In a paper that just appeared in pre-publication in the American Journal of Clinical Nutrition -with Janneke van Wijngaarden and Karin Swart as the main authors- the methods and results of the B-vitamins for the PRevention Of Osteoporotic Fractures (B-PROOF)] study are presented. The rationale and full description of the design of this study was published in an earlier paper in BMC Geriatrics. This study aimed to determine whether vitamin B-12 and folic acid supplementation reduces osteoporotic fracture incidence in hyperhomocysteinemic elderly individuals.
This was a double-blind, randomized, placebo-controlled trial in 2919 participants aged ≥65 y with elevated homocysteine concentrations. Participants were assigned to receive daily 500 μg vitamin B-12 plus 400 μg folic acid or placebo supplementation for 2 y. Both intervention and placebo tablets
also contained 600 IU vitamin D3.
Osteoporotic fractures occurred in 61 persons (4.2%) in the intervention group and 75 persons (5.1%) in the placebo group. Osteoporotic fracture risk was not significantly different between groups. For persons >80 y, osteoporotic fracture risk appeared to be somewhat lower in the intervention group than in the placebo group. The total number of adverse events (including mortality) did not differ between groups. However, 63 and 42 participants in the intervention and placebo groups, respectively, reported incident cancer.These data show that combined vitamin B-12 and folic acid supplementation had no effect on osteoporotic fracture incidence in this elderly population. Exploratory subgroup analyses suggest a beneficial effect on osteoporotic fracture prevention in the very old. However, supplement use was also associated with increased incidence of cancer, although the study was not designed for assessing cancer outcomes. Therefore, vitamin B-12 plus folic acid supplementation cannot be recommended at present for fracture prevention in elderly people.
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