Kiarri N. Kershaw

Reconsidering the Role of Social Disadvantage in Physical and Mental Health: Stressful Life Events, Health Behaviors, Race, and Depression

Prevalence of depression is associated inversely with some indicators of socioeconomic position, and the stress of social disadvantage is hypothesized to mediate this relation. Relative to whites, blacks have a higher burden of most physical health conditions but, unexpectedly, a lower burden of depression. This study evaluated an etiologic model that integrates mental and physical health to account for this counterintuitive patterning. The Baltimore Epidemiologic Catchment Area Study (Maryland, 1993-2004) was used to evaluate the interaction between stress and poor health behaviors (smoking, alcohol use, poor diet, and obesity) and risk of depression 12 years later for 341 blacks and 601 whites. At baseline, blacks engaged in more poor health behaviors and had a lower prevalence of depression compared with whites (5.9% vs. 9.2%). The interaction between health behaviors and stress was nonsignificant for whites (odds ratio (OR = 1.04, 95% confidence interval: 0.98, 1.11); for blacks, the interaction term was significant and negative (β: -0.18, P < 0.014). For blacks, the association between median stress and depression was stronger for those who engaged in zero (OR = 1.34) relative to 1 (OR = 1.12) and ≥2 (OR = 0.94) poor health behaviors. Findings are consistent with the proposed model of mental and physical health disparities.

Racial and Ethnic Residential Segregation, the Neighborhood Socioeconomic Environment, and Obesity Among Blacks and Mexican Americans

We used cross-sectional data on 2,660 black and 2,611 Mexican-American adult participants in the National Health and Nutrition Examination Survey (1999-2006) to investigate the association between metropolitan-level racial/ethnic residential segregation and obesity and to determine whether it was mediated by the neighborhood socioeconomic environment. Residential segregation was measured using the black and Hispanic isolation indices. Neighborhood poverty and negative income incongruity were assessed as mediators. Multilevel Poisson regression with robust variance estimates was used to estimate prevalence ratios. There was no relationship between segregation and obesity among men. Among black women, in age-, nativity-, and metropolitan demographic-adjusted models, high segregation was associated with a 1.29 (95% confidence interval (CI): 1.00, 1.65) times higher obesity prevalence than was low segregation; medium segregation was associated with a 1.35 (95% CI: 1.07, 1.70) times higher obesity prevalence. Mexican-American women living in high versus low segregation areas had a significantly lower obesity prevalence (prevalence ratio, 0.54; 95% CI: 0.33, 0.90), but there was no difference between those living in medium versus low segregation areas. These associations were not mediated by neighborhood poverty or negative income incongruity. These findings suggest variability in the interrelationships between residential segregation and obesity for black and Mexican-American women.

Metropolitan-Level Racial Residential Segregation and Black-White Disparities in Hypertension

Few studies have examined geographic variation in hypertension disparities, but studies of other health outcomes indicate that racial residential segregation may help to explain these variations. The authors used data from 8,071 black and white participants in the National Health and Nutrition Examination Survey (1999-2006) who were aged 25 years or older to investigate whether black-white hypertension disparities varied by level of metropolitan-level racial residential segregation and whether this was explained by race differences in neighborhood poverty. Racial segregation was measured by using the black isolation index. After adjustment for demographics and individual-level socioeconomic position, blacks had 2.74 times higher odds of hypertension than whites (95% confidence interval (CI): 2.32, 3.25). However, race differences were significantly smaller in low- than in high-segregation areas (P(interaction) = 0.006). Race differences in neighborhood poverty did not explain this heterogeneity, but poverty further modified race disparities: Race differences were largest in segregated, low-poverty areas (odds ratio = 4.14, 95% CI: 3.18, 5.38) and smallest in nonsegregated, high-poverty areas (odds ratio = 1.24, 95% CI: 0.77, 2.01). These findings suggest that racial disparities in hypertension are not invariant and are modified by contextual levels of racial segregation and neighborhood poverty, highlighting the role of environmental factors in the genesis of disparities.

“White Box” Epidemiology and the Social Neuroscience of Health Behaviors: The Environmental Affordances Model

Crucial advances have been made in our knowledge of the social determinants of health and health behaviors. Existing research on health disparities, however, generally fails to address a known paradox in the literature: While blacks have higher risk of medical morbidity relative to non-Hispanic whites, blacks have lower rates of common stress-related forms of psychopathology such as major depression and anxiety disorders. In this article we propose a new theoretical approach, the Environmental Affordances Model, as an integrative framework for the origins of both physical and mental health disparities. We highlight early empirical support and a growing body of experimental animal and human research on self-regulatory health behaviors and stress coping that is consistent with the proposed framework. We conclude that transdisciplinary approaches, such as the Environmental Affordances Model, are needed to understand the origins of group-based disparities to implement effective solutions to racial and ethnic group inequalities in physical and mental health.

Chronic stress, depressive symptoms, anger, hostility, and risk of stroke and transient ischemic attack in the multi-ethnic study of atherosclerosis.

Background and Purpose— This study investigated chronic stress, depressive symptoms, anger, and hostility in relation to incident stroke and transient ischemic attacks in middle-aged and older adults. Methods— Data were from the Multi-Ethnic Study of Atherosclerosis (MESA), a population-based cohort study of 6749 adults, aged 45 to 84 years and free of clinical cardiovascular disease at baseline, conducted at 6 US sites. Chronic stress, depressive symptoms, trait anger, and hostility were assessed with standard questionnaires. The primary outcome was clinically adjudicated incident stroke or transient ischemic attacks during a median follow-up of 8.5 years. Results— One hundred ninety-five incident events (147 strokes; 48 transient ischemic attacks) occurred during follow-up. A gradient of increasing risk was observed for depressive symptoms, chronic stress, and hostility (all P for trend ⩽0.02) but not for trait anger (P>0.10). Hazard ratios (HRs) and 95% confidence intervals indicated significantly elevated risk for the highest-scoring relative to the lowest-scoring group for depressive symptoms (HR, 1.86; 95% confidence interval, 1.16–2.96), chronic stress (HR, 1.59; 95% confidence interval, 1.11–2.27), and hostility (HR, 2.22; 95% confidence interval, 1.29–3.81) adjusting for age, demographics, and site. HRs were attenuated but remained significant in risk factor–adjusted models. Associations were similar in models limited to stroke and in secondary analyses using time-varying variables. Conclusions— Higher levels of stress, hostility, and depressive symptoms are associated with significantly increased risk of incident stroke or transient ischemic attacks in middle-aged and older adults. Associations are not explained by known stroke risk factors.

Socioeconomic position, health behaviors, and C-reactive protein: A moderated-mediation analysis

OBJECTIVE We sought to understand the link between low socioeconomic position (SEP) and cardiovascular disease (CVD) by examining the association between SEP, health-related coping behaviors, and C-reactive protein (CRP), an inflammatory marker and independent risk factor for CVD, in a U.S. sample of adults. DESIGN We used a multiple mediation model to evaluate how these behaviors work in concert to influence CRP levels and whether these relationships were moderated by gender and race/ethnicity. MAIN OUTCOME MEASURES CRP levels were divided into two categories: elevated CRP (3.1-10.0 mg/L) and normal CRP (< or =3.0 mg/L). RESULTS Both poverty and low educational attainment were associated with elevated CRP, and these associations were primarily explained through higher levels of smoking and lower levels of exercise. In the education model, poor diet also emerged as a significant mediator. These behaviors accounted for 87.9% of the total effect of education on CRP and 55.8% the total effect of poverty on CRP. We also found significant moderation of these mediated effects by gender and race/ethnicity. CONCLUSION These findings demonstrate the influence of socioeconomically patterned environmental constraints on individual-level health behaviors. Specifically, reducing socioeconomic inequalities may have positive effects on CVD disparities through reducing cigarette smoking and increasing vigorous exercise.

Neighborhood-Level Racial/Ethnic Residential Segregation and Incident Cardiovascular Disease: The Multi-Ethnic Study of Atherosclerosis

Background— Previous research suggests that neighborhood-level racial/ethnic residential segregation is linked to health, but it has not been studied prospectively in relation to cardiovascular disease (CVD). Methods and Results— Participants were 1595 non-Hispanic black, 2345 non-Hispanic white, and 1289 Hispanic adults from the Multi-Ethnic Study of Atherosclerosis free of CVD at baseline (aged 45–84 years). Own-group racial/ethnic residential segregation was assessed by using the Gi* statistic, a measure of how the neighborhood racial/ethnic composition deviates from surrounding counties’ racial/ethnic composition. Multivariable Cox proportional hazards modeling was used to estimate hazard ratios for incident CVD (first definite angina, probable angina followed by revascularization, myocardial infarction, resuscitated cardiac arrest, coronary heart disease death, stroke, or stroke death) over 10.2 median years of follow-up. Among blacks, each standard deviation increase in black segregation was associated with a 12% higher hazard of developing CVD after adjusting for demographics (95% confidence interval, 1.02–1.22). This association persisted after adjustment for neighborhood-level characteristics, individual socioeconomic position, and CVD risk factors (hazard ratio, 1.12; 95% confidence interval, 1.02–1.23). For whites, higher white segregation was associated with lower CVD risk after adjusting for demographics (hazard ratio, 0.88; 95% confidence interval, 0.81–0.96), but not after further adjustment for neighborhood characteristics. Segregation was not associated with CVD risk among Hispanics. Similar results were obtained after adjusting for time-varying segregation and covariates. Conclusions— The association of residential segregation with cardiovascular risk varies according to race/ethnicity. Further work is needed to better characterize the individual- and neighborhood-level pathways linking segregation to CVD risk.

Racial and Ethnic Differences in the Association Between Obesity and Depression in Women

BACKGROUND It is generally accepted that obesity and depression are positively related in women. Very little prior research, however, has examined potential variation in this relationship across different racial/ethnic groups. This paper examines the association between obesity and depression in non-Hispanic White, non-Hispanic Black, and Mexican American women. METHODS The sample included women aged 20 years and older in the 2005-2008 National Health and Nutrition Examination Surveys (n=3666). Logistic regression was used to assess the relationship between obesity and depression syndrome (assessed using the Patient Health Questionnaire-9), after adjusting for covariates. We then investigated whether this association varied by race/ethnicity. RESULTS Overall, obese women showed a 73% greater odds of depression (odds ratio [OR]=1.73; 95% confidence interval [CI]=1.19, 2.53) compared with normal weight women. This association varied significantly, however, by race/ethnicity. The obesity-depression associations for both Black and Mexican American women were different from the positive association found for White women (ORBlack*obese=0.24; 95% CI=0.10,0.54; ORMexican American*obese=0.42; 95% CI=1.04). Among White women, obesity was associated with significantly greater likelihood of depression (OR=2.37; 95% CI=1.41, 4.00) compared to normal weight. Among Black women, although not statistically significant, results are suggestive that obesity was inversely associated with depression (OR=0.56; 95% CI=0.28, 1.12) relative to normal weight. Among Mexican American women, obesity was not associated with depression (OR=1.01; 95% CI=0.59, 1.72). CONCLUSIONS The results reveal that the association between obesity and depression varies by racial/ethnic categorization. White, but not Black or Mexican American women showed a positive association. Next research steps could include examination of factors that vary by race/ethnicity that may link obesity to depression.

Geographic variation in hypertension prevalence among blacks and whites: the multi-ethnic study of atherosclerosis

BACKGROUND Many studies have examined differences in hypertension across race/ethnic groups but few have evaluated differences within groups. METHODS We investigated within-group geographic variations in hypertension prevalence among 3,322 black and white participants of the Multi-Ethnic Study of Atherosclerosis (MESA). Place of birth and place of residence were included in multivariate Poisson regression analyses. RESULTS Blacks born in southern states were 1.11 (95% confidence interval (CI): 1.02, 1.23) times more likely to be hypertensive than non-southern states after adjusting for age and sex. Findings were similar, though not statistically significant, for whites (prevalence ratio (PR): 1.15, 95% CI: 0.98, 1.35). Blacks and whites living in Forsyth (blacks, PR: 1.23, 95% CI: 1.07, 1.42; whites, PR: 1.32, 95% CI: 1.09, 1.60) and Baltimore (blacks, PR: 1.14, 95% CI: 1.00, 1.31; whites, PR: 1.24, 95% CI: 1.05, 1.47) were also significantly more likely to be hypertensive than those living in Chicago after adjusting for age and sex. Among blacks, those living in New York were also significantly more likely to be hypertensive. Geographic heterogeneity was partially explained by socioeconomic indicators, neighborhood characteristics or hypertension risk factors. There was also evidence of substantial heterogeneity in black-white differences depending on which geographic groups were compared (ranging from 82 to 13% higher prevalence in blacks compared with whites). CONCLUSIONS A better understanding of geographic heterogeneity may inform interventions to reduce racial/ethnic disparities.

Race/ethnicity, residential segregation, and exposure to ambient air pollution: The Multi-Ethnic Study of Atherosclerosis (MESA)

OBJECTIVES We described the associations of ambient air pollution exposure with race/ethnicity and racial residential segregation. METHODS We studied 5921 White, Black, Hispanic, and Chinese adults across 6 US cities between 2000 and 2002. Household-level fine particulate matter (PM2.5) and nitrogen oxides (NOX) were estimated for 2000. Neighborhood racial composition and residential segregation were estimated using US census tract data for 2000. RESULTS Participants in neighborhoods with more than 60% Hispanic populations were exposed to 8% higher PM2.5 and 31% higher NOX concentrations compared with those in neighborhoods with less than 25% Hispanic populations. Participants in neighborhoods with more than 60% White populations were exposed to 5% lower PM2.5 and 18% lower NOX concentrations compared with those in neighborhoods with less than 25% of the population identifying as White. Neighborhoods with Whites underrepresented or with Hispanics overrepresented were exposed to higher PM2.5 and NOX concentrations. No differences were observed for other racial/ethnic groups. CONCLUSIONS Living in majority White neighborhoods was associated with lower air pollution exposures, and living in majority Hispanic neighborhoods was associated with higher air pollution exposures. This new information highlighted the importance of measuring neighborhood-level segregation in the environmental justice literature.