Association between fruit and vegetable consumption and the risk of renal cell carcinoma among 40-76 year-old Swedish women

Results of epidemiologic studies on the relationship between fruit and vegetable consumption and the renal cell carcinoma (RCC) risk have been inconsistent and inconclusive so far. This study was conducted to further explore the issue and throw more light on the subject. In a population-based prospective cohort study of Swedish women (Swedish Mammography Cohort) dietary information from 61,000 women 40–76 years old was collected using a food-frequency questionnaire. A 13-year follow-up showed that 122 of the women developed RCC. Cox proportional hazards models were used to estimate relative risks (RR) with 95% confidence interval (CI). Women consuming 5 or more combined servings of fruit and vegetables daily had a relative risk of 0.59 (95% CI=0.26–1.34) in comparison with those consuming less than once serving. When fruits and vegetables were examined separately, those women who had consumed more than 75 servings of either fruits or vegetables per month had a multivariate relative risk of 0.59 (95% CI=0.27–1.25) and 0.60 (95% CI=0.31–1.17), respectively, compared with those consuming 11 or less servings per month. Within the fruit group, bananas showed the strongest inverse association (p=0.07 by Wald test), while of all the vegetables studied root vegetables proved to have the strongest inverse association (p = 0.03 by Wald test), with RCC. The risk of RCC decreased with an increase in the consumption frequency of white cabbage (p for trend=0.07). The data also revealed that the consumption by women of salad vegetables (at least once per day) could reduce the RCC risk by 40% (RR= 0.60; 95% CI =0.30 –1.22), in comparison to those not consuming this type of vegetables. Our results suggest that a high consumption of fruits and vegetables may reduce the risk of RCC in women.