Gender Differences in the Response of Plasma Leptin Concentrations to Weight Loss in Obese Older Individuals

Plasma leptin concentration is directly related to the degree of obesity and is higher in women than in men of the same body mass index (BMI). We hypothesized that fasting plasma leptin concentrations and the response of leptin to weight loss would differ in older men and women of a similar fat mass. Plasma leptin concentrations (radioimmunoassay) and fat mass (DXA) were measured in 47 older, obese (BMI=30 ± 4 kg/m²) women and 23 older, obese (BMI=31 ± 3 kg/m²) men after a 2 to 4 week period of weight and dietary stabilization, and then in 22 of the women and 18 of the men after a 6-month weight loss intervention (250–350 kcal/d deficit). Leptin correlated with fat mass in men and women (r=0.75 and r=0.77, respectively; p values<0.0001), but women had 3-fold higher leptin levels for a given fat mass than men (p=0.01). In response to the 6-month hypocaloric diet, men and women lost a similar percentage of fat mass (?13% and ?16%, respectively), but the relative decline in circulating leptin was greater in women than men (-45% and ?21%, respectively; p<0.0001). In addition, when leptin was normalized for fat mass using the ratio method, the decrease in leptin per kilogram of fat mass was greater in women than men (-0.37 ± 0.34 vs. ?0.04 ± 0.06 ng/mL/kg; p<0.01). After weight loss, the change in leptin concentrations correlated positively with the change in fat mass in men (r=0.60; p<0.01), but not in women (r=0.31; p=0.17). Furthermore, the loss in fat mass correlated negatively with baseline leptin levels in women (r=-0.47; p<0.05), but not in men (r=0.03, p=NS). These results indicate that the decline in leptin concentration with weight loss correlates with the loss in fat mass in men; but, in women, other factors affect the decrease in leptin concentration. This suggests that the role of leptin in the regulation of obesity is gender-specific and may account for gender differences in response to hypocaloric treatment and maintenance of lost weight.     

Obesity‐related Comorbidities in Obese African Americans in an Outpatient Weight Loss Program

Objective: To identify, among obese African‐American enrollees in an outpatient weight loss program, differences between those with and without obesity‐related comorbidities (ORCMs). Research Methods and Procedures: Data were from 237 obese African Americans (BMI, 30 to 50 kg/m²; 90% women) who enrolled in a 10‐week lifestyle weight loss program. Analyses compared subgroups defined by ORCM status (from medical history) on baseline characteristics, program attendance, and postprogram weight change. Results: Most participants (76%) had one or more ORCMs. Those with versus without ORCMs, respectively, were older (mean age, 45.6 vs. 37.1 years; p < 0.001), were less educated (59.2% vs. 76.6% with >12 years; p = 0.031), were more likely to perceive a physical limitation affecting activity (22.2% vs. 1.8%; p < 0.001), and had higher waist circumference (mean, 113.7 vs. 106.9 cm; p < 0.001) but not BMI (38.3 vs. 37.0 kg/m²; p = 0.095). Logistic regression analyses confirmed the independence of these associations. Having ORCMs was not associated with class attendance or return for data collection after the 10‐week program. Postprogram weight change (n = 134) was unrelated to ORCMs, but better weight loss was seen among those without perceived physical limitations (1.9 vs. 0.4 kg in those without versus with limitations; p = 0.069). Conclusion: Data from this clinical sample of obese African Americans suggest that waist circumference is relevant to ORCM status at BMI levels up to 50 kg/m². Clear indications for tailoring of treatment based on ORCM status were not identified, although the possible influence of ORCM‐related activity limitations warrants further study.     

Serum Leptin Concentration and Insulin Sensitivity in Men with Abdominal Obesity

JOHANNSSON, GUDMUNDUR, CECILIA KARLSSON, LARS LÖNN, PER MÅRIN, PER BJÖRNTORP, LARS SJÖSTRÖM, BJÖRN CARLSSON, LENA M.S. CARLSSON, BENGT-ÅKE BENGTSSON. Serum leptin concentration and insulin sensitivity in men with abdominal obesity. Obes Res. 1998;6:416–421. Objective : We have examined the association between generalized adiposity, abdominal adiposity, insulin sensitivity, and serum levels of leptin in a cross-sectional study of abdominally obese men. Research Methods and Procedures : Thirty men, 48 to 66 years of age with a body mass index (BMI) of between 25 kg/m² and 35 kg/m² and a waist hip ratio of <0.95, were included in the study. Serum leptin concentration was measured using radioimmunoassay. Total body fat percentage was determined from total body potassium, abdominal adiposity was measured by computed tomography, and the glucose disposal rate (GDR) was measured during an euglycemic, hyperinsulinemic glucose clamp. Results : Significant correlations were found between serum leptin concentration and BMI, percentage body fat, abdominal subcutaneous adipose tissue, serum insulin, GDR, and 24-hour urinary-free Cortisol. In a multiple regression analysis, it was shown that abdominal subcutaneous adipose tissue, GDR, and BMI explained 72% of the variability of serum leptin concentration. GDR demonstrated an independent inverse correlation with serum leptin concentration. Discussion : In abdominally obese men with insulin resistance, it was demonstrated that most of the individual variability in serum leptin concentration was explained by the amount of subcutaneous abdominal adipose tissue, insulin sensitivity, and BMI.     

Relative Body Weight and Self-Esteem among African Americans in Four Nationally Representative Samples

FAITH, MYLES S., ELIZABETH MANIBAY, MEREDYTH KRAVITZ, JOHN GRIFFITH, DAVID B. ALLISON. Relative body weight and self-esteem among African Americans in four nationally representative samples. Obes. Res. 1998;6:430–437. Objective : Obesity is an increasingly common health problem among African Americans, especially women, in the United States. However, limited data are available on the psychological correlates of obesity in this population. This study examined the association between self-esteem and relative body weight (RBW) in four large nationally representative samples of African American individuals. Research Methods and Procedures : Data from The Adolescent Health Care Evaluation Study, The National Longitudinal Survey of Youth, The High School and Beyond, and The National Survey of Black Americans were analyzed. Within each database, regression analyses tested the association between RBW and self-esteem while adjusting for age and sex. Results : In three of the four databases, there was no significant association between RBW and self-esteem. In the only database detecting a statistically significant effect, the magnitude of the effect was small. The combined effects of RBW and its interaction with age and sex accounted for <2% of the variance in self-esteem across databases. Discussion : Results suggest that elevated RBW is not associated with a poorer general self-concept, on average, among African American individuals.     

Prader-Willi Syndrome: Relationship of Adiposity to Plasma Leptin Levels

Objective : Prader-Willi syndrome (PWS) is an autosomal dominant disorder involving the proximal long arm of chromosome 15, in which obesity is common. However, there is limited information on the underlying physiological mechanisms promoting obesity in this population. We tested whether there was a significant positive association between leptin and total body fat (TBF) in subjects with PWS, and whether this association was stronger among subjects with than without PWS. Research Methods and Procedures : We studied 21 PWS patients and 64 non-PWS controls on whom we measured serum leptin, total body fat, glucose, insulin, and resting energy expenditure. We tested whether the slope of the regression line between leptin and TBF (in kg), measured by dual energy X-ray absorptiometry, was the same for PWS patients and aon-PWS controls. Results : Regression analyses indicated that the leptin-TBF association was significantly stronger among PWS patients. In contrast, the slope of the leptin-body mass index association did not significantly differ between PWS patients and non-PWS controls. None of the other outcome variables showed associations with leptin. Discussion : Results suggest that the role of leptin in promoting obesity may be greater among subjects with PWS than among non-PWS controls.     

Percent Body Fat and Lean Mass Explain the Gender Difference in Leptin: Analysis and Interpretation of Leptin in Hispanic and Non‐Hispanic White Adults

Objective: To reassess the relationship between body fat and fasting leptin concentrations comparing plasma vs. serum assessments of leptin; ratios vs. regression adjustment for body composition; fat and lean mass vs. percent body fat; and gender‐, ethnic‐, and age‐related variations. Research Methods and Procedures: Subjects included 766 adults from the nondiabetic cohort of the San Luis Valley Diabetes Study examined at follow up (1997 to 1998). Body composition was determined by dual energy X‐ray absorptiometry. Leptin concentrations were determined after an overnight fast. Results: Fasting serum and plasma assessments of leptin were correlated with percent body fat to the same degree. Women had significantly higher serum leptin concentrations than men when leptin concentrations were divided by body mass index, fat mass in kilograms or percent body fat. The methodological problem inherent in interpreting these ratio measures is pictorially demonstrated. In regression analysis, fat mass alone did not explain the gender difference. However, lean body mass was inversely related to leptin concentrations (p < 0.0001) and explained 71% of the gender difference at a given fat mass. Percent body fat explained all of the gender difference in leptin concentrations in both Hispanics and non‐Hispanic whites. Similar to findings about gender differences, ethnic‐ and age‐related variations in the leptin‐body fat association were minimized when percent body fat was employed as the body fat measure. Discussion: Regression analysis and percent body fat measured with dual energy X‐ray absorptiometry are recommended when assessing the relationship between leptin and body fat. Gender differences in leptin concentrations were accounted for by percent body fat in free living (no diet control), Hispanic and non‐Hispanic white adults.     

Frequency and chronological distribution of dental enamel hypoplasia in enslaved African Americans: A test of the weaning hypothesis

The dentition of 27 enslaved African Americans from archaeological sites in Maryland and Virginia were examined. All 17 males and 7 of the 10 females in this study exhibited enamel hypoplastic defects indicative of systemic nutritional and disease stresses interfering with amelogenesis. Estimates of the ages of occurrence of these defects show that most occur between 1.5 and 4.5 years of age, 0.5–3.75 years later than historically documented weaning age (9–12 months of age) in similar plantation populations. Comparisons are made with studies of dental enamel hypoplasia in contemporaneous enslaved and free African American populations, including our data on 75 individuals from the First African Baptist Church cemetery in Philadelphia. These populations were highly stressed. While there appears to be a modest effect of early weaning stress, no direct relationship of peak frequencies to weaning age can be shown. These data raise questions about the attribution of peak hypoplasia frequencies to age at weaning or “post-weaning” stresses in previous paleopathological studies. High hypoplasia frequencies during the middle years of enamel development are more likely the result of a combination of 1) multiple environmental stresses, 2) differences in hypoplastic susceptibility in enamel, and 3) random factors. © 1994 Wiley-Liss, Inc.     

Heroin addiction in African Americans: a hypothesis-driven association study

Heroin addiction is a chronic complex disease with a substantial genetic contribution. This study was designed to identify gene variants associated with heroin addiction in African Americans. The emphasis was on genes involved in reward modulation, behavioral control, cognitive function, signal transduction and stress response. We have performed a case–control association analysis by screening with 1350 variants of 130 genes. The sample consisted of 202 former severe heroin addicts in methadone treatment and 167 healthy controls with no history of drug abuse. Single nucleotide polymorphism (SNP), haplotype and multi-SNP genotype pattern analyses were performed. Seventeen SNPs showed point-wise significant association with heroin addiction (nominal P < 0.01). These SNPs are from genes encoding several receptors: adrenergic ( ADRA1A ), arginine vasopressin ( AVPR1A ), cholinergic ( CHRM2 ), dopamine (DRD1 ), GABA-A ( GABRB3 ), glutamate ( GRIN2A ) and serotonin ( HTR3A ) as well as alcohol dehydrogenase ( ADH7 ), glutamic acid decarboxylase ( GAD1 and GAD2 ), the nucleoside transporter ( SLC29A1 ) and diazepam-binding inhibitor ( DBI ). The most significant result of the analyses was obtained for the GRIN2A haplotype G-A-T (rs4587976-rs1071502-rs1366076) with protective effect ( P _uncorrected = 9.6E- 05, P _corrected = 0.058). This study corroborates several reported associations with alcohol and drug addiction as well as other related disorders and extends the list of variants that may affect the development of heroin addiction. Further studies will be necessary to replicate these associations and to elucidate the roles of these variants in drug addiction vulnerability.     

Influence of Leptin on Changes in Body Fat during Growth in African American and White Children

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

The color of punishment: African Americans,skin tone,and the criminal justice system

Public debate and scholarly research has largely concentrated on the vast array of disparities between blacks and whites in their treatment by and experiences with the criminal justice system. Nevertheless, a growing body of research shows that African Americans’ life chances are internally stratified by gradational differences in their skin tone. This study brings together research on race, color, and the criminal justice system by using nationally-representative data to examine whether (and to what extent) skin tone is associated with policing and punishment among African Americans. I find that skin tone is significantly associated with the probability of having been arrested and/or incarcerated, net of relevant controls. Further analyses, using a sub-sample of whites drawn from the same nationally-representative survey, show that disparities in policing and punishment within the black population along the colour continuum are often comparable to or even exceed disparities between blacks and whites as a whole.     

MicroRNAs that affect prostate cancer: emphasis on prostate cancer in African Americans

Abstract

Although concerted efforts have been directed toward eradicating health disparities in the United States, the disease and mortality rates for African American men still are among the highest in the world. We focus here on the role of microRNAs (miRNAs) in the signaling pathways of androgen receptors and growth factors that promote the progression of prostate cancer to more aggressive disease. We explore also how differential expression of miRNAs contributes to aggressive prostate cancer including that of African Americans.     

Both Subcutaneous and Visceral Adipose Tissue Correlate Highly with Insulin Resistance in African Americans

Objective: The contribution of visceral adipose tissue (VAT) to insulin resistance is well‐established; however, the role of subcutaneous abdominal adipose tissue (SAT) in insulin resistance remains controversial. Sex may determine which of these two components of abdominal obesity is more strongly related to insulin resistance and its consequences. The aim of this study was to determine whether both VAT and SAT contribute to insulin resistance in African Americans and to examine the effects of sex on this relationship. Research Methods and Procedures: This was a cross‐sectional study of 78 nondiabetic African‐American volunteers (44 men, 35 women; age 33.8 ± 7.3 years; BMI 30.9 ± 7.4 kg/m²). VAT and SAT volumes were measured using serial computerized tomography slices from the dome of the diaphragm to the iliac crest. The insulin sensitivity index (S_I) was determined from the minimal model using data obtained from the frequently sampled intravenous glucose tolerance test. Results: In men, both VAT and SAT were negatively correlated with S_I (r for both correlations = ?0.57; p < 0.01). In women, the correlation coefficient between VAT and S_I was ?0.50 (p < 0.01) and between SAT and S_I was ?0.67 (p < 0.01). In women, the correlation coefficient for S_I with SAT was significantly greater than the correlation coefficient with VAT (p = 0.02). Discussion: Both SAT and VAT are strongly correlated with insulin resistance in African Americans. For African‐American women, SAT may have a greater effect than VAT on insulin resistance.     

Plasma Leptin and Blood Pressure in Men: Graded Association Independent of Body Mass and Fat Pattern

Objective: The role of leptin in the association between body mass, central adiposity, and blood pressure (BP) is controversial. This study evaluated the relationship between leptin and BP in relation to body mass index (BMI) and fat distribution in a large sample of untreated male adults. Research Methods and Procedures: The study population was made up of 457 untreated male employees of the Olivetti factory in Naples. Plasma leptin, complete anthropometry, BP, and relevant biochemical variables were measured. Results: Log‐transformed plasma leptin levels were directly associated with BMI (r = 0.661, p < 0.001) and waist circumference (r = 0.630; p < 0.001). Leptin also correlated with systolic (r = 0.258) and diastolic (r = 0.277) BP (p < 0.001). The association between leptin and BP was maintained after accounting for age, BMI (or waist circumference), log‐insulin, and serum creatinine (p < 0.01); this association was stronger than that with BMI. Logistic regression analysis showed that an increased prevalence of hypertension (BP ≥ 140 and/or 90 mm Hg) was associated with high plasma leptin levels when controlling for age and waist circumference (odds ratio, 1.99; 95%CI, 1.06 to 3.72) or for age and BMI (odds ratio, 1.92; 95%CI, 1.02 to 3.61). Discussion: A graded positive relationship between plasma leptin levels and BP was observed in this sample of untreated male adults. This association was independent of age, BMI, abdominal adiposity, and fasting plasma insulin. Moreover, elevated plasma leptin concentrations were associated with greater probability of hypertension, again independently of potential confounders.     

运动改善肥胖症瘦素抵抗及其机制研究进展

大部分肥胖患者体内出现瘦素抵抗,表现为血清瘦素水平异常升高,但机体对瘦素不敏感或无反应,使瘦素抑制食欲、增加能量消耗和降低血糖等功能不能有效发挥.减轻瘦素抵抗被认为是治疗肥胖及肥胖相关疾病的有效途径.运动减轻肥胖、改善糖脂代谢和增强胰岛素敏感性的作用与运动降低瘦素水平、改善瘦素抵抗密切相关.本文在概述瘦素实现生理功能的机制、肥胖症的中枢及外周瘦素抵抗的基础上,主要综述近年来运动减轻肥胖症瘦素抵抗机制的研究进展,包括减轻高瘦素血症、改善中枢和外周瘦素抵抗,以期为运动防治肥胖机制的研究提供新视角.     

The Relationship of Body Mass Index to Reproductive Factors in Pre- and Postmenopausal African-American Women With and Without Breast Cancer

To date, there are virtually no existing data on the relationship between obesity, menopausal status, and breast cancer in African-Americans. Therefore, the present study was designed to test the following hypotheses in an African-American population: (1) there exists a positive association between BMI and breast cancer among postmenopausal women; (2) there exists an inverse association between BMI and breast cancer among premenopausal women; and (3) similar associations between BMI and reproductive factors exist for both pre- and postmenopausal breast cancer cases. The study population comprised 357 African-American women (n=193 breast cancer cases; n=164 controls). No significant differences were observed between premenopausal cases and controls for BMI, obesity categories, and reproductive factors. Among the postmenopausal women, the cases had significantly lower weight and BMI levels than the controls. Age at first pregnancy and parity were significantly lower among postmenopausal cases than their controls. No significant associations were revealed between body mass index and breast cancer for pre- and postmenopausal women. In the present study, early age at menarche was the only reproductive factor that was an independent predictor of BMI for both pre- and postmenopausal women, irrespective of breast cancer status. Also, these findings strongly suggest the need to consider reproductive factors, particularly age at menarche, as a covariate of BMI and other obesity-related diseases.     

Relationship Between Muscle Sympathetic Nerve Activity and Plasma Leptin Concentration

SNITKER, SØREN, RICHARD E PRATLEY, MARGERY NICOLSON, P ANTONIO TATARANNI, ERIC RAVUSSIN, Relationship between muscle sympathetic nerve activity and plasma leptin concentration. In humans, basal muscle sympathetic nerve activity (MSNA), a direct measure of sympathetic nervous outflow, is correlated with percentage of body fat. The underlying physiological mechanism is unknown. On the basis of the observation that leptin increases sympathetic nervous outflow in the oblob mouse, we hypothesized that leptin, a hormone secreted by the adipose tissue, may act as a peripheral signal to increase sympathetic nervous outflow from the central nervous system. We therefore tested whether basal MSNA is correlated with plasma leptin concentration. Fasting plasma samples and recordings of basal MSNA in the peroneal nerve were obtained from 37 healthy, nondiabetic men (35 whites and 2 Mexican-Americans; 29 ± 7 years, 86 ± 14 kg, 24 ± 10% body fat; mean ± SD) who were fed a weight-maintenance diet on a metabolic ward. As expected, plasma leptin concentration (geometric mean, 6.4 ng/mL; 95% confidence interval, 4.6 ng/mL to 9.0 ng/mL) correlated with % body fat (r=0.93, p<0.001). Basal MSNA was 31.6 ± 10.0 bursts/min and correlated with % body fat (r=0.53, p<0.001) and with plasma leptin concentration (r=0.44, p<0.01). In conclusion, the results demonstrate a correlation between MSNA and plasma leptin concentration of a magnitude similar to that between MSNA and % body fat. Leptin may therefore be the peripheral signal explaining the correlation between MSNA and % body fat. A full understanding of the relationship between leptin and the activity of the sympathetic nervous system requires further studies, including the administration of leptin in humans.     

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

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

Deep learning prediction of attention-deficit hyperactivity disorder in African Americans by copy number variation

Current understanding of the underlying molecular network and mechanism for attention-deficit hyperactivity disorder (ADHD) is lacking and incomplete. Previous studies suggest that genomic structural variations play an important role in the pathogenesis of ADHD. For effective modeling, deep learning approaches have become a method of choice, with ability to predict the impact of genetic variations involving complicated mechanisms. In this study, we examined copy number variation in whole genome sequencing from 116 African Americans ADHD children and 408 African American controls. We divided the human genome into 150 regions, and the variation intensity in each region was applied as feature vectors for deep learning modeling to classify ADHD patients. The accuracy of deep learning for predicting ADHD diagnosis is consistently around 78% in a two-fold shuffle test, compared with ∼50% by traditional k-mean clustering methods. Additional whole genome sequencing data from 351 European Americans children, including 89 ADHD cases and 262 controls, were applied as independent validation using feature vectors obtained from the African American ethnicity analysis. The accuracy of ADHD labeling was lower in this setting (∼70–75%) but still above the results from traditional methods. The regions with highest weight overlapped with the previously reported ADHD-associated copy number variation regions, including genes such as GRM1 and GRM8, key drivers of metabotropic glutamate receptor signaling. A notable discovery is that structural variations in non-coding genomic (intronic/intergenic) regions show prediction weights that can be as high as prediction weight from variations in coding regions, results that were unexpected.     

Stop ‘blaming the man’: perceptions of inequality and opportunities for success in the Obama era among middle-class African Americans

Abstract

This paper builds upon work that has shown that African Americans exhibit a dual consciousness when explaining persistent inequality. We draw upon 45 in-depth interviews with middle-class African Americans following the 2008 election to explore how they explain persistent disadvantage for African Americans, the destigmatization strategies they employ, and the impact they believe the election of Barack Obama will have on opportunities for African Americans. Consistent with dual consciousness theory, we find that respondents explain persistent disadvantage for African Americans by citing structural and motivational factors. We also extend previous work to show that for the majority of respondents the use of individualistic de-stigmatization strategies reinforces their dual consciousness. These respondents are optimistic about Obama's election because it supports their belief that African Americans should assume responsibility for improving their circumstances. A minority of respondents express more concern about the persistence of racial inequality, and consequentially are less optimistic about changes that Obama's election may bring about.