Antioxidant micronutrients and the risk of renal cell carcinoma in the Women's Health Initiative cohort

BACKGROUND: Renal cell carcinoma (RCC) is the eighth leading cancer among women in incidence and commonly is diagnosed at a more advanced stage. Oxidative stress has been considered to play an important role in the pathogenesis of RCC. Various dietary micronutrients have antioxidant properties, including carotenoids and vitamins C and E; thus, diets rich in these nutrients have been evaluated in relation to RCC prevention. The objective of this study was to explore the correlation between antioxidant micronutrients and the risk of RCC. METHODS: In total, 96,196 postmenopausal women who enrolled in the Women's Health Initiative (WHI) between 1993 and 1998 and were followed through July 2013 were included in this analysis. Dietary micronutrient intake was estimated from the baseline WHI food frequency questionnaire, and data on supplement use were collected using an interview-based inventory procedure. RCC cases were ascertained from follow-up surveys and were centrally adjudicated. The risks for RCC associated with intake of α-carotene, β-carotene, β-cryptoxanthin, lutein plus zeaxanthin, lycopene, vitamin C, and vitamin E were analyzed using Cox proportional hazards regression adjusted for confounders. RESULTS: Two hundred forty women with RCC were identified during follow-up. Lycopene intake was inversely associated with RCC risk (P=.015); compared with the lowest quartile of lycopene intake, the highest quartile of intake was associated with a 39% lower risk of RCC (hazard ratio, 0.61; 95% confidence interval, 0.39-0.97). No other micronutrient was significantly associated with RCC risk. CONCLUSIONS: The current results suggest that further investigation into the correlation between lycopene intake and the risk of RCC is warranted.