Cortical bone porosity in patients with asthma

In previous studies, we have demonstrated that chronic administration of systemic glucocorticoids decreases cortical bone mineral density (BMD), cortical bone volume, bone strength, and induces development of pathologic fractures in asthmatic patients. We have also demonstrated that glucocorticoid administration appears to be responsible for the process of cortical bone porosity at both endosteal and intracortical sites in postmenopausal asthmatic patients. There is a difference of gonadal hormones between male and female. To investigate the influence of hormonal difference on glucocorticoid-induced cortical bone porosity, we studied cortical bone volume and BMD in both male and female patients with asthma in this report. A total of 99 asthmatic patients (male 26 cases, female 73 cases) were enrolled in the study. Peripheral quantitative computed tomography (pQCT) was used to measure cortical BMD and relative cortical volume. The cortical volume-density relationship appeared to remain constant regardless of the level of systemic glucocorticoid administration, age or sex, suggesting cortical bone porosity causes similar and simultaneous decreases in cortical bone volume and density. In conclusion, glucocorticoid administration appears to be responsible for the process of cortical bone porosity at both endosteal and intracortical sites despite the gonadal hormonal differences.

【目的】これまでに我々は,気管支喘息症例において経口ステロイドによる皮質骨骨密度,容積の減少が骨折に関与する新知見を報告し,閉経後女性では皮質骨骨密度一容積の減少はステロイド投与量にかかわらず一定であることを報告してきた｡この皮質骨骨密度-容積の関係において性差による違いを検討するために,男性,女性患者の両方について検討を行った｡【方法】対象はステロイド依存性喘息99例(男性26例,女性73例)｡性別,年齢,経口ステロイド積算総投与量により6群に分類した｡椎体圧迫骨折はⅩ線側面像にて評価 し,皮質骨容積比および皮質骨骨密度はpQCT(Stratec XCT960)を用いて測定した｡それぞれの群の皮質骨骨密度-容積比の関係を算出し比較検定をおこなった｡【結果】それぞれの群の皮質骨の骨密度と容積比は有意に相関した｡それぞれの群の皮質骨骨密度-容積比の傾きは,いずれも有意差を認めなかった｡【結論】気管支喘息症例におけるステロイド投与による皮質骨の骨密度と容積の減少は,性別にかかわらずほぼ一定で,皮質骨は内側と外側において同様に海綿化してゆくと考えられた｡