Resting Energy Expenditure in Obese African American and Caucasian Women

The prevalence of obesity among African American women approaches 50% and greatly exceeds rates for Caucasian women. In addition, black women lose less weight than white during obesity treatment and gain more weight when untreated. This study assessed resting energy expenditure (REE) and body composition in obese white (n=122) and black (n=44) women to explore the relationship between biological variables and these observed differences. REE and body composition were assessed by indirect calorimetry and densitometry, respectively, before weight loss. REE was significantly lower in black subjects (1637.6 ± 236.9 kcal/d) than in white (1731.4 ± 262.0) (p=0.04). REE remained significantly lower in blacks than whites after adjusting for body weight (p=0.02). REE, adjusted for fat-free mass, was also significantly lower in blacks than whites (p<0.0001), although the overestimation of fat-free mass by densitometry in blacks may have contributed to this finding. There were no differences between the groups in respiratory quotient. These results suggest that a decreased REE may exist in obese black women, and it may be related to the observed differences between black and white women in the prevalence of obesity and in the response to weight loss treatment. These crosssectional findings await confirmation in longitudinal studies.     

Energy Intake and Physical Activity in Pima Indians: Comparison with Energy Expenditure Measured by Doubly-Labeled Water

To test the validity of survey techniques for measuring diet and activity patterns of Pima Indians, sequential 24-hour recalls, a food frequency ques tionnaire (FFQ), and an activity questionnaire were compared to free-living energy expenditure. Total energy expenditure (TEE) measured by doubly labeled water was 13.27 ± 2.95 MJ/d for the 12 males (mean±SD: 35 ± 14 yr; 97 ± 35 kg; 32 + 9% body fat) and 11.67 ± 1.85 MJ/d for the 9 females (31 ± 13 yr; 106 ± 32 kg; 49 ± 6% body fat). Energy intake assessed by 24-hour recall was 13.59 ± 7.81 MJ/d for men and 9.29 ± 2.77 MJ/d for women, compared to 12.84 ± 2.85 and 9.40 ± 2.61 MJ/d for men and women, respectively, by FFQ. Both dietary methods indicated significant underreporting by women when compared to TEE. Energy intake assessed by FFQ was significantly correlated with TEE (r=0.48, p=0.03). This was true with 24-hour recall energy intake only when data from two extremely large alcohol consumers were eliminated (r=0.64, p=0.03, N=19). Although a low level of activity was apparent, the activity questionnaire produced significant correlations with measurements of energy expenditure and therefore represents an important tool for examining the relationship between physical activity and diseases.     

Racial Differences in Selection of Ideal Body Size by Adolescent Females

Cultural differences may partially account for the fact that more black women than white women are overweight in the United States. This study measured perceptions of ideal body size among 93 black and 80 white females, 14–17 years old, who were randomly selected from three public high schools in a southeastern state. The subjects' height and weight were measured along with their estimates of their mother's body size, weight control attitudes, and demographic variables . Blacks preferred a significantly larger body sue than whites when asked to select ideal body size (p=0.045). Subjects who estimated their mother's size to be larger, also selected a larger ideal body size (p=.047). Those who perceived themselves as too fat were more likely to skip meals to help control their weight, compared with those who perceived themselves as normal or too thin (p=.003). Approximately 30% of the sample was overweight or obese. There were not significant racial differences in weight or BMI . These results suggest that overweight is more acceptable among black females than among white females and may help explain why more black females are obese .     

Ethnic Differences in the Responsiveness of Adipocyte Lipolytic Activity to Insulin

Objective: The goal of this study was to quantify differences in lipid metabolism and insulin sensitivity in black and white subjects to explain ethnic clinicopathological differences in type 2 diabetes. Research Methods and Procedures: The in vitro lipolytic activity of adipocytes isolated from obese black and white women was measured in the presence of insulin and isoproterenol. Insulin resistance was assessed in vivo using the euglycemic hyperinsulinemic clamp technique. Results: Fasting plasma levels of insulin and nonesterified fatty acid (NEFA) in black and white women were 67 ± 5 pM vs. 152 ± 20 pM (p < 0.01) and 863 ± 93 μM vs. 412 ± 34 μM (p < 0.01), respectively. Euglycemic hyperinsulinemic clamp studies showed that obese black subjects were more insulin‐resistant than their white counterparts (glucose infusion rates: 1.3 ± 0.2 vs. 2.2 ± 0.3 mg/kg per min; p < 0.05). Isolated adipocytes from white women were more responsive to insulin than those from black women with 0.7 nM insulin causing a 55 ± 4% inhibition of isoproterenol‐stimulated lipolysis compared with 27 ± 10% in black women (p < 0.05). Discussion: The low responsiveness of adipocyte lipolytic activity to insulin in black women in the presence of a relative insulinopenia may account for the high plasma NEFA levels seen in these women, which may, in turn, account for their higher in vivo insulin resistance. High NEFA levels may also contribute to the low insulin secretory activity observed in the obese black females. These data suggest that the pathogenesis of insulin resistance and type 2 diabetes within the black obese community is strongly influenced by their adipocyte metabolism.     

Can Ethnic Differences in Men's Preferences for Women's Body Shapes Contribute to Ethnic Differences in Female Adiposity?

In the United States, obesity is more common among black and Hispanic than white women. One putative cause of this difference is different cultural norms for attractiveness. Two studies assessed ethnic differences in men's perceptions of the attractiveness of females of varying sizes. In the fmst, 108 men recruited on the New York subway were shown sets of silhouettes depicting female bodies varying in fatness and were asked to pick the silhouette they found most attractive. They were also asked to indicate the thinnest and fattest figures they would consider dating. A measure of “latitude of acceptance” was computed as the difference between the thinnest and fattest figures considered. Results indicated no relationship between ethnicity and preference (F = 1.383, p =.257) or “latitude” (F =.102, p =.903). In Study 2, “personal advertisements” placed by 373 black, 1915 white, 110 Hispanic, and 30 Asian men from 35 newspapers and magazines were coded as: 1) thinness preferred; 2) no information on weight preference; 3) fatness preferred; or 4) states weight or looks unimportant. Results indicated a statistically significant but small association between ethnicity and preference (χ² = 49.55, df=9, p<.00001). Relative to white and Asian men, black and Hispanic men more frequently requested fat women, Hispanic men less frequently requested thin women, and black men more frequently stated that looks or weight did not matter. Ethnicity explained only 2.1% of the variance in preference. Thus, it seems unlikely that ethnic differences in men's preferences for women's body shapes contribute substantially to ethnic differences in female adiposity.     

Ethnic Differences in Correlates of Obesity between Latin‐American and Black Women

Objective: To date, no studies have examined dietary intake, physical activity, and body image in a large sample of Latin‐American and black women recruited using the same methodology. The aim of this study was to examine three potential correlates of obesity (dietary intake, body image, and physical activity) in a large sample of Latin‐American and black women across the weight spectrum. Research Methods and Procedures: Participants were black (n = 271) and Latin‐American (n = 234) adult women who completed a 24‐hour dietary recall and physical activity and body image questionnaires. Results: After controlling for BMI, education, marital status, and number of children, black women consumed more kilocalories, dietary fat (grams), and percent calories from fat than Latin‐American women, who consumed more carbohydrates (grams) and dietary fiber (total and soluble). Black women engaged in more sedentary behavior than Latin‐American women. Although Latin‐American women weighed less than black women, they perceived their current body image as heavier and reported greater body image dissatisfaction than black women. Black women also reported a higher ideal body image than Latin‐American women. Discussion: The combined effect of a diet higher in calories and fat, increased sedentary behavior, and more accepting body image could account for higher rates of obesity among black women. Future studies should further explore cultural attitudes and beliefs related to weight that could provide information for the development of culturally competent obesity interventions.     

Determination of copper and zinc levels in human hair

The Cu and Zn levels of both 607 men (1–85 y old) and 649 women (1–92 y old) were determined by atomic absorption spectrometry. Sex does not influence Cu (14.89±0.89 μg/g and 15.26±0.79 μg/g hair for males and females, respectively) and Zn contents (200.97±9.68 μg/g for men and 209.81±9.49 μg/g hair for women). Age influences Cu and Zn concentrations, but only significantly in females: Cu levels decrease over 60 y of age; whereas Zn levels increase significantly from age groups 2–5 to 20–40 years. Hair color influences Cu concentrations in both males and females. In males, white hair containes less Cu than black hair; in females, white hair's Cu levels are significantly lower than those of dark blond, red, light brown, and brown hair. There are no significant differences in Zn concentrations with respect to different hair colors, in either males or females.     

Physical Activity in Confined Conditions as an Indicator of Free‐Living Physical Activity

Objective: The main determinants of daily energy expenditure are body size and physical activity. Activity energy expenditure is the most variable component of total energy expenditure. It was assessed whether the physical activity level in confined conditions is an indicator of free‐living physical activity. Research Methods and Procedures: Activity energy expenditure was measured over 1 day in a confined environment of a respiration chamber (floor space, 7.0 m²), where activities were restricted to low‐intensity activities of daily living, and over 2 weeks in a free‐living environment using doubly labeled water. Subjects were 16 women and 29 men (age, 31 ± 10 years; BMI, 24.2 ± 2.7 kg/m²). Results: The free‐living activity level of the subjects, as a multiple of resting energy expenditure, was 1.76 ± 0.13. Activity energy expenditure in the chamber was 47 ± 13% of the value in daily life, and the two values were correlated (r = 0.50, p < 0.001; partial correlation corrected for age, gender, and BMI: 0.40, p < 0.01). The chamber value explained 25% of the total variance in free‐living activity energy expenditure. Discussion: The activity level of a subject under sedentary conditions is an indicator of activity energy expenditure in daily life, showing the importance of nonexercise activity for daily energy expenditure.     

Education,Health Behaviors,and the Black-White Difference in Waist-to-Hip Ratio

Few epidemiologic studies have investigated the impact of body mass index, low educational attainment, cigarette smoking, and physical activity on the considerable black-white difference in waist-to-hip ratio. These relationships were assessed with multi-variable linear regression among 3,094 adults (24% black) who were examined in 1987 in South Carolina. The unadjusted mean waist-to-hip ratio was lower for black men than for white men (-0.03 units) and higher for black women than for white women (+0.03 units). After adjustment for age, body mass index, education, smoking, and physical activity, the black-white difference in mean waist-to-hip ratio was ?0.02 units (p<0.001) among men and +0.01 units (p<0.01) among women. Although differing distributions of age, body mass index, and educational attainment accounted for a 59% reduction in the black-white difference among women, these factors did not explain the difference among men. Thus, these results suggest that other environmental or biologic factors may also play an important role in the marked variation in body fat distribution between the two ethnic groups. The results also support the importance of the prevention of cigarette smoking and overweight in potentially preventing abdominal obesity in both black adults and white adults.     

Relationship between the percentage of body fat and surrogate indices of fatness in male and female Polish active and sedentary students

Background

Limited data have indicated that body mass index (BMI), waist circumference (WC), waist to hip ratio (WHR) and waist to height ratio (WHtR) of athletes and young adults provide misleading results concerning body fat content. This study was aimed at the evaluation of the relationship between different surrogate indices of fatness (BMI, WC, WHR, WHtR and body adiposity index (BAI)) with the percentage of body fat in Polish students with respect to their sex and physical activity.

Methods

A total of 272 students volunteered to participate in the study. Of these students, 177 physical education students (90 males and 87 females) were accepted as active (physical activity of 7 to 9 hours/week); and 95 students of other specializations (49 males and 46 females) were accepted as sedentary (physical activity of 1.5 hours/week). Weight, height, waist and hip circumferences were measured, and BMI, WHR, WHtR and BAI were calculated. Body fat percentage was assessed using four skinfold measurements.

Results

Classification of fatness according to the BMI and the percentage of body fat have indicated that BMI overestimates fatness in lean subjects (active men and women, sedentary men), but underestimates body fat in obese subjects (sedentary women). In all groups, BMI, WHR, WHtR and BAI were significantly correlated with the percentage of body fat (with the exception of WHR and hip circumference in active and sedentary women, respectively). However, coefficients of determination not exceeding 50% and Lin’s concordance correlation coefficients lower than 0.9 indicated no relationship between measured and calculated body fat.

Conclusion

The findings in the present study support the concept that irrespective of physical activity and sex none of the calculated indices of fatness are useful in the determination of body fat in young adults. Thus, it seems that easily calculated indices may contribute to distorted body image and unhealthy dietary habits observed in many young adults in Western countries, but also in female athletes.     

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.     

Comparative analysis of gonadal and adrenal activity in the black and white rhinoceros in North America by noninvasive endocrine monitoring

Patterns of fecal reproductive steroid metabolites and adrenal corticoids were characterized for 12‐ to 24‐month periods in black (n = 10 male, 16 female) and white (n = 6 male, 13 female) rhinoceroses at 14 institutions. All black rhinoceros females exhibited at least some ovarian cyclicity on the basis of fecal progestogen analysis (range, 2–12 cycles/yr). However, cycles often were erratic, with many being shorter (<20 days; 18% of cycles) or longer (>32 days; 21%) than the average of 26.8 ± 0.5 days (n = 104 cycles). Five females exhibited periods of acyclicity of 2–10‐month duration that were unrelated to season. One complete and seven partial pregnancies were evaluated in the black rhinoceros. Fecal progestogens increased over luteal phase concentrations after 3 months of gestation. Females resumed cyclicity within 3 months postpartum, before calves were weaned (n = 5). Approximately half of white rhinoceros females (6 of 13) showed no evidence of ovarian cyclicity. Of the cycles observed, 5 were “short” (32.8 ± 1.2 days) and 24 were “long” (70.1 ± 1.6 days). Only two females cycled continuously throughout the study. One had both long (n = 9) and short (n = 2) cycles, whereas the other exhibited long cycles only (n = 5). Fecal estrogen excretion was variable, and profiles were not useful for characterizing follicular activity or diagnosing pregnancy in either species. Males of both species showed no evidence of seasonality on the basis of fecal androgen profiles. Androgen metabolite concentrations were higher (P < 0.05) in the black (27.6 ± 6.9 ng/g) than in the white (16.8 ± 3.1 ng/g) rhinoceros. An adrenocorticotropin hormone challenge in four black rhinoceros males demonstrated that the clearance rate of corticoid metabolites into feces was ～24 hours. Fecal corticoid concentrations did not differ between males and females, but overall means were higher in the black (41.8 ± 3.1 ng/g) than in the white (31.2 ± 1.7 ng/g) rhinoceros. In summary, fecal steroid analysis identified a number of differences in hormonal secretory dynamics between the black and white rhinoceros that may be related to differences in reproductive rates in captivity. Most black rhinoceros females exhibited some cyclic ovarian activity. In contrast, few white rhinoceroses demonstrated evidence of regular estrous cyclicity, and those females that were active had comparatively long cycles. Results also suggest that fecal corticoid concentrations reflect adrenal activity and may be species specific. Continued studies are needed to determine whether fecal corticoid measurements will be useful for understanding the cause of inconsistent gonadal activity in these two species. Because all but three (15.8%) of the white rhinoceroses evaluated in this study were less than 20 years of age compared to 73.1% (19 of 26) of the black rhinoceroses, the impact of age on reproductive and adrenal activity also needs to be evaluated further. Zoo Biol 20:463–486, 2001. © 2002 Wiley‐Liss, Inc.     

Racial Differences in Metabolic Predictors of Obesity among Postmenopausal Women

NICKLAS, BARBARA S., DORA M. BERMAN, DAWN C. DAVIS, C. LYNNE DOBROVOLNY, AND KAREN E. DENNIS. Racial differences in metabolic predictors of obesity among postmenopausal women. Ober Res. Objective: This study determined whether there are racial differences in resting metabolic rate (RMR), fat oxidation, and maximal oxygen consumption (VO,max) in obese [body mass index (BMI = 34±2 kg/m²)], postmenopausal (58±2 years) women. Research Methods and Procedures: Twenty black and 20 white women were matched for fat mass and lean mass (LM), as determined by dual energy X-ray absorptiometry. RMR and fat oxidation were measured by indirect calorimetry in the early morning after a 12-hour fast using the ventilated hood technique. VO₂max was measured on a treadmill during a progressive exercise test to voluntary exhaustion. Results: RMR, adjusted for differences in LM, was 5% higher in white than black women (1566±27 and 1490±26 kcal/day, respectively; p<0. 05); and fat oxidation rate was 17% higher in white than black women (87±4 and 72±3 g/day, respectively; p<0. 01). VO₂max (L/minute) was 150 mL per minute (8%) higher (p<0. 05) in white than black women. VO₂max correlated with LM in black (r = 0. 44, p = 0. 05) and white (r=0. 53, p<0. 05) women, but the intercept of the regression line was higher in white than black women (p<0. 05), with no significant difference in slopes. In a multiple regression model including race, body weight, LM, and age, LM was the only independent predictor of RMR (r² = 0. 46, p<0. 0001), whereas race was the only independent predictor of fat oxidation (r² = 0. 18,p<0. 05). The best predictors of VO,max were LM (r² = 0. 22, p<0. 05) and race (cumulative r² = 0. 30, p<0. 05). Discussion: These results show there are racial differences in metabolic predictors of obesity. Determination of whether these ethnic differences lead to, or are an effect of, obesity status or other lifestyle factors requires further study.     

Differences in Resting Metabolic Rate between White and African‐American Young Adults

Objective: A reported lower resting metabolic rate (RMR) in African‐American women than in white women could explain the higher prevalence of obesity in the former group. Little information is available on RMR in African‐American men. Research Methods and Procedures: We assessed RMR by indirect calorimetry and body composition by DXA in 395 adults ages 28 to 40 years (100 African‐American men, 95 white men, 94 African‐American women, and 106 white women), recruited from participants in the Coronary Artery Risk Development in Young Adults (CARDIA), Birmingham, Alabama, and Oakland, California, field centers. Results: Using linear models, fat‐free mass, fat mass, visceral fat, and age were significantly related to RMR, but the usual level of physical activity was not. After adjustment for these variables, mean RMR was significantly higher in whites (1665.07 ± 10.78 kcal/d) than in African Americans (1585.05 ± 11.02 kcal/d) by 80 ± 16 kcal/d (p < 0.0001). The ethnic × gender interaction was not significant (p = 0.9512), indicating that the difference in RMR between African‐American and white subjects was similar for men and women. Discussion: RMR is ～5% higher in white than in African‐American participants in CARDIA. The difference was the same for men and women and for lean and obese individuals. The prevalence of obesity is not higher in African‐American men than in white men. Because of these reasons, we believe that RMR differences are unlikely to be a primary explanation for why African‐American women are more prone to obesity than white women.     

The influence of short-term sedentary behavior on circadian rhythm of heart rate and heart rate variability

The notion that sedentary behavior is harmful to human health is widespread. Little is known about the short term influence of sedentary behavior on heart rate (HR) and heart rate variability (HRV) circadian rhythms. Therefore the purpose of the present study was to examine the influence of short term sedentary behavior on the circadian rhythms of HR and HRV using cosine periodic regression analysis. Sixteen healthy young students were included in a randomized crossover study. All subjects underwent 24-h ECG Holter monitoring in two different states of physical activity, an active condition (more than 15,000 steps per day) and a sedentary condition (less than 1,000 steps per day). Hourly mean values were calculated for HR and HRV, and then were evaluated using cosine periodic regression analysis. The circadian rhythm parameters, amplitude, mesor, and acrophase for HR and HRV variables were obtained. As a result, the significance of the circadian rhythm was confirmed for all variables in each condition. The measure of fit R2 value was decreased in sedentary condition. The amplitude of the sedentary condition was significantly smaller than that of the active condition with respect to HR (7.94 ± 1.91 bpm vs. 15.4 ± 3.93 bpm, p < 0.001), natural log of the high frequency measurement (lnHF) (0.38 ± 0.21 ms2 vs. 0.80 ± 0.28 ms2, p < 0.001), and low frequency/high frequency ratio (LF/HF) (0.75 ± 0.54 vs. 1.24 ± 0.69, p = 0.008). We found that sedentary behavior not only significantly lowered the amplitude of HR and HRV variables, but also might have led to weakness of the circadian rhythm of the HR and HRV variables.     

Differential Effects of Abdominal Adipose Tissue Distribution on Insulin Sensitivity in Black and White South African Women

Black South African women are more insulin resistant than BMI‐matched white women. The objective of the study was to characterize the determinants of insulin sensitivity in black and white South African women matched for BMI. A total of 57 normal‐weight (BMI 18–25 kg/m²) and obese (BMI > 30 kg/m²) black and white premenopausal South African women underwent the following measurements: body composition (dual‐energy X‐ray absorptiometry), body fat distribution (computerized tomography (CT)), insulin sensitivity (S_I, frequently sampled intravenous glucose tolerance test), dietary intake (food frequency questionnaire), physical activity (Global Physical Activity Questionnaire), and socioeconomic status (SES, demographic questionnaire). Black women were less insulin sensitive (4.4 ± 0.8 vs. 9.5 ± 0.8 and 3.0 ± 0.8 vs. 6.0 ± 0.8 × 10^?5/min/(pmol/l), for normal‐weight and obese women, respectively, P < 0.001), but had less visceral adipose tissue (VAT) (P = 0.051), more abdominal superficial subcutaneous adipose tissue (SAT) (P = 0.003), lower SES (P < 0.001), and higher dietary fat intake (P = 0.001) than white women matched for BMI. S_I correlated with deep and superficial SAT in both black (R = ?0.594, P = 0.002 and R = 0.495, P = 0.012) and white women (R = ?0.554, P = 0.005 and R = ?0.546, P = 0.004), but with VAT in white women only (R = ?0.534, P = 0.005). In conclusion, body fat distribution is differentially associated with insulin sensitivity in black and white women. Therefore, the different abdominal fat depots may have varying metabolic consequences in women of different ethnic origins.     

Contributing factors and variability of energy expenditure in non-obese, obese, and post-obese adolescents

Energy expenditure (EE) is a major determinant of energy balance and body composition. The objectives of this paper were to review the contributing factors of the main components of daily EE (DEE) and the inter-individual variability in these components in non-obese (NOb), obese (Ob), and post-obese (POb) adolescents. Body composition especially fat-free mass (FFM), is the major determinant of the basal metabolic rate which contributes 50-70% of DEE, whereas fat mass (FM) is a significant factor only in obese subjects. Physical activity is the second main variation factor of DEE, whereas growth, the thermic effect of food, and thermoregulation are generally of marginal importance. The energy costs and EE associated with various sedentary and physical activities were assessed in NOb, Ob and POb subjects both in standardised and in free-living conditions. The interindividual variability of DEE is high, even after adjustment for body composition, mainly because of great differences in time devoted to the various physical activities. DEE and EE associated with sleep and sedentary activities are significantly higher in Ob than in NOb, but not after adjustment for FFM. On the contrary, EE associated with physical activities is not significantly different between Ob and NOb adolescents, but 61% lower in Ob subjects after adjustment for body composition. Multidisciplinary weight-reduction programmes including moderate energy restriction and physical training result in great FM loss, maintenance of FFM, improvement of physical capacities, but reductions in organ and tissue metabolic rate and in EE associated with the various sedentary and physical activities, which may favour body weight regain in the less active POb subjects.     

Measurement of Physical Activity Among Black and White Obese Women

Several recent self-reported surveys have suggested that African-American women may engage in less leisure-time physical activity (PA) than whites. Objective measurements of PA have not been performed, however. Therefore, the purpose of this study was to compare the components of energy expenditure, including PA, between black and white obese women. Using the doubly labeled water method, total dairy energy expenditure (TDEE), basalmetabolic rate (BMR), thermic effect of a meal (TEM), and PA were measured in 14 black and 15 white moderately obese women over 2 weeks. No statistically significant differences were seen between the 2 groups in BMR, TEM or TDEE. Mean PA was significantly (p=0.05) lower among black women compared to whites when expressed as MJ. d^?1 (3.49 vs. 4.30) or kJ.kg^?1.d^?1 (37.6 vs. 47.7). Our study supports the survey differences seen in PA among black and white women.     

IAAT, catecholamines, and parity in African-American and European-American women

Objective: We have recently reported that parous European‐American (EA) women have disproportionately more intra‐abdominal adipose tissue (IAAT) than their nulliparous counterparts. Mediating mechanisms for IAAT accumulation remain unknown; however, some evidence suggests a possible catecholamine link. The objective of this study was to determine whether the IAAT‐parity relationship found in EA women exists in African‐American (AA) women and to determine whether catecholamines play a mediating role. Methods and Procedures: Subjects included 44 EA and 47 AA premenopausal women. Free‐living physical activity by doubly labeled water (activity‐related time equivalent (ARTE)), body composition (air plethysmography, computed tomography), and 24‐h fractionated urinary catecholamines were measured. Results: Repeated measures ANOVA revealed parous EA and AA women had significantly higher IAAT than their nulliparous counterparts (100.1 ± 28.5 and 76.2 ± 34.8 cm² vs. 75.9 ± 29.1 and 59.6 ± 15.0 cm²). In AA women and nulliparous women, 24‐h urinary dopamine was significantly higher (AA parous 260.8 ± 88; EA parous 197.2 ± 78.8; AA nulliparous 376.5 ± 81; EA nulliparous 289.6 ± 62). Multiple regression analysis for modeling IAAT indicated that race, parity, dopamine, ARTE, and VO_2max were all significant and independent contributors to the model (Unstandardized βs: race ?32.6 ± 7.4; parity (number of births) 10.0 ± 3.4; 24‐h urinary dopamine 0.08 ± 0.04; ARTE (min/day) ?0.09 ± 0.04; VO_2max (ml/kg/min) ?2.8 ± 1.0). Discussion: Independent of the potential confounders: age, race, percent body fat, IAAT, 24‐h fractionated urinary catecholamines, physical activity, and VO_2max, parous EA and AA women had more IAAT than their nulliparous counterparts. Of the catecholamines, dopamine was found to be significantly lower in parous women and higher in AA's. Dopamine, however, did not explain racial or parity differences in IAAT.