Division of Gastroenterology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts.
Gastroenterology. 2013 Nov;145(5):970-7. doi: 10.1053/j.gastro.2013.07.050. Epub 2013 Aug 2.
BACKGROUND & AIMS: Increased intake of dietary fiber has been proposed to reduce the risk of inflammatory bowel disease (Crohn's disease [CD] and ulcerative colitis [UC]). However, few prospective studies have examined associations between long-term intake of dietary fiber and risk of incident CD or UC.
We collected and analyzed data from 170,776 women, followed up over 26 years, who participated in the Nurses' Health Study, followed up for 3,317,425 person-years. Dietary information was prospectively ascertained via administration of a validated semiquantitative food frequency questionnaire every 4 years. Self-reported CD and UC were confirmed through review of medical records. Cox proportional hazards models, adjusting for potential confounders, were used to calculate hazard ratios (HRs).
We confirmed 269 incident cases of CD (incidence, 8/100,000 person-years) and 338 cases of UC (incidence, 10/100,000 person-years). Compared with the lowest quintile of energy-adjusted cumulative average intake of dietary fiber, intake of the highest quintile (median of 24.3 g/day) was associated with a 40% reduction in risk of CD (multivariate HR for CD, 0.59; 95% confidence interval, 0.39-0.90). This apparent reduction appeared to be greatest for fiber derived from fruits; fiber from cereals, whole grains, or legumes did not modify risk. In contrast, neither total intake of dietary fiber (multivariate HR, 0.82; 95% confidence interval, 0.58-1.17) nor intake of fiber from specific sources appeared to be significantly associated with risk of UC.
Based on data from the Nurses' Health Study, long-term intake of dietary fiber, particularly from fruit, is associated with lower risk of CD but not UC. Further studies are needed to determine the mechanisms that mediate this association.
膳食纤维摄入量的增加被认为可以降低炎症性肠病（克罗恩病[CD]和溃疡性结肠炎[UC]）的风险。然而，很少有前瞻性研究检查长期膳食纤维摄入量与 CD 或 UC 发病风险之间的关系。
我们收集并分析了 170776 名女性的数据，这些女性参加了护士健康研究，随访时间超过 26 年，随访期间共 3317425 人年。通过每 4 年进行一次验证后的半定量食物频率问卷来前瞻性地确定饮食信息。通过审查医疗记录来确认 CD 和 UC 的自我报告病例。使用 Cox 比例风险模型，调整潜在混杂因素，计算风险比（HR）。
我们确认了 269 例 CD （发病率为 8/100000 人年）和 338 例 UC （发病率为 10/100000 人年）。与能量调整后累积平均膳食纤维摄入量最低五分位数相比，摄入量最高五分位数（中位数为 24.3g/天）与 CD 风险降低 40%相关（CD 的多变量 HR 为 0.59；95%置信区间为 0.39-0.90）。这种明显的降低似乎主要与水果来源的纤维有关；谷物、全谷物或豆类来源的纤维不能改变风险。相比之下，膳食纤维的总摄入量（多变量 HR，0.82；95%置信区间，0.58-1.17）或特定来源纤维的摄入量与 UC 风险均无显著相关性。
基于护士健康研究的数据，长期摄入膳食纤维，特别是水果纤维，与 CD 风险降低相关，但与 UC 无关。需要进一步研究以确定介导这种关联的机制。
