Relationship between homocysteine and trabecular bone in postmenopausal women

Abstract

Epidemiological studies have shown that total homocysteine (tHcy) is negatively related to bone, but have not distinguished between cortical and trabecular bone. We determined the relationship between tHcy and composite bone (lumbar spine and hip) and distinguished between cortical (femur) and trabecular (tibia) volumetric bone in relationship to tHcy in healthy postmenopausal women (N=121). We used HPLC to determine tHcy, dual energy X-ray absorptiometry (Hologic, Inc.) to assess bone mineral content (BMC) and bone mineral density (BMD) of the spine and hip, and peripheral quantitative computed tomography (pQCT; STRATEC) to assess trabecular content and density of the tibia and cortical content and density of the femur. Since tHcy (median=7.11 μmol/L) was not normally distributed, we used Spearman's rho correlation analysis. tHcy was not related to lumbar spine (p>0.50) or hip (p>0.60) BMC and BMD, but was inversely related to trabecular content (r = −0.200, p=0.028) and not to trabecular density (p=0.20) of the tibia. Further, tHcy was not related to cortical content or density of the femur. Our results indicating the negative relationship between tHcy and trabecular content of the tibia illustrate that the previously reported inverse relationship between tHcy and bone is attributable mainly to trabecular and not cortical bone. This is important because it is trabecular bone that is primarily lost during menopause and the type of bone most amenable to intervention. Supported by Center for Designing Foods to Improve Nutrition, AHA, NIAMS/NIH (AR046922 A2)