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.     

Maternal cigarette smoking, Down syndrome in live births, and infant race.

Previous studies have suggested that maternal smoking is negatively associated with a Down syndrome live birth. We analyzed the data of the U.S. Perinatal Collaborative Study in a search for racial variation in Down syndrome risk factors. There were 22 cases in 25,346 live births to smoking mothers (4/10,780 blacks, 18/13,320 whites, and 0/1,246 other races) and 42/29,130 live births to nonsmoking mothers (24/14,665 blacks, 14/11,694 whites, and 4/2,771 others). The crude overall rates per 1,000 live births were 0.4 in black smokers and 1.6 in black nonsmokers but 1.4 in white smokers and 1.2 in white non-smokers. Adjusted for maternal age, the summary relative risk for a Down syndrome live birth to a smoking mother was 0.2 in blacks (95% interval 0.1-0.7) but 1.2 in whites (95% interval 0.6-2.5). Stratification on variables associated with socioeconomic status or gestational age at time of entry into the study did not alter the racial difference. A comparison of smokers with those who never smoked revealed essentially the same trends. Among all nonsmokers the ratio of the maternal age-adjusted risks for a Down syndrome live birth in whites compared with blacks was 0.7 (95% interval 0.3-1.3), and among all smokers this ratio was 3.6 (95% interval 1.3-9.9). If the results are not attributable to statistical fluctuation or undetected confounding, then differences in the probability of intrauterine survival of the Down syndrome fetus would appear to be one plausible explanation for the difference.     

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.     

Overall and recurrence-free survival among black and white bladder cancer patients in an equal-access health system

BackgroundWhile the incidence of bladder cancer is twice as high among whites than among blacks, mortality is higher among blacks than whites. Unequal access to medical care may be an important factor. Insufficient access to care could delay cancer detection and treatment, which can result in worse survival. The purpose of this study was to evaluate whether survival differed between black and white bladder cancer patients in the Department of Defense (DoD), which provides universal healthcare to all beneficiaries regardless of racial background.MethodsThis study was based on data from the U.S. DoD Automated Central Tumor Registry (ACTUR). White and black patients histologically diagnosed with bladder cancer between 1990 and 2004 were included in the study and followed to the end of 2007. The outcomes were all-cause mortality and recurrence. We assessed the relationship between race and outcomes of interest using Cox proportional hazard ratios (HRs) for all, non-muscle invasive (NMIBC), and muscle invasive (MIBC) bladder cancers, separately.ResultsThe survival of black and white individuals did not differ statistically. No significant racial differences in survival (HR: 0.96, 95% CI: 0.76–1.22) or recurrence-free survival (HR: 0.94, 95% CI: 0.69–1.30) were observed after adjustment for demographic variables, tumor characteristics, and treatment. Similar findings were observed for NMIBC and MIBC patients, respectively.ConclusionBlack patients were more likely to present with MIBC than white patients. However, white and black patients with bladder cancer were not significantly different in overall and recurrence-free survival regardless of muscle invasion. Our study suggests the importance of equal access to healthcare in reducing racial disparities in bladder cancer survival.     

Trends in Breast Cancer Stage and Mortality in Michigan (1992–2009) by Race,Socioeconomic Status,and Area Healthcare Resources

The long-term effect of socioeconomic status (SES) and healthcare resources availability (HCA) on breast cancer stage of presentation and mortality rates among patients in Michigan is unclear. Using data from the Michigan Department of Community Health (MDCH) between 1992 and 2009, we calculated annual proportions of late-stage diagnosis and age-adjusted breast cancer mortality rates by race and zip code in Michigan. SES and HCA were defined at the zip-code level. Joinpoint regression was used to compare the Average Annual Percent Change (AAPC) in the median zip-code level percent late stage diagnosis and mortality rate for blacks and whites and for each level of SES and HCA. Between 1992 and 2009, the proportion of late stage diagnosis increased among white women [AAPC = 1.0 (0.4, 1.6)], but was statistically unchanged among black women [AAPC = −0.5 (−1.9, 0.8)]. The breast cancer mortality rate declined among whites [AAPC = −1.3% (−1.8,−0.8)], but remained statistically unchanged among blacks [AAPC = −0.3% (−0.3, 1.0)]. In all SES and HCA area types, disparities in percent late stage between blacks and whites appeared to narrow over time, while the differences in breast cancer mortality rates between blacks and whites appeared to increase over time.     

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.     

Resting Energy Expenditure in Obese African American and Caucasian Women

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

Predictors of long-term weight loss in adults with modest initial weight loss, by sex and race

Effective weight management interventions could reduce race-sex disparities in cardiovascular disease (CVD), yet little is known about factors associated with successful weight loss maintenance in race-sex subgroups. In the Weight Loss Maintenance trial (WLM), overweight/obese (BMI 25-45 kg/m(2)) adults who lost ≥4 kg in a 6-month behavioral weight loss intervention (phase I) were randomized into one of three 30-month maintenance interventions (phase II). To investigate predictors in subgroups, randomized groups were combined for this analysis. Of 1,685 phase I participants, 1,032 (61%) entered phase II, including 12% black men (BM), 26% black women (BW), 25% white men (WM), and 37% white women (WW). Weight change over the 36-month study ranged from -2.3% (95% confidence interval = -3.1 to -1.5%) in BW to -4.5% (95% confidence interval = -5.7 to -4.0%) in WM, the result of differential weight loss during phase I. Within race, men lost significantly more weight than women, but within sex group, weight loss did not differ significantly between races. Although participants regained weight during phase II, regain did not differ by race-sex group, and mean weight at the end of the study was significantly lower than phase I entry weight for each subgroup. In regression models, phase I weight loss predicted overall 36-month weight loss in all race-sex groups. Healthy dietary pattern at entry, improvement in dietary pattern, or both were predictive in three of four race-sex groups. Few other variables other than initial weight loss and dietary pattern were predictive. Future research should identify additional modifiable influences on long-term maintenance after a modest weight loss.     

Explaining racial disparities in access to employment benefits

This research examines disparities in access to pension and health insurance plans between white, blacks, Latino and Asian workers in the American labour force. Using data from the 2006 March Supplement of the Current Population Survey, the analysis reveals that Latino workers are the most disadvantaged and white workers are the most advantaged. The entire gap in likelihood of receiving benefits between whites and Asians, and a substantial portion of the gap between whites and blacks, can be accounted for by socio-demographic and employment-related variables, but only a small portion of the gap between whites and Latinos can be attributed to such variables. The findings suggest that reliance on earnings for estimation of inequality underestimates the economic gap between racial groups. Explanations for disparities in access to employment benefits are offered and the relevance of the findings to other societies is discussed.     

Duration between marriage and first birth and marital instability

This paper considers whether marital instability varies by the duration between marriage and 1st birth among ever-married white and black American women. Analysis of data from the June 1985 Current Population Survey suggests that the duration between marriage and 1st birth has a generally monotonic relationship with the probability of white women separating or divorcing from their 1st marriage; the relationship has remained relatively constant over time. For blacks, no consistent association is found between marital dissolution and the duration between marriage and 1st birth. Black women having a premarital conception and postmarital birth and those having their 1st birth during their 2nd year of marriage have a similarly high risk of dissolution. Conversely, blacks having their 1st birth 8-12 or 25-42 months after marrying have a low probability of dissolution. Childless women and those with premarital births generally has the greatest probability of marital disruption for whites. Racial differences may occur because blacks view the 1st birth and marriage differently than whites. That is, because blacks are much more likely to have premarital births and to have a shorter duration between marriage and 1st birth, blacks and whites in the same 1st birth interval category may be dissimilar and have different values resulting in a differential effect of the timing of the 1st birth on marital instability by race. Caution is needed when interpreting the pattern of association between delayed childbearing (and to a lesser extent, births occuring a few years after marriage) and marital instability. Results for whites were similar at each marriage duration and it is assumed delayed childbearing was not a result of marital instability. Marital instability was expected to have its strongest effect on the timing of the 1st birth during the 1st years of marriage. Marital instability may be partially responsible for the delaying of childbearing among blacks. However, blacks who delay but are married at 1st birth have a relatively low risk of separating or divorcing.     

Racial disparities in treatment and survival from ovarian cancer

BackgroundBlack women with ovarian cancer in the U.S. have lower survival than whites. We aimed to identify factors associated with racial differences in ovarian cancer treatment and overall survival (OS).MethodsWe examined data from 365 white and 95 black ovarian cancer patients from the Hollings Cancer Center Cancer Registry in Charleston, S.C. between 2000 and 2015. We used unconditional logistic regression to estimate odds ratios (ORs) and 95% confidence intervals (CIs) between race and receipt of surgery and chemotherapy, and Cox proportional hazards regression to estimate hazard ratios (HRs) and 95% CIs between race and OS. Model variables included diagnosis center, stage, histology, insurance status, smoking, age-adjusted Charlson comorbidity index (AACI) and residual disease. Interactions between race and AACI were assessed using −2 log likelihood tests.ResultsBlacks vs. whites were over two-fold less likely to receive a surgery-chemotherapy sequence (multivariable-adjusted OR 2.46, 95% CI 1.43–4.21), particularly if they had a higher AACI (interaction p = 0.008). In multivariable-adjusted Cox models, black women were at higher risk of death (HR 1.81, 95% CI 1.35–2.43) than whites, even when restricted to patients who received a surgery-chemotherapy sequence (HR 1.79, 95% CI 1.10–2.89) and particularly for those with higher AACI (HR 4.70, 95% CI 2.00 − 11.02, interaction p = 0.01).ConclusionsAmong blacks, higher comorbidity associates with less chance of receiving guideline-based treatment and also modifies OS. Differences in receipt of guideline-based care do not completely explain survival differences between blacks and whites with ovarian cancer. These results highlight opportunities for further research.     

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.     

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.     

Comparisons for Body Mass Index and Body Fat Percent Among Puerto Ricans,Blacks, Whites and Asians Living in the New York City Area

The latest data (NHANES III) from the National Center for Health Statistics (NCHS) show that the black population has the highest proportion of overweight among all adult populations in the United States. The present study compared the body mass index (BMI) and body fat percent from dual-photon absorptiometry in 1,324 healthy adults aged 18 to 107 years recruited from four ethnic groups in the New York City area; 523 whites, 280 blacks, 267 Asians and 254 Puerto Ricans. Puerto Ricans had the largest BMI and the largest percent of subjects with body weight more than 120% of their ideal weight, and the largest fat percent of the four ethnic groups: 76% of Puerto Rican males had fat percent above the median value for white males (fat percent = 19.6%) and 95% of Puerto Rican females had fat percent above the median for white females (fat percent = 30.8%). Asians had the smallest BMI, but 63% of them had fat percent above the median values for whites in each gender. Puerto Ricans also had the largest waist-to-hip ratios among the four ethnic groups. In blacks, the percent of subjects with fat percent larger than the median for whites was slightly smaller than that for Puerto Ricans, 64% and 82% of males and females respectively. These results differ from the latest NCHS data and show that Puerto Ricans in this sample are heavier and fatter than blacks.     

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.     

Recent trends in the epidemiology of cervical neoplasia

Incidence and survival rates were estimated for all white and black women in metropolitan Atlanta with a new diagnosis of in situ or invasive cervical carcinoma between 1975 and 1986. During this period, the average annual age-adjusted incidence (per 100,000) of in situ lesions declined from 51.4 to 25.6 among whites and from 102.2 to 34.6 among blacks. The average annual age-adjusted incidence rate of invasive cervical cancer decreased from 11.8 to 8.2 for whites and from 33.0 to 26.7 for blacks. Although the black-to-white ratio of carcinoma in situ incidence rates declined progressively over time, the excess of invasive cancer among blacks did not decrease. The five-year cumulative survival percentages by stage for whites and blacks, respectively, were 99.1 and 99.1 for in situ carcinoma, 92.2 and 80.5 for locally invasive carcinoma, 49.2 and 40.5 for regionally invasive carcinoma and 3.1 and 3.4 for cases with distant metastases. No improvements in stage at diagnosis of invasive cancer or stage-specific survival rates were observed during this period.     

Trends in the Educational Gradient of U.S. Adult Mortality from 1986 to 2006 by Race, Gender, and Age Group

The educational gradient of U.S. adult mortality became steeper between 1960 and the mid 1980s, but whether it continued to steepen is less clear given a dearth of attention to these trends since that time. This study provides new evidence on trends in the education-mortality gradient from 1986 to 2006 by race, gender, and age among non-Hispanic whites and blacks using data from the 2010 release of the National Health Interview Survey Linked Mortality File. Results show that, for white and black men, the gradient steepened among older ages because declines in mortality risk across education levels were greater among the higher educated. The gradient steepened among white women, and to a much lesser and only marginally significant extent among black women, largely because mortality risk decreased among the college-educated but increased among women with less than a high school degree. Greater returns to higher education and compositional changes within educational strata likely contributed to the trends.     

Initial screening transferrin saturation values, serum ferritin concentrations, and HFE genotypes in whites and blacks in the Hemochromatosis and Iron Overload Screening Study

We compared initial screening data of 44,082 white and 27,124 black Hemochromatosis and Iron Overload Screening (HEIRS) Study participants. Each underwent serum transferrin saturation (TfSat) and ferritin (SF) measurements without regard to fasting, and HFE C282Y and H63D genotyping. Elevated measurements were defined as: TfSat more than 50% (men), more than 45% (women); and SF more than 300 ng/ml (men), more than 200 ng/ml (women). Mean TfSat and percentages of participants with elevated TfSat were significantly greater in whites than in blacks. Mean SF and percentages of participants with elevated SF were significantly greater in blacks than in whites. TfSat and SF varied by gender and age in whites and blacks. Prevalences of genotypes that included either C282Y or H63D were significantly greater in whites than in blacks. The prevalence of elevated TfSat and SF plus genotypes C282Y/C282Y, C282Y/H63D, or H63D/H63D was 0.006 in whites and 0.0003 in blacks. Among whites with HFE C282Y homozygosity, 76.8% of men and 46.9% of women had elevated TfSat and SF values. Three black participants had HFE C282Y homozygosity; one had elevated TfSat and SF values. Possible explanations for differences in TfSat and SF in whites and blacks and pertinence to the detection of hemochromatosis, iron overload, and other disorders with similar phenotypes are discussed.     

Uncoupling protein 3 gene is associated with body composition changes with training in HERITAGE study.

The uncoupling protein 3 (UCP3) is a mitochondrial membrane transporter mainly expressed in skeletal muscle that we have shown to be associated with obesity. We have analyzed UCP3 polymorphisms, Val102Ile, Tyr210Tyr, and a new microsatellite GAIVS6 located in the sixth intron, among 276 black and 503 white subjects from the HERITAGE Family Study. Linkage and association studies were undertaken with body composition variables measured in a sedentary state (baseline) and after 20 wk of endurance training (changes). Allele and genotype frequencies were found to be significantly different between whites and blacks. Suggestive linkages (0.009 < or = P < or = 0.033) with Tyr210Tyr were found in blacks and whites for baseline body mass index, fat mass, or leptin level and with GAIVS6 in whites for changes in fat mass and percent body fat. Associations were also found in whites between GAIVS6 and changes in the sum of eight skinfold thicknesses (P = 0.0006), with a borderline result for body mass index (P = 0.06). We concluded that UCP3 could be involved in body composition changes after regular exercise.     

The Contribution of Weight Status to Black-White Differences in Mortality

This article examines the contribution of weight status to black-white (B-W) differences in mortality at ages 40–79 using data from the National Health and Nutrition Examination Survey. We measured body mass index (BMI) based on the highest BMI attained and contrasted the contribution of BMI to that of smoking and educational attainment. We estimated both additive and multiplicative models. In addition to estimating regression coefficients we asked what would happen to B-W differences in mortality if blacks had the BMI distribution of whites, the smoking prevalence of whites, or the educational distribution of whites. B-W differences in BMI account for close to 30 percent of the B-W difference in female mortality but only about 1 percent of the B-W difference in male mortality at ages 40–79. In contrast, smoking makes a much larger contribution to the B-W difference in male (17 percent) than female (6 percent) mortality. Differences in educational attainment in turn explain 19 to 25 percent of the B-W mortality difference among men and women, respectively. Our results underscore the importance of two key risk factors as well as educational attainment in generating B-W differences in mortality.