Morris Martha Savaria, Jacques Paul F, Selhub Jacob
Nutritional Epidemiology Program, Jean Mayer US Department of Agriculture Human Nutrition Research Center on Aging, Tufts University Boston, Tufts JM-USDA HNRCA, 711 Washington Street, Room 901D, Boston, MA 02111, USA.
Bone. 2005 Aug;37(2):234-42. doi: 10.1016/j.bone.2005.04.017.
Recent studies have found a connection between hyperhomocysteinemia and hip fracture. If this association is causal, it could be mediated through detrimental effects of low B-vitamin status on bone mineral density (BMD). Studies have linked homocysteine (Hcy) and the established Hcy determinants folate and vitamin B12, to BMD, but results have been inconsistent. Furthermore, only one study considered the specific marker of tissue vitamin B12 status, methylmalonic acid (MMA), and none have considered red blood cell (RBC) folate. To further explore associations between Hcy and B-vitamin status indicators and bone health, we used data collected on older (i.e., aged >55 years) men and women who underwent DEXA scans of the hip as participants in phase 2 of the third U.S. National Health and Nutrition Examination Survey (n = 1550). We used BMD at the total hip as a continuous outcome variable in some analyses. In others, we used osteoporosis defined on a sex- and race/ethnicity-specific basis according to World Health Organization (WHO) guidelines. After adjusting for demographic factors, body mass index, and other osteoporosis risk factors, BMD decreased and osteoporosis increased significantly with increasing serum MMA quartile category (P < 0.01). Serum vitamin B12 was related to BMD in dose-response fashion up to about 200 pmol/L, and subjects with serum Hcy > or = 20 micromol/L had significantly lower BMD than subjects with serum Hcy < 10 micromol/L. Furthermore, the OR (95% CI) relating a serum vitamin B12 concentration below the 25th percentile to osteoporosis/osteopenia was 2.0 (1.0-3.9), and dose-response trends relating both serum B12 and Hcy to this outcome were marginally statistically significant. Neither serum nor RBC folate was related to BMD or osteoporosis. We conclude that Hcy and vitamin B12 status indicators are associated with BMD in older Americans. Whether this association reflects a causal relation remains unclear and merits further study in light of age-related declines in B12 status and BMD, and the need for low-risk, easily implemented strategies for osteoporosis prevention.
近期研究发现高同型半胱氨酸血症与髋部骨折之间存在关联。如果这种关联是因果关系，那么可能是通过低水平B族维生素状态对骨矿物质密度（BMD）的有害影响来介导的。研究已将同型半胱氨酸（Hcy）以及已确定的Hcy决定因素叶酸和维生素B12与BMD联系起来，但结果并不一致。此外，仅有一项研究考虑了组织维生素B12状态的特定标志物甲基丙二酸（MMA），而没有研究考虑红细胞（RBC）叶酸。为了进一步探究Hcy与B族维生素状态指标以及骨骼健康之间的关联，我们使用了在美国第三次国家健康和营养检查调查第二阶段中接受髋部双能X线吸收测定扫描的年龄较大（即年龄>55岁）的男性和女性所收集的数据（n = 1550）。在一些分析中，我们将全髋部的BMD作为连续的结果变量。在其他分析中，我们根据世界卫生组织（WHO）的指南，在性别和种族/族裔特异性基础上定义骨质疏松症。在调整了人口统计学因素、体重指数和其他骨质疏松症风险因素后，随着血清MMA四分位数类别增加，BMD显著降低，骨质疏松症显著增加（P < 0.01）。血清维生素B12与BMD呈剂量反应关系，直至约200 pmol/L，血清Hcy≥20 μmol/L的受试者的BMD显著低于血清Hcy < 10 μmol/L的受试者。此外，血清维生素B12浓度低于第25百分位数与骨质疏松症/骨量减少相关的OR（95% CI）为2.0（1.0 - 3.9），血清B12和Hcy与该结果的剂量反应趋势在统计学上具有边际显著性。血清叶酸和红细胞叶酸均与BMD或骨质疏松症无关。我们得出结论，Hcy和维生素B12状态指标与美国老年人的BMD相关。这种关联是否反映因果关系仍不清楚，鉴于B12状态和BMD随年龄增长而下降，以及需要低风险、易于实施的骨质疏松症预防策略，值得进一步研究。
