Design, Setting, and Participants
digestive tract cancers
This was a post hoc subgroup analysis of the AMATERASU randomized, double-blind, placebo-controlled clinical trial. This trial included patients at a single university hospital in Japan with digestive tract cancers between January 2010 and February 2018 followed up for a median (IQR) of 3.5 (2.5-5.3) years to compare the effects of vitamin D supplementation with placebo and was reported in 2019. Patients from among 417 participants in the AMATERASU trial whose residual serum samples were available were included. Data were analyzed from October 20 to November 24, 2022.