Fibre intake and renal cell carcinoma: a case-control study from Italy.

Only 2 previous studies, conducted in Australia, United States and northern Europe, considered the role of dietary fibre intake on renal cell carcinoma (RCC) risk, and both showed a modest, inverse association. Therefore, we investigated in depth the topic of fibres and RCC, using data from a multicenter case-control study conducted in Italy from 1992 to 2004, including 767 cases with incident, histologically confirmed RCC and 1,534 controls admitted to the same network of hospitals as cases with acute nonmalignant conditions. Multivariate odds ratios (OR) and 95% confidence intervals (CI) were obtained after allowance for major identified confounding factors, including total energy intake. The continuous OR for an increase in intake equal to the difference between the 80th and the 20th percentile were 0.94 (95% CI: 0.82-1.08) for total dietary fibre, 0.98 (95% CI: 0.85-1.13) for soluble noncellulose polysaccharides, 0.92 (95% CI: 0.80-1.05) for total insoluble fibre, 0.90 (95% CI: 0.78-1.04) for cellulose, 0.95 (95% CI: 0.84-1.06) for insoluble noncellulose polysaccharides and 1.06 (95% CI: 0.93-1.21) for lignin. With reference to the sources of fibre, we found an inverse association with vegetable fibre (OR = 0.84, 95% CI: 0.73-0.97), but no association with fruit (OR = 0.98, 95% CI: 0.86-1.12) and grain fibre (OR = 1.05, 95% CI: 0.95-1.15). The inverse association with vegetable fibre may reflect a real favorable effect, or be an indicator of a beneficial role of a diet rich in vegetable on RCC risk.