Vitamin B₁₂ is important to DNA synthesis and may affect bone formation. We examined the association between this vitamin and BMD in 2576 adults. Men with plasma B₁₂ < 148 pM had significantly lower BMD at the hip, and women at the spine, relative to those with higher B₁₂, and trends were similar for both at all sites. Low vitamin B₁₂ may be a risk factor for low BMD.

Introduction: Vitamin B₁₂ is important to DNA synthesis and may affect bone formation. It has been linked to osteoblastic activity in clinical studies and cell culture.

Materials and Methods: We examined the relationship between plasma vitamin B₁₂ status and BMD in 2576 adult participants in the Framingham Offspring Osteoporosis Study (1996-2001). BMD was measured by DXA at the hip and spine. Plasma vitamin B₁₂ was measured by radioassay. Mean BMD measures were estimated for four categories of vitamin B₁₂ concentration, based on commonly used cut-offs, using analysis of covariance, adjusted for age, BMI, physical activity score for the elderly (PASE), alcohol use, smoking status, total calcium and vitamin D intake, season of bone measurement, and for women, menopause status and current estrogen use. Further adjustment for protein intake and total homocysteine concentration was also performed.

Results: Both men and women with vitamin B₁₂ concentrations <148 pM had lower average BMD than those with vitamin B₁₂ above this cut-off. These differences were significant (p < 0.05) for men at most hip sites and for women at the spine. Significance remained after further adjustment for protein intake and plasma homocysteine.

Conclusions: Vitamin B₁₂ deficiency may be an important modifiable risk factor for osteoporosis.