Racial differences in metabolic predictors of obesity among postmenopausal women

Lower mitochondrial respiration does not lead to decreased fat oxidation in young African American women without obesity

OBJECTIVE

The prevalence of type 2 diabetes in African American women (AAW) is nearly twice that of White women. Lower insulin sensitivity and decreased mitochondrial function may be contributing factors. The purpose of this study was to compare fat oxidation in AAW and White women.

METHODS

Participants were 22 AAW and 22 White women, matched for age (18.7-38.3 years) and BMI (< 28 kg/m2). Participants completed two submaximal (50% VO2max) exercise tests with indirect calorimetry and stable isotope tracers to assess total, plasma, and intramyocellular triglyceride fat oxidation.

RESULTS

The respiratory quotient during the exercise test was nearly identical in AAW and White women (0.813 ± 0.008 vs. 0.810 ± 0.008, p = 0.83). Although absolute total and plasma fat oxidation was lower in AAW, adjusting for the lower workload in AAW eliminated these racial differences. There was no racial difference in plasma and intramyocellular triglyceride source of fat for oxidation. No racial differences were observed in rates of ex vivo fat oxidation. Exercise efficiency was lower in AAW when adjusted to leg fat free mass.

CONCLUSIONS

The data suggest that fat oxidation is not lower in AAW compared with White women, but additional studies are needed across exercise intensity, body weight, and age to confirm these results.

Racial/ethnic disparity in habitual sleep is modified by caloric intake in adolescents

STUDY OBJECTIVES

We investigated the moderation of caloric intake on the association between race/ethnicity and habitual sleep in adolescents.

METHODS

We analyzed the data obtained from 324 adolescents who completed the follow-up examination of the Penn State Child Cohort study. We collected actigraphy-measured sleep duration on 7 consecutive nights and computed their mean and standard deviation as habitual sleep duration (HSD) and habitual sleep variability (HSV), respectively. We also measured participants' daily intakes of total calorie, total fat, carbohydrates, and protein, through the Youth/Adolescent Food Frequency Questionnaire. Adjusted mean HSD and HSV among non-Hispanic whites and racial/ethnic minorities were compared by using analysis of covariance (ANCOVA), while controlling for age, sex, BMI percentile, total caloric intake, and socioeconomic status. The significance of the interaction between race/ethnicity and caloric intake was further tested in ANCOVA models.

RESULTS

The study sample consisted of 79.3% non-Hispanic whites, 13.0% African American, 4.6% Hispanics, 2.2% Asian, and 0.9% American Indian. Adolescents who are racial/ethnic minorities showed shorter HSD (mean (SE): 6.80 (0.10) vs. 7.07 (0.05) hours/night, p = 0.02) and higher HSV (mean (SE): 1.31 (0.07) vs. 1.15 (0.04) hours/night, p = 0.04) than non-Hispanic whites. Racial/ethnic differences in HSV were significantly more pronounced among adolescents with high caloric intake (p interaction = 0.01), especially from carbohydrates (p interaction = 0.03) and fat (p interaction = 0.05).

CONCLUSION

Adolescents who are racial/ethnic minorities slept objectively shorter and with greater night-to-night variability than non-Hispanic whites. The racial/ethnic disparity in habitual sleep variability was more pronounced among adolescents with high caloric intake, particularly from carbohydrates and fat.

Influence of Asian Ethnicities on Short- and Mid-term Outcomes Following Laparoscopic Sleeve Gastrectomy

PURPOSE

Prevalence of obesity in Asia has been on the increasing trend, with corresponding increase in utilisation of bariatric surgery. The objective of this study was to examine differences in weight loss outcomes following bariatric surgery between Asian ethnicities.

MATERIALS AND METHODS

A retrospective database review was conducted of patients undergoing primary laparoscopic sleeve gastrectomy between 2009 and 2013 in 14 centres from Singapore, Malaysia, Taiwan, Hong Kong, Japan, Korea, India, Australia, Switzerland, and the USA. All patients with available follow-up data at 12 months and 36 months post-surgery were included in this study. Outcome measures used were percentage excess weight loss (%EWL) and percentage total weight loss (%TWL). Differences in outcomes between ethnicities were analysed after adjusting for age, gender, baseline body mass index (BMI), and presence of diabetes.

RESULTS

The study population (n = 2150) consisted of 1122 Chinese, 187 Malays, 309 Indians, 67 Japanese, 259 Koreans, and 206 Caucasians. 67.1% were female and 32.9% were male. Mean age was 37.1 ± 11.2 years. Mean pre-operative BMI was 40.7 ± 8.1 kg/m². With the Caucasian population as reference, Japanese had the best %TWL (3.90, 95% CI 1.16-6.63, p < 0.05) and %EWL (18.55, 95% CI 10.33-26.77, p < 0.05) while the Malays had the worst outcomes. Both Chinese and Koreans had better %EWL but worse %TWL as compared to Caucasians and there were no significant differences with the Indian study group.

CONCLUSION

There are differences in weight loss outcomes following bariatric surgery between Asian ethnicities.

Exercise with weight loss improves adipose tissue and skeletal muscle markers of fatty acid metabolism in postmenopausal women

OBJECTIVE

The effects of 6-month weight loss (WL) versus aerobic exercise training (AEX)+WL on fat and skeletal muscle markers of fatty acid metabolism were determined in normal (NGT) and impaired (IGT) glucose tolerant African-American and Caucasian postmenopausal women with overweight/obesity.

METHODS

Fat (gluteal and abdominal) lipoprotein lipase (LPL), skeletal muscle LPL, acyl-CoA synthase (ACS), ß-hydroxacyl-CoA dehydrogenase, carnitine palmitoyltransferase (CPT-1), and citrate synthase (CS) activities were measured at baseline (n = 104) and before and after WL (n = 34) and AEX+WL (n = 37).

RESULTS

After controlling for age and race, muscle LPL and CPT-1 were lower in IGT, and the ratios of fat/muscle LPL activity were higher in IGT compared to NGT. Muscle LPL was related to insulin sensitivity (M value) and inversely related to G₁₂₀ , fasting insulin, and homeostatic model assessment of insulin resistance. AEX+WL decreased abdominal fat LPL and increased muscle LPL, ACS, and CS. The ratios of fat/muscle LPL decreased after AEX+WL. The change in VO₂ max was related to the changes in LPL, ACS, and CS and inversely related to the changes in fat/muscle LPL activity ratios.

CONCLUSIONS

Six-month AEX+WL, and not WL alone, is capable of enhancing skeletal muscle fatty acid metabolism in postmenopausal African-American and Caucasian women with NGT, IGT, and overweight/obesity.

Sociodemographic, Behavioral, and Psychological Correlates of Current Overweight and Obesity in Older, Urban African American Women

To better understand obesity and overweight among urban African American women, the authors examined sociodemographic, behavioral, and psychological factors within body mass index (BMI) categories. A total of 496 women were recruited for cardiovascular risk factor screening from 20 urban African American churches. Study participants had a mean age of 52.8 years, 13.5 years of education, and an average BMI of 32 kg/m2. Bivariate analyses showed increased overall energy intake and decreased physical performance on a walk test, and general well-being declined as the BMI class increased; obese women had the lowest physical performance and well-being levels and the highest energy intake levels. There was no difference by BMI category, however, in social variables such as educational attainment, employment, marital status, or household income. This study suggests that although women with increasing BMI have some physical and well-being concerns, the major social variables are not differentially distributed by BMI in this sample of women.

Bariatric surgery outcomes in ethnic minorities

BACKGROUND

The primary aim of this study was to examine percent excess weight loss (%EWL) across and between racial groups at 6, 12, 24, and 36 months follow-up in patients who received sleeve gastrectomy (SG) or a Roux-en-Y gastric bypass (RYGB) operation. We hypothesized that ethnic minorities (blacks and Hispanics) would have a lower %EWL than whites at 6, 12, 24, and 36 months for both SG and RYGB operations. The secondary aim was to examine %EWL within racial groups at 6, 12, 24, and 36 months as a function of the type of bariatric operation. We hypothesized that whites, blacks, and Hispanics would have a greater %EWL with RYGB than with SG.

METHODS

A total of 749 patients who underwent an SG or an RYGB operation from January 2008 to June 2014 were included. Data were collected from patients' electronic medical records. Self-reported data on race/ethnicity were also obtained from the electronic medical record and were classified into the following categories: white, Hispanic/Latino, African American or black, or other.

RESULTS

Results revealed overall differences in %EWL between blacks and whites (P < .05) and no overall differences in %EWL between Hispanics and whites (P = .697). Follow-up analyses revealed that Hispanics differed from blacks in %EWL at 6, 12, 24, and 36 months (all P < .01) and that whites differed from blacks at 6 months (P < .05). There were no significant differences between whites and Hispanics during any follow-up period. Overall, the %EWL differed by operation type (P < .01), with RYGB associated with greater %EWL than SG. When stratified by race, the only difference was found in blacks, who had a greater %EWL after RYGB compared with SG (P < .01).

CONCLUSION

Our primary hypothesis was partially supported, as blacks but not Hispanics had a lower %EWL compared to whites at 6 months. An interesting finding is that blacks had a lower %EWL than Hispanics at every time point. Moreover, our secondary hypothesis was partially supported. Results revealed that overall RYGB was related to greater %EWL compared with SG, and within racial groups, among blacks only, RYGB was associated with a greater %EWL compared with SG.

Effect of a 1-week, eucaloric, moderately high-fat diet on peripheral insulin sensitivity in healthy premenopausal women

OBJECTIVES

To determine whether a weight-maintaining, moderate (50%) high-fat diet is deleterious to insulin sensitivity in healthy premenopausal women.

DESIGN/SETTING/PARTICIPANTS

23 African-American and non-Hispanic white, healthy, overweight, and obese premenopausal women recruited in New York City, USA, fed either a eucaloric, 1-week long high-fat (50% of total Kcal from fat) diet or a eucaloric, 1-week long low-fat (30% of total Kcal from fat) diet, assigned in a randomized crossover design.

MAIN OUTCOME MEASURES

Peripheral insulin sensitivity and metabolic flexibility during a euglycemic hyperinsulinemic (80 mU/m(2)/min) clamp measured during the follicular phase of the menstrual cycle, at the end of each diet period.

RESULTS

Peripheral insulin sensitivity (mg kg/fat-free mass/min (µU/mL)×10(-1)) was not decreased after the high-fat diet vs the low-fat diet (0.09±0.01 vs 0.08±0.01, p=0.09, respectively) in the combined group of African-American and white women, with no significant diet by race interaction (p=0.6). Metabolic flexibility (change in substrate utilization, ΔNPRQ, in response to insulin during the clamp) was similarly unaltered by the diet (0.12±0.01 vs 0.11, p=0.48, for the high-fat diet vs the low-fat diet, respectively) in the combined group of women, with no significant diet by race interaction (p=0.9). African-American women had a lower insulin clearance compared with the white women, regardless of the diet (p<0.05).

CONCLUSIONS

We conclude that a short term (1 week), moderate (50%), eucaloric high-fat diet does not lower peripheral insulin sensitivity in healthy, overweight and obese premenopausal women.

Urinary F2-isoprostanes, obesity, and weight gain in the IRAS cohort

Obesity has been associated with increased F(2)-isoprostane (F(2)-IsoP) levels cross-sectionally. However, the prospective association may be inverse, based on our earlier finding that elevated urinary F(2)-IsoP levels predict lower risk of diabetes. This earlier finding led us to hypothesize that urinary F(2)-IsoPs reflect the intensity of oxidative metabolism and as such predict lower risk of both diabetes and weight gain. We examined cross-sectional relationships with obesity and prospective relationships with weight gain using the data from 299 participants of the Insulin Resistance Atherosclerosis Study (IRAS), all of whom were free of diabetes at baseline. Four urinary F(2)-IsoPs were assayed in stored baseline urine samples using liquid chromatography with tandem mass spectrometry: iPF(2α)-III, 2,3-dinor-iPF(2α)-III, iPF(2α)-VI, and 8,12-iso-iPF(2α)-VI (F(2)-IsoP 1-4, respectively). Baseline F(2)-IsoPs were positively associated with baseline measures of obesity; the strongest associations were found with two F(2)-IsoPs: odds ratios (95% confidence intervals) for overall and abdominal obesity were 1.74 (1.26-2.40) and 1.63 (1.18-2.24) for F(2)-IsoP2 and 1.47 (1.12-1.94) and 1.64 (1.22-2.20) for F(2)-IsoP4. F(2)-IsoP2 showed the strongest and significant inverse association with weight gain during the 5-year follow-up period: increase in F(2)-IsoP2 equal to 1 s.d. was associated with 0.90 kg lower weight gain (P = 0.02) and the odds ratios for relative (≥5%) and absolute (≥5 kg) weight gain were 0.67 (0.47-0.96) and 0.57 (0.37-0.87), respectively. The other three F(2)-IsoPs were consistently inversely associated with weight gain, although not significantly, suggesting that different F(2)-IsoPs vary in their ability to detect the association with weight gain.

Do African American women require fewer calories to maintain weight?: Results from a controlled feeding trial

BACKGROUND

The high prevalence of obesity in African American (AA) women may result, in part, from a lower resting metabolic rate (RMR) than non-AA women. If true, AA women should require fewer calories than non-AA women to maintain weight. Our objective was to determine in the setting of a controlled feeding study, if AA women required fewer calories than non-AA women to maintain weight.

MATERIALS AND METHODS

This analysis includes 206 women (73% AA), aged 22-75 years, who participated in the Dietary Approaches to Stop Hypertension (DASH) trial-a multicenter, randomized, controlled, feeding study comparing the effects of 3 dietary patterns on blood pressure in individuals with prehypertension or stage 1 hypertension. After a 3-week run-in, participants were randomized to 1 of 3 dietary patterns for 8 weeks. Calorie intake was adjusted during feeding to maintain stable weight. The primary outcome of this analysis was average daily calorie (kcal) intake during feeding.

RESULTS

AA women had higher baseline weight and body mass index than non-AA women (78.4 vs 72.4 kg, P < .01; 29.0 vs 27.6 kg/m(2), P < .05, respectively). During intervention feeding, mean (SD) kcal was 2168 (293) in AA women and 2073 (284) in non-AA women. Mean intake was 94.7 kcal higher in AA women than in non-AA women (P < .05). After adjustment for potential confounders, there was no difference in caloric intake between AA and non-AA women (Δ = -2.8 kcal, P = .95).

CONCLUSION

These results do not support the view that AA women are at greater risk for obesity because they require fewer calories to maintain weight.

Pharmacotherapy for overweight/obesity in ethnic minorities and White Caucasians: a systematic review and meta-analysis

Ethnic minorities in the West exhibit a higher prevalence of obesity and also under-achieve in weight management compared to White Caucasians. A systematic review of randomized controlled trials (RCTs) in adults (mean age ≥18 years, duration ≥6 months and published in the English language) was undertaken to evaluate the effectiveness of antiobesity drugs in ethnic minorities and White Caucasians. Data sources between 1990 and 2010 were searched including MEDLINE, EMBASE, Cochrane Controlled Trials Register, CINAHL and references cited in the included studies of other reviews. Eighteen RCTs that met the inclusion criteria were included in this review (6 sibutramine and 12 orlistat). A random effects model was used for meta-analysis. An indirect comparison of weight loss in sibutramine-treated patients in ethnic minorities was significantly lower than in White Caucasians: -2.7 kg (95% CI: -3.1 to -2.3) versus -4.4 kg (95% CI: -5.0 to -3.8), respectively. For orlistat, weight loss was similar in the two groups: -2.3 kg (95% CI: -2.6 to -2.0) in ethnic minorities and -2.8 kg (95% CI: -5.1 to -0.5) in White Caucasian participants. Overall, there were few studies of weight loss pharmacotherapy for comparison of this review and it was not possible to analyse data based on ethnic groupings. More ethnically tailored studies are needed to assess the most effective weight loss strategies in these most metabolically vulnerable groups.

Dietary and lifestyle interventions for weight management in adults from minority ethnic/non-White groups: a systematic review

Minority ethnic/non-White populations are more prone to weight gain and more susceptible to obesity-related complications. The objective of this study was to systematically review dietary and lifestyle interventions for weight management in minority ethnic groups. Electronic databases and reference lists of original studies and reviews were searched for studies on dietary and lifestyle weight management interventions published. Randomized clinical trials with ≥6-month duration were included. Nineteen studies met the inclusion criteria. Fourteen studies involved African-Americans, one in non-White Hispanics, one in Japanese Americans and three in both African-Americans and non-White Hispanics. Most of the interventions proved relatively effective. However, significant drawbacks were noted for several of these studies, such as small sample size, high attrition rates and lack of follow-up data. Better quality and long-term trials are required in order to investigate in detail the effectiveness of lifestyle changes for weight management in these populations and eventually support evidence-based recommendations.

Effects of a single exercise bout on insulin sensitivity in black and white individuals

BACKGROUND

Previous research suggests non-Hispanic blacks (blacks) are more insulin resistant than non-Hispanic whites (whites). Physical activity can play an important role in reducing insulin resistance. However, it is unknown whether racial differences exist in response to exercise. Therefore, the purpose of this study was to compare metabolic responses to a single bout of exercise in blacks and age-, sex-, and body mass index-matched whites.

METHODS

Whole-body insulin sensitivity, glucose storage, glucose oxidation, and respiratory exchange ratio (RER) were assessed during a hyperinsulinemic-euglycemic clamp in normoglycemic blacks (n = 11) and whites (n = 10). Outcome measures were evaluated in a sedentary control condition and 12 h after treadmill walking at 75% of maximal heart rate for 75 min.

RESULTS

In the control condition, there were no differences in insulin sensitivity between blacks and whites (P = 0.54). During the clamp, glucose oxidation and insulin-stimulated RER values were significantly higher in blacks compared with whites (P = 0.04 and P < 0.01, respectively). Despite similar RER values during exercise, RER values at 60, 90, and 120 min after exercise in blacks were also significantly higher compared with whites (P < 0.05). After exercise, there were no significant improvements in insulin sensitivity (P = 0.57) or glucose storage (P = 0.42) in blacks or whites; however, glucose oxidation was significantly lower in both racial groups (P < 0.05).

CONCLUSIONS

These data suggest that insulin sensitivity is similar in blacks and age-, sex-, and body mass index-matched whites, but the glucose disposal pathways (storage vs. oxidation) are somewhat different. Compared with whites, blacks appear to have a greater capacity to increase glucose oxidation immediately after exercise and during insulin stimulation.

Diet quality and weight gain among black and white young adults: the Coronary Artery Risk Development in Young Adults (CARDIA) Study (1985-2005)

BACKGROUND

Little is known about the long-term health consequences of following the 2005 Dietary Guidelines for Americans (DGA; Washington, DC: US Government Printing Office, 2005).

OBJECTIVE

The objective was to examine the longitudinal association between diets consistent with the 2005 DGA and subsequent weight gain.

DESIGN

We used data from the Coronary Artery Risk Development in Young Adults (CARDIA) Study, a cohort of black and white men and women aged 18-30 y at baseline who attended ≤7 examinations from 1985-1986 to 2005-2006 (n = 4913). We created a 100-point Diet Quality Index (2005 DQI) to rate participants' diets based on meeting the 2005 DGA key recommendations. Longitudinal models of weight gain were adjusted for physical activity, smoking, energy intake, age, education, sex, and initial body mass index (BMI) and included interaction terms of DQI by race and initial BMI (if statistically significant).

RESULTS

We found effect modification by race (likelihood ratio test, P < 0.03 in all models). The mean adjusted 20-y weight change was +19.4 kg for blacks and +11.2 kg for whites with high diet quality (DQI >70) and +17.8 for blacks and +13.9 for whites with a DQI <50 (P < 0.05). In race-specific Cox models (with interaction terms for DQI × initial BMI, P < 0.05), a 10-point increase in DQI score was associated with a 10% lower risk of gaining 10 kg in whites with an initial BMI (in kg/m(2)) <25 but with a 15% higher risk in blacks with baseline obesity (P < 0.001).

CONCLUSIONS

Our findings do not support the hypothesis that a diet consistent with the 2005 DGA benefits long-term weight maintenance in American young adults. Greater need for attention to obesity prevention in future DGAs is warranted.

Associations of free fatty acids with insulin secretion and action among African-American and European-American girls and women

Ethnic differences in insulin secretion and action between African Americans (AAs) and European Americans (EAs) may influence mobilization of free fatty acids (FFAs). We tested the hypotheses that FFA concentrations would be associated with measures of insulin secretion and action before and during a glucose challenge test. Subjects were 48 prepubertal girls, 60 premenopausal women, and 46 postmenopausal women. Fasting insulin (insulin(0)), the acute insulin response to glucose (AIR(g)), the insulin sensitivity index (S(I)), basal and nadir FFA (FFA(0), FFA(nadir)), and nadir time (TIME(nadir)) were determined during an intravenous glucose tolerance test (IVGTT). Stepwise multiple linear regression (MLR) analysis was conducted to identify associations of FFA(0), FFA(nadir), and TIME(nadir) with ethnicity, age group, insulin measures, indexes of body composition from dual-energy X-ray absorptiometry, and measures of fat distribution from computed tomography scan. In this population, insulin(0) and AIR(g) were higher among AAs vs. EAs, whereas S(I) was lower, independent of age group. MLR analyses indicated that FFA(0) was best predicted by lean tissue mass (LTM), leg fat mass, ethnicity (lower in AAs), S(I), and insulin(0). FFA(nadir) was best predicted by FFA(0), age group, and intra-abdominal adipose tissue (IAAT). TIME(nadir) was best predicted by leg fat mass, AIR(g), and S(I). In conclusion, indexes of insulin secretion and action were associated with FFA dynamics in healthy girls and women. Lower FFA(0) among AAs was independent of insulin(0) and S(I). Whether lower FFA(0) is associated with substrate oxidation or risk for obesity remains to be determined.

Resting energy expenditure changes with weight loss: racial differences

It is controversial whether weight loss reduces resting energy expenditure (REE) to a different magnitude in black and white women. This aim of this study was to determine whether changes in REE with weight loss were different between black and white postmenopausal women, and whether changes in body composition (including regional lean and fat mass) were associated with REE changes within each race. Black (n = 26) and white (n = 65) women (age = 58.2 +/- 5.4 years, 25 < BMI < 40 kg/m(2)) completed a 20-week weight-loss intervention. Body weight, lean and fat mass (total body, limb, and trunk) via dual-energy X-ray absorptiometry, and REE via indirect calorimetry were measured before and after the intervention. We found that baseline REE positively correlated with body weight, lean and fat mass (total, limb, and trunk) in white women only (P < 0.05 for all). The intervention decreased absolute REE in both races similarly (1,279 +/- 162 to 1,204 +/- 169 kcal/day in blacks; 1,315 +/- 200 to 1,209 +/- 185 kcal/day in whites). REE remained decreased after adjusting for changes in total or limb lean mass in black (1,302-1,182 kcal/day, P = 0.043; 1,298-1,144 kcal/day, P = 0.006, respectively), but not in white, women. Changes in REE correlated with changes in body weight (partial r = 0.277) and fat mass (partial r = 0.295, 0.275, and 0.254 for total, limb, and trunk, respectively; P < 0.05) independent of baseline REE in white women. Therefore, with weight loss, REE decreased in proportion to the amount of fat and lean mass lost in white, but not black, women.

Do sex or race differences influence strength training effects on muscle or fat?

PURPOSE

To examine the influence of sex and race on the effects of strength training (ST) on thigh muscle volume (MV), midthigh subcutaneous fat (SCF), and intermuscular fat (IMF).

METHODS

One hundred eighty-one previously inactive healthy Caucasian (N = 117) and African American (N = 54) men (N = 82) and women (N = 99), aged 50-85 yr, underwent about 10 wk of unilateral knee extension ST. Ten subjects were neither Caucasian nor African American and were, therefore, not included in the race analysis. Quadriceps MV and midthigh SCF and IMF cross-sectional area were measured with computed tomography before and after ST. Sex and race comparisons were made with a 2 x 2 (sex by race) analysis of covariance.

RESULTS

Training-induced increases in absolute MV were significantly greater (P < 0.001) in men than in women, though both sex groups increased MV significantly with ST (P < 0.001), and the relative (%) increases were similar. There were significant increases in MV within race groups (P < 0.001), but no significant differences between races. There were no significant changes in SCF or IMF, whether sex and racial groups were separated or combined. In addition, there was no sex by race interaction for changes in MV, SCF, or IMF with ST.

CONCLUSION

Strength training does not alter subcutaneous or intermuscular fat, regardless of sex or racial differences. Although men exhibit a greater muscle hypertrophic response to strength training than do women, the difference is small. Race does not influence this response.

Ethnicity, energy expenditure and obesity: are the observed black/white differences meaningful?

PURPOSE OF REVIEW

Recent studies have suggested that black individuals have lower energy expenditure than whites. Many investigators hypothesized that this is why black women experience higher rates of obesity than white women. These findings initiated much research on race as a primary biological determinant of obesity and energy expenditure as a potential pathway. Race is a difficult construct to use in biomedical research.

RECENT FINDINGS

Recent findings have included: an explanation for the lower resting energy expenditure observed among black adults, data showing that relative resting energy expenditure may not be a significant predictor of weight change in African-origin populations, and inconsistent data on the role of activity energy expenditure as a determinant of children's weight change.

SUMMARY

The data suggest that black individuals have lower resting energy expenditure and possibly activity energy expenditure than white individuals. The lower resting energy expenditure is probably caused by a smaller mass of high metabolically active organs. It is unlikely that increased weight gain is associated with lower resting energy expenditure or activity among blacks, because no association has been found within populations. Clinically, it is important to focus on personal modifiable risk factors, e.g., energy intake and physical activity levels.

Metabolic inflexibility in substrate use is present in African-American but not Caucasian healthy, premenopausal, nondiabetic women

CONTEXT

There is an increased prevalence of obesity and insulin resistance in African-American compared with Caucasian females. Metabolic inflexibility (MI) is the inability to switch the use of lipids and carbohydrates in the peripheral tissue (i.e. muscle) based upon substrate availability.

OBJECTIVE

We examined whether MI exists in African-American females. MAIN OUTCOME MEASURES AND DESIGN: We measured substrate use differences during eucaloric, macronutrient-manipulated diets [high fat (50% fat, 35% carbohydrate, 15% protein) vs. low fat (30% fat, 55% carbohydrate, 15% protein)] between Caucasian and African-American women. We also compared differences in substrate use in response to insulin infusion during two-step pancreatic-euglycemic clamps and epinephrine infusion during lipolysis studies. In each study, similar groups of Caucasian and African-American women were compared.

RESULTS

Caucasians had significantly higher fat oxidation (FO) (P = 0.01) and lower carbohydrate oxidation (P < 0.01) during the high-fat vs. low-fat diet, whereas no significant differences were observed in African-Americans. The African-American women also failed to significantly suppress FO during the second step of the pancreatic-euglycemic clamp despite a doubling of their fasting plasma insulin and failed to increase their FO or decrease their carbohydrate oxidation in response to epinephrine infusion as much as Caucasian women did. The response of free fatty acid turnover rates to insulin and epinephrine stimulation was similar between races.

CONCLUSION

The impaired substrate use observed in African-American women during these three studies demonstrates the existence of MI and may contribute to their greater prevalence of obesity and insulin resistance.

Predictive clinical parameters for therapeutic efficacy of rosiglitazone in Korean type 2 diabetes mellitus

This study evaluated the efficacy of rosiglitazone in non-obese and obese Korean type 2 diabetic patients of long duration. A total of 125 patients (M:F=44:81, mean age: 58.4+/-9.1 years, BMI: 24.2+/-2.7 kg/m2, duration of diabetes: 11.0+/-6.4 years) were randomly allocated to 12 weeks of rosiglitazone treatment (4 mg per day) or a control group. Responders were defined as patients who experienced fasting plasma glucose (FPG) reduction of >20% or HbA1c reduction of >1 (%). Rosiglitazone significantly improved glycemic control by reducing FPG and HbA1c (-3.4 mmol/l and -1.1%, P<0.001, respectively). It also significantly increased HOMA(beta-cell function) (+9.7, P<0.01) and QUICKI (+0.029, P<0.001), and decreased HOMA(IR) (-1.73, P<0.001). Females and those with higher waist-hip ratio made up a greater portion of rosiglitazone-responders. Responders (45 patients, 75%) also showed significantly higher FPG, HbA1c, systolic blood pressures, fasting insulin levels and HOMA(IR), and lower QUICKI than nonresponders. Among these parameters of responders, waist-hip ratio of non-obese subgroup, initial glycemic control of obese subgroup, and systolic blood pressure of both subgroups lost their significance after subdivision analysis. However, the baseline HOMA(IR) and QUICKI were significantly correlated with the response rate to rosiglitazone. Moreover, in multiple logistic regression analysis, HOMA(IR) and QUICKI retained their significance as the independent predictors. Even in Korean type 2 diabetic patients of long duration but with relatively preserved beta-cell function, rosiglitazone improved glycemic control, insulin sensitivity, and beta-cell function. In this ethnic group, female gender, central obesity, and especially severe insulin resistance were identified as predictive clinical parameters of rosiglitazone-responders.

Regulation of lipolysis and lipoprotein lipase after weight loss in obese, postmenopausal women

OBJECTIVE

To test the hypothesis that the greater beta-adrenoceptor (beta-AR)-stimulated lipolysis and sensitivity (half-maximal lipolytic response) in abdominal (ABD) adipocytes, greater gluteal (GLT) adipose tissue-lipoprotein lipase (AT-LPL) activity, and dyslipidemia associated with obesity in older women are modifiable by weight loss (WL) and are not due to menopause or aging.

RESEARCH METHODS AND PROCEDURES

The metabolic effects of 6 months of hypocaloric diet and low-intensity walking WL program on the regional regulation of in vitro lipolysis and AT-LPL activity in subcutaneous ABD and GLT adipocytes were measured in 34 obese (48.7 +/- 0.7% body fat, mean +/- SE) postmenopausal (59 +/- 1 years) white women.

RESULTS

The lipolytic responsiveness to the beta-AR agonist isoproterenol and basal lipolysis in the presence of 1 U/mL adenosine deaminase-uninhibited (lipolysis) were greater (p < 0.01) in ABD than GLT adipocytes before and after WL, but there were no regional differences in postreceptor (dibutyryl 3',5'-cyclic adenosine monophosphate)-stimulated lipolysis. beta-AR sensitivity was greater in ABD than GLT adipocytes before (p < 0.01) but not after WL. Regional AT-LPL did not change after WL, but the change in the activity of ABD (but not GLT) AT-LPL correlated with the baseline adenosine deaminase-uninhibited lipolysis (r = 0.38, p = 0.03). There were no relationships between the declines in plasma triglyceride or increases in high-density lipoprotein cholesterol associated with WL and the changes in regional fat cell metabolism.

DISCUSSION

Thus, despite improving lipoprotein lipid profiles in obese, postmenopausal women, WL does not affect the regulation of regional fat metabolism, and a greater tonic inhibition of basal lipolysis by endogenous adenosine may increase the activity of AT-LPL after WL and predispose older women to develop ABD adiposity.

A comparison of self-reported energy intake with total energy expenditure estimated by accelerometer and basal metabolic rate in African-American women with type 2 diabetes

OBJECTIVE

This study assesses the validity of dietary data from African-American women with type 2 diabetes by comparing reported energy intake (EI) with total energy expenditure (TEE) estimated by an accelerometer and basal metabolic rate (BMR).

RESEARCH DESIGN AND METHODS

EI of 200 African-American women was assessed by three telephone-administered 24-h diet recalls using a multiple-pass approach. Physical activity was measured over a 7-day period by accelerometer, which also provided an estimate of TEE. Underreporting of EI was determined by using cutoffs for EI-to-TEE and EI-to-BMR ratios.

RESULTS

Participants, on average, were 59 years of age, with a BMI of 35.7, 10.5 years of diagnosed diabetes, and 10.7 years of education. Mean EI was 1,299 kcal/day; mean EI-to-TEE and EI-to-BMR ratios were 0.65 and 0.88, respectively. Among the 185 subjects with complete dietary data, 81% (n=150) were classified as energy underreporters using the EI-to-TEE ratio cutoff; 58% (n=107) were classified as energy underreporters using the EI-to-BMR ratio. Energy underreporters had significantly lower reported fat, higher protein, but similar carbohydrate intakes compared with non-underreporters. The EI-to-TEE ratio was not significantly associated with any demographic variables or following a diet for diabetes, but it was inversely associated with BMI (r=-0.37, P<0.0001). In a multivariate model, demographic variables, BMI, and following a diet for diabetes explained 16% of the variance in the EI-to-TEE ratio, with the latter two variables being the only significant predictors (inversely associated).

CONCLUSIONS

Widespread energy underreporting among this group of overweight African-American women with type 2 diabetes severely compromised the validity of self-reported dietary data.

Cigarette smoking is associated with energy balance in premenopausal African-American adult women differently than in similarly aged white women

OBJECTIVE

To investigate the differential association of cigarette smoking with energy balance in African-American and white premenopausal women.

DESIGN

Cross-sectional study of energy balance, weight, and smoking in women.

SUBJECT

A total of 374 women: 191 African-American (mean age=29.8+/-6.5 y) and 183 white women (mean age=28.9+/-7.1 y).

MEASUREMENTS

Weight, cigarette smoking habits, resting energy expenditure, dietary intake, and physical activity.

RESULTS

There were no significant differences in dietary intake by race or smoking status. The model for physical activity was significant (P=0.0004), with body mass index (BMI) having the largest effect on activity (P<0.001). Smoking status was related to activity, with the heaviest smokers reporting more activity than nonsmokers (P=0.008) or light smokers (P=0.028). The model for resting energy expenditure (REE) was significant (P<0.0001), with the largest again being BMI (P<0.001). There was also an interaction between ethnicity and smoking status (P<0.0001) such that African-American nonsmokers and light smokers tended to have lower REE than several other groups, most often the African-American moderate heavy smokers. The model for BMI was significant (P<0.0001) with an interaction for ethnicity and smoking status (P=0.0009). African-American nonsmokers and light smokers had significantly higher BMIs than most of the other groups.

CONCLUSION

African-American women who were the heaviest smokers had a lower adjusted BMI than the heaviest smoking white women. This effect, at least partially, may be related to an increased REE in the African-American smoking women. While energy intake did not appear to be important in this relationship, energy expended in physical activity appeared to be increased with smoking, as was REE.

Association of African genetic admixture with resting metabolic rate and obesity among women

OBJECTIVE

To investigate the role of genetic admixture in explaining phenotypic variation in obesity-related traits in a sample of African-American women (n = 145) and to determine significant associations between obesity traits and admixture genetic markers.

RESEARCH METHODS AND PROCEDURES

Associations between genetic admixture and BMI, resting metabolic rate, fat mass, fat-free mass, and bone mineral density were tested using linear regression considering the estimation of admixture by 1) a maximum-likelihood approach (MLA) and 2) a Bayesian analysis.

RESULTS

Both the conservative MLA and the Bayesian approach support an association between African genetic admixture and BMI. Evidence for the associations of African genetic admixture with fat mass and fat-free mass was supported by the Bayesian analysis; the MLA supported an association with bone mineral density. When the individual ancestry informative markers that were used to estimate admixture were tested for associations with BMI, significant associations were identified in chromosomes 1, 11, and 12.

DISCUSSION

These results provide evidence supporting the application of admixture mapping methods to the identification of genes that result in higher levels of obesity among African-American women. Further research is needed to replicate and further explore these findings.

Fatty acid oxidation by skeletal muscle homogenates from morbidly obese black and white American women

The purpose of this study was to determine if there were differences in the capacity of skeletal muscle from morbidly obese Black and White American women to oxidize fatty acids. The oxidation rates of (14)C-palmitate, (14)C-palmitoyl-CoA, and (14)C-palmitoyl-carnitine were measured in whole homogenates of rectus abdominus from Black and White women who were similar in age and body mass index (BMI). The activities of muscle citrate synthase (CS), beta-hydroxy acyl-CoA dehydrogenase (beta-HAD), and mitochondrial and microsomal acyl-CoA synthetase (ACS) were measured in the 2 groups. The results showed that the rate of (14)C-palmitate oxidation by muscle of Black women was 25% that of Whites (8.7 +/- 1.5 v 34.4 +/- 6.8 nmol (14)CO(2) produced/gram tissue wet weight/ hour; P <.05), but the rates of (14)C-palmitoyl-CoA and (14)C-palmitoyl-carnitine oxidation were not different in the 2 groups. No differences were found in the activities of CS or beta-HAD. However, the activities of both mitochondrial and microsomal ACS were lower in the Black women than the Whites (mitochondrial ACS 25.1 +/- 3.9 v 36.4 +/- 5.0 nmol/mg protein/min; P <.05; microsomal ACS 6.2 +/- 0.5 v 8.5 +/- 0.5; nmol/mg protein/min; P <.005). The lower rate of palmitate oxidation, and the lack of differences in the rates of palmitoyl-CoA and palmitoyl-carnitine oxidation indicate that there is a defect in the activation of the fatty acid in the muscle of the Black women. This was confirmed by the decrease in mitochondrial ACS activity in the Black women. The decreased fatty acid oxidation by skeletal muscle of obese Black women could result in shunting these fuels from muscle to adipose tissue for storage, which may contribute to the maintenance of obesity in the Black women.

Correlation between midthigh low-density muscle and insulin resistance in obese nondiabetic patients in Korea

OBJECTIVE

We investigated the link between lipid-rich skeletal muscle, namely low-density muscle, and insulin resistance in Korea.

RESEARCH DESIGN AND METHODS

Abdominal adipose tissue areas and midthigh skeletal muscle areas of 75 obese nondiabetic subjects (23 men, 52 women; mean age +/- SD, 41.9 +/- 14.1 years) were measured by computed tomography (CT). The midthigh skeletal muscle areas were subdivided into low-density muscle (0 to +30 Hounsfield units) and normal-density muscle (+31 to +100 Hounsfield units). The homeostasis model assessment (HOMA) score was calculated to assess whole-body insulin sensitivity.

RESULTS

The abdominal visceral fat area and the midthigh low-density muscle area were found to be well correlated with the HOMA score (r = 0.471, P < 0.01 and r = 0.513, P < 0.01, respectively). The correlation between low-density muscle area and insulin resistance persisted after adjusting for BMI or total body fat mass (r = 0.451, P < 0.01 and r = 0.522, P < 0.01, respectively) and even after adjusting for abdominal visceral fat area (r = 0.399, P < 0.01).

CONCLUSIONS

The midthigh low-density muscle area seems to be a reliable determinant of insulin resistance in Korean obese nondiabetic patients.

Muscle fiber type is associated with obesity and weight loss

The purpose of this study was to test the hypothesis that muscle fiber type is related to obesity. Fiber type was compared 1) in lean and obese women, 2) in Caucasian (C) and African-American (AA) women, and 3) in obese individuals who lost weight after gastric bypass surgery. When lean (body mass index 24.0 +/- 0.9 kg/m(2), n = 28) and obese (34.8 +/- 0.9 kg/m(2), n = 25) women were compared, there were significant (P < 0.05) differences in muscle fiber type. The obese women possessed fewer type I (41.5 +/- 1.8 vs. 54.6 +/- 1.8%) and more type IIb (25.1 +/- 1.5 vs. 14.4 +/- 1.5%) fibers than the lean women. When ethnicity was accounted for, the percentage of type IIb fibers in obese AA was significantly higher than in obese C (31.0 +/- 2.4% vs. 19.2 +/- 1.9%); fewer type I fibers were also found in obese AA (34.5 +/- 2.8% vs. 48.6 +/- 2.2%). These data are consistent with the higher incidence of obesity and greater weight gain reported in AA women. With weight loss intervention, there was a positive relationship (r = 0.72, P < 0.005) between the percentage of excess weight loss and the percentage of type I fibers in morbidly obese patients. These findings indicate that there is a relationship between muscle fiber type and obesity.

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 insulin resistance and mid-thigh fat deposition in postmenopausal women

OBJECTIVE

To determine whether racial differences in insulin resistance between African American (AA) and white women exist in postmenopausal women and whether they are related to physical fitness and/or obesity.

RESEARCH METHODS AND PROCEDURES

We studied 35 obese AA (n = 9) and white (n = 26) women of comparable maximal oxygen consumption, obesity, and age. Total body fat was measured by DXA. Abdominal and mid-thigh low-density lean tissue (a marker of intramuscular fat) were determined with computed tomography. Glucose utilization (M) was measured during the last 30 minutes of a 3-hour hyperinsulinemic-euglycemic clamp. Insulin sensitivity was estimated from the relationship of M to the concentration of insulin during the last 30 minutes of the clamp.

RESULTS

The percentage of fat and total body fat mass were similar between AA and white women, whereas fat-free mass was higher in African American women. Visceral adipose tissue was not different between groups, but subcutaneous abdominal fat was 17% higher in the AA than in the white women. AA women had an 18% greater mid-thigh muscle area (p < 0.01) and a 34% greater mid-thigh low-density lean tissue area than the white women. Fasting glucose concentrations were not different, but fasting insulin concentrations were 29% higher in AA women. Glucose utilization was 60% lower in the AA women because of a lower non-oxidative glucose disposal. Insulin sensitivity was 46% lower in the AA women.

DISCUSSION

AA postmenopausal women have more mid-thigh intramuscular fat, lower glucose utilization, and are less insulin sensitive than white women despite comparable fitness and relative body fat levels.

Fatty acid oxidation in African-American and Caucasian women during physical activity

The goal of this study was to determine whether differences in physical activity-related fat oxidation exist between lean and obese African-American (LAA and OAA) and lean and obese Caucasian (LC and OC) premenopausal women. Lean AA (28.4 +/- 2.8 yr, n = 7), LC (24.7 +/- 1.8 yr, n = 9), OAA (30.9 +/- 2.2 yr, n = 11), and OC (34.1 +/- 2.5 yr, n = 9) women underwent preliminary assessment of peak aerobic capacity (VO2 peak). On a subsequent testing day, participants exercised after an 8-h fast on a cycle ergometer at 15 W (approximately 40% VO2 peak) for 10 min and then for 10 min at approximately 65% VO2 peak). Fatty acid oxidation was determined using the average respiratory exchange ratio and O2 consumption during minutes 5-9 of the exercise session. Percent body fat and fat-free mass were lower (P < 0.05) in LAA (25.8 +/- 2.8% and 48.3 kg) and LC (26.4 +/- 2.0% and 45.8 +/- 1.7 kg) than in OAA (41.2 +/- 1.3% and 58.8 +/- 3.3 kg) and OC (39.3 +/- 2.7% and 58.6 kg) women. Fat oxidation among the groups was analyzed statistically using analysis of covariance with fat-free mass and VO2 peak) as covariates. During exercise at 15 W, fat oxidation was as low in LAA (0.134 +/- 0.024 g/min) as in OAA (0.144 +/- 0.026 g/min) and OC (0.156 +/- 0.020 g/min) women: all these rates of fat oxidation were lower than in LC women (0.200 +/- 0.021 g/min, P < 0.05, LC vs. all other groups). Fatty acid oxidation during higher-intensity exercise (65% VO2 peak)) was higher in LC than in OC women but was not statistically different between African-American and Caucasian groups. Fatty acid oxidation was therefore lower during low-intensity physical activity in OAA, LAA, and OC than in LC women.

From ecology to base pairs: nursing and genetic science

With the mapping of the human genome has come the opportunity for nursing research to explore topics of concern to the maintenance, restoration, and attainment of genetic-related health. Initially, nursing research on genetic topics originated primarily from physical anthropology and from a clinical, disease-focused perspective. Nursing research subsequently focused on psychosocial aspects of genetic conditions for individuals and their family members. As findings emerge from current human genome discovery, new programs of genetic nursing research are originating from a biobehavioral interface, ranging from the investigations of the influence of specific molecular changes on gene function to social/ethical issues of human health and disease. These initiatives reflect nursing's response to discoveries of gene mutations related to phenotypic expression in both clinical and community-based populations. Genetic research programs are needed that integrate or adapt theoretical and methodological advances in epidemiology, family systems, anthropology, and ethics with those from nursing. Research programs must address not only populations with a specific disease but also community-based genetic health care issues. As genetic health care practice evolves, so will opportunities for research by nurses who can apply genetic concepts and interventions to improve the health of the public. This article presents an analysis of the evolution of genetic nursing research and challengesfor the future.

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

BACKGROUND

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.

OBJECTIVE

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.

DESIGN

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.

RESULTS

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.

CONCLUSION

Ethnic differences in EE and the intake of certain nutrients may influence the effect of menopausal transition on obesity in African American women.

Racial disparities in metabolism, central obesity, and sex hormone-binding globulin in postmenopausal women

Increased total and intraabdominal fat (IAF) obesity as well as other metabolic conditions associated with the insulin resistance syndrome (IRS) are related to low levels of sex hormone-binding globulin (SHBG) in young and older Caucasian (CAU) and young African-American (AA) women. We examined whether postmenopausal AA women, a population with a high incidence of obesity and IRS despite low IAF, would have higher levels of circulating SHBG compared with CAU women, and whether there would be negative relationships between indexes of obesity and risk factors associated with IRS and SHBG levels. We measured body composition, SHBG, free testosterone, leptin, glucose tolerance, insulin, and lipoprotein lipids in 55 CAU (mean +/- SD, 59 +/- 7 yr) and 35 AA (57 +/- 6 yr) sedentary women of comparable obesity (48% body fat, by dual energy x-ray absorptiometry). Compared with CAU women, AA women had larger waist (101 vs. 96 cm), larger fat mass (44.9 +/- 8.8 vs. 39.9 +/- 8.1 kg), larger sc fat area (552 +/- 109 vs. 452 +/- 109 cm(2)), and lower IAF/SC ratio (0.28 +/- 0.12 vs. 0.38 +/- 0.15; P < 0.01), but similar waist to hip ratio (0.83). Both groups had similar SHBG (117 vs. 124 nmol/L) and free testosterone (3.7 vs. 3.4 pmol/L) levels, but AA women had a 35% higher leptin, 34% higher fasting insulin, and 39% greater insulin response to a glucose load (P < 0.05) compared with CAU women. In CAU, but not AA, women SHBG correlated negatively with body mass index (r = -0.28; P < 0.05), waist (r = -0.36; P = 0.01), IAF (r = -0.34; P = 0.01), and insulin response to oral glucose (r = -0.37; P < 0.05) and positively with high density lipoprotein cholesterol (r = 0.30; P = 0.03). The relationship between insulin area and SHBG in CAU women disappeared after adjusting for IAF, whereas the relationship between high density lipoprotein cholesterol and SHBG persisted after adjusting for IAF, but not for fat mass. Leptin was positively related to fat mass (P < 0.05) in both groups, but it was related to insulin only in the Caucasian women (P< 0.01). There was a racial difference in the slopes (P< 0.05) of the relationships of leptin to fat mass (P < 0.05). Racial differences in leptin disappeared after adjustment for fasting insulin. These results suggest that the metabolic relationships between total and regional obesity, glucose, and lipid metabolism with SHBG in CAU women are different from those in postmenopausal obese AA women.

The adoption of eating behaviors conducive to weight loss

Given the plethora of eating behavior techniques that obese individuals might adopt for weight loss, it is not likely that they could, or would be willing to, adopt all of them. Therefore, the purpose of this study was to identify the specific eating behaviors conducive to weight loss adopted during the behavioral treatment of obesity, and to distinguish those that were deemed beneficial from the ones that were not. Fifty obese (BMI 32+/-4 kg/m(2), mean+/-SD), postmenopausal women (60+/-6 years old) participated in a 6-month behavior modification, dietary, low-intensity walking weight loss program. For analysis, they were divided into two groups: "no weight loss" (<or=5 kg, n=18) versus "weight loss" (>5 kg, n=32). At pre- and posttreatment women completed the Eating Behavior Inventory (EBI) that measures specific strategies conducive to weight loss. Women who lost weight increased their total eating behavior score by 20% (p<0.001) and improved the adoption of 14 eating behaviors, which was more than twice that of the non-weight losers. Topping the list of most strongly adopted behaviors were carefully watching and recording the type and quantity of food consumed. Maintaining a weight graph and weighing daily also were important to these women. Neither group of women adopted potentially helpful eating behaviors such as leaving food uneaten, refusing food offered by others, or shopping from a list. In studies of obesity treatment, attendance at class sessions is one marker of program adherence. More definitively, implementing the EBI in clinical and research obesity treatment programs will provide its leaders with insight into whether participants adopt, ignore, or fight the essential behaviors that will facilitate success toward their personal weight loss goals.