Department of Medicine, Norwich Medical School University of East Anglia, Norwich, UK; Norfolk & Norwich University Hospitals NHS Trust, Norwich, UK.
Aliment Pharmacol Ther. 2014 Apr;39(8):834-42. doi: 10.1111/apt.12670. Epub 2014 Feb 24.
There are plausible mechanisms for how dietary docosahexaenoic acid (DHA), an n-3 polyunsaturated fatty acid, could prevent Crohn's disease (CD).
To conduct a prospective study to investigate the association between increased intake of DHA and risk of CD.
Overall, 229 702 participants were recruited from nine European centres between 1991 and 1998. At recruitment, dietary intakes of DHA and fatty acids were measured using validated food frequency questionnaires. The cohort was monitored through to June 2004 to identify participants who developed incident CD. In a nested case-control analysis, each case was matched with four controls; odds ratios (ORs) were calculated for quintiles of DHA intake, adjusted for total energy intake, smoking, other dietary fatty acids, dietary vitamin D and body mass index.
Seventy-three participants developed incident CD. All higher quintiles of DHA intake were inversely associated with development of CD; the highest quintile had the greatest effect size (OR = 0.07; 95% CI = 0.02-0.81). The OR trend across quintiles of DHA was 0.54 (95% CI = 0.30-0.99, Ptrend = 0.04). Including BMI in the multivariate analysis, due to its correlation with dietary fat showed similar associations. There were no associations with the other dietary fatty acids studied.
There were inverse associations, with a biological gradient between increasing dietary docosahexaenoic acid intakes and incident Crohn's disease. Further studies in other populations should measure docosahexaenoic acid to determine if the association is consistent and the hypothesis tested in randomised controlled trials of purely docosahexaenoic acid supplementation.
二十二碳六烯酸（DHA）作为一种 n-3 多不饱和脂肪酸，其预防克罗恩病（CD）的作用机制似乎合理。
进行一项前瞻性研究，以调查 DHA 摄入量增加与 CD 风险之间的关联。
1991 年至 1998 年期间，共有 229702 名参与者从欧洲的 9 个中心招募而来。在招募时，使用经过验证的食物频率问卷来测量 DHA 和脂肪酸的饮食摄入量。通过监测该队列，直至 2004 年 6 月，以确定发生新发病例的 CD 参与者。在嵌套病例对照分析中，每个病例与 4 个对照匹配；使用多变量逻辑回归模型计算 DHA 摄入量五分位数的比值比（OR），并调整总能量摄入、吸烟、其他饮食脂肪酸、饮食维生素 D 和体重指数。
73 名参与者发生了新发病例 CD。所有更高的 DHA 摄入量五分位数与 CD 的发展呈负相关；最高五分位数的效果最大（OR=0.07；95%CI=0.02-0.81）。DHA 五分位数的 OR 趋势为 0.54（95%CI=0.30-0.99，Ptrend=0.04）。由于 BMI 与饮食脂肪相关，在多变量分析中包含 BMI 后，也显示出类似的关联。与研究的其他饮食脂肪酸无关联。
饮食中二十二碳六烯酸摄入量增加与新发病例 CD 之间存在负相关关系，且呈生物学梯度。在其他人群中进行的进一步研究应测量二十二碳六烯酸，以确定关联是否一致，并在纯二十二碳六烯酸补充的随机对照试验中检验该假设。
