骨代謝評価に役立つ血液・尿検査法の進歩

Evaluation of Bone；Up Date from Research to Clinical Application. Evaluation of bone for using of bone metabolic markers in the diagnosis and treatment of osteoporosis.

　骨代謝は日々変化しているため，骨密度（BMD）が同じであっても骨の状態が同じとは限らない。骨代謝マーカーは，測定時点での状態を鋭敏に反映し，BMDのように半年から１年の観察期間を持たずに，骨代謝回転を臨床的に評価できるツールとなる可能性がある。骨代謝マーカー以外に骨代謝回転の評価を臨床的に評価する手段がないとされている。日本骨粗鬆症学会より新たに公表されたガイドライン（2012年版）を中心に，骨代謝評価法として実地臨床で使用されているバイオマーカーである骨代謝マーカーについて，そのガイドライン活用法および課題，そして将来の展望などについて概説する。

　Quantification of BMD is being used as the main method to diagnose osteoporosis and measurement accuracy has dramatically improved. However, essential clinical parameters of osteoporosis include more dynamic markers such as bone metabolic markers. Bone metabolism undergoes daily dynamic changes, and even with the same BMD, the metabolic state differs and the pathologic significance also differs. Therefore, to use BMD measurement as a dynamic marker, one must wait for an observation period of 6 months to 1 year before remeasurement, whereas bone metabolic markers accurately reflect the state of bone metabolism at the point in time of the measurement. 　Bone metabolic markers can also be used as a guide to selecting pharmacotherapy. When there is doubt about choosing a drug, the use of bone metabolic markers can enable more appropriate selection. Furthermore, to evaluate the effects of drug therapy on disease improvement, assessing the state of bone metabolism at the time of diagnosis is recommended whenever possible. However, if a decision is made to select treatment with little influence on bone metabolism, then measuring bone metabolic markers to monitor drug treatment effects has little clinical significance. 　Recently the clinical application of bone metabolic markers have been achieved significant progress and the measurements of these indices give us better understanding of pathological of osteoporosis. Therefore, it is very important to guide the proper application and assessment of bone metabolic markers in clinical practice.