 1.034 mmol/L (40 mg/dl) difference in LDL cholesterol was associated with a 0.028 mm IMT difference in whites but a 0.019 difference in African Americans. Similarly, for HDL cholesterol, a 0.44 mmol/L (17 mg/dl) difference is associated wth 0.026 mm difference in carotid IMT in whites and 0.011 mm difference in African Americans. The associations are much weaker in African Americans than whites at the bifurcation and internal carotid, the carotid sites most prone to atherosclerosis. Analysis was done stratifying for risk factors that differ between African Americans and whites, but within most, the relationships remained substantially weaker in African Americans. CONCLUSIONS: We have observed a statistically significant difference in the association between many lipids/lipoproteins and carotid IMT between African Americans and whites. Analysis of many potential cofactors have not provided an explanation for the weaker association. Although possible differences in prior levels of these lipids may provide one explanation for the finding, these results need confirmation in other studies.     

Race and sex differences in the use of cardiac procedures for patients with ischemic heart disease in Maryland

This study analyzes administrative data from the Maryland Health Services Cost Review Commission to compare differences by race and sex in the use of cardiac procedures performed in hospitals in Maryland. African Americans discharged from Maryland hospitals were less likely than whites to have received cardiac procedures after controlling for age, insurance status, and the number of comorbidities (e.g., hypertension and diabetes). Overall, the general pattern of care suggests that African American women may receive high-technology cardiac treatment significantly less often than all other race and sex categories.     

Comparison of regional fat distribution and health risk factors in middle-aged white and African American women: The Healthy Transitions Study

OBJECTIVE: Both ethnicity and menopause appear to influence intra-abdominal fat distribution. This study evaluated intra-abdominal fat distribution and obesity-related health risks in perimenopausal white and African American women. RESEARCH METHODS AND PROCEDURES: Baseline data from a longitudinal study of changes in body composition and energy balance during menopause are reported. Healthy women (55 African Americans and 103 whites) who were on no medication and had at least five menstrual cycles in the previous 6 months were recruited. Body composition was assessed by DXA, and visceral adipose tissue (VAT) and subcutaneous adipose tissue (SAT) were assessed by computed tomography scan. SAT was divided into deep and superficial layers demarcated by the fascia superficialis. RESULTS: African American women were slightly younger (46.7 +/- 0.2 vs. 47.7 +/- 0.2 years, p = 0.002) and fatter (42.4% +/- 1.0% vs. 39.4% +/- 0.8% body fat, p = 0.02) than white women. In unadjusted data, African Americans had significantly more total abdominal fat and total, deep, and superficial SAT than whites. After adjustment for percent body fat and age, only total and superficial SAT remained significantly higher in African Americans. VAT, although slightly less in African American women, did not differ significantly by race. In multiple regression analysis, VAT was the strongest predictor of serum lipids, glucose, and insulin in women of both races, although superficial SAT was significantly associated with fasting glucose in whites. CONCLUSIONS: Middle-aged African American women have larger SAT depots, adjusted for total body fatness, but do not differ from white women with regard to VAT. The complexity of the relationship between abdominal fat and metabolic risk is increased by ethnic differences in such associations.     

Evaluating Race/Ethnicity in Moderating Baseline Cardiometabolic Risk and Body Composition Changes in North Carolina First-Year College Women

The roles of race/ethnicity and geographical region in the context of first-year college weight gain remain largely under-examined. The present study evaluated whether race/ethnicity: (1) at baseline was associated with greater representation in cardiometabolic health risk categories for body mass index, percent body fat, waist circumference, and waist-to-hip ratio in the full sample of 54 Black/African American and 80 White/European American first-year female undergraduates attending a North Carolina state university; and (2) moderated body composition changes between the beginning of the fall and spring semesters among the 83 participants who completed baseline and follow-up visits (N = 39 Black/African Americans). More Black/African Americans than White/European Americans had percent body fat values ≥32% at baseline; a greater proportion of White/European Americans than Black/African Americans had a waist-to-hip ratio >0.80. Among those who completed baseline and follow-up visits, White/European Americans had higher waist-to-hip ratios (unadjusted: p <0.01, adjusted for family income: p < 0.01) and waist circumferences (adjusted for family income: p < 0.05) at both time points. No strong moderating effects of race/ethnicity were detected. Preliminary results suggested that greater consideration of racial/ethnic indicators and potential regional variation in these biometric attributes among first-year college students is warranted.