Understanding racial disparities in renal cell carcinoma incidence: estimates of population attributable risk in two US populations

Renal cell carcinoma (RCC) incidence is higher among black than white Americans. The reasons for this disparity remain unclear. We calculated race- and sex-specific population attributable risk percentages (PAR%) and their 95% confidence intervals (CI) for hypertension and chronic kidney disease (CKD) among black and white subjects ≥  50 years of age from the US Kidney Cancer Study (USKC; 965 cases, 953 controls), a case-control study in Chicago and Detroit, and a nested case-control study in the Kaiser Permanente Northern California health care network (KPNC; 2,162 cases, 21,484 controls). We also estimated PAR% for other modifiable RCC risk factors (cigarette smoking, obesity) in USKC. In USKC, the PAR% for hypertension was 50% (95% CI 24-77%) and 44% (95% CI 25-64%) among black women and men, respectively, and 29% (95% CI 13-44%) and 27% (95% CI 14-39%) for white women and men, respectively. In KPNC, the hypertension PAR% was 40% (95% CI 18-62%) and 23% (95% CI 2-44%) among black women and men, and 27% (95% CI 20-35%) and 19% (95% CI 14-24%) among white women and men, respectively. The PAR% for CKD in both studies ranged from 7 to 10% for black women and men but was negligible (

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