Dynamics of human populations

This study expands on earlier findings of racial/ethnic and education–allostatic load associations by assessing whether racial/ethnic differences in allostatic load persist across all levels of educational attainment. This study used data from four recent waves of the National Health and Nutrition Survey (NHANES). Results from this study suggest that allostatic load differs significantly by race/ethnicity and educational attainment overall, but that the race/ethnicity association is not consistent across education level. Analysis of interactions and education-stratified models suggest that allostatic load levels do not differ by race/ethnicity for individuals with low education; rather, the largest allostatic load differentials for Mexican Americans (p < .01) and non-Hispanic blacks (p < .001) are observed for individuals with a college degree or more. These findings add to the growing evidence that differences in socioeconomic opportunities by race/ethnicity are likely a consequence of differential returns to education, which contribute to higher stress burdens among minorities compared to non-Hispanic whites.     

Variation in LPA is associated with Lp(a) levels in three populations from the Third National Health and Nutrition Examination Survey

The distribution of lipoprotein(a) [Lp(a)] levels can differ dramatically across diverse racial/ethnic populations. The extent to which genetic variation in LPA can explain these differences is not fully understood. To explore this, 19 LPA tagSNPs were genotyped in 7,159 participants from the Third National Health and Nutrition Examination Survey (NHANES III). NHANES III is a diverse population-based survey with DNA samples linked to hundreds of quantitative traits, including serum Lp(a). Tests of association between LPA variants and transformed Lp(a) levels were performed across the three different NHANES subpopulations (non-Hispanic whites, non-Hispanic blacks, and Mexican Americans). At a significance threshold of p<0.0001, 15 of the 19 SNPs tested were strongly associated with Lp(a) levels in at least one subpopulation, six in at least two subpopulations, and none in all three subpopulations. In non-Hispanic whites, three variants were associated with Lp(a) levels, including previously known rs6919246 (p = 1.18 × 10(-30)). Additionally, 12 and 6 variants had significant associations in non-Hispanic blacks and Mexican Americans, respectively. The additive effects of these associated alleles explained up to 11% of the variance observed for Lp(a) levels in the different racial/ethnic populations. The findings reported here replicate previous candidate gene and genome-wide association studies for Lp(a) levels in European-descent populations and extend these findings to other populations. While we demonstrate that LPA is an important contributor to Lp(a) levels regardless of race/ethnicity, the lack of generalization of associations across all subpopulations suggests that specific LPA variants may be contributing to the observed Lp(a) between-population variance.     

Injury mortality in New Mexico's American Indians,Hispanics, and non-Hispanic whites, 1958 to 1982.

New Mexico has extraordinarily high injury mortality rates. To better characterize the injury problem in New Mexico, we calculated proportionate injury mortality and age-adjusted and age-specific injury mortality rates for the state''s 3 major ethnic groups--American Indians, Hispanics, and non-Hispanic whites. According to death certificate data collected from 1958 to 1982 and US population census figures, age-adjusted mortality rates for total external causes varied widely between the sexes and among the ethnic groups. Males in each ethnic group consistently had higher average annual age-adjusted external mortality rates than females. Injury mortality rates for American Indians of both sexes were 2 to 3 times higher than those for the other New Mexico ethnic groups. Motor vehicle crashes were the leading cause of death from injury for all 3 groups. Homicide accounted for twice the proportion of injury death in Hispanic compared with non-Hispanic white males (12.5% and 6.1%, respectively), while the proportion of males dying of suicide was highest in non-Hispanic whites. Deaths from excessive cold and exposure were leading causes of injury mortality for American Indians, but these causes were not among the leading causes of injury mortality for Hispanics or non-Hispanic whites. We conclude that the minority populations in New Mexico are at high risk for injury-related death and that the major causes of injury mortality vary substantially in the state''s predominant ethnic populations.     

Ethnic differences in atherosclerosis, cardiovascular disease and lipid metabolism

PURPOSE OF REVIEW: Comparison of risk factors and cardiovascular disease among racial and ethnic groups is a powerful approach to study genetics and lifestyle, or environmental interactions. RECENT FINDINGS: Most, mean or median, cardiovascular risk factor levels are similar among black and white people. There are much greater differences in the distribution of risk factor level within a specific race and ethnic group than between US populations. There are also very large differences in levels of risk factors for coronary heart disease between specific ethnic migrant populations such as comparing black people in Africa with those in the US, or Japanese people in Japan with those in Hawaii and California. Differences in distribution of risk factors and disease between race and ethnic group are a function of the frequency of specific genotypes and interaction with environmental factors. Several of the most important differences between racial groups are higher blood pressure, lower triglycerides and higher HDL cholesterol among blacks, higher prevalence of diabetes and insulin resistance among Mexican Americans and American Indians, and higher triglyceride levels among the Japanese. SUMMARY: Further studies of racial and ethnic differences should focus on unique phenotypes and genotypic differences, international and migrant studies and large enough sample sizes to provide robust results. The sprinkling of a percentage of minority participants in each study is worthless. The study of racial and ethnic differences in disease and detection of risk factor levels must be based on solid hypotheses that can evaluate the interaction of lifestyle and possible genetic attributes. Many of the reported ethnic differences in risk factors and disease in US populations are primarily a function of differences in education, socioeconomic variations, and utilization of preventive and clinical treatments.     

Risk Factors for Acute Stroke among South Asians Compared to Other Racial/Ethnic Groups

Background

Studies of racial/ethnic variations in stroke rarely consider the South Asian population, one of the fastest growing sub-groups in the United States. This study compared risk factors for stroke among South Asians with those for whites, African-Americans, and Hispanics.

Methods

Data on 3290 stroke patients were analyzed to examine risk differences among the four racial/ethnic groups. Data on 3290 patients admitted to a regional stroke center were analyzed to examine risk differences for ischemic stroke (including subtypes of small and large vessel disease) among South Asians, whites, African Americans and Hispanics.

Results

South Asians were younger and had higher rates of diabetes mellitus, blood pressure, and fasting blood glucose levels than other race/ethnicities. Prevalence of diabetic and antiplatelet medication use, as well as the incidence of small-artery occlusion ischemic stroke was also higher among South Asians. South Asians were almost a decade younger and had comparable socioeconomic levels as whites; however, their stroke risk factors were comparable to that of African Americans and Hispanics.

Discussion

Observed differences in stroke may be explained by dietary and life style choices of South Asian-Americans, risk factors that are potentially modifiable. Future population and epidemiologic studies should consider growing ethnic minority groups in the examination of the nature, outcome, and medical care profiles of stroke.     

Survival disparities among racial/ethnic groups of women with ovarian cancer: An update on data from the Surveillance,Epidemiology and End Results (SEER) registry

ObjectiveUpdate information on racial disparities in ovarian cancer survival from the Surveillance, Epidemiology, and End Results (SEER) Program.MethodsData on women with epithelial ovarian cancer from the SEER Program between 1995–2015 were collected including; patient ID, age at diagnosis, year of diagnosis, surgery, chemotherapy, radiation, insurance status, region of registry, tumor grade, tumor histology, tumor summary stage, survival months, race/ethnicity, and vital status. Multivariable analyses were performed to examine overall survival, differences in survival by age at diagnosis, by year of diagnosis, risk of not receiving surgery, and risk of 12-month death across racial/ethnic groups.ResultsNon-Hispanic black women (n = 4261) had an increased risk of overall mortality (HR = 1.28, CI: 1.23–1.33) when compared to non-Hispanic white women (n = 47,475), which appears more pronounced among women diagnosed under age 50. Hispanic women (n = 7052) had no difference in survival when compared to non-Hispanic white women (HR = 1.03, CI: 0.99–1.07). Non-Hispanic Asian/PI women (n = 5008) exhibited slightly reduced risk (HR = 0.95, CI: 0.91–0.99) when compared to non-Hispanic white women. Risk of not receiving surgical intervention remains high among non-Hispanic black women and Hispanic women, when compared to non-Hispanic white women. Non-Hispanic black women, non-Hispanic Asian/PI women, and Hispanic women were all at significantly greater risk of dying within the first 12 months of cancer diagnosis when compared to non-Hispanic white women.ConclusionDisparities in survival remain across various racial/ethnic groups, when compared to non-Hispanic white women with ovarian cancer. These disparities should continue to be examined in an effort to decrease such gaps.     

Differential Impact of Obesity in Related Populations

To search for genetic and environmental determinants of obesity, we compared the prevalences and the impact of obesity in three populations from two cities: Mexican Amcricans (n=820) and non-Hispanic whites (n=1112)from San Antonio, Texas, and Mexicans from Mexico City (n= 1878). In the age range examined, 35–64 years, only Mexican men and women showed a significant increase in the prevalence of obesity with age. On the other hand, genetic ancestry, especially in women, made significant differences in the rates of obesity. Mexican Americans showed relatively high, and non-Hispanic whites low, rates of obesity. To discriminate between genetic and environmental influences mediating the impact of obesity on a set of hemodynamic and metabolic variables, we compared this impact between Mexican Americans and both non-Hispanic whites (same macro-environment, different gene pools), and Mexicans (same gene pool, different environments). We found that obesity always worsens the hemodynamic and metabolic profiles of individuals, but the magnitude of the effects may be variable. We showed that the levels of insulin concentrations for a given level of obesity were similar in Mexicans and Mexican Americans, suggesting that genetic influences predominate in determining insulin levels; the levels of triglycerides and HDL for a given level of obesity were similar in Mexican Americans and non-Hispanic whites, suggesting predominant environmental influences on lipid levels. On the other hand, the levels of glucose and systolic blood pressure for a given level of obesity were usually different between Mexican Americans and either of the other two populations, suggesting that these levels may result from genotype-by-environment interactions.     

Obesity and C-reactive protein levels among white, black, and hispanic US adults

Objective: Studies suggest that obesity's adverse impact on cardiovascular mortality may be reduced in African Americans relative to white Americans. We examined whether obesity's association with novel cardiovascular risk factors such as C‐reactive protein (CRP) also varies by race and ethnicity. Methods and Procedures: We analyzed data from 10,492 white, African‐American, and Hispanic‐American participants of the 1999–2004 National Health and Nutrition Examination Survey, who were aged 20 years and older, with a BMI ≥18.5 kg/m² and CRP ≤10 mg/l. We fit sex‐specific multivariable models of the association of BMI or waist circumference with log CRP levels and tested for interactions of BMI or waist circumference with race/ethnicity. Results: Higher BMI was significantly associated with higher CRP in all racial/ethnic groups for both men and women (P > 0.05 for BMI–race/ethnicity interaction) before and after adjustment for age, education, and health behaviors. Larger waist circumference was also associated with higher CRP levels in all racial/ethnic groups before and after adjustment; among women, the relationship was strongest for Mexican Hispanics (P < 0.01 for waist circumference–race/ethnicity interaction). Results were similar after additional adjustment for medications that might affect CRP levels. Discussion: The association between obesity and CRP is at least as strong in African Americans and Hispanic Americans as in white Americans. Racial differences in the relationship between obesity and cardiovascular mortality are unlikely to be due to racial differences in obesity's impact on CRP.     

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.     

Detection of Pleiotropy through a Phenome-Wide Association Study (PheWAS) of Epidemiologic Data as Part of the Environmental Architecture for Genes Linked to Environment (EAGLE) Study

We performed a Phenome-wide association study (PheWAS) utilizing diverse genotypic and phenotypic data existing across multiple populations in the National Health and Nutrition Examination Surveys (NHANES), conducted by the Centers for Disease Control and Prevention (CDC), and accessed by the Epidemiological Architecture for Genes Linked to Environment (EAGLE) study. We calculated comprehensive tests of association in Genetic NHANES using 80 SNPs and 1,008 phenotypes (grouped into 184 phenotype classes), stratified by race-ethnicity. Genetic NHANES includes three surveys (NHANES III, 1999–2000, and 2001–2002) and three race-ethnicities: non-Hispanic whites (n = 6,634), non-Hispanic blacks (n = 3,458), and Mexican Americans (n = 3,950). We identified 69 PheWAS associations replicating across surveys for the same SNP, phenotype-class, direction of effect, and race-ethnicity at p<0.01, allele frequency >0.01, and sample size >200. Of these 69 PheWAS associations, 39 replicated previously reported SNP-phenotype associations, 9 were related to previously reported associations, and 21 were novel associations. Fourteen results had the same direction of effect across more than one race-ethnicity: one result was novel, 11 replicated previously reported associations, and two were related to previously reported results. Thirteen SNPs showed evidence of pleiotropy. We further explored results with gene-based biological networks, contrasting the direction of effect for pleiotropic associations across phenotypes. One PheWAS result was ABCG2 missense SNP rs2231142, associated with uric acid levels in both non-Hispanic whites and Mexican Americans, protoporphyrin levels in non-Hispanic whites and Mexican Americans, and blood pressure levels in Mexican Americans. Another example was SNP rs1800588 near LIPC, significantly associated with the novel phenotypes of folate levels (Mexican Americans), vitamin E levels (non-Hispanic whites) and triglyceride levels (non-Hispanic whites), and replication for cholesterol levels. The results of this PheWAS show the utility of this approach for exposing more of the complex genetic architecture underlying multiple traits, through generating novel hypotheses for future research.     

Characterization of mitochondrial haplogroups in a large population-based sample from the United States

Mitochondrial DNA (mtDNA) haplogroups are valuable for investigations in forensic science, molecular anthropology, and human genetics. In this study, we developed a custom panel of 61 mtDNA markers for high-throughput classification of European, African, and Native American/Asian mitochondrial haplogroup lineages. Using these mtDNA markers, we constructed a mitochondrial haplogroup classification tree and classified 18,832 participants from the National Health and Nutrition Examination Surveys (NHANES). To our knowledge, this is the largest study to date characterizing mitochondrial haplogroups in a population-based sample from the United States, and the first study characterizing mitochondrial haplogroup distributions in self-identified Mexican Americans separately from Hispanic Americans of other descent. We observed clear differences in the distribution of maternal genetic ancestry consistent with proposed admixture models for these subpopulations, underscoring the genetic heterogeneity of the United States Hispanic population. The mitochondrial haplogroup distributions in the other self-identified racial/ethnic groups within NHANES were largely comparable to previous studies. Mitochondrial haplogroup classification was highly concordant with self-identified race/ethnicity (SIRE) in non-Hispanic whites (94.8 %), but was considerably lower in admixed populations including non-Hispanic blacks (88.3 %), Mexican Americans (81.8 %), and other Hispanics (61.6 %), suggesting SIRE does not accurately reflect maternal genetic ancestry, particularly in populations with greater proportions of admixture. Thus, it is important to consider inconsistencies between SIRE and genetic ancestry when performing genetic association studies. The mitochondrial haplogroup data that we have generated, coupled with the epidemiologic variables in NHANES, is a valuable resource for future studies investigating the contribution of mtDNA variation to human health and disease.     

Racial differences in nasopharyngeal carcinoma in the United States

Background: Nasopharyngeal carcinoma (NPC) is a malignant neoplasm arising from the mucosal epithelium of the nasopharynx. Different races can have different etiology, presentation, and progression patterns. Methods: Data were analyzed on NPC patients in the United States reported to the SEER (Surveillance, Epidemiology, and End Results) database between 1973 and 2009. Racial groups studied included non-Hispanic whites, Hispanic whites, blacks, Asians, and others. Patient characteristics, age-adjusted incidence and mortality rates, treatment, and five-year relative survival rates were compared across races. Stratification by stage at diagnosis and histologic type was considered. Multivariate regression was conducted to evaluate the significance of racial differences. Results: Patient characteristics that were significantly different across races included age at diagnosis, histologic type, in situ/malignant tumors in lifetime, stage, grade, and regional nodes positive. Incidence and mortality rates were significantly different across races, with Asians having the highest rates overall and stratified by age and/or histologic type. Asians also had the highest rate of receiving radiation only. The racial differences in treatment were significant in the multivariate stratified analysis. When stratified by stage and histologic type, Asians had the best five-year survival rates. The survival experience of other races depended on stage and type. In the multivariate analysis, the racial differences were significant. Conclusions: Analysis of the SEER data shows that racial differences exist among NPC patients in the U.S. This result can be informative to cancer epidemiologists and clinicians.     

Economic distress and cause-of-death patterns for black and non-black men in Chicago: reconsidering the relevance of classic epidemiological transition theory

The mortality disadvantage of African Americans is well documented, but previous studies have not considered its implications for population theory in the general case of industrialized nation states with high levels of income inequality. This paper examines the relevance of classic epidemiological theory to the extremes of income and mortality observed in Chicago, one of America's most racially divided cities. We analyze cause-specific death rates for black and non-black male populations residing in Chicago's community areas by using linked data from the 1990 Census and from 1989-1991 individual death certificates. The same cause-of-death patterns explain much of the mortality of black and non-black men. These two major structures include one, degenerative diseases, the other, "tough-living" causes (accidents, homicides, and liver disease). Community socioeconomic status is strongly related to tough-living deaths within each racial group, and to degenerative deaths for African Americans. Black men's tough-living mortality is much greater than non-blacks', but their younger age structure suppresses their degenerative death rates. Aggregate unemployment and social disorganization account for the most salient disparities in mortality across racial groups. This patterning of mortality along a socioeconomic continuum supports epidemiological theory and extends its applicability to highly unequal populations within industrialized countries.     

Leading Causes of Death among Asian American Subgroups (2003–2011)

Background

Our current understanding of Asian American mortality patterns has been distorted by the historical aggregation of diverse Asian subgroups on death certificates, masking important differences in the leading causes of death across subgroups. In this analysis, we aim to fill an important knowledge gap in Asian American health by reporting leading causes of mortality by disaggregated Asian American subgroups.

Methods and Findings

We examined national mortality records for the six largest Asian subgroups (Asian Indian, Chinese, Filipino, Japanese, Korean, Vietnamese) and non-Hispanic Whites (NHWs) from 2003-2011, and ranked the leading causes of death. We calculated all-cause and cause-specific age-adjusted rates, temporal trends with annual percent changes, and rate ratios by race/ethnicity and sex. Rankings revealed that as an aggregated group, cancer was the leading cause of death for Asian Americans. When disaggregated, there was notable heterogeneity. Among women, cancer was the leading cause of death for every group except Asian Indians. In men, cancer was the leading cause of death among Chinese, Korean, and Vietnamese men, while heart disease was the leading cause of death among Asian Indians, Filipino and Japanese men. The proportion of death due to heart disease for Asian Indian males was nearly double that of cancer (31% vs. 18%). Temporal trends showed increased mortality of cancer and diabetes in Asian Indians and Vietnamese; increased stroke mortality in Asian Indians; increased suicide mortality in Koreans; and increased mortality from Alzheimer’s disease for all racial/ethnic groups from 2003-2011. All-cause rate ratios revealed that overall mortality is lower in Asian Americans compared to NHWs.

Conclusions

Our findings show heterogeneity in the leading causes of death among Asian American subgroups. Additional research should focus on culturally competent and cost-effective approaches to prevent and treat specific diseases among these growing diverse populations.     

Ethnic inequalities in mortality: the case of Arab-Americans

Background

Although nearly 112 million residents of the United States belong to a non-white ethnic group, the literature about differences in health indicators across ethnic groups is limited almost exclusively to Hispanics. Features of the social experience of many ethnic groups including immigration, discrimination, and acculturation may plausibly influence mortality risk. We explored life expectancy and age-adjusted mortality risk of Arab-Americans (AAs), relative to non-Arab and non-Hispanic Whites in Michigan, the state with the largest per capita population of AAs in the US.

Methodology/Principal Findings

Data were collected about all deaths to AAs and non-Arab and non-Hispanic Whites in Michigan between 1990 and 2007, and year 2000 census data were collected for population denominators. We calculated life expectancy, age-adjusted all-cause, cause-specific, and age-specific mortality rates stratified by ethnicity and gender among AAs and non-Arab and non-Hispanic Whites. Among AAs, life expectancies among men and women were 2.0 and 1.4 years lower than among non-Arab and non-Hispanic White men and women, respectively. AA men had higher mortality than non-Arab and non-Hispanic White men due to infectious diseases, chronic diseases, and homicide. AA women had higher mortality than non-Arab and non-Hispanic White women due to chronic diseases.

Conclusions/Significance

Despite better education and higher income, AAs have higher age-adjusted mortality risk than non-Arab and non-Hispanic Whites, particularly due to chronic diseases. Features specific to AA culture may explain some of these findings.     

Ethnic-immigrant differentials in health behaviors, morbidity, and cause-specific mortality in the United States: an analysis of two national data bases

This study examines the extent to which various ethnic-immigrant and US-born groups differ in their risks of all-cause and cause-specific mortality, morbidity, and health behaviors. Using data from the National Longitudinal Mortality Study, 1979-1989, we estimated, for major US racial and ethnic groups, mortality risks of immigrants relative to those of the US-born. The Cox regression model was used to adjust mortality differentials by age, sex, marital status, rural/urban residence, education, and family income. Logistic regression was fitted to the National Health Interview Survey data to determine whether health status and behaviors vary among ethnic-immigrant groups and by length of US residence. Compared with US-born whites of equivalent socioeconomic and demographic background, foreign-born blacks, Hispanics, and Asians/Pacific Islanders (APIs), US-born APIs, US-born Hispanics, and foreign-born whites had, respectively, 48%, 45%, 43%, 32%, 26%, and 16% lower mortality risks. While American Indians did not differ significantly from US-born whites, US-born blacks had an 8% higher mortality risk. Black and Hispanic immigrants experienced, respectively, 52% and 26% lower mortality risks than their US-born counterparts. Considerable differentials were also found in mortality for cancer, cardiovascular, respiratory, infectious disease, and injury, and in morbidity and health behaviors, with API and Hispanic immigrants generally experiencing the lowest risks. Consistent with the acculturation hypothesis, immigrants' risks of smoking, obesity, hypertension, and chronic condition, although substantially lower than those for the US-born, increased with increasing length of US residence. Given the substantial nativity differences in health status and mortality, future waves of immigrants of diverse ethnic and cultural backgrounds will likely have a sizeable impact on the overall health, disease, and mortality patterns in the United States.     

Susceptibility gene search for nephropathy and related traits in Mexican–Americans

The rising global epidemic of diabetic nephropathy (DN) will likely lead to increase in the prevalence of cardiovascular morbidity and mortality posing a serious burden for public health care. Despite greater understanding of the etiology of diabetes and the development of novel treatment strategies to control blood glucose levels, the prevalence and incidence rate of DN is increasing especially in minority populations including Mexican–Americans. Mexican–Americans with type 2 diabetes (T2DM) are three times more likely to develop microalbuminuria, and four times more likely to develop clinical proteinuria compared to non-Hispanic whites. Furthermore, Mexican–Americans have a sixfold increased risk of developing renal failure secondary to T2DM compared to Caucasians. Prevention and better treatment of DN should be a high priority for both health-care organizations and society at large. Pathogenesis of DN is multi-factorial. Familial clustering of DN-related traits in MAs show that DN and related traits are heritable and that genes play a susceptibility role. While, there has been some progress in identifying genes which when mutated influence an individual’s risk, major gene(s) responsible for DN are yet to be identified. Knowledge of the genetic causes of DN is essential for elucidation of its mechanisms, and for adequate classification, prognosis, and treatment. Self-identification and collaboration among researchers with suitable genomic and clinical data for meta-analyses in Mexican–Americans is critical for progress in replicating/identifying DN risk genes in this population. This paper reviews the approaches and recent efforts made to identify genetic variants contributing to risk for DN and related phenotypes in the Mexican–American population.     

Ethnicity and human genetic linkage maps

Human genetic linkage maps are based on rates of recombination across the genome. These rates in humans vary by the sex of the parent from whom alleles are inherited, by chromosomal position, and by genomic features, such as GC content and repeat density. We have examined--for the first time, to our knowledge--racial/ethnic differences in genetic maps of humans. We constructed genetic maps based on 353 microsatellite markers in four racial/ethnic groups: whites, African Americans, Mexican Americans, and East Asians (Chinese and Japanese). These maps were generated using 9,291 subjects from 2,900 nuclear families who participated in the National Heart, Lung, and Blood Institute-funded Family Blood Pressure Program, the largest sample used for map construction to date. Although the maps for the different groups are generally similar, we did find regional and genomewide differences across ethnic groups, including a longer genomewide map for African Americans than for other populations. Some of this variation was explained by genotyping artifacts--namely, null alleles (i.e., alleles with null phenotypes) at a number of loci--and by ethnic differences in null-allele frequencies. In particular, null alleles appear to be the likely explanation for the excess map length in African Americans. We also found that nonrandom missing data biases map results. However, we found regions on chromosome 8p and telomeric segments with significant ethnic differences and a suggestive interval on chromosome 12q that were not due to genotype artifacts. The difference on chromosome 8p is likely due to a polymorphic inversion in the region. The results of our investigation have implications for inferences of possible genetic influences on human recombination as well as for future linkage studies, especially those involving populations of nonwhite ethnicity.     

Decline of tuberculosis mortality in an urban Mexican‐origin population, 1935–1984

Abstract

Through a series of life table analyses, this paper describes the natural history of tuberculosis mortality in a Mexican‐origin community over five decades (1935–84) during which the disease underwent a transition from a major underlying cause of death to a disease conditioned mentioned more often on death certificates as contributing to death than causing death. The decline in death rates from 1940 to 1950 was especially remarkable. Successive birth cohorts of Mexican Americans, separated by as little as five years of age, experienced distinctly lower risk of death from tuberculosis as they entered young adulthood. There was a rapid convergence in age‐specific patterns of tuberculosis death rates in Mexican Americans toward those of non‐Hispanic whites, so that by 1960 tuberculosis was primarily a cause of death in old age rather than young adulthood. The impact of changing environment, both through improvements of conditions within neighborhoods and through residential mobility, on birth cohorts at risk of tuberculosis needs to be examined in further research.     

Abdominal Obesity and Ethnic Differences in Diabetes Awareness,Treatment, and Glycemic Control

Objective: To compare racial/ethnic differences in diabetes awareness, treatment, and glycemic control between non-Hispanic white, non-Hispanic black, and Hispanic Americans. We also determined the impact of abdominal obesity on racial/ethnic differences in diabetes awareness, treatment, and glycemic control between these population groups. Research Methods and Procedures: Third National Health and Nutrition Examination Survey (NHANES III) data were utilized for this study. Diabetes awareness was defined as acknowledging diabetic status. Diabetes treatment was defined as current use of anti-diabetic medications, good glycemic control as HbA_1c < 8%, and abdominal obesity as waist circumference larger than expected. The impacts of abdominal obesity on racial/ethnic differences in diabetes awareness, treatment, and glycemic control were assessed using logistic regression analyses. Adjustments were made for age, education, smoking, alcohol intake, and health insurance. Results: Rates of diabetes awareness in whites, blacks, and Hispanics suffering from abdominal obesity were ∼74%, 30%, and 21% in men and 77%, 32%, and 19% in women, respectively. Rates of diabetes treatment were 70%, 23%, and 14% in men and 57%, 45%, and 23% in women, respectively. In men, rates of glycemic control were 64%, 40%, and 30%, and in women, they were 62%, 51%, and 27%, respectively. Abdominal obesity was associated with decreased diabetes awareness and glycemic control in women. Discussion: Subjects with abdominal obesity were found to have poorer glycemic controls compared to those without abdominal obesity. Because diabetes prevalences were partially explained by racial/ethnic differences in diabetes awareness, treatment, and glycemic control, there is a need to craft diabetes awareness, treatment, and control programs along racial/ethnic origins.