Components of One-carbon Metabolism other than Folate and Colorectal Cancer Risk
Menée à partir d'échantillons plasmatiques prélevés sur 613 patients atteints d'un cancer colorectal et sur 1 190 témoins (durée médiane de suivi : 8,2 ans), cette étude suédoise analyse la relation entre la concentration de cinq substances impliquées dans le métabolisme monocarboné (choline, bétaïne, diméthylglycine, sarcosine et méthionine) et le risque de cancer colorectal
Background : Despite extensive study, the role of folate in colorectal cancer remains unclear. Research has therefore begun to address the role of other elements of the folate-methionine metabolic cycles. This study investigated factors other than folate involved in one-carbon metabolism, i.e. choline, betaine, dimethylglycine, sarcosine, and methionine and relevant polymorphisms, in relation to the risk of colorectal cancer in a population with low intakes and circulating levels of folate. Methods : This was a prospective case-control study of 613 case subjects and 1190 matched control subjects nested within the population-based Northern Sweden Health and Disease Study. We estimated odds ratios (OR) by conditional logistic regression, and marginal risk differences with weighted maximum likelihood estimation using incidence data from the study cohort. Results : Higher plasma concentrations of methionine and betaine were associated with modest colorectal cancer risk reductions (OR (95% confidence interval (CI)) for highest versus lowest tertile: 0.76 (0.57-0.99) and 0.72 (0.55-0.94), respectively). Estimated marginal risk differences corresponded to approximately 200 fewer colorectal cancer cases per 100 000 individuals on average. We observed no clear associations between choline, dimethylglycine, or sarcosine and colorectal cancer risk. The inverse association of methionine was modified by plasma folate concentrations (OR (95% CI) for highest/lowest versus lowest/lowest tertile of plasma methionine/folate concentrations 0.39 (0.24-0.64), Pinteraction = 0.06). Conclusions : In this population-based, nested case-control study with a long follow-up time from screening to diagnosis (median: 8.2 years), higher plasma concentrations of methionine and betaine were associated with lower colorectal cancer risk. This is an open-access article distributed under the terms of the Creative Commons Attribution-Non Commercial-No Derivatives License 4.0 (CCBY-NC-ND), where it is permissible to download and share the work provided it is properly cited. The work cannot be changed in any way or used commercially.
Epidemiology 2016