The polyp prevention trial-continued follow-up study: No effect of a low-fat, high-fiber, high-fruit, and -vegetable diet on adenoma recurrence eight years after randomization
ABSTRACT The Polyp Prevention Trial (PPT) was a multicenter randomized clinical trial to evaluate the effects of a high-fiber (18 g/1,000 kcal), high-fruit and -vegetable (3.5 servings/1,000 kcal), and low-fat (20% of total energy) diet on the recurrence of adenomatous polyps in the large bowel over a period of 4 years. Although intervention participants reported a significantly reduced intake of dietary fat, and increased fiber, fruit, and vegetable intakes, their risk of recurrent adenomas was not significantly different from that of the controls. Since the PPT intervention lasted only 4 years, it is possible that participants need to be followed for a longer period of time before treatment differences in adenoma recurrence emerge, particularly if diet affects early events in the neoplastic process. The PPT-Continued Follow-up Study (PPT-CFS) was a post-intervention observation of PPT participants for an additional 4 years from the completion of the trial. Of the 1,905 PPT participants, 1,192 consented to participate in the PPT-CFS and confirmed colonoscopy reports were obtained on 801 participants. The mean time between the main trial end point colonoscopy and the first colonoscopy in the PPT-CFS was 3.94 years (intervention group) and 3.87 years (control group). The baseline characteristics of 405 intervention participants and 396 control participants in the PPT-CFS were quite similar. Even though the intervention group participants increased their fat intake and decreased their intakes of fiber, fruits, and vegetables during the PPT-CFS, they did not go back to their prerandomization baseline diet (P < 0.001 from paired t tests) and intake for each of the three dietary goals was still significantly different from that in the controls during the PPT-CFS (P < 0.001 from t tests). As the CFS participants are a subset of the people in the PPT study, the nonparticipants might not be missing completely at random. Therefore, a multiple imputation method was used to adjust for potential selection bias. The relative risk (95% confidence intervals) of recurrent adenoma in the intervention group compared with the control group was 0.98 (0.88-1.09). There were no significant intervention-control group differences in the relative risk for recurrence of an advanced adenoma (1.06; 0.81-1.39) or multiple adenomas (0.92; 0.77-1.10). We also used a multiple imputation method to examine the cumulative recurrence of adenomas through the end of the PPT-CFS: the intervention-control relative risk (95% confidence intervals) for any adenoma recurrence was 1.04 (0.98-1.09). This study failed to show any effect of a low-fat, high-fiber, high-fruit and -vegetable eating pattern on adenoma recurrence even with 8 years of follow-up. (Cancer Epidemiol Biomarkers Prev 2007;16(9):1745-52).
- SourceAvailable from: usu.edu[Show abstract] [Hide abstract]
ABSTRACT: This study aimed to increase vegetable consumption and preference in elementary school-aged children using two interventions: 1) flavor-flavor conditioning; and 2) sensory-based, vegetable-themed education. In both interventions, increase in consumption was measured by visual observation of how many vegetables children took and consumed from a vegetable buffet. Preferences were measured with a self-administered survey.In the flavor-flavor intervention, children ages 5 to 11 (n=59) were exposed to sweetened and nonsweetened vegetable purees. Preferences were assessed prior to intervention using a rating and ranking system. Nine paired tastings were presented. Children received a posttest immediately after the final conditioning (n=27) and again 2 to 3 weeks after the final conditioning (n=24). A repeated measures ANOVA was used to examine the effect of conditioning (sweetened vegetable purees) on flavor preference. The change in attitudes and behaviors related to vegetables was evaluated using independent samples t-tests. Pre- and post-flavor conditioning change in whole vegetable consumption was assessed using paired t-tests. Flavor-flavor conditioning is not an effective strategy to increase whole vegetable consumption or preference for vegetables in elementary school-aged children.The vegetable-themed curriculum focused on four vegetables (carrots, peas, cauliflower, broccoli) and included three 30-minute lessons on each vegetable. Lessons included information on how the vegetable tastes, where it grows, and what it looks, feels, sounds, and smells like. Lessons were taught once per week for 3 weeks each month over four months. Children ages 5-11 enrolled in an after-school program at one elementary school were invited to participate (n=27). The amount of vegetables consumed by participants during a vegetable buffet was observed pre- and post-intervention (n = 20, 12 respectively). Differences in these amounts were assessed using independent samples t-tests. The education intervention was associated with increased consumption of carrots (p-value =0.001) and peas (p-value=0.003) but not cauliflower or broccoli. There was no change in vegetable-related attitudes/behaviors post-intervention. The results support the use of sensory-based, vegetable-themed education to increase vegetable consumption among children. Future studies should involve a larger sample size and should consider in-school rather than after-school education.
- [Show abstract] [Hide abstract]
ABSTRACT: Colorectal cancer is a major cause of cancer-related mortality. Most colorectal cancers arise in precursor lesions over a number of years. The carcinogenetic pathway is modulated by a wide array of genetic and epigenetic factors. Two major approaches to halting carcinogenesis are chemoprevention and early detection. Chemoprevention is an attractive emerging option—advances in understanding the carcinogenetic pathways and progress in evaluating various putative agents are promising. However, several issues regarding efficacy, safety, and acceptability require answers before an ideal agent can come into widespread use. Early detection and removal of precursor lesions show promise in reducing disease burden. Although the concept has been around and has been widely advocated for several years, participation in screening remains low. The ideal test in terms of practicality, accuracy, and safety is still debated. This article reviews the recent literature related to screening and chemoprevention of colorectal cancer.Current Colorectal Cancer Reports 01/2009; 5(1):48-54. DOI:10.1007/s11888-009-0008-7
- [Show abstract] [Hide abstract]
ABSTRACT: La prévention des cancers en France, comme dans les autres pays, a longtemps été de facto considérée comme une prévention primaire exclusivement. À partir du moment où un diagnostic de malignité était posé, le patient entrait dans une prise en charge faisant uniquement appel aux traitements antitumoraux spécifiques, principalement la chirurgie, la radiothérapie et la chimiothérapie.