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
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
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DOI：
10.1158/1055-9965.epi-07-0127
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发表时间：
2007-09-01
影响因子：
3.8
通讯作者：
Schatzkin, Arthur
中科院分区：
文献类型：
--
作者：
Lanza, Elaine;Yu, Binbing;Schatzkin, Arthur
息肉预防试验（PPT）是一项多中心随机临床试验，旨在评估高纤维（18 g/1，000 kcal），高水果和蔬菜（3.5份/1，000 kcal）和低脂（总能量的20%）饮食对大肠腺瘤性息肉复发的影响，为期4年。尽管干预参与者报告膳食脂肪摄入量显著减少，纤维、水果和蔬菜摄入量增加，但他们复发腺瘤的风险与对照组没有显著差异。由于PPT干预仅持续了4年，因此在腺瘤复发的治疗差异出现之前，参与者可能需要更长时间的随访，特别是如果饮食影响肿瘤过程中的早期事件。PPT持续随访研究（PPT-CFS）是对PPT参与者进行的干预后观察，从试验完成后再观察4年。在1，905名PPT参与者中，1，192名同意参加PPT-CFS，并获得了801名参与者的确认结肠镜检查报告。PPT-CFS中主要试验终点结肠镜检查与首次结肠镜检查之间的平均时间为3.94年（干预组）和3.87年（对照组）。PPT-CFS中405名干预参与者和396名对照参与者的基线特征非常相似。尽管干预组参与者在PPT-CFS期间增加了脂肪摄入量，减少了纤维，水果和蔬菜的摄入量，但他们并没有回到随机化前的基线饮食（配对t检验P < 0.001），并且在PPT-CFS期间，三个饮食目标中的每一个的摄入量仍然与对照组有显著差异（t检验P < 0.001）。由于CFS参与者是PPT研究中的一个子集，非参与者可能不会完全随机缺失。因此，使用多重插补方法调整潜在选择偏倚。与对照组相比，干预组腺瘤复发的相对风险（95%置信区间）为0.98（0.88-1.09）。在晚期腺瘤（1.06; 0.81-1.39）或多发性腺瘤（0.92; 0.77-1.10）复发的相对风险方面，干预组与对照组之间没有显著差异。我们还使用了多重插补方法来检查PPT-CFS结束时腺瘤的累积复发：任何腺瘤复发的干预对照相对风险（95%置信区间）为1.04（0.98-1.09）。这项研究没有显示任何影响低脂肪，高纤维，高水果和蔬菜的饮食模式对腺瘤复发，即使是8年的随访。
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.