Micronutrients and the risk of renal cell cancer: a case-control study from Italy.

The role of various micronutrients on the risk of renal cell cancer (RCC) was examined in a multicentric case-control study from Italy, in which information on dietary habits were collected using a validated food-frequency questionnaire. Cases were 767 patients (494 men and 273 women) with incident, histologically confirmed RCC; controls were 1,534 subjects (988 men and 546 women) admitted to the same hospitals as cases for a wide spectrum of acute, nonneoplastic conditions. After allowing for energy and other major covariates, a significant inverse association was found for vitamin E (odds ratio, OR, for the highest quintile of intake versus the lowest one 0.56, 95% confidence interval, CI 0.41-0.75), and vitamin C (OR = 0.72, 95% CI = 0.54-0.96), although the trend in risk for vitamin C was of borderline significance. No significant trend of decreasing risk was found for other micronutrients analyzed, although for most of them the risk estimates were below unity for intakes above the lowest. The ORs for the upper quintile of intake when compared with the lowest one were 0.80 (95% confidence interval, CI = 0.59-1.08) for retinol, 0.82 (95% CI = 0.61-1.10) for alpha-carotene, 0.90 (95% CI = 0.68-1.20) for beta-carotene, 0.94 (95% CI = 0.73-1.21) for beta-criptoxanthin, 0.85 (95% CI = 0.63-1.14) for lutein/zeaxanthin, 0.76 (95% CI = 0.57-1.01) for vitamin D, 0.75 (95% CI = 0.55-1.01) for thiamine, 0.88 (95% CI = 0.66-1.19) for riboflavin, 0.85 for vitamin B6 (95% CI = 0.64-1.13), 0.85 (95% CI = 0.64-1.12) for folate and 0.80 (95% CI = 0.60-1.07) for niacin. No meaningful associations emerged for lycopene (OR = 1.11). The present findings support a possible beneficial effect of vitamin E and C on RCC.