思春期特発性側弯症女児における骨減少症

Osteopenia in Girls with Adolescent Idiopathic Scoliosis

　思春期特発性側弯症の女児に全身性の骨量減少がみられるが，そのメカニズムは不明である．そこで思春期特発性側弯症の女児100名を対象に骨量減少の有無および初潮時年齢，Cobb角，運動との関連性を検討した．その結果，初潮時年齢が12歳以降の症例の半数に骨量減少がみられたが，力学的負荷が加わる運動症例は高値であった．一方，Cobb角の重症度と骨量減少には相関性がみられなかった．特発性側弯症の発現・進行にメラトニンの関与およびメラトニンが骨芽細胞の分化・増殖を促進することから，本症の骨量減少にはメラトニンの関与が考えられる．

　An association between osteopenia and adolescent idiopathic scoliosis (AIS) has been widely reported in previous studies, however, the mechanism of osteopenia in AIS is still unknown. To clarify the mechanism of developing the osteopenia in AIS, we investigated the relationships between initial menarche, severity of Cobb angle, activity of sports, and BMD of lumbar spine in 100 AIS. The prevalence of osteopenia was 54％, especially, 60％ of AIS with delayed 12 years of initial menarche was affected osteopenia. However, AIS with playing high impact sports was normal range of BMD. No differences in Cobb angle and BMD were found. Our previous studies suggested that melatonin deficiency may be one of the underlying factors for deterioration of scoliosis. Recent studies have shown that melatonin have an osteoinductive effect on bone formation in vitro and vivo studies. We speculated that the osteopenia in AIS is related to the deficiency of melatonin.