Intakes of fruit, vegetables, and carotenoids and renal cell cancer risk: a pooled analysis of 13 prospective studies

Abstract

Fruit and vegetable consumption has been hypothesized to reduce the risk of renal cell cancer. We conducted a pooled analysis of 13 prospective studies, including 1,478 incident cases of renal cell cancer (709 women and 769 men) among 530,469 women and 244,483 men followed for up to 7 to 20 years. Participants completed a validated food-frequency questionnaire at baseline. Using the primary data from each study, the study-specific relative risks (RR) were calculated using the Cox proportional hazards model and then pooled using a random effects model. We found that fruit and vegetable consumption was associated with a reduced risk of renal cell cancer. Compared with <200 g/d of fruit and vegetable intake, the pooled multivariate RR for >or=600 g/d was 0.68 [95% confidence interval (95% CI) = 0.54-0.87; P for between-studies heterogeneity = 0.86; P for trend = 0.001]. Compared with <100 g/d, the pooled multivariate RRs (95% CI) for >or=400 g/d were 0.79 (0.63-0.99; P for trend = 0.03) for total fruit and 0.72 (0.48-1.08; P for trend = 0.07) for total vegetables. For specific carotenoids, the pooled multivariate RRs (95% CIs) comparing the highest and lowest quintiles were 0.87 (0.73-1.03) for alpha-carotene, 0.82 (0.69-0.98) for beta-carotene, 0.86 (0.73-1.01) for beta-cryptoxanthin, 0.82 (0.64-1.06) for lutein/zeaxanthin, and 1.13 (0.95-1.34) for lycopene. In conclusion, increasing fruit and vegetable consumption is associated with decreasing risk of renal cell cancer; carotenoids present in fruit and vegetables may partly contribute to this protection.

Figure 1

Study-specific and pooled multivariate RRs and 95% CIs of renal cell cancer for a 280 g/d increment of total fruit and vegetable intake. The RRs were adjusted for the same covariates listed in Table 2. The black squares indicate the study-specific relative risks; the horizontal lines represent the 95% CIs. The area of the black squares reflects the study-specific weights (inverse of the variance). The dashed line represents the pooled RR and the diamond represents the 95% CI for the pooled RR. CTS = California Teachers Study; BCDDP = Breast Cancer Detection Demonstration Project Follow-Up Study; NLCS = Netherlands Cohort Study; CPS II = Cancer Prevention Study II Nutrition Cohort; NYS = New York State Cohort; WHS = Women’s Health Study; SMC = Swedish Mammography Cohort; ATBC = Alpha-Tocopherol, Beta-Carotene Cancer Prevention Study; CNBSS = Canadian National Breast Screening Study; MCCS = Melbourne Collaborative Cohort Study; NHS = Nurses’ Health Study; HPFS = Health Professionals Follow-up Study; IWHS = Iowa Women’s Health Study; M = men; W = women.