Excess Risk of Chronic Kidney Disease among African-American versus White Subjects in the United States

Abstract

Abstract. African Americans experience higher rates of chronic kidney disease (CKD) than do whites. It was hypothesized that racial differences in modifiable factors would account for much of the excess risk of CKD. A cohort study of 9082 African-American and white adults of age 30 to 74 yr, who participated in the Second National Health and Nutrition Examination Survey in 1976 to 1980 and were monitored for vital status through 1992 in the Second National Health and Nutrition Examination Survey Mortality Study, was conducted. Incident CKD was defined as treated CKD cases (ascertained by linkage to the Medicare Registry) and deaths related to kidney disease. The incidence of all-cause CKD was 2.7 times higher among African Americans, compared with whites. Adjustment for sociodemographic factors decreased the relative risk (RR) to 2.49, explaining 12% of the excess risk of CKD among African Americans. Further adjustment for lifestyle factors explained 24% of the excess risk, whereas adjustment for clinical factors alone explained 32%. Simultaneous adjustment for sociodemographic, lifestyle, and clinical factors attenuated the RR to 1.95 (95% confidence interval, 1.05 to 3.63), explaining 44% of the excess risk. Although the excess risk of CKD among African Americans was much greater among middle-age adults (30 to 59 yr of age; RR ϭ 4.23, statistically significant) than among older adults (60 to 74 yr of age; RR ϭ 1.27), indicating an interaction between race and age, the same patterns of explanatory factors were observed for the two age groups. Nearly one-half of the excess risk of CKD among African-American adults can be explained on the basis of potentially modifiable risk factors; however, much of the excess risk remains unexplained.

Epidemiology of Chronic Kidney Disease

“…When all of these factors were controlled, the adjusted relative risk was 1.95 (95% CI, 1.05-3.63), accounting for 44% of the excess risk. Furthermore, the excess risk among black people for ESRD reported by Tarver-Carr and her colleagues was much greater among middle-aged than among older adults [65].…”

“…Factors associated with these racial disparities in ESRD incidence include access to health care, poverty, and community poverty [62][63][64]. Tarver-Carr and her associates used follow-up data from NHANES II to examine risk factors associated with racial differences in the incidence of all-cause ESRD [65]. They reported a 2.7-fold-higher ESRD incidence for black people compared with white people.…”

Risk Factors for Progressive Chronic Kidney Disease

“…A recent report by Tarver-Carr et al illustrates how multivariate risk models can be used to estimate the fraction of excess risk for CKD among African-Americans that can be attributed to risk factors other than race (59). They used data from the second National Health and Nutrition Examination survey (NHANES II) follow-up study to examine risk factors associated with higher risk of ESRD among African Americans compared with whites.…”

The State of U.S. Living Kidney Donors

“…The median time from donation to listing was 21 years for white donors and 16 years for AfricanAmerican donors; 43% of such donors were African Americans, who made up and do make up ϳ12% of living kidney donors. These data suggest that the risk of postdonation ESRD is not equal among ethnic/racial groups and mirrors the increased risk of ERSD that these groups experience in the general population (25)(26)(27). For instance, focal sclerosis and hypertensive renal disease in African Americans has recently been tied to genetic variations in nonmuscle myosin heavy chain 9, perhaps making changes in intrarenal hemodynamics more problematic in certain African-American donors (28 -31).…”