The risk of hip fracture is significantly higher in stroke patients than in other individuals of the same age, and is thought to be associated with increased blood levels of a substance called homocysteine, Dr. Yoshihiro Sato and others note in this week's Journal of the American Medical Association.
Because folate and mecobalamin (vitamin B12) reduce homocysteine levels, the team thought that supplements of these nutrients could reduce fracture risk.
Sato, at Mitate Hospital in Tagawa, and colleagues studied 628 patients aged 65 years or more who had residual paralysis on one side of the body a year or more after having a stroke. The participants were randomly assigned to take folate and mecobalamin daily, or inactive placebos.
During 2 years of follow-up, the number of falls in each group was virtually the same, but there were only six hip fractures in the supplement group compared with 27 in the placebo group.
Even though homocysteine levels dropped in the active treatment group and rose in the placebo group, bone mineral density did not differ significantly between groups -- so that didn't explain the fewer number of fractures.
As two editorialists point out, although the results support a link between homocysteine levels and fracture risk, "final proof of causality will have to come from elucidation of the biological mechanism underlying this relationship."
Also, Sato's group cautions that while they found folate and mecobalamin treatment to be associated with striking decreases in fracture risk, "generalization to broader non-Japanese populations should be performed with caution."
SOURCE: Journal of the American Medical Association, March 2, 2005.