Low serum folate and vitamin B-6 are associated with an altered cancellous bone structure in humans

Background: Several clinical trials have reported B vitamins to be associated with osteoporosis. Objective: Our objective was to investigate whether low serum B vitamins are associated with altered structural and biomechanical properties of human bone. Design: Femoral heads of 94 men and women who underwent hip arthroplasty were analyzed by using dual-energy X-ray absorptiometry (DXA), biomechanical testing ( indentation method), and histomorphometry. In addition, blood was collected to measure serum concentrations of homocysteine, folate, vitamin B-6, vitamin B-12, the bone formation marker osteocalcin, and the bone resorption marker tartrate-resistant acid phosphatase ( TRAP). Measurement outcomes were grouped according to subjects with high and low serum concentrations, respectively, of folate, vitamin B-6, and vitamin B-12 (n = 47 for each group). Results: Histomorphometric analysis showed a significantly lower trabecular thickness and trabecular area in subjects with low serum folate concentrations than in those with high serum folate concentrations and a significantly lower trabecular number in subjects with low serum vitamin B-6 concentrations than in those with high serum vitamin B-6 concentrations. In contrast, we found a comparable trabecular structure in subjects with high and low serum vitamin B-12 concentrations. DXA and biomechanical testing did not show significant differences between subjects with high and low serum B vitamin concentrations. Osteocalcin was significantly lowered in subjects with a low serum B vitamin concentration, whereas there was no association between serum B vitamins and TRAP. Conclusion: The results of the present study indicate that low serum folate and vitamin B-6 concentrations, but not low serum vitamin B-12 concentrations, are associated with an altered morphology of human bone. Am J Clin Nutr 2009;90:1440-5.