Elshorbagy Amany K, Gjesdal Clara Gram, Nurk Eha, Tell Grethe S, Ueland Per M, Nygård Ottar, Tverdal Aage, Vollset Stein E, Smith A David, Refsum Helga
Department of Physiology, Le Gros Clarke Building, Anatomy and Genetics, Oxford University, UK.
Bone. 2009 May;44(5):954-8. doi: 10.1016/j.bone.2008.12.018. Epub 2009 Jan 3.
Plasma total cysteine (tCys) and homocysteine (tHcy) are associated with body composition, which in turn affects bone mineral density (BMD).
To investigate whether associations of tCys and tHcy with BMD are mediated through body composition (fat mass and/or lean mass).
Using data from 5238 Hordaland Homocysteine Study participants, we fit multiple linear regression models and concentration-response curves to explore the relationships between tCys, tHcy, and BMD, with and without adjustment for body mass index (BMI), lean mass and/or fat mass.
All associations were stronger in women. tCys was positively associated with BMD (women, partial r=0.11; men, partial r=0.07, p<or=0.001 for both), but this association was markedly attenuated after adjustment for fat mass. tHcy showed an inverse association with BMD in women (partial r=-0.09, p<0.001), which remained significant after adjustment for lean mass and fat mass. In men and women, changes in tCys or tHcy during 6 years were not associated with BMD at follow-up. Weight gain during 6 years predicted higher BMD at follow-up (p<or=0.009) independent of nutrient intakes, physical activity and baseline BMI. Baseline tHcy inversely predicted BMD measured 6 years later (partial r=-0.11, p<0.001 in women; partial r=-0.07, p=0.002 in men) independent of baseline BMI, while a positive association of baseline tCys with BMD at follow-up (partial r=0.10 in women, 0.09 in men, p<or=0.001) disappeared after adjustment for baseline BMI.
tHcy is inversely associated with BMD independent of body composition, while the positive association of tCys with BMD appears to be mainly mediated through fat mass.
血浆总半胱氨酸（tCys）和同型半胱氨酸（tHcy）与身体组成相关，而身体组成又会影响骨矿物质密度（BMD）。
研究tCys和tHcy与BMD之间的关联是否通过身体组成（脂肪量和/或瘦体重）介导。
利用来自5238名霍达兰同型半胱氨酸研究参与者的数据，我们拟合了多元线性回归模型和浓度-反应曲线，以探索tCys、tHcy与BMD之间的关系，同时对体重指数（BMI）、瘦体重和/或脂肪量进行了调整和未调整的情况。
所有关联在女性中更强。tCys与BMD呈正相关（女性，偏相关系数r = 0.11；男性，偏相关系数r = 0.07，两者p≤0.001），但在调整脂肪量后，这种关联明显减弱。tHcy在女性中与BMD呈负相关（偏相关系数r = -0.09，p < 0.001），在调整瘦体重和脂肪量后仍具有显著性。在男性和女性中，6年内tCys或tHcy的变化与随访时的BMD无关。6年内体重增加预测随访时BMD更高（p≤0.009），与营养摄入、身体活动和基线BMI无关。基线tHcy反向预测6年后测量的BMD（女性偏相关系数r = -0.11，p < 0.001；男性偏相关系数r = -0.07，p = 0.002），与基线BMI无关，而基线tCys与随访时BMD的正相关（女性偏相关系数r = 0.10，男性偏相关系数r = 0.09，p≤0.001）在调整基线BMI后消失。
tHcy与BMD呈负相关，与身体组成无关，而tCys与BMD的正相关似乎主要通过脂肪量介导。
