A case-control study of reproductive factors and renal cell carcinoma among black and white women in the United States

Abstract

Objective: Renal cell carcinoma (RCC) incidence is higher among blacks than whites in the United States and has been associated with the frequency and timing of childbirth among women in some epidemiologic studies. We investigated whether reproductive factors are associated with RCC, overall and by race, within a population-based case-control study.

Methods: Between 2002 and 2007, 497 female cases of incident RCC (136 black, 361 white) and 546 female controls (273 black, 273 white) within the Detroit and Chicago metropolitan areas were enrolled. Information on reproductive history and other factors was collected through in-person interviews. Multivariate-adjusted odds ratios (OR) and 95% confidence intervals (CI) were computed using unconditional logistic regression.

Results: Reduced RCC risk was observed among women aged ≥30 years at first live birth, relative to an age of <20 years (OR 0.5, 95% CI 0.3-0.9). This association was present among both white (OR 0.4, 95% CI 0.2-0.9) and, though not statistically significant, black women (OR 0.6, 95% CI 0.2-1.8). In analyses restricted to clear cell adenocarcinoma, the most common RCC histological subtype, the association was particularly strong (OR 0.3, 95% CI 0.2-0.8). We did not observe clear evidence of association with RCC for other reproductive factors.

Conclusions: Our findings further support an association between late maternal age at first birth and reduced RCC risk, and suggest that the association may be particularly strong for clear cell adenocarcinoma.