ECTS2014 Oral Communications Osteoporosis epidemiology (6 abstracts)
1Division of Human Nutrition, Wageningen University, Wageningen, The Netherlands; 2Dept Epidemiology and Biostatistics, EMGO Institute, VU University Medical Center, Amsterdam, The Netherlands; 3Dept Internal Medicine, Erasmus University, Rotterdam, The Netherlands; 4Dept Internal Medicine/Geriatric Medicine, Academic Medical Center, Amsterdam, The Netherlands; 5Dept Internal Medicine/Endocrinology, VU University Medical Center, Amsterdam, The Netherlands.
Background: Elevated plasma homocysteine levels are a risk factor for osteoporotic fractures. Supplementation with vitamin B12/folic acid lowers homocysteine levels. This study aimed to determine whether vitamin B12/folic acid supplementation reduces osteoporotic fracture incidence in hyperhomocysteinemic elderly.
Methods: B-PROOF is a double-blind, randomized, placebo-controlled trial including 2 919 participants aged ≧65 years with elevated homocysteine levels (1250 μmol/l). Participants were assigned to daily 500 μg vitamin B12 and 400 μg folic acid or placebo supplementation for 2 years. Both tablets also contained 600 IU vitamin D3. The study was approved by the medical ethical committees of the 3 participating centers. Primary endpoint was time-to-first osteoporotic fracture. Stratified analyses were conducted if pre-specified covariates interacted significantly with treatment. Data were analyzed according to intention-to-treat and per-protocol principles.
Results: Osteoporotic fractures occurred in 61 persons (4.2%) in the intervention group compared with 75 (5.1%) in placebo. Osteoporotic fracture risk was not significantly different between groups in the intention-to-treat analyses (Hazard Ratio (HR)=0.84, 95%CI 0.581.22) or per-protocol analyses (HR=0.82, 95%CI 0.551.22). For persons >80 years, in per-protocol analyses, osteoporotic fracture risk was 72% lower in the intervention group compared with placebo (HR=0.28, 95%CI 0.100.74). Mortality did not differ between groups. Sixty-three vs 42 participants in the intervention and placebo group, respectively, reported incident cancer (HR=1.55, 95%CI 1.042.30).
Conclusion: Combined vitamin B12/folic acid supplementation had no effect on osteoporotic fracture incidence in this elderly population. Stratified analyses suggested a beneficial effect on osteoporotic fracture prevention in compliant persons >80 years. However, treatment was also associated with increased cancer risk, although this possible adverse effect should be interpreted with caution. In conclusion, vitamin B12/folic acid supplementation cannot be recommended at present for fracture prevention in elderly people.