https://immattersacp.org/weekly/archives/2010/05/18/4.htm

High-dose vitamin D may make falls, fractures more likely

Physician cost profiling systems frequently come to different results


Annual high doses of vitamin D increased elderly women's risk of falls and fracture, according to a new study.

The controlled trial recruited 2,256 community-dwelling women who were 70 or over and considered to be at high risk of fracture. For the next three to five years, the women received either a single dose of 500,000 IU of cholecalciferol or a placebo every winter. Data on falls and fractures (which were radiologically confirmed) were compared between the two groups; the results appeared in the May 12 Journal of the American Medical Association.

Contrary to the study's hypothesis, women who received the vitamin D had significantly more fractures (171 in the intervention group vs. 135 in the placebo group) and falls (2,892 vs. 2,512). A post-hoc analysis found that the higher risk of falls was particularly acute immediately in the three months after the dose was given. There was also a trend toward more fractures in this period. A substudy looked at patients' 25-hydroxycholecalciferol levels and found that they increased substantially a month after a dose, then gradually decreased, but remained an average of 41% higher than levels in the placebo recipients.

An accompanying editorial offered possible explanations for the results. It's possible that the large dose triggered a protective reaction, causing blood and tissue levels of 1,25-dihydroxyvitamin D to decrease in the months immediately after the dose. Alternatively, the vitamin D could have resulted in other health benefits, such as improved mood, reduced pain or fewer flu infections, which caused the women to be more active, and therefore have more falls and fractures.

The study, which confirmed previous findings of a fracture risk with high vitamin D supplementation but was the first to show the risk of falls, should raise concerns about providing infrequent high doses of vitamin D, the authors of the study and the editorial agreed. The results cannot be directly translated to the practice of providing high-dose vitamin D throughout the year, but do suggest that the safety of that regimen should be studied, the study authors concluded.

The editorialists cautioned, however, that the study's findings should not negate the importance of correcting vitamin D deficiency and insufficiency, and they recommended daily, weekly or monthly dosing of vitamin D3 as the appropriate treatment.