Obese African American Women Research Articles

Challenges in Improving Fitness: Results of a Community-Based, Randomized, Controlled Lifestyle Change Intervention

This study tested the efficacy of an 8-week culturally targeted nutrition and physical activity intervention on body composition. A randomized, attention-controlled, two-group trial was conducted in a blackowned commercial gym with a sample of 366 predominantly healthy, obese African American women. A free 1-year membership to the study site gym was provided to participants in both groups. Data were collected at baseline, 2, 6, and 12 months. Sample retention at 1 year was 71%. Between-group longitudinal analysis including only participants with complete data revealed a trend toward weight stability in the intervention group at 2 months compared with controls (+0.05 kg/m(2), p = 0.75; +0.32 kg/m(2), p = 0.08, respectively), disappearing at 12 months (+1.37 kg/m(2), p = 0.0001; +1.02 kg/m(2), p = 0.001, respectively). Within-group analysis demonstrated that intervention and control participants' fitness (1-mile run-walk) improved by 1.9 minutes (p = 0.0001) and 2.3 minutes (p = 0.0001), respectively, at 12 months. Mixed model regression analyses demonstrated a significant main effect of the intervention on fitness (p = 0.0185) and a marginally significant effect on body mass index (BMI) (p = 0.057), at 2 months, disappearing by 6 months. By 12 months, however, the controls exhibited a significant advantage in waist circumference stability compared with intervention participants (+1.1 cm, p = 0.2763; +2.1 cm, p = 0.0002, respectively). The intervention produced modest short-term improvements in body composition, but the economic incentive of a free 1-year gym membership provided to all participants was a more potent intervention than the education and social support intervention tested. However, longer-term fitness enhancement remains elusive and demands research and policy attention. These findings have policy implications in that employer-/insurer-subsidized gym memberships may require interventions targeting other levels of change (e.g., physical or social/environmental) to foster sustainable fitness improvements.

Comparison of Body Composition Methods in Obese African‐American Women

To compare the accuracy of percentage body fat (%BF) estimates between bioelectrical impedance analysis (BIA) and DXA in obese African-American women. Fifty-five obese African-American women (mean age, 45 years; mean BMI, 38; mean %BF, 48%) were studied. BF was assessed by both BIA (RJL Systems BIA 101Q; RJL Systems, Clinton Township, MI) and DXA (Hologic QDR-2000 Bone Densitometer; Hologic Inc., Bedford, MA). Generalized and ethnicity- and obese-specific equations were used to calculate %BF from the BIA. Bland-Altman analyses were used to compare the agreement between the BIA and the DXA, with the DXA serving as the criterion measure. Two of the generalized equations provided consistent estimates across the weight range in comparison with the DXA estimates, whereas most of the other equations increasingly underestimated %BF as BF increased. One of the generalized and one of the ethnicity-specific equations had mean differences that were not significantly different from the DXA value. The findings show that the Lukaski equation provided the most precise and accurate estimates of %BF in comparison with the QDR 2000 and provide preliminary support for the use of this equation for obese African-American women.

Life-Course Socioeconomic Position and Obesity in African American Women: The Pitt County Study

We studied obesity in African American women in relationship to their socioeconomic position (SEP) in childhood and adulthood. On the basis of parents' occupation, we classified 679 women in the Pitt County (North Carolina) Study into low and high childhood SEP. Women's education, occupation, employment status, and home ownership were used to classify them into low and high adulthood SEP. Four life-course SEP categories resulted: low childhood/low adulthood, low childhood/high adulthood, high childhood/low adulthood, and high childhood/high adulthood. The odds of obesity were twice as high among women from low versus high childhood SEP backgrounds, and 25% higher among women of low versus high adulthood SEP. Compared to that in women of high SEP in both childhood and adulthood, the odds of obesity doubled for low/low SEP women, were 55% higher for low/high SEP women, and were comparable for high/low SEP women. Socioeconomic deprivation in childhood was a strong predictor of adulthood obesity in this community sample of African American women. Findings are consistent with both critical period and cumulative burden models of life-course socioeconomic deprivation and long-term risk for obesity in African American women.

Life-Course Socioeconomic Position and Obesity in African American Women: The Pitt County Study

Life-Course Socioeconomic Position and Obesity in African American Women: The Pitt County Study

Differences in transport of fatty acids and expression of fatty acid transporting proteins in adipose tissue of obese black and white women

We have reported that the rate of de novo triglyceride (TG) synthesis by omental, but not subcutaneous, adipose tissue was higher in African-American women (AAW) than in Caucasian women (CAW). The purpose of this study was to explore the potential mechanisms underlying this increase. Toward that end, we determined the activities of key enzymes in the pathway of TG synthesis, the rates of uptake of fatty acids by adipocytes, mRNA and protein levels of the fatty acid-transporting proteins FAT/CD36 and FATP, and mRNA and protein levels of PPARgamma in omental fat of AAW and CAW. The results showed 1) no difference in the activity of phosphofructokinase, glycerol-3-phosphate dehydrogenase, or diacylglycerol acyltransferase; 2) a higher rate of fatty acid uptake by adipocytes of the AAW; 3) an increase in the mRNA and protein levels of CD36 and FATP4 in the fat of the AAW; and 4) an increase in the mRNA and protein levels of PPARgamma, which can stimulate the expression of CD36 and FATP. These results suggest that the increase in the transport of fatty acid, which is mediated by the overexpression of the transport proteins in the omental adipose tissue of the AAW, might contribute to the higher prevalence of obesity in AAW.

Achieving Healthy Weight in African‐American Communities: Research Perspectives and Priorities

The longstanding high burden of obesity in African-American women and the more recent, steeper than average rise in obesity prevalence among African-American children constitute a mandate for an increased focus on obesity prevention and treatment research in African-American communities. The African-American Collaborative Obesity Research Network (AACORN) was formed to stimulate and support greater participation in framing and implementing the obesity research agenda by investigators who have both social and cultural grounding in African-American life experiences and obesity-related scientific expertise. AACORN's examination of obesity research agenda issues began in 2003 in conjunction with the Think Tank on Enhancing Obesity Research at the National Heart, Lung, and Blood Institute (NHLBI). The assessment was subsequently expanded to take into account the overall NIH strategic plan for obesity research, literature reviews, and descriptions of ongoing studies. In identifying priorities, AACORN members considered the quality, quantity, focus, and contextual relevance of published research relevant to obesity prevention and treatment in African-American adults or children. Fifteen recommended research priorities are presented in five categories adapted from the NHLBI Think Tank proceedings: health effects, social and environmental context, prevention and treatment, research methods, and research training and funding. These recommendations from an African-American perspective build on and reinforce certain aspects of the NHLBI and overall NIH research agendas by providing more specific rationale and directions on areas for enhancement in the type of research being done or in the conceptualization and implementation of that research.

The interrelationship between ethnicity and obesity on obstetric outcomes

The purpose of this study was to evaluate the interrelationship between ethnicity and obesity on obstetric outcomes. This was a retrospective study examining the interaction between ethnicity and obesity for obstetric outcomes. Statistical methods included univariate and multivariate regression models. In this study population of 22,658 women, 2150 (9.4%) were obese (body mass index [BMI] >29). Obesity increased the rate of cesarean delivery, gestational diabetes, preeclampsia, and macrosomia in each ethnic group. When compared with obese white women, higher rates of cesarean delivery were noted in obese African American (odds ratio [OR] 1.50, P < .05) and Asian (OR 1.73, P < .05) women. Gestational diabetes was increased twofold in obese Latina (OR 1.94, P < .05) and Asian (OR 2.20, P < .05) women, while preeclampsia was increased only in obese Latina (1.93, P < .05) women. Obesity increases the risk of cesarean delivery, gestational diabetes, preeclampsia, and macrosomia, but this effect varies among different ethnicities. The biometrics of different ethnicities and associated obstetric outcomes needs further exploration.

Perceived body image among African Americans with type 2 diabetes

Objective To assess current, desired and best body image in the opposite sex and examine correlates of body image dissatisfaction. Methods We conducted a cross-sectional analysis at baseline of 185 (141 women, 44 men) African Americans with type 2 diabetes in Project Sugar 1, a randomized controlled trial of primary care-based interventions to improve diabetic control. Results Women had a significantly lower desired body image compared to their current body image (BMI ∼ 27.7 versus ∼35.3). Men preferred a body image for women that was similar to the body image that women desired for themselves (BMI ∼ 28.3 versus ∼27.7). Significant correlates of body image dissatisfaction included self-perception of being overweight and attempting weight-loss ( P < 0.05). Practical implications Among overweight and obese African–American women with diabetes, it is important to first address an individual's perceived body image, perceived risk of disease, desired body image, and weight-loss perceptions. In addition to the aesthetic benefits of weight-loss, there is a need to focus on the health benefits in order to intervene among African Americans with diabetes.

The Relationships Between Testosterone, Body Composition, and Insulin Resistance

Association between hyperandrogenism and insulin resistance is well recognized in women with polycystic ovary syndrome (PCOS) (1). However, earlier evidence (2) suggesting an insulin-antagonizing effect of androgens has been overshadowed by more recent studies demonstrating that antiandrogen treatment with flutamide (3) or GnRH agonists (4,5) does not alter insulin resistance in PCOS. Conflicting results have been reported in non-PCOS women, with some studies (1,6–9) suggesting that testosterone may be related to insulin resistance and others (10,11) showing no correlation. Recent data suggest that some of these discrepancies may be explained by racial disparities, since only obese African-American women exhibited a positive relationship between insulin resistance and gonadal androgens (6). Inconclusive data have also been reported in men given testosterone in replacement or supraphysiologic doses, with some studies (12) suggesting a sensitizing effect of testosterone on glucose metabolism and others (13–16) showing no effect. Nonetheless, androgens can influence body composition, which is associated with insulin sensitivity. Thus, it is conceivable that testosterone might indirectly influence insulin sensitivity via its effects on body composition. We report the results of hormonal, metabolic, and body composition studies before and 1 month and 9 months after a Leydig cell tumor removal in a postmenopausal woman. A 64-year-old gravida 7, para 7, Hispanic woman was referred for evaluation of virilization starting ∼10 years earlier and progressing over the past 3 years. Menses were regular before menopause (age 50). Diabetes was diagnosed 2 months before presentation and was well controlled by 1.5 mg glyburide daily (HbA1c 4.8%). She had a 22-year history of hypertension, treated with benazepril and amlodipine. A physical examination revealed male pattern alopecia, masculine habitus, abdominal obesity, clitoromegaly, and breast atrophy …

Use of the Weight Efficacy Lifestyle Questionnaire with African American women: Validation and extension of previous findings

While the Weight Efficacy Lifestyle Questionnaire (WEL) shows promise as a measure of self-efficacy for eating control, there is a lack of research examining the psychometric properties of this measure with ethnic minorities. The current study examined the WEL with a sample of 144 overweight and obese African American females. Analyses indicated similar self-efficacy levels compared to predominantly Caucasian samples. Supporting the validity of the WEL, participants undergoing obesity treatment demonstrated modest improvement in WEL scores, while standard care participants showed no changes in self-efficacy over time. Factor analysis indicated a four-factor structure rather than the five factors previously found. The four-factor structure accounted for 61.85% of the variance. Results indicate the WEL may be a valid measure of self-efficacy for overweight and obese African American women, although researchers should be mindful of the variation in scale properties when using the WEL with this population.

Distribution of the metabolic syndrome risk factors in obese African american women

OR-59 Key Words: Metabolic Syndrome, Obesity, African American Women

Class III obesity continues to rise in African-American women.

The Behavior Risk Factor Surveillance System (BRFSS) survey, a random telephone survey of the United States, found a rising prevalence of Class III obesity, body mass index (BMI) >40 kg/m(2). African-American women were largely responsible for this increase. The prevalence of Class III obesity in African-American women in the BRFSS during the year 2000 was 6%, identical to the Pennington Biomedical Research Center (PBRC) database during the same year. The PBRC Database might predict the trend in class III obesity in the years 2000-2002. The PBRC is an academic research center in Baton Rouge, that maintains a database with information collected by telephone regarding BMI and race, for subjects responding to solicitations to participate in clinical trials. This database contains 7787 subjects entered from 1995 through 2002, of which 1820 were African-American women and 3006 were Caucasian women. The prevalence of Class III obesity was plotted for women of these 2 racial groups and compared with the year 2000 prevalence in the BRFSS. The prevalence of Class III obesity in African-American women increased from 0.5% in 1995 to 6% in 2000 (identical to the BRFSS) and to 7.5% in 2002. The prevalence of Class III obesity in Caucasian women remained about 3%. The prevalence of Class III obesity continues to rise in African-American women, a group with greater need and less access to obesity surgery, the only effective treatment, than Caucasian women, an inequality deserving of public policy attention.

Correlates of the Metabolic Syndrome in Obese African American Women

Correlates of the Metabolic Syndrome in Obese African American Women

Differences in β-adrenergic receptor densities in omental and subcutaneous adipose tissue from obese African American and Caucasian women

African American women lose less weight and at a slower rate than Caucasian women under the same weight loss conditions. This is likely due to decreased mobilization of fat, possibly involving differences in the responsiveness of adipose tissue to adrenergic stimulation. To better understand the causes behind the decreased lipolysis in African American women, this study was initiated to determine if there were differences in the numbers and affinities of β adrenoreceptors in omental and subcutaneous adipose tissue of obese African American and Caucasian women. We determined the number of β receptors using a nonselective antagonist and found the total number of receptors in both omental and subcutaneous adipose tissue preparations were higher in African American than Caucasian women. β 1 , β 2, and β 3 densities were higher in omental adipose tissue ( P < .05), but not different in the subcutaneous tissue of the African American women. No racial differences in kd values for adrenergic agents (agonists and antagonists) were found with regard to β 1, β 2, or β 3 receptors in either the omental or the subcutaneous preparations. β 1 and β 2 receptor protein (mass) was significantly increased in African American omental tissue preparations, but not subcutaneous. Our in vitro data demonstrating increased β receptor numbers in omental tissue from obese African Americans suggest that the potential for lipolysis would be higher in these women. Future studies should determine the biologic significance of the differences in the β adrenergic receptors in vivo.

Assessment of global coronary heart disease risk in overweight and obese African-American women.

To examine, with the use of national guidelines, coronary heart disease (CHD) risk with increasing BMI for primary prevention in urban African-American women. 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. 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. 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.

Breast Cancer and Obesity: An Update

Obesity has a complicated relationship to both breast cancer risk and the clinical behavior of the established disease. In postmenopausal women, particularly the elderly, various measures of obesity have been positively associated with risk. However, before menopause increased body weight is inversely related to breast cancer risk. In both premenopausal and postmenopausal breast cancer, the mechanisms by which body weight and obesity affect risk have been related to estrogenic activity. Obesity has also been related to advanced disease at diagnosis and with a poor prognosis in both premenopausal and postmenopausal breast cancer. Breast cancer in African-American women, considering its relationship to obesity, exhibits some important differences from those described in white women, although the high prevalence of obesity in African-American women may contribute to the relatively poor prognosis compared with white American women. Despite the emphasis on estrogens to explain the effects of obesity on breast cancer, other factors may prove to be equally or more important, particularly as they relate to expression of an aggressive tumor phenotype. Among these, this review serves to stress insulin, insulin-like growth factor-I, and leptin, and their relationship to angiogenesis, and transcriptional factors.

Racial disparity in the dose and dose intensity of breast cancer adjuvant chemotherapy.

The purpose of this study was to investigate the impact of race and obesity on dose and dose intensity of adjuvant chemotherapy. We abstracted data on patient/tumor characteristics, treatment course, physicians' intention to give a first cycle dose reduction, and reasons for dose reductions/delays from oncology records of 489 women treated from 1985 to 1997 in 10 treatment sites in two geographical regions. Administered doses and dose intensity were compared to standard regimens. Multivariate regression models determined the impact of race and body mass index (BMI) on dose proportion (actual:expected doses) and relative dose intensity (RDI) controlling for patient characteristics, comorbidity, chemotherapy regimen, site, and year of treatment. Logistic regressions explored race and BMI versus use of first cycle dose reductions. African-Americans received lower chemotherapy dose proportion and RDI than whites (0.80 vs. 0.85, p = 0.03 and 0.76 vs. 0.80, p = 0.01). In multivariate analyses, dose proportion was 0.09 lower (p = 0.002), and RDI was 0.10 (p < 0.001) lower in non-overweight African-Americans than whites. Obesity was associated with lower dose proportion (p < 0.01) and RDI (p < 0.03). Race and BMI were independently associated with first cycle dose reductions. Non-overweight African-Americans (p < 0.05) and overweight and obese African-American and white women (p < 0.001) were more likely to have first cycle dose reductions than non-overweight whites. We identified systematic differences in the administration of chemotherapy given to African-Americans and to overweight and obese women. These differences may contribute to documented disparities in outcome.

Effects of a low-calorie, low-salt diet and treadmill exercise on atherosclerotic risk factors in obese African-American women

C disease risk factors encompass a multitude of conditions; however, certain factors are clearly related to the risk of heart disease, atherosclerosis, hypertension, and stroke, each of which affects millions of Americans each year. Obesity, an independent, modifiable major risk factor for the development of cardiovascular disease, is a complex multifactorial chronic condition. An estimated 97 million adults in the USA are overweight or obese: body mass index (BMI) 25 kg/m. Overweight and obesity are especially evident in some minority groups and in those with lower income and less education. According to the National Health and Nutrition Examination Survey of 1998, the prevalence is highest in non-Hispanic black women (66%). Clinical trials have demonstrated the effectiveness of behavior modification in reducing body weight, blood pressure, serum lipids, and blood glucose level. However, few studies or clinical trials conducted thus far have focused on blacks. There is a need for comprehensive programs targeting African-American women that can have lasting impact on cardiovascular risk factors. This study, conducted at the Howard University General Clinical Research Center (the study center), recruited subjects from the community to demonstrate the feasibility of achieving the intended goal.

Ethnic differences in dietary intakes, physical activity, and energy expenditure in middle-aged, premenopausal women: the Healthy Transitions Study

Menopause is a time of increased risk of obesity in women. The effect of menopause in African American women, in whom obesity is already highly prevalent, is unknown. We compared dietary intakes and energy expenditure (EE) between middle-aged, premenopausal African American and white women participating in a longitudinal study of the menopausal transition. Dietary intakes by food record, EE by triaxial accelerometer, physical activity by self-report, and body composition by dual-energy X-ray absorptiometry were compared in 97 white and 52 African American women. Twenty-four-hour and sleeping EE were measured by whole-room indirect calorimetry in 56 women. Sleeping EE (adjusted for lean and fat mass) was lower in African American than in white women (5749 +/- 155 compared with 6176 +/- 75 kJ/d; P = 0.02); however, there was no significant difference in 24-h EE between groups. Reported leisure activity over the course of a week was less in African American than in white women (556 +/- 155 compared with 1079 +/- 100 kJ/d; P = 0.02), as were the daily hours spent standing and climbing stairs. Dietary intakes of protein, fiber, calcium, magnesium, and several fatty acids were significantly less in African Americans, whereas there were no observed ethnic differences in intakes of fat or carbohydrate. Body fat within the whole group was positively correlated with total, saturated, and monounsaturated fat intakes and inversely associated with fiber and calcium intakes. Fiber was the strongest single predictor of fatness. Ethnic differences in EE and the intake of certain nutrients may influence the effect of menopausal transition on obesity in African American women.

Risk Ratios for Obesity in Families of Obese African-American and Caucasian Women

We examined age- and sex-standardized risk ratios (SRRs) in matched samples of 1,185 families of obese African-American and Caucasian women. Familial risk ratios increased with body mass index (BMI) of proband and BMI thresholds of relative. Ratios were higher in Caucasian than African-American families, apparently because Caucasian probands were more extreme relative to their population mean. Risk ratios for moderate obesity (BMI ≥ 30) were around 2 for African-Americans and were a little higher in Caucasians. Ratios for extreme obesity (BMI ≥ 40) ranged from 3 to 5 in African-Americans and from about 5 to 9 in Caucasians. Thin relatives were rare in families of both races. Risk ratios appear high enough in both racial groups to facilitate the identification of quantitative trait loci underlying common obesity phenotypes. The high population prevalence of obesity in African-American women will require particularly high selection thresholds to achieve risk ratios comparable to those for Caucasians. The scarcity of thin siblings in both groups will greatly increase the effort required in sample recruitment for discordant pair designs.