Doctors frequently recommend older patients take Vitamin D supplements to treat or prevent osteoporosis, but a new study says they don't prevent fractures, falls, or improve bone mineral density.

The study appears in The Lancet Diabetes and Endocrinology journal.  It's the largest meta-analysis of Vitamin D supplement use to date and includes data from 81 randomised controlled trials.

Despite some earlier promising reports suggesting benefits for bone health that led doctors to recommend Vitamin D, the review found no benefits of vitamin D supplementation on bone mineral density, falls or fractures.  Since there were no effects, higher or lower doses simply didn't matter.

The authors say it's time for doctors to change their advice.  "Clinical guidelines should be changed to reflect these findings," said lead author Dr. Mark J. Bolland of the University of Auckland.  "On the strength of existing evidence, we believe there is little justification for more trials of vitamin D supplements looking at musculoskeletal outcomes."