Population genetics of alpha-1-antitrypsin polymorphism in US whites, US blacks and African blacks.

An isoelectric focusing (IEF) procedure in an ultra-narrow pH range, 4.2-4.9, has been utilized to detect alpha 1-antitrypsin or alpha 1-protease inhibitor (PI) allele products in 2 US white and 3 US black populations as well as 1 native African black population. In addition to the 3 common alleles PI*M1, PI*M2 and PI*M3, products of the 4th allele PI*M4 have been identified in US whites at low-level frequency. The presence of the PI*S, PI*Z and PI*I alleles has also been verified in our population samples. While the PI*S allele is present at a polymorphic level in US whites, it is only present sporadically in US blacks and is completely absent in African blacks. The PI*Z allele was not detected in the black populations tested. The PI allele frequency data have been used to calculate white admixture in US blacks.     

Room at the top? Minority mobility and the transition to demographic diversity in the USA

We examine the ramifications of the demographic transition to diversity in the USA through an analysis of changes at the top of the occupational hierarchy, as glimpsed in recent census data. We find evidence that, among the incumbents of better-paid occupations, the percentage of non-Hispanic whites, the historically dominant majority, is sharply declining, while the proportion of immigrant-origin minorities, Asians, both foreign and US born, and US-born Hispanics, is growing. African Americans, or US-born blacks, are not so far sharing much in this growth. However, whites still retain important advantages in terms of occupational placement net of education and in terms of earnings net of occupational placement. We conclude overall that demographic shifts are highly likely to drive further diversification at the top of the US workforce; the question of whether whites can hold on to their advantages in the face of these changes cannot be answered yet.     

Gendered segmented assimilation: earnings trajectories of African immigrant women and men

Racial stratification in immigrant earnings has been widely influential in theories of immigrant socioeconomic assimilation, but discussions of how racial stratification might differ by gender are underdeveloped. Segmented assimilation theory attempts to explain the underlying mechanisms that cause racial disparities, but it fails to incorporate gendered dynamics like occupational sex segregation and the feminization of particular labour flows. In this paper, we address that gap. Using data from the 1990 decennial census and the American Community Survey in 2009–11, we compare the earnings of black and white African migrants to US-born blacks and whites separately by gender. Our findings indicate that black African migrant women experience no racial disadvantage in their earnings, but black African migrant men do. Our results highlight the importance of examining racial differences in immigrant earnings interacting with gender.     

Racial/Ethnic Disparities in Obesity Among US‐born and Foreign‐born Adults by Sex and Education

This study examines sex and education variations in obesity among US‐ and foreign‐born whites, blacks, and Hispanics utilizing 1997–2005 data from the National Health Interview Survey on 267,585 adults aged ≥18 years. After adjusting for various demographic, health, and socioeconomic factors via logistic regression, foreign‐born black men had the lowest odds for obesity relative to US‐born white men. The largest racial/ethnic disparity in obesity was between US‐born black and white women. High educational attainment diminished the US‐born black–white and Hispanic–white disparities among women, increased these disparities among men, and had minimal effect on foreign‐born Hispanic–white disparities among women and men. Comprehension of these relationships is vital for conducting effective obesity research and interventions within an increasingly diverse United States.     

Inequality in the American South: evidence from the nineteenth century missouri state prison

The use of height data to measure living standards is now a well-established method in economic history. Moreover, a number of core findings in the literature are widely agreed upon. There are still some populations, places and times, however, for which anthropometric evidence remains thin. One example is 19th century African-Americans in US border-states. This paper introduces a new data set from the Missouri state prison to track the heights of comparable black and white men born between 1820 and 1904. Modern blacks and whites come to comparable terminal statures when brought to maturity under optimal conditions; however, whites were persistently taller than blacks in the Missouri prison sample by two centimetres. Throughout the 19th century, black and white adult statures remained approximately constant, while black youth stature increased during the antebellum period.     

Human erythrocyte galactokinase and galactose-1-phosphate uridylyltransferase: a population survey.

Erythrocyte (RBC) galactokinase (GALK) and galactose-1-phosphate uridylyl-transferase (GALT) activities were measured in a random sample of 1,700 (1.082 black and 618 white) pregnant women from the Philadelphia area to estimate the frequency of the genes GALKG and GALTG responsible for the two biochemically distinct forms of galactosemia. Blacks have significantly lower mean RBC GALK activities than whites (P less than .0005). The distribution of individual GALK activities for blacks differs from a normal distribution (X227=43.0, P less than .03) whereas that for whites does not (X224=25.5, P approximately equal to .30). These results are consistent with the thesis that reduced RBC GALK activity in blacks is due to the Philadelphia variant (GALKP), which is common in blacks and rare in whites. The frequency of heterozygotes (GALKG/GALKA, GALKG/GALKP) for GALK galactosemia observed in this sample is 1/340 for the total, 1/347 for blacks, and 1/309 for whites. The existence of the GALKP variant allele has been considered in this determination. However, because a method for distinguishing the GALKP and GALKG alleles became available only in the latter part of the study, the frequency of the GALK G allele in the black population may be underestimated. The mean RBC GALT activity for blacks is higher than that for whites, a difference that may be due to a higher frequency of the Duarte variant allele GALTD in whites. Heterozygotes (GALTG/GALTA) for GALT galactosemia were distinguished by family studies and starch gel electrophoresis from individuals who have half-normal RBC GALT activity due to the GALTD allele. The GALTG/GALTA frequency is 1/212 for the total, 1/217 for blacks, and 1/206 for whites. Of the 1,700 individuals surveyed three had atypically high RBC GALK activity, similar to that found in red blood cells of newborns.     

Comparison of Cardiovascular Risk Factors in Obese Blacks and Whites

Blacks are known to have higher blood pressure levels, a higher prevalence of hypertension, and higher body weights than whites. However, the interrelationships of these and other cardiac risk factors have not been analyzed in an obese population. We compared blood pressure (BP) and lipid levels in 174 obese blacks and 939 obese white patients who were entering a weight loss program; we also assessed the effects of weight loss on these factors. Prevalence of treated hypertension was similar in blacks and whites (28% vs. 25%, respectively). In patients not taking BP medication, black women weighed more (108 kg) than white women (102 kg) and black and white males' weights were similar (135 kg vs. 131 kg). Systolic and diastolic BP were similar in black and white women; black males had similar SBP but a significantly lower DBP than white males (83 mmHg vs. 89 mmHg, respectively). Lipid levels were similar in black and white women except black women had lower triglycerides (1.30 mmol/L) than white women (1.58 mmol/L, p<0.05); and black males compared to white males had significantly lower total cholesterol (4.76 mmol/L vs. 5.56 mmol/L), LDL-cholesterol (3.15 mmol/L vs. 3.52 mmol/L) and triglycerides (1.31 mmol/L vs. 2.17 mmol/L, p<0.05). Adult-onset obesity adversely affected a number of cardiovascular risk factors in whites, but not in blacks. Blacks lost significantly less weight (?13 kg) than whites (?19 kg). However, controlling for the difference in weight loss, blacks sustained comparable improvement in lipids and blood pressure, except for TC/HDL-C (whites improved significantly more, ?0.36 kg/m2, than blacks, 0.03 kg/m2). Thus, the impact of obesity on cardiovascular risk factors seems ameliorated in blacks com-pared to whites.     

Tissue contributions to sex and race: differences in tooth crown size of deciduous molars.

This study describes size of constituent deciduous tooth crown components (enamel, dentine, and pulp) to address the manner in which males characteristically have larger teeth than females, and the observation that teeth of American blacks are larger than those of American whites. Measurements were collected (n = 333 individuals) from bitewing radiographs using computer-aided image analysis. Tissue thicknesses (enamel, dentine, pulp) were measured at the crown's mesial and distal heights of contour. Deciduous mesiodistal molar crown length is composed of about 1/7 enamel, 1/3 dentine, and 1/2 pulp. Details differ by tooth type, but males typically have significantly larger dentine and pulp dimensions than females; there is no sexual dimorphism in marginal enamel thickness. Males scale isometrically with females for all variables tested here. Blacks significantly exceed whites in size of all tissues, but tissue types scale isometrically with blacks and whites with one exception: enamel thickness is disproportionately thick in blacks. While the absolute difference is small (5.56 mm of enamel in blacks summed over all four deciduous molar tooth types vs. 5.04 mm in whites), the statistical difference is considerable (P < 0.001). Aside from enamel, crown size in blacks is increased proportionately vis-à-vis whites. Principal components analysis confirmed these univariate relationships and emphasizes the statistical independence of crown component thicknesses, which is in keeping with the sequential growth and separate embryonic origins of the tissues contributing to a tooth crown. Results direct attention to the rates of enamel and dentine deposition (of which little is known), since the literature suggests that blacks (with larger crowns and thicker enamel) spend less time in tooth formation than whites.     

Geographic and racial variation in premature mortality in the U.S.: analyzing the disparities

Life expectancy at birth, estimated from United States period life tables, has been shown to vary systematically and widely by region and race. We use the same tables to estimate the probability of survival from birth to age 70 (S(70)), a measure of mortality more sensitive to disparities and more reliably calculated for small populations, to describe the variation and identify its sources in greater detail to assess the patterns of this variation. Examination of the unadjusted probability of S(70) for each US county with a sufficient population of whites and blacks reveals large geographic differences for each race-sex group. For example, white males born in the ten percent healthiest counties have a 77 percent probability of survival to age 70, but only a 61 percent chance if born in the ten percent least healthy counties. Similar geographical disparities face white women and blacks of each sex. Moreover, within each county, large differences in S(70) prevail between blacks and whites, on average 17 percentage points for men and 12 percentage points for women. In linear regressions for each race-sex group, nearly all of the geographic variation is accounted for by a common set of 22 socio-economic and environmental variables, selected for previously suspected impact on mortality; R(2) ranges from 0.86 for white males to 0.72 for black females. Analysis of black-white survival chances within each county reveals that the same variables account for most of the race gap in S(70) as well. When actual white male values for each explanatory variable are substituted for black in the black male prediction equation to assess the role explanatory variables play in the black-white survival difference, residual black-white differences at the county level shrink markedly to a mean of -2.4% (+/-2.4); for women the mean difference is -3.7% (+/-2.3).     

Forward to the past: race,the colour scale and Michael Banton

This study examined differences in religious participation and spirituality among African Americans, Caribbean blacks (black Caribbeans) and non-Hispanic whites. Data are taken from the National Survey of American Life, a nationally representative study of African Americans, black Caribbeans and non-Hispanic whites. Selected measures of organizational, non-organizational and subjective religious participation were examined. African American and Caribbean blacks were largely similar in their reports of religious involvement; both groups generally indicated higher levels of religious participation than non-Hispanic whites. African Americans were more likely than black Caribbeans to be official members of their places of worship, engage in activities (choirs, church clubs) at their place of worship and request prayer from others. Black Caribbeans reported reading religious materials more frequently than African Americans. The discussion notes the importance of examining ethnic differences within the black American population of the United States.     

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.     

Huntington disease in Maryland: clinical aspects of racial variation.

In a Maryland survey of Huntington disease, the prevalence in blacks was unexpectedly high and equal to that in whites. Age at onset was earlier in blacks, and their clinical features, at all ages at onset, were similar to those seen in juvenile-onset Huntington disease. Blacks had more severe bradykinesia and abnormalities of eye movement and less frequent psychiatric disorder, particularly depression.     

Suburbanization and segregation in the United States: 1970–2010

Analysis of trends in the suburbanization of whites, blacks, Asians, and Hispanics reveal that all groups are becoming more suburbanized, though the gap between whites and minorities remains large. Although central cities have made the transition to a majority-minority configuration, suburbs are still overwhelmingly white. Levels of minority-white segregation are nonetheless lower in suburbs than in cities. Blacks remain the most segregated group at both locations. Black segregation and isolation levels are declining in cities and suburbs; however, while Hispanic and Asian segregation levels have remained stable, spatial isolation levels have risen. Multivariate analyses suggest that Hispanics achieve desegregation indirectly by using socio-economic achievements to gain access to less-segregated suburban communities and directly by translating their status attainments into residence in white neighbourhoods. Blacks do not achieve desegregation indirectly through suburbanization and they are much less able than Hispanics to use their socio-economic attainments directly to enter white neighbourhoods.     

Population-Level Correlates of Preterm Delivery among Black and White Women in the U.S

Objective

This study examined the ability of social, demographic, environmental and health-related factors to explain geographic variability in preterm delivery among black and white women in the US and whether these factors explain black-white disparities in preterm delivery.

Methods

We examined county-level prevalence of preterm delivery (20–31 or 32–36 weeks gestation) among singletons born 1998–2002. We conducted multivariable linear regression analysis to estimate the association of selected variables with preterm delivery separately for each preterm/race-ethnicity group.

Results

The prevalence of preterm delivery varied two- to three-fold across U.S. counties, and the distributions were strikingly distinct for blacks and whites. Among births to blacks, regression models explained 46% of the variability in county-level risk of delivery at 20–31 weeks and 55% for delivery at 32–36 weeks (based on R-squared values). Respective percentages for whites were 67% and 71%. Models included socio-environmental/demographic and health-related variables and explained similar amounts of variability overall.

Conclusions

Much of the geographic variability in preterm delivery in the US can be explained by socioeconomic, demographic and health-related characteristics of the population, but less so for blacks than whites.     

Caucasian genes in American blacks: new data.

Data on 15 polymorphic protein-coding loci are used to estimate the proportion of Caucasian genes in U.S. blacks from the greater-metropolitan area of Pittsburgh. Allele frequencies from U.S. whites of the same region and from a sample of Nigerians are used as representatives of the genetic contributions of the source populations between which admixture has occurred. These materials provide 18 unique variants that occur exclusively in the blacks and 5 variants that are restricted to the Caucasians only. As a result, when all segregating alleles (52) at these 15 loci are considered, the proportion (mean +/- SE) of Caucasian genes in U.S. blacks (25.2% +/- 2.7%) is estimated with a precision much better than that of all other previous estimates. The estimate based on the frequencies of these 18 unique variants of African origin (24.8% +/- 6.2%) is also consistent with the pooled estimate obtained from the 15 loci by the weighted least-square method. The homogeneity of locus-specific estimates of admixture indicates that these loci are appropriate for studying the proportion of black genes in any admixed population involving African admixture. The advantages of employing such loci for genetic-epidemiologic studies in U.S. blacks is discussed in the context of the availability of these large number of unique African variants at these protein loci.     

Hepatocellular carcinoma in urban born blacks: frequency and relation to hepatitis B virus infection.

Chronic hepatitis B virus infection is far less common in urban born than in rural born southern African blacks, who also have a high incidence of hepatocellular carcinoma. A case-control study was carried out to determine the relative frequency of hepatocellular carcinoma and its relation to hepatitis B virus infection in urban born blacks. Three hundred and ninety two black patients with hepatocellular carcinoma and matched controls seen at two city hospitals were classified by questioning as urban born or rural born. The ratio of rural born to urban born blacks among the controls was 1.1:1.0 (207/185), whereas in the patients with cancer the ratio was 4.8:1.0 (324/68) (p less than 0.0001). Analysis of the prevalence of hepatitis B markers in 62 urban born and matched rural born blacks with hepatocellular carcinoma showed no differences in the frequency of current or past hepatitis B virus infection. It is concluded that urban born blacks are less likely than rural born blacks to develop hepatocellular carcinoma, but when they do the tumour is equally likely to be related to infection with hepatitis B virus. The findings lend further support to an important role for chronic hepatitis B virus infection in the aetiology of hepatocellular carcinoma.     

Differences of Ca2+ regulation in skin fibroblasts from blacks and whites

Black people have a higher propensity than caucasians toward essential hypertension. To explore the possibility that this racial difference relates to cellular Ca2+ metabolism, we measured 45Ca2+ washout and uptake and cytosolic free concentration of Ca2+ [Ca2+]i in serially passed skin fibroblasts from normotensive black and white males. Depending on the experimental conditions, 45Ca2+ washout in these cells was described by either two or three exponential functions, whereas 45Ca2+ uptake was described only by a two-exponent function. There were no racial differences in 45Ca2+ uptake and washout of unstimulated fibroblasts. However, stimulation by human serum resulted in an increase in the 45Ca2+ washout that was higher in fibroblasts from blacks than from whites. The racial differences were expressed primarily by higher values of the apparent washout rate constant (k1) of 45Ca2+ from the largest and most rapidly exchangeable cellular pool. The effect of human serum was not related to its origin (blacks vs. whites). In 2 mM Ca2+ medium and 10% serum from blacks, the respective k1 (mean +/- SEM; x 10(-2)/min) values for fibroblasts from blacks and whites were 89.68 +/- 5.23 and 73.29 +/- 4.0; in the presence of 10% serum from whites, the k1 values for cells from blacks and whites were 84.14 +/- 2.80 and 76.36 +/- 3.23 (overall significance of P less than .01). In Ca2+-deficient medium in the presence of 10% human serum, the k1 for fibroblasts from blacks and whites were 115.57 +/- 3.76 and 102.15 +/- 3.30 (P less than .05). Serum substantially increased the 45Ca2+ uptake in fibroblasts from both blacks and whites; however, racial differences were not observed. Basal levels of [Ca2+]i were not different in fibroblasts of blacks vs. whites (46.8 +/- 6.8 and 43.2 +/- 7.1 nM for blacks and whites, respectively). However, the peak response of Cai2+ transients for cell stimulated by 5% human serum was significantly higher in blacks than whites (blacks = 963 +/- 213, whites = 481 +/- 162 nM; P = .0286). We conclude that Ca2+ regulation is different in serum-stimulated fibroblasts from blacks and whites and that, at least in part, this difference may relate to a greater agonist-induced mobilization of Ca2+ in fibroblasts from blacks.     

A matched study of Chagas' cardiopathy in Rio Grande do Sul, Brazil. Behavior of electrocardiographic changes according to the skin color

The pattern of ECG changes of 150 black individuals from rural areas of southern Rio Grande do Sul, Brazil, was compared with that of a group of 150 whites of similar age, sex and geographical residence. The mean age of the study group was 39.2 years (9-78 years), and 62% were women. 84 out of the 150 showed positive serological reactions to infection by Trypanosoma cruzi. The prevalence of ECG changes was significantly higher among the blacks, irrespective of their serological state. Those changes which were considered as suggestive of Chagas cardiopathy were more common among blacks with positive serological reactions. Blacks with seronegative reactions had more frequent ECG changes which were of increased severity, than those of whites with negative reactions. The increased prevalence and severity of ECG changes among black might be attributed to several factors, including: higher levels of poverty, leading to strenuous working conditions; poorer housing quality facilitating infestations by triatominae; inadequate feeding habits. In addition, the increased levels of arterial tension found among the blacks, might be associated with possible racial factors, in collaborating to increase the likelihood of myocardial lesions.     

Race/ethnicity and telomere length in the Multi-Ethnic Study of Atherosclerosis

Telomere length has emerged as a marker of exposure to oxidative stress and aging. Race/ethnic differences in telomere length have been infrequently investigated. Leukocyte telomere length (LTL) was assessed 981 white, black and Hispanic men and women aged 45–84 years participating in the Multi-Ethnic Study of Atherosclerosis. Direct measurement and questionnaire were used to assess covariates. Linear regression was used to estimate associations of LTL with race/ethnicity and age after adjustment for sex, income, education, smoking, physical activity, diet and body mass index. On average blacks and Hispanics had shorter telomeres than whites [adjusted mean differences (standard error) in T/S ratio compared to whites: −0.041 (0.018) for blacks and −0.044 (0.018) for Hispanics]. Blacks and Hispanics showed greater differences in telomere length associated with age than whites (adjusted mean differences in T / S ratio per 1 year increase in age −0.0018, −0.0047 and −0.0055 in whites, blacks and Hispanics respectively). Differences in age associations were more pronounced and only statistically significant in women. Race/ethnic differences in LTL may reflect the cumulative burden of differential exposure to oxidative stress (and its predictors) over the lifecourse.