QCTにより測定した骨塩量と骨代謝マーカーについての検討

当院内科に通院または入院中の女性患者24例(57～89才,平均71.8才)を対象とし,定量的QCT法による骨塩量測定と同時に血中骨代謝マーカーを測定し検討を行った｡年齢についての検討では,カルシウム(Ca)が70才台で60才台に比べ有意に高値であった以外は年代による有意差は認められなかった｡オステオカルシン(OC)とイオン化Ca(Ca(2+))との間にr=-0.50,p<0.01の有意の逆相関を認め,OCとBody mass indexとの間に有意の正の相関(r=0.41,p<0.05)を認めた｡平均骨塩量と各生化学parameterとの間には有意な相関はみられなかった｡副腎皮質ステロイド剤(ステロイド)投与群では非投与群に比べ,投与群でALP骨型アイソザイム(ALP3)高値,OC低値の傾向がみられた｡またステロイド投与症例はすべてOC値が8.4ng/mℓ以下であり,ステロイドによる骨粗鬆症誘発の機序として骨形成の抑制が関与している可能性が考えられた｡今後骨塩量と骨代謝マーカーとの関連について,若年者を含めた検討が必要と考えられた｡

Bone mineral densities (BMD) were measured with QCT (quantitative computed tomography) in 24 females aged 57 to 89 years old to evaluate about relationship between BMD and biochemical parameters on bone metabolism (calcium : Ca, ionized calcium : Ca(2+), alkaline phosphatase : ALP, bone type isozyme of alkaline phosphatase : ALP 3 and osteocalcin : OC) in blood. As for exception that Ca was significantly higher in patients aged of 60's in comparison with those of 70's in the examination with regard to age, no significant differences were observed. Significant opposite correlation (r=-0.50, p<0.01) between OC and Ca(2+) and significant positive correlation (r=0.41, p<0.05) between OC and body bass index were observed. No significant correlation was observed between mean BMD and biochemical parameters. A trend of higher ALP 3 and lower OC was observed in adrenocortical steroid (steroid) administration group in comparison with patients with no steroid therapy. Also in steroid administration group, OC value was below 8.4ng/mℓ in all patients. Thus, it was suspected that the suppression of bone formation was related to the mechanism of osteoporosis induced by steroid. Then, the further studies on the relationship of BMD and these biochemical parameters including those of younger cases were considered necessary to clarify the mechanism of osteoporosis.