Renal cell carcinoma (RCC) accounts for nearly all adult kidney malignancies. The age-adjusted incidence of RCC has more than doubled over the last three decades in the U.S., mirroring the growing epidemic of obesity, which along with smoking comprise the most well-established RCC risk factors. Plant-based and fiber-rich diets high in vegetables, fruits, and whole grains are recommended for the prevention of cancer, as well as chronic conditions positively associated with RCC incidence, such as hypertension and diabetes. Thus, diet may play a role in RCC etiology directly and/or indirectly. In a large prospective cohort of U.S. men and women, we comprehensively investigated dietary intake of a range of plant foods and their nutritional components in relation to RCC risk. We further examined whether associations varied by history of hypertension or diabetes, body mass index, smoking status, or alcohol intake. At baseline (1995-1996), 492,186 participants of the National Institutes of Health-AARP Diet and Health Study completed a self-administered questionnaire of demographics, diet, lifestyle, and medical history. Over 9 (mean) years of follow-up we identified 1,814 incident cases of RCC. Hazard ratios (HR) and 95% confidence intervals (CI) were estimated within quintiles (Q) using multivariable Cox proportional hazards regression. Intake of legumes, whole grains, and cruciferous vegetables were associated with a statistically significant 16-18% reduced risk of RCC. Conversely, refined grain intake was positively associated with RCC risk [Q5 vs. Q1, HR and 95% CI: 1.19 (1.02-1.39); P-trend =0.04] and we found no association with fruit intake. These findings were consistent with the strong inverse association we observed for total dietary fiber intake [Q5 vs. Q1, HR and 95% CI: 0.81 (0.69-0.95); Ptrend =0.005], as well as fiber derived from various dietary sources. The association between fiber intake and RCC did not vary substantially by smoking status [Q5 vs. Q1, HR and 95% CI: 0.65 (0.49-0.87) and 0.50 (0.25-1.02) in never vs. current smokers, respectively], history of hypertension [0.73 (0.52-1.02) and 0.75(0.57-1.00) in negative vs. positive history, respectively], or other major risk factors. In conclusion, intake of fiber and fiber-rich plant foods was associated with a significantly lower risk of renal cell carcinoma in this large U.S. cohort.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 659. doi:1538-7445.AM2012-659