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 (<1%) for white subjects. In USKC, the PAR% for current smoking was 20% and 8% among black and white men, respectively, and negligible and 8.6% for black and white women, respectively. The obesity PAR% ranged from 12 to 24% across all race/sex strata.
If the associations found are causal, interventions that prevent hypertension and CKD among black Americans could potentially eliminate the racial disparity in RCC incidence (hypothetical black:white RCC incidence ratio of 0.5).
Cancer causes & control : CCC. 2019 Nov 28 [Epub ahead of print]
Catherine L Callahan, Kendra Schwartz, Douglas A Corley, Julie J Ruterbusch, Wei K Zhao, Brian Shuch, Barry I Graubard, Nathaniel Rothman, Wong-Ho Chow, Debra T Silverman, Mark P Purdue, Jonathan N Hofmann
Occupational and Environmental Epidemiology Branch, Division of Cancer Epidemiology and Genetics, National Cancer Institute, 9609 Medical Center Drive, Rockville, MD, 20850, USA., Department of Family Medicine and Public Health Sciences, Karmanos Cancer Institute, Wayne State University, Detroit, MI, USA., Division of Research, Kaiser Permanente Northern California, Oakland, CA, USA., Department of Urology, Yale School of Medicine, New Haven, CT, USA., Biostatistics Branch, Division of Cancer Epidemiology and Genetics, National Cancer Institute, Rockville, MD, USA., Department of Epidemiology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA., Occupational and Environmental Epidemiology Branch, Division of Cancer Epidemiology and Genetics, National Cancer Institute, 9609 Medical Center Drive, Rockville, MD, 20850, USA. .