Larsson Susanna C, Håkansson Niclas, Giovannucci Edward, Wolk Alicja
Division of Nutritional Epidemiology, The National Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden.
J Natl Cancer Inst. 2006 Mar 15;98(6):407-13. doi: 10.1093/jnci/djj094.
Epidemiologic evidence supports an association between high folate intake and reduced risk of some cancers, in particular colorectal cancer. However, epidemiologic data concerning the relationship between folate and pancreatic cancer risk are sparse. We examined the association between folate intake and risk of pancreatic cancer in a population-based prospective study of Swedish women and men.
We prospectively followed 81,922 women and men in the Swedish Mammography Cohort and the Cohort of Swedish Men who were cancer-free and completed a 96-item food-frequency questionnaire in 1997. Cox proportional hazards models were used to estimate multivariable rate ratios (RRs) with 95% confidence intervals (CIs). All statistical tests were two-sided.
A total of 135 incident pancreatic cancer cases were diagnosed during a mean follow-up of 6.8 years. In multivariable analyses controlling for age, smoking, fruit and vegetable consumption, and other potential confounders, dietary and total folate intakes were statistically significantly inversely associated with risk of pancreatic cancer. The multivariable rate ratios of pancreatic cancer for those in the highest category of folate intake (> or = 350 microg/day) compared with the lowest category of intake (< 200 microg/day) were 0.25 (95% CI = 0.11 to 0.59; Ptrend = .002) for dietary folate and 0.33 (95% CI = 0.15 to 0.72; Ptrend = .01) for total folate (combining dietary and supplemental sources). Folic acid from supplements was not associated with pancreatic cancer (for > or = 300 microg/day compared with 0 microg/day of supplemental folic acid, multivariable RR = 1.02; 95% CI = 0.56 to 1.88). The sex- and age-standardized incidence rates of pancreatic cancer per 100,000 person-years were 41 for the lowest and 18 for the highest category of dietary folate intake.
Our results suggest that increased intake of folate from food sources, but not from supplements, may be associated with a reduced risk of pancreatic cancer.
流行病学证据支持高叶酸摄入量与某些癌症风险降低之间存在关联，尤其是结直肠癌。然而，关于叶酸与胰腺癌风险之间关系的流行病学数据较为稀少。我们在一项针对瑞典男性和女性的基于人群的前瞻性研究中，研究了叶酸摄入量与胰腺癌风险之间的关联。
我们对瑞典乳腺X线摄影队列和瑞典男性队列中的81922名男性和女性进行了前瞻性随访，这些人在1997年时均无癌症，并完成了一份包含96个项目的食物频率问卷。使用Cox比例风险模型来估计多变量率比（RRs）及其95%置信区间（CIs）。所有统计检验均为双侧检验。
在平均6.8年的随访期间，共诊断出135例胰腺癌新发病例。在控制了年龄、吸烟、水果和蔬菜摄入量以及其他潜在混杂因素的多变量分析中，膳食叶酸摄入量和总叶酸摄入量与胰腺癌风险在统计学上呈显著负相关。叶酸摄入量最高类别（≥350微克/天）与最低类别（<200微克/天）相比，膳食叶酸的多变量率比为0.25（95%CI = 0.11至0.59；P趋势 = 0.002），总叶酸（膳食和补充剂来源合计）的多变量率比为0.33（95%CI = 0.15至0.72；P趋势 = 0.01）。补充剂中的叶酸与胰腺癌无关（补充叶酸≥300微克/天与补充叶酸0微克/天相比，多变量RR = 1.02；95%CI = 0.56至1.88）。每10万人年中，膳食叶酸摄入量最低类别和最高类别胰腺癌的性别和年龄标准化发病率分别为41和18。
我们的结果表明，从食物来源而非补充剂中增加叶酸摄入量，可能与降低胰腺癌风险有关。
