The secondary analysis of a US randomized, double-blind, placebo-controlled clinical trial suggested that vitamin D3 apparently reduced the risk of developing advanced cancer among adults who have normal but not elevated body mass index (BMI). The trial included 25 871 randomized participants (51% female; mean age, 67.1 years), 1617 were diagnosed with invasive cancer over a median intervention period of 5.3 years. No significant differences for cancer incidence by treatment arm were observed. However, a significant reduction in advanced cancers (metastatic or fatal) was found for those randomized to vitamin D3 compared with placebo (226 of 12 927 assigned to vitamin D3 [1.7%, 2000 IU/d] and 274 of 12 944 assigned to placebo [2.1%]; HR, 0.83). When stratified by BMI, there was a significant reduction for the vitamin D3 arm in incident metastatic or fatal cancer among those with normal BMI (BMI<25: HR, 0.62) but not among those with overweight or obesity (BMI 25-<30: HR, 0.89; BMI≥30: HR, 1.05). The results are in line with previous studies and suggest a stronger benefit of vitamin D on cancer mortality and survival than cancer incidence, especially in individuals with normal weight. Source: https://jamanetwork.com/; https://www.nejm.org/
