Marino A. Bruce

Association of Socioeconomic Status and CKD among African Americans: The Jackson Heart Study

BACKGROUND Socioeconomic status (SES) is recognized as a key social environmental factor because it has implications for access to resources that help individuals care for themselves and others. Few studies have examined the association of SES with chronic kidney disease (CKD) in high-risk populations. STUDY DESIGN Single-site longitudinal population-based cohort. SETTING & PARTICIPANTS Data for this study were drawn from the baseline examination of the Jackson Heart Study. The analytic cohort consisted of 3,430 African American men and women living in the tricounty region of the Jackson, MS, metropolitan area with complete data to determine CKD status. PREDICTOR High SES (defined as having a family income at least 3.5 times the poverty level or having at least 1 undergraduate degree). OUTCOMES & MEASUREMENTS CKD (defined as the presence of albuminuria or decreased estimated glomerular filtration rate [<60 mL/min/1.73 m(2)]). Associations were explored using bivariable analyses and multivariable logistic regression analyses adjusting for CKD and cardiovascular disease risk factors, as well as demographic factors. RESULTS The prevalence of CKD in the Jackson Heart Study was 20% (865 of 3,430 participants). Proportions of the Jackson Heart Study cohort with albuminuria and decreased estimated glomerular filtration rate were 12.5% (429 of 3,430 participants) and 10.1% (347 of 3,430 participants), respectively. High SES was associated inversely with CKD. The odds of having CKD were 41% lower for affluent participants than their less affluent counterparts. There were no statistically significant interactions between sex and education or income, although subgroup analysis showed that high income was associated with CKD in men (OR, 0.47; 95% CI, 0.23-0.97), but not women (OR, 0.64; 95% CI, 0.40-1.03). LIMITATIONS Models were estimated using cross-sectional data. CONCLUSION CKD is associated with SES. Additional research is needed to elucidate the impact of wealth and social contexts in which individuals are embedded and the mediating effects of sociocultural factors.

Perceived Discrimination and Hypertension Among African Americans in the Jackson Heart Study

OBJECTIVES Using Jackson Heart Study data, we examined whether perceived discrimination was associated with prevalent hypertension in African Americans. METHODS Everyday discrimination, lifetime discrimination, burden of discrimination, and stress from discrimination were examined among 4939 participants aged 35 to 84 years (women = 3123; men = 1816). We estimated prevalence ratios of hypertension by discrimination, and adjusted for age, gender, socioeconomic status, and risk factors. RESULTS The prevalence of hypertension was 64.0% in women and 59.7% in men. After adjustment for age, gender, and socioeconomic status, lifetime discrimination and burden of discrimination were associated with greater hypertension prevalence (prevalence ratios for highest vs lowest quartile were 1.08 [95% confidence interval (CI) = 1.02, 1.15] and 1.09 [95% CI = 1.02,1.16] for lifetime discrimination and burden of discrimination, respectively). Associations were slightly weakened after adjustment for body mass index and behavioral factors. No associations were observed for everyday discrimination. CONCLUSIONS Further understanding the role of perceived discrimination in the etiology of hypertension may be beneficial in eliminating hypertension disparities.

Social Environmental Stressors, Psychological Factors, and Kidney Disease

Kidney disease is one of the most striking examples of health disparities in American public health. Disparities in the prevalence and progression of kidney disease are generally thought to be a function of group differences in the prevalence of kidney disease risk factors such as diabetes, hypertension, and obesity. However, the presence of these comorbidities does not completely explain the elevated rate of progression from chronic kidney disease (CKD) to end-stage renal disease among high-risk populations such as African Americans. We believe that the social environment is an important element in the pathway from CKD risk factors to CKD and end-stage renal disease. This review of the literature draws heavily from social science and social epidemiology to present a conceptual frame specifying how social, economic, and psychosocial factors interact to affect the risks for and the progression of kidney disease.

Sociodemographic factors contribute to the depressive affect among African Americans with chronic kidney disease

Depression is common in end-stage renal disease and is associated with poor quality of life and higher mortality; however, little is known about depressive affect in earlier stages of chronic kidney disease. To measure this in a risk group burdened with hypertension and kidney disease, we conducted a cross-sectional analysis of individuals at enrollment in the African American Study of Kidney Disease and Hypertension Cohort Study. Depressive affect was assessed by the Beck Depression Inventory II and quality of life by the Medical Outcomes Study-Short Form and the Satisfaction with Life Scale. Beck Depression scores over 14 were deemed consistent with an increased depressive affect and linear regression analysis was used to identify factors associated with these scores. Among 628 subjects, 166 had scores over 14 but only 34 were prescribed antidepressants. The mean Beck Depression score of 11.0 varied with the estimated glomerular filtration rate (eGFR) from 10.7 (eGFR 50-60) to 16.0 (eGFR stage 5); however, there was no significant independent association between these. Unemployment, low income, and lower quality and satisfaction with life scale scores were independently and significantly associated with a higher Beck Depression score. Thus, our study shows that an increased depressive affect is highly prevalent in African Americans with chronic kidney disease, is infrequently treated with antidepressants, and is associated with poorer quality of life. Sociodemographic factors have especially strong associations with this increased depressive affect. Because this study was conducted in an African-American cohort, its findings may not be generalized to other ethnic groups.

Quality of Life and Psychosocial Factors in African Americans with Hypertensive Chronic Kidney Disease

Health-related quality of life (HRQOL) is poorly understood in patients with chronic kidney disease (CKD) prior to end-stage renal disease. The association between psychosocial measures and HRQOL has not been fully explored in CKD, especially in African Americans. We performed a cross-sectional analysis of HRQOL and its association with sociodemographic and psychosocial factors in African Americans with hypertensive CKD. There were 639 participants in the African American Study of Kidney Disease and Hypertension Cohort Study. The Short Form-36 was used to measure HRQOL. The Diener Satisfaction with Life Scale measured life satisfaction, the Beck Depression Inventory-II assessed depression, the Coping Skills Inventory-Short Form measured coping, and the Interpersonal Support Evaluation List-16 was used to measure social support. The mean participant age was 60 years at enrollment, and men comprised 61% of participants. Forty-two percent reported a household income less than

Explaining Racial Disparities in Obesity Among Men: Does Place Matter?

15,000/year. Higher levels of social support, coping skills, and life satisfaction were associated with higher HRQOL, whereas unemployment and depression were associated with lower HRQOL (P < 0.05). A significant positive association between higher estimated glomerular filtration rate (eGFR) was observed with the Physical Health Composite (PHC) score (P = 0.004) but not in the Mental Health Composite (MHC) score (P = 0.24). Unemployment was associated with lower HRQOL, and lower eGFR was associated with lower PHC. African Americans with hypertensive CKD with better social support and coping skills had higher HRQOL. This study demonstrates an association between CKD and low HRQOL, and it highlights the need for longitudinal studies to examine this association in the future.

Stress and the Kidney

National data indicate that Black men have higher rates of obesity than White men. Black men also experience earlier onset of many chronic conditions and premature mortality linked to obesity. Explanations for these disparities have been underexplored, and existing national-level studies may be limited in their ability to explicate these long-standing patterns. National data generally do not account for race differences in risk exposures resulting from racial segregation or the confounding between race and socioeconomic status. Therefore, these differences in obesity may be a function of social environment rather than race. This study examined disparities in obesity among Black and White men living in the same social and environmental conditions, who have similar education levels and incomes using data from the Exploring Health Disparities in Integrated Communities-SWB (EHDIC-SWB) study. The findings were compared with the 2003 National Health Interview Survey (NHIS). Logistic regression was used to examine the association between race and obesity adjusting for demographics, socioeconomic status, and health conditions. In the NHIS, Black men had a higher odds of obesity (odds ratio = 1.29, 95% confidence interval = 1.12-1.49) than White men. However in the EHDIC-SWB, which accounts for social and environmental conditions of where these men live, Black men had similar odds of obesity (odds ratio = 1.06, 95% confidence interval = 0.70-1.62) compared with White men. These data highlight the importance of the role that setting plays in understanding race disparities in obesity among men. Social environment may be a key determinant of health when seeking to understand race disparities in obesity among Black and White men.

Elevated depressive affect is associated with adverse cardiovascular outcomes among African Americans with chronic kidney disease

The prevalence of CKD has increased considerably over the past 2 decades. The rising rates of CKD have been attributed to known comorbidities such as diabetes, hypertension, and obesity; however, recent research has begun to explore the degree to which social, economic, and psychological factors have implications for the prevalence and progression of CKD, especially among high-risk populations such as African Americans. It has been suggested that stress can have implications for CKD, but this area of research has been largely unexplored. One contributing factor associated with the paucity of research on CKD is that many of the social, psychological, and environmental stressors cannot be recreated or simulated in a laboratory setting. Social science has established that stress can have implications for health, and we believe that stress is an important determinant of the development and progression of CKD. We draw heavily from the social scientific and social epidemiologic literature to present an intersectional conceptual frame specifying how stress can have implications for kidney disease, its progression, and its complications through multiple stressors and pathways.

Race, Kidney Disease Progression, and Mortality Risk in HIV-Infected Persons

This study was designed to examine the impact of elevated depressive affect on health outcomes among participants with hypertensive chronic kidney disease in the African-American Study of Kidney Disease and Hypertension (AASK) Cohort Study. Elevated depressive affect was defined by Beck Depression Inventory II (BDI-II) thresholds of 11 or more, above 14, and by 5-Unit increments in the score. Cox regression analyses were used to relate cardiovascular death/hospitalization, doubling of serum creatinine/end-stage renal disease, overall hospitalization, and all-cause death to depressive affect evaluated at baseline, the most recent annual visit (time-varying), or average from baseline to the most recent visit (cumulative). Among 628 participants at baseline, 42% had BDI-II scores of 11 or more and 26% had a score above 14. During a 5-year follow-up, the cumulative incidence of cardiovascular death/hospitalization was significantly greater for participants with baseline BDI-II scores of 11 or more compared with those with scores <11. The baseline, time-varying, and cumulative elevated depressive affect were each associated with a significant higher risk of cardiovascular death/hospitalization, especially with a time-varying BDI-II score over 14 (adjusted HR 1.63) but not with the other outcomes. Thus, elevated depressive affect is associated with unfavorable cardiovascular outcomes in African Americans with hypertensive chronic kidney disease.

Perceived discrimination is associated with health behaviours among African-Americans in the Jackson Heart Study

BACKGROUND AND OBJECTIVES The burden of HIV-associated chronic kidney disease (CKD) is growing in the United States, partially because of increased HIV-infection rates among African Americans. We determined the prevalence, incidence, and risk of rapid estimated GFR (eGFR) decline, ESRD, and death among HIV-infected (HIV+) African-American and non-African-American individuals cared for at the Comprehensive Care Center in Nashville, Tennessee, from January 1, 1998, through December 31, 2005. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS Mixed effects, competing risks, and Poisson and Cox regression models were used to assess the risk of rapid eGFR decline (defined as ≥50% decrease in baseline eGFR), CKD5/ESRD, and death. The Chronic Kidney Disease Epidemiology Collaboration equation was used to calculate eGFR. Confounders were adjusted with a propensity score that related patient characteristics to the probability of being African American. Mixed effects models compared the rate of rapid eGFR decline for HIV-infected African Americans and non-African Americans. RESULTS There were 2468 HIV-infected individuals in the study: 33% African American; 21% female. Among all patients, HIV-infected African Americans did not have a statistically significant increased risk for rapid eGFR decline compared with non-African Americans. However, African Americans had a significantly higher risk of ESRD and tended toward a higher risk of death. CONCLUSIONS HIV-infected African Americans did not have a statistically significant difference in the risk of eGFR decline when compared with HIV-infected non-African Americans. The findings in this study have potential public health significance.