Causes Of Racial Differences Research Articles

Low Perfusion and Missed Diagnosis of Hypoxemia by Pulse Oximetry in Darkly Pigmented Skin: A Prospective Study.

Retrospective clinical trials of pulse oximeter accuracy report more frequent missed diagnoses of hypoxemia in hospitalized Black patients than White patients, differences that may contribute to racial disparities in health and health care. Retrospective studies have limitations including mistiming of blood samples and oximeter readings, inconsistent use of functional versus fractional saturation, and self-reported race used as a surrogate for skin color. Our objective was to prospectively measure the contributions of skin pigmentation, perfusion index (PI), sex, and age on pulse oximeter errors in a laboratory setting. We enrolled 146 healthy subjects, including 25 with light skin (Fitzpatrick class I and II), 78 with medium (class III and IV), and 43 with dark (class V and VI) skin. We studied 2 pulse oximeters (Nellcor N-595 and Masimo Radical 7) in prevalent clinical use. We analyzed 9763 matched pulse oximeter readings (pulse oximeter measured functional saturation [Sp o2 ]) and arterial oxygen saturation (hemoximetry arterial functional oxygen saturation [Sa o2 ]) during stable hypoxemia (Sa o2 68%-100%). PI was measured as percent infrared light modulation by the pulse detected by the pulse oximeter probe, with low perfusion categorized as PI < 1%. The primary analysis was to assess the relationship between pulse oximeter bias (difference between Sa o2 and Sp o2 ) by skin pigment category in a multivariable mixed-effects model incorporating repeated-measures and different levels of Sa o2 and perfusion. Skin pigment, PI, and degree of hypoxemia significantly contributed to errors (bias) in both pulse oximeters. For PI values of 1.0% to 1.5%, 0.5% to 1.0%, and <0.5%, the P value of the relationship to mean bias or median absolute bias was <.00001. In lightly pigmented subjects, only PI was associated with positive bias, whereas in medium and dark subjects bias increased with both low perfusion and degree of hypoxemia. Sex and age was not related to pulse oximeter bias. The combined frequency of missed diagnosis of hypoxemia (pulse oximeter readings 92%-96% when arterial oxygen saturation was <88%) in low perfusion conditions was 1.1% for light, 8.2% for medium, and 21.1% for dark skin. Low peripheral perfusion combined with darker skin pigmentation leads to clinically significant high-reading pulse oximeter errors and missed diagnoses of hypoxemia. Darkly pigmented skin and low perfusion states are likely the cause of racial differences in pulse oximeter performance in retrospective studies.

Racial differences in longitudinal toxicities of anticancer agents in early phase cancer clinical trials.

Racial differences have been reported in toxicity outcomes for anticancer drug treatments. However, these observations were often from studies with small sample sizes, and many only reported the maximum grade of toxicity and no longitudinal information. This current analysis aims to investigate racial differences in longitudinal toxicities using a large-scale clinical trials database. Early-phase clinical trials sponsored by the Cancer Therapy Evaluation Program at the National Cancer Institute, USA, that evaluated cytotoxic drugs and molecularly targeted agents between March 2000 and December 2012 were studied. Race was categorized as White, Black or African-American, and Asian. Each toxicity's grade prevalence, mean grade at each cycle, and time to develop grade 2 or higher toxicity was evaluated. In total, 25,442 patients from 697 trials were included in this study. The number of patients categorized as White, Black, and Asian designations was 22,756 (89%), 1874 (7%), and 812 (3%), respectively. Notable findings include the rate of any grade of diarrhea in Black people was 26% and 21% lower than that of White and Asian people. The median time to the first grade 2 or higher event was 6 cycles in White people, 8 in Black people, and 6 in Asian people. The rate of any grade hyperglycemia was significantly higher in Asian people. Although we identified several racial differences in longitudinal toxicities, most were of generally lower grade. Further study is needed to clarify the cause of racial differences in treatment-associated toxicities.

Practical consequences of flawed social psychological research on bias.

The flaws in social psychological research pointed out by Cesario have societal costs. These include ignoring crucial base rates thereby degrading the effectiveness of policy decisions, generalizing the conclusions derived from experiments on non-professionals thereby distorting the public's view of professional law enforcement personnel, questionable accusations of racism, and mis-attributions of the causes of racial differences in behavior.

Role of ambulatory blood pressure monitoring for the management of hypertension in Asian populations.

Out-of-clinic blood pressure (BP) measurement, eg, ambulatory BP monitoring, has a strong association with target organ damage and is a powerful predictor of cardiovascular events compared with clinic BP measurement. Ambulatory BP monitoring can detect masked hypertension or various BP parameters in addition to average 24-hour BP level. Short-term BP variability assessed by standard deviation or average real variability, diminished nocturnal BP fall, nocturnal hypertension, and morning BP surge assessed by ambulatory BP monitoring have all been associated with target organ damage and cardiovascular prognosis. Recently, the authors compared the degree of sleep-trough morning BP surge between a group of Japanese and a group of Western European untreated patients with hypertension and found that sleep-trough morning BP surge in Japanese persons was significantly higher than that in Europeans. Although Asian persons have been known to have a higher incidence of stroke than heart disease, the difference in characteristics of BP indices assessed by ambulatory BP monitoring might be the cause of racial differences in stroke incidence between Asian and Western populations. This review focuses on Asian characteristics for the management of hypertension using ambulatory BP monitoring.

Increased Perinatal Morbidity and Mortality Among Asian American and Pacific Islander Women in the United States.

Asian American/Pacific Islanders (AAPIs) are the fastest-growing racial group in the United States. Despite a higher socioeconomic status, AAPI women experience higher rates of maternal morbidity and mortality. Using the National Inpatient Sample, we performed a retrospective cohort analysis of women who were hospitalized for delivery from 2002 to 2013. The primary outcome variable was inpatient mortality rate, and the presence of severe maternal morbidities was estimated using the Bateman Comorbidity Index, a validated tool for predicting obstetric morbidity. AAPI women presenting for delivery between 2003 and 2012 were older, more likely to reside in a zip code in the top quartile of annual income, be privately insured than Caucasian women, and less likely to have a higher Bateman Comorbidity Index. However, AAPI women had a higher likelihood of postpartum hemorrhage (3.4% vs 2.7%, P < .001), uterine atony, severe perineal lacerations, and severe maternal morbidities. Procedures such as transfusion, hysterectomy, and mechanical ventilation were also more common in AAPI women. Furthermore, AAPI women had a higher mortality rate that persisted despite adjustment for an apparently higher income and comorbidities (odds ratio 1.72, 95% confidence interval: 1.14-2.59, P = .01). Despite having a higher socioeconomic status, AAPI women had higher rates of maternal mortality during hospitalization for delivery. This increase persisted even after adjustment for factors known to affect peripartum outcomes. Further investigation is needed to better clarify the causes of racial differences in maternal morbidity and mortality.

Is Racism a Fundamental Cause of Inequalities in Health?

We previously proposed that socioeconomic status (SES) is a fundamental cause of health inequalities and, as such, that SES inequalities in health persist over time despite radical changes in the diseases, risks, and interventions that happen to produce them at any given time. Like SES, race in the United States has an enduring connection to health and mortality. Our goals here are to evaluate whether this connection endures because systemic racism is a fundamental cause of health inequalities and, in doing so, to review a wide range of empirical data regarding racial differences in health outcomes, health risks, and health-enhancing resources such as money, knowledge, power, prestige, freedom, and beneficial social connections. We conclude that racial inequalities in health endure primarily because racism is a fundamental cause of racial differences in SES and because SES is a fundamental cause of health inequalities. In addition to these powerful connections, however, there is evidence that racism, largely via inequalities in power, prestige, freedom, neighborhood context, and health care, also has a fundamental association with health independent of SES.

Discrimination in the Credential Society: An Audit Study of Race and College Selectivity in the Labor Market

Racial inequality in economic outcomes, particularly among the college educated, persists throughout US society. Scholars debate whether this inequality stems from racial differences in human capital (e.g., college selectivity, GPA, college major) or employer discrimination against black job candidates. However, limited measures of human capital and the inherent difficulties in measuring discrimination using observational data make determining the cause of racial differences in labor-market outcomes a difficult endeavor. In this research, I examine employment opportunities for white and black graduates of elite top-ranked universities versus high-ranked but less selective institutions. Using an audit design, I create matched candidate pairs and apply for 1,008 jobs on a national job-search website. I also exploit existing birth-record data in selecting names to control for differences across social class within racialized names. The results show that although a credential from an elite university results in more employer responses for all candidates, black candidates from elite universities only do as well as white candidates from less selective universities. Moreover, race results in a double penalty: When employers respond to black candidates, it is for jobs with lower starting salaries and lower prestige than those of white peers. These racial differences suggest that a bachelor’s degree, even one from an elite institution, cannot fully counteract the importance of race in the labor market. Thus, both discrimination and differences in human capital contribute to racial economic inequality.

Racial differences in disability after stroke: results from a nationwide study.

We sought to characterize racial differences in disability among older stroke survivors. A cross-sectional study of 806 self-reported stroke survivors from the 2011 National Health and Aging Trends Study was performed. Race was based on self-report. Primary outcome was activity limitations (requiring assistance with mobility, self-care, and household activities). Secondary outcome was participation restrictions, which were defined as reductions/absence in valued social activities because of health. Physical capacity was measured by a validated scale (0 low-12 high). Logistic regression was used to estimate average marginal effects of activity limitations and participation restrictions by race before and after adjusting for sociodemographics, comorbidities, and physical and cognitive capacity. Non-Hispanic black participants had lower physical capacity than non-Hispanic white participants (mean 5.1 vs 6.9, p < 0.01). For most activities, black participants had significantly greater limitations than white participants. These differences persisted after accounting for sociodemographic factors and comorbidities, but largely became nonsignificant after accounting for physical capacity. The only unadjusted racial difference in participation restriction was in religious service attendance (18.2% of white participants vs 28.6% of black participants, p < 0.01). After stroke, black individuals have a greater prevalence of activity limitations than white individuals, largely due to their greater physical capacity limitations. Further understanding of the causes of racial differences in capacity after stroke is needed to reduce activity limitations after stroke and decrease racial disparities.

Discrimination in the Credential Society: An Audit Study of Race, Social Class, and College Selectivity in the Labor Market

Racial inequality in economic outcomes, particularly among the college educated, persists throughout US society. Scholars debate whether this inequality stems from racial differences in human capital (e.g., college selectivity, GPA, college major) or employer discrimination against black job candidates. However, limited measures of human capital and the inherent difficulties in measuring discrimination using observational data make determining the cause of racial differences in labor-market outcomes a difficult endeavor. In this research, I examine employment opportunities for white and black graduates of elite top-ranked universities versus high-ranked but less selective institutions. Using an audit design, I create matched candidate pairs and apply for 1,008 jobs on a national job-search website. I also exploit existing birth-record data in selecting names to control for differences across social class within racialized names. The results show that although a credential from an elite university results in more employer responses for all candidates, black candidates from elite universities only do as well as white candidates from less selective universities. Moreover, race results in a double penalty: When employers respond to black candidates, it is for jobs with lower starting salaries and lower prestige than those of white peers. These racial differences suggest that a bachelor’s degree, even one from an elite institution, cannot fully counteract the importance of race in the labor market. Thus, both discrimination and differences in human capital contribute to racial economic inequality.

Mind the gap: racial differences in breast cancer incidence and biologic phenotype, but not stage, among low-income women participating in a government-funded screening program

Breast cancer mortality rates in South Carolina (SC) are 40 % higher among African-American (AA) than European-American (EA) women. Proposed reasons include race-associated variations in care and/or tumor characteristics, which may be subject to income effects. We evaluated race-associated differences in tumor biologic phenotype and stage among low-income participants in a government-funded screening program. Best Chance Network (BCN) data were linked with the SC Central Cancer Registry. Characteristics of breast cancers diagnosed in BCN participants aged 47-64 years during 1996-2006 were abstracted. Race-specific case proportions and incidence rates based on estrogen receptor (ER) status and histologic grade were estimated. Among 33,880 low-income women accessing BCN services, repeat breast cancer screening utilization was poor, especially among EAs. Proportionally, stage at diagnosis did not differ by race (607 cancers, 53 % among AAs), with about 40 % advanced stage. Compared to EAs, invasive tumors in AAs were 67 % more likely (proportions) to be of poor-prognosis phenotype (both ER-negative and high-grade); this was more a result of the 46 % lesser AA incidence (rates) of better-prognosis (ER+ lower-grade) cancer than the 32 % greater incidence of poor-prognosis disease (p values <0.01). When compared to the general SC population, racial disparities in poor-prognostic features within the BCN population were attenuated; this was due to more frequent adverse tumor features in EAs rather than improvements for AAs. Among low-income women in SC, closing the breast cancer racial and income mortality gaps will require improved early diagnosis, addressing causes of racial differences in tumor biology, and improved care for cancers of poor-prognosis biology.

Racial differences in physician usage among the elderly poor in the United States

Despite the rapidly growing ranks of the elderly in America, the increasing racial and ethnic diversity of this population, and the large number of seniors who are poor, there are relatively few systematic investigations that examine the causes of racial differences in health care use specifically among elders living in poverty. This article addresses this issue by examining differences in patterns of having and using a physician among the elderly poor, the role that race plays and what might explain it. We demonstrate that even within this disadvantaged and medically engaged population there are persistent and significant racial differences in having and using a doctor. Specifically, we show: (1) Whites and women are more likely to have a regular doctor than men and African Americans; (2) Among those who have a doctor, whites and women also visit the doctor with greater frequency than other groups even at the same levels of health or illness; (3) After accounting for the varying levels and effects of social connectedness, racial differences in having a doctor essentially disappear; and (4) While differences in having a regular doctor can be accounted for using measures of social connectedness, substantial and robust racial and gender differences in doctor use remain. In the end, we provide an analysis that examines typical factors known to influence health care use, and find that while need, structural factors, perceptions of care, and social connectedness have a powerful effect on doctor visits, the racial variation in using a doctor cannot be explained away with the available measures.

Abstract ED04-02: Are we moving beyond race in clinical care? Lessons from the RACE Project

Abstract Physicians hold attitudes about the causes of racial differences in health conditions, and they use race as a heuristic in their clinical practice. The presentation will explore the interaction of patient and provider characteristics on health care providers’ use of genetics and genomics knowledge in their clinical practice. Advancing this field of study requires research to assess how clinicians use and think about race and human genetic variation. Understanding physicians’ perceptions of race and genetics and its use in the clinical encounter as a context to shed light on contributors to racial and ethnic health disparities and the role genetic screening programs and genomic medicine may or may not have in reducing those racial and ethnic health disparities. Citation Information: Cancer Epidemiol Biomarkers Prev 2011;20(10 Suppl):ED04-02.

Are there racial differences in patients' shared decision-making preferences and behaviors among patients with diabetes?

In the United States, African Americans are more likely to experience lower quality patient/provider communication and less shared decision making (SDM) than whites, which may be an important contributor to racial health disparities. Patient factors have not been fully explored as a potential contributor to communication disparities. The authors analyzed cross-sectional data from a survey of 974 patients with diabetes seen at 34 community health centers (HC) in 17 midwestern and west-central states. They used ordinal and logistic regression models to investigate racial differences in patients' preferences for SDM and in patients' behaviors that may facilitate SDM (initiating discussions about diabetes care). The response rate was 67%. In bivariate and multivariate analyses, race was not associated with patient preference for a shared role in the 3 measured SDM domains: agenda setting (odds ratio [OR]: 1.13 [0.86, 1.49]), information sharing (OR: 1.26 [0.97, 1.64]), or decision making (OR: 1.16 [0.85, 1.59]). African Americans were more likely to report initiating discussions with their physicians about 4 of 6 areas of diabetes care-blood pressure measurement (66% v. 52%, P < 0.001), foot examination (54% v. 47%, P = 0.04), eye examination (57% v. 46%, P = 0.002), and microalbumin testing (38% v. 29%, P = 0.01)-but not HbA1c testing (39% v. 43%, P = 0.31) or cholesterol testing (53% v. 51%, P = 0.52). In multivariate analysis, African Americans were still more likely to report initiating conversations about diabetes care (OR: 1.78 [1.10, 2.89]). The authors found that African Americans in this study preferred shared decision making as much as whites and were more likely to report initiating more discussions with their doctors about their diabetes care. This research suggests that, among diabetes patients receiving care at community health centers, patient preference or patient behaviors may be an unlikely cause of racial differences in shared decision making.

Racial Disparity In Immunotherapy for Diffuse Large B-Cell Lymphoma Explained by HIV Status In Veterans Administration Patients

AbstractAbstract 936 Background-Previous studies have demonstrated that African-American (AA) patients with diffuse large B-cell lymphoma (DLBCL) are less likely to receive rituximab (R) compared to Caucasian patients, despite the incorporation of R into the standard of care in 2002. Reasons for this difference are unclear, though insurance coverage differences have been suggested as one potential cause. We evaluated DLBCL patients treated at Veterans Health Administration (VHA) hospitals in an effort to identify other potential causes of racial differences in R use. Since VHA patients receive treatment regardless of insurance coverage, insurance status should not influence treatment decisions in this population. Methods-Electronic records of patients diagnosed with DLBCL between October 2002 and September 2008 were identified in the Veterans Administration Central Cancer Registry. Data was obtained on patient demographics and stage at diagnosis. Each record was then linked to pharmacy records and ICD-9 diagnostic codes, to identify drugs used in treatment of DLBCL and concurrent co-morbidities respectively. Of 2,164 newly diagnosed DLBCL patients identified in the VACCR, drug records were obtained for 1,942 (90%), and CHOP or R-CHOP was used as first treatment in 1446 (67%). Only patients who received CHOP or R-CHOP were included in the analysis. Demographic and stage variables were reported in approximately 95% of patients. Results-For comparison between AA and Caucasian patients, see Table. Univariate analyses demonstrated significant differences in R use based on age (p =0.002), race (p= 0.006), and HIV status (p<0.0001), while stage and sex were not significant. A logistic regression model was constructed using statistically significant univariate predictor variables and a categorical variable to differentiate year of treatment (2003 vs. ≥ 2004). In the final logistic model, only HIV + status (OR = 0.096, p <0.0001) and year of treatment ≥ 2004 (OR = 4.311, p<0.0001) remained significant predictors of R use. Linear regression analysis of variables predicting of age at diagnosis demonstrated independent effect of both AA race (β= - 5.13, p <0.0001) and HIV + (β= -13.97, p<0.0001), suggesting that HIV status accounts for only part of the difference in age at diagnosis noted between AA and Caucasians. Conclusions-After controlling for HIV status, race no longer predicted use of R in patients treated within the VHA system. The decreased use of R in HIV+ patients is likely a related in part to a 2005 publication which demonstrated increased infectious toxicity in HIV associated lymphoma patients treated with R. Given the higher prevalence of HIV in the AA population compared to the Caucasian population in the United States (546.7/100,000 vs. 80.4/100,000 in 2007), differential rates of HIV may be responsible for some of the previously observed disparity in R use outside the VHA. On the other hand, race based differences in age at diagnosis are only partially explained by HIV status. In conclusion, HIV status is an important co-morbid factor that should be considered in future studies of racial disparities in lymphoma patients.RaceCaucasian (n=1251)AA (n=162)SignificanceMean Age (years)65.858.2p <0.0001Stage I291 (24%)19 (12%)II225 (18%)29 (19%)III278 (23%)40 (16%)IV423 (35%)65 (42%)p = 0.01HIV + (%)38 (3%)33 (20%)p <0.0001Sex = Male1217 (97%)156 (96%)p = 0.47rituximab used1165 (93%)141 (87%)p = 0.006 Disclosures:Carson:Genentech, Inc.: Consultancy, Speakers Bureau; American Cancer Society, IRG 58-010-52: Research Funding.

Racial differences in C-reactive protein levels during normal pregnancy

The purpose of this study was to characterize serum C-reactive protein (CRP) levels in a diverse population of healthy pregnant women with the use of a high sensitivity assay. We conducted a cross-sectional analysis of a cohort of 775 pregnant women. CRP was measured on serum specimens that were drawn at < 26 weeks of gestation with highly sensitive enzyme-linked immunosorbent assay kits. Median CRP was 4.8 mg/L (interquartile range, 0.63-15.7). Black women had higher median CRP values than did white women (7.68 vs 2.59 mg/L; P < .001). Black women demonstrated higher levels of CRP, even after the data were controlled for known confounding factors such as smoking and maternal weight. Pregnancy is an inflammatory stressor. The cause of racial differences is unclear but may be important for understanding racial disparities in the incidence of inflammatory disorders such as preterm labor and preeclampsia.

Prostate Tissue Androgens: History and Current Clinical Relevance

Direct determination of androgen levels in prostate tissue provides a perspective on the organ that is not available via androgen serum levels. The principle prostatic androgens, primarily dihydrotestosterone (DHT) and secondarily testosterone, can be readily assayed in quick-frozen prostate biopsy cores or surgical specimens. Such assays have proved important in establishing (1) that DHT is a permissive factor in BPH pathogenesis, (2) a mechanism for the treatment of BPH, (3) an understanding of prostate cancer chemoprevention, (4) an explanation for the 'escape' of prostate cancer from castration therapy, (5) prostate safety of testosterone replacement therapy, and (6) insights into the cause of racial differences of prostate cancer. Future opportunities include clarification of new drug mechanisms for BPH and prostate cancer, as well as a better understanding of the pathogenesis of both, and as an aid in individual patient management. Determination of prostate tissue androgens may soon transition from research tool to clinical test.

Age and racial differences in the presentation and treatment of Generalized Anxiety Disorder in primary care

Despite the prevalence and impact of Generalized Anxiety Disorder (GAD) in the primary care setting, little is known about its presentation in this setting. The purpose of this study is to examine age and racial differences in the presentation and treatment of GAD in medical patients. Participants were recruited from one family medicine clinic and one internal medicine clinic. The prevalence of GAD was lowest for older adults. Age differences were found in the presentation of GAD, with young adults reporting greater cognitive symptoms of anxiety, negative affect, and depressive symptoms. African-Americans with GAD reported more positive affect and lower rates of treatment. The lower levels of negative affect and depressive symptoms reported among older adults may affect the recognition of GAD by primary care physicians. Further research is needed to better understand the causes of racial differences in treatment.

Outcomes in Adult and Pediatric Liver Transplantation Among Various Ethnic Groups

Background The reported patient and graft survivals among adults post–orthotopic liver transplantation (OLT) are variable, with an apparent discrepancy between ethnic groups. The aim of this study was to evaluate the impact of ethnicity on patient and graft survivals among adult and pediatric patients. Methods A retrospective analysis from the UNOS/OPTN databank between January 1995 and December 2006 was performed on adult and pediatric liver transplant recipients. Patients were divided into 4 groups based on ethnicity: African Americans, Hispanic, Caucasians, and other. Kaplan-Meier (KM) analysis was used to calculate patient and graft survival. Log-rank tests were used to compare survival rates between groups. Results In our study 42,710 OLT patients were included in the analysis, 90% of whom were adults. Of the 38,639 adult recipients, 29,432 (76.1%) were Caucasian, 4369 (11.3%) were Hispanic, 2963 (7.7%) were African American, and the remaining 1875 (4.9%) were of other ethnicities. KM estimates and Cox regression analyses demonstrated that there was a significant ethnic difference in both patient and graft survivals at 1, 3, 5, and 10 years. African Americans showed a lower rate ( P < .001). Of the 4341 pediatric recipients, 2461 (56.7%) were Caucasian, 797 (18.4%) were Hispanic, 824 (18.9%) were African American, and the remaining 259 (5.9%) were of other ethnicities. Unlike the adults, there were no significant differences among ethnic groups in terms of patient ( P = .31) and graft ( P = .33) survival at 1, 3, 5, and 10 years after OLT. Conclusion These results showed that adult African American OLT patients have a reduced transplantation rate and a worse survival rate when compared with other ethnicities in the adult but not in the pediatric population. This information suggests that further studies are indicated to identify the causes of racial differences in transplant access and outcomes in the adult patient population.

Race and the Digital Divide

In recent years, a plethora of public and private programs in the United States have been created to close the "Digital Divide." Interestingly, however, we know very little about the underlying causes of racial differences in rates of computer and Internet access. In this paper, I use data from the Computer and Internet Use Supplement to the August 2000 Current Population Survey (CPS) to explore this question. Estimates from the CPS indicate that Mexican-Americans are roughly one-half as likely to own a computer and one-third as likely to have Internet access at home as whites. The black home computer rate is 59 percent of the white rate and the black home Internet access rate is 51 percent of the white rate. Using Blinder-Oaxaca decompositions, I find that racial differences in education, income and occupation contribute substantially to the black/white and Mexican-American/white gaps in home computer and Internet access rates. The digital divide between races, however, is not simply an "income divide" as income differences explain only 10 to 30 percent of the gaps in access to technology. I do not find evidence that price or school differences are responsible for the remaining gaps. I find some evidence, however, that language barriers may be important in explaining low rates of computer and Internet access among Mexican-Americans.

Racial residential segregation: a fundamental cause of racial disparities in health.

Racial residential segregation is a fundamental cause of racial disparities in health. The physical separation of the races by enforced residence in certain areas is an institutional mechanism of racism that was designed to protect whites from social interaction with blacks. Despite the absence of supportive legal statutes, the degree of residential segregation remains extremely high for most African Americans in the United States. The authors review evidence that suggests that segregation is a primary cause of racial differences in socioeconomic status (SES) by determining access to education and employment opportunities. SES in turn remains a fundamental cause of racial differences in health. Segregation also creates conditions inimical to health in the social and physical environment. The authors conclude that effective efforts to eliminate racial disparities in health must seriously confront segregation and its pervasive consequences.