Randomized trial of intake of fat, fiber, and beta carotene to prevent XXXX .

@entity1 @entity2066 @entity1127 @entity5 @entity14 @entity3505 @entity652 @entity2513
BACKGROUND: Epidemiologic evidence of associations between the high intake of fat and low intake of dietary fiber, beta carotene, and other dietary constituents and the risk of @entity14 has been inconsistent and has not provided a sufficient basis for recommendations concerning the dietary prevention of @entity5 in @entity1 . PURPOSE: We conducted a clinical trial to assess the effects on the incidence of @entity652 of reducing dietary fat to 25% of total calories and supplementing the diet with 25 g of @entity3505 bran daily and a capsule of @entity2066 (20 mg daily). METHODS: We performed a randomized, partially double-blinded, placebo-controlled factorial trial in which half the @entity1 were assigned to each intervention, resulting in seven intervention groups and one control group. Eligibility criteria included histologic confirmation of at least one @entity2513 and confidence expressed by the colonoscopist that all @entity1127 had been removed. Dietary changes were individually initiated and monitored by dietitians and research nurses. At surveillance colonoscopy, the size and location of all @entity1127 were recorded, and their histology was later centrally reviewed. Among 424 @entity1 who were randomly assigned in the trial, 13 were found to be ineligible upon histologic review. Among the remaining 411, complete outcome data were collected from 390 at 24 months and from 306 at 48 months. All P values are from two-sided tests of statistical significance. RESULTS: There was no statistically significant prevention of total new @entity652 with any of the interventions. We found a statistically non-significant reduced risk of large @entity652 (> or = 10 mm) with the low-fat intervention: At 24 months, the odds ratio (OR) adjusted for potential confounders = 0.4 and 95% confidence interval (CI) = 0.1-1.1; at 48 months, OR = 0.3 and 95% CI = 0.1-1.0. Less and statistically nonsignificant reductions in the risk of large @entity652 were found with @entity3505 bran: At 24 months, OR = 0.8 and 95% CI = 0.3-2.2; at 48 months, OR = 0.8 and 95% CI = 0.3-2.5. @entity1 on the combined intervention of low fat and added @entity3505 bran had zero large @entity652 at both 24 and 48 months, a statistically significant finding (P = .03). CONCLUSIONS: Because only small numbers of @entity1 were studied, our finding that the combination of fat reduction and a supplement of @entity3505 bran reduced the incidence of large @entity652 in this randomized, controlled trial must be treated with caution. The results do suggest, however, that these interventions may reduce the transition from smaller to larger @entity652 , a step that may critically define those @entity652 most likely to progress to @entity5 .
