Knudsen Markus Dines, Kyrø Cecilie, Olsen Anja, Dragsted Lars O, Skeie Guri, Lund Eiliv, Aman Per, Nilsson Lena M, Bueno-de-Mesquita H B, Tjønneland Anne, Landberg Rikard
Am J Epidemiol. 2014 May 15;179(10):1188-96. doi: 10.1093/aje/kwu031. Epub 2014 Apr 3.
Self-reported food frequency questionnaires (FFQs) have occasionally been used to investigate the association between whole-grain intake and the incidence of colorectal cancer, but the results from those studies have been inconsistent. We investigated this association using intakes of whole grains and whole-grain products measured via FFQs and plasma alkylresorcinol concentrations, a biomarker of whole-grain wheat and rye intake, both separately and in combination (Howe's score with ranks). We conducted a nested case-control study in a cohort from a research project on Nordic health and whole-grain consumption (HELGA, 1992-1998). Incidence rate ratios and 95% confidence intervals were calculated using conditional logistic regression. Plasma alkylresorcinol concentrations alone and Howe's score with ranks were inversely associated with the incidence of distal colon cancer when the highest quartile was compared with the lowest (for alkylresorcinol concentrations, incidence rate ratio = 0.34, 95% confidence interval: 0.13, 0.92; for Howe's score with ranks, incidence rate ratio = 0.35, 95% confidence interval: 0.15, 0.86). No association was observed between whole-grain intake and any colorectal cancer (colon, proximal, distal or rectum cancer) when using an FFQ as the measure/exposure variable for whole-grain intake. The results suggest that assessing whole-grain intake using a combination of FFQs and biomarkers slightly increases the precision in estimating the risk of colon or rectal cancer by reducing the impact of misclassification, thereby increasing the statistical power of the study.
自我报告的食物频率问卷（FFQ）偶尔被用于调查全谷物摄入量与结直肠癌发病率之间的关联，但这些研究的结果并不一致。我们通过FFQ测量的全谷物和全谷物产品摄入量以及血浆烷基间苯二酚浓度（全谷物小麦和黑麦摄入量的生物标志物），分别以及联合使用（Howe评分及排名）来研究这种关联。我们在一项关于北欧健康与全谷物消费的研究项目（HELGA，1992 - 1998年）的队列中进行了一项巢式病例对照研究。使用条件逻辑回归计算发病率比和95%置信区间。当将最高四分位数与最低四分位数进行比较时，单独的血浆烷基间苯二酚浓度以及Howe评分及排名与远端结肠癌的发病率呈负相关（对于烷基间苯二酚浓度，发病率比 = 0.34，95%置信区间：0.13，0.92；对于Howe评分及排名，发病率比 = 0.35，95%置信区间：0.15，0.86）。当使用FFQ作为全谷物摄入量的测量/暴露变量时，未观察到全谷物摄入量与任何结直肠癌（结肠癌、近端结肠癌、远端结肠癌或直肠癌）之间存在关联。结果表明，通过使用FFQ和生物标志物相结合的方法评估全谷物摄入量，可通过减少错误分类的影响，略微提高估计结肠癌或直肠癌风险的精度，从而增加研究的统计效力。
