Vitamin D Supplementation to Lower Mortality?

In the randomized VITAL trial, which involved 26,000 middle-aged and older U.S. adults, a 2000 IU daily dose of vitamin D3 did not lower the incidence of invasive cancer, cardiovascular events, or death at 5 years (NEJM JW Gen Med Dec 15 2018 and N Engl J Med 2019; 380:33). Now, researchers report results from a similarly large trial, in which 21,000 relatively healthy Australian adults (age, ≥60) were randomized to receive a monthly dose of 60,000 IU of vitamin D₃ or placebo. Vitamin D levels were not measured at baseline; however, during the study, mean serum 25-hydroxyvitamin D levels in randomly sampled vitamin D and placebo recipients were 46 and 31 ng/mL, respectively.

Participants took study medication for 5 years, and follow-up was e…