Racial disparities in renal function: the role of racial discrimination. The Brazilian Longitudinal Study of Adult Health (ELSA-Brasil).

Background: Racial discrimination may play a significant role in higher incidence and poorer prognosis of chronic kidney disease among Black individuals. This study set out to investigate the association between racial discrimination and renal function and to estimate the contribution of racial discrimination to existing racial disparities in renal function.

Methods: A cross-sectional analysis using baseline data (2008-2010) of 14 355 participants (35-74 years) in the Brazilian Longitudinal Study of Adult Health cohort study. Renal function was estimated based on estimated glomerular filtration rates (eGFR) obtained by the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation. Racial discrimination was assessed using a modified version of the Lifetime Major Events Scale ; race/colour was self-reported. Covariates included were age, sex, level of education and selected health-related factors.

Results: Racial discrimination was reported by 31.6%, 6.3% and 0.8% of Black, Brown and White individuals, respectively. The older the age, the lower the prevalence of racial discrimination among Blacks. Racial discrimination was independently associated with lower mean eGFR (β=-2.38; 95% CI -3.50 to -1.25); however, associations were limited to individuals aged under 55 years. In this age group, eGFR differences between Black and White individuals were reduced by 31% when exposure to racial discrimination was accounted for.

Conclusion: Blacks are approximately 40 times more likely to report racial discrimination than Whites. Racial discrimination was associated with lower mean eGFR and explained a significant portion of eGFR differences between Black and White individuals aged under 55 years. Exposure to experiences of racial discrimination should be accounted for in studies investigating racial disparities in renal function.