The Pharmaceutical Journal
Vol 270 No 7239 p324
8 March 2003

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Taking vitamin D three times a year reduces fracture risk in elderly

Taking a large dose of vitamin D three times a year may prevent fractures in elderly people, a new UK study suggests. Supplementation with the vitamin reduced fractures in both men and women.

The randomised controlled trial recruited 2,686 people aged 65–85 years living in the community. One capsule containing 100,000 IU vitamin D₃ (colecalciferol) or matching placebo was sent by post every four months for five years. Participants were asked to take the capsule immediately and to complete and return a checklist of events (fracture or major illness).

Compliance was estimated to be 80 per cent. After five years, 268 people had reported a fracture, of whom 147 had fractures in common osteoporotic sites (hip, wrist or forearm, or vertebrae). The vitamin D group had a 22 per cent lower rate for first fracture at any site and a 33 per cent lower rate for a fracture in major osteoporotic sites. This translates to approximately 250 people treated for one year to prevent any fracture.

There was no significant difference between the groups in major health events (cancer or cardiovascular disease) or in total mortality.

Vitamin D and calcium supplements are known to reduce fracture risk, but previous studies of vitamin D on its own have been inconclusive. This trial was intended as a pilot feasibility study for a larger trial, which was not subsequently carried out because of lack of funding.

To date, most fracture prevention trials have focused on clinically defined high-risk groups and have usually involved women. The authors comment that many interventions effective in high-risk groups are not feasible for primary prevention in the general population because of poor compliance or side effects or because they are not cost effective. Four-monthly vitamin D costs less than £1 annually, they say (BMJ 2003;326:469).

Study author Kay-Tee Khaw, professor of clinical gerontology, Addenbrooke's Hospital, Cambridge, told The Journal that the results now need to be confirmed. "No single trial should be sufficient to make general policy. Fortunately, there are a number of other trials currently ongoing using a variety of approaches, ie, 300,000 IU once a year, 100,000 IU three monthly, and 800 IU vitamin D daily. These are all due to report soon and we look forward to their results."

There has been debate on whether it is safe to give a 100,000 IU single dose of vitamin D but Professor Khaw says that before the reported trial there was extensive work investigating the safety of the dose.

A 100,000 IU formulation of vitamin D is not currently marketed.