Heterogeneity of the Effect of Vitamin D Supplementation in Randomized Controlled Trials on Cancer Prevention
Menée à partir des données d'un essai randomisé incluant 25 871 personnes (âge moyen : 67 ans ; 51 % de femmes), cette étude analyse, selon l'indice de masse corporelle, l'association entre une supplémentation en vitamine B3 et le risque de cancer colorectal de stade avancé (1 617 cas)
Vitamin D has been suspected to play a role in cancer prevention for the past 4 decades, but definitive proof of benefit has been difficult to determine. In a randomized, double-blind, placebo-controlled trial, Chandler et al found that vitamin D supplementation reduced the incidence of advanced cancer in the Vitamin D and Omega-3 Trial study cohort. The authors found a difference in treatment effects: protective effect was observed among individuals who had normal body mass index (BMI) but not among overweight individuals, most likely because of the simple volumetric dilution of this fat-soluble vitamin in fat tissue. The notion that treatment effect may vary according to BMI indicates the Achilles heel of randomized controlled trials (RCTs).
JAMA Network Open , commentaire en libre accès, 2019