サルコペニアと骨量減少、骨粗鬆症

日本女性のサルコペニアの有病割合と骨量減少、骨粗鬆症との関連をみた論文を紹介します。

Miyakoshi N, Hongo M, Mizutani Y, Shimada Y. Prevalence of sarcopenia in Japanese women with osteopenia and osteoporosis. J Bone Miner Metab. 2013 Mar 21. [Epub ahead of print]

対象は40-88歳の日本の女性2400人で、DEXAでサルコペニア、骨量減少osteopenia、骨粗鬆症osteoporosisを評価しています。若年の2標準偏差以下の筋肉量だった場合をサルコペニアとしています。

結果ですが、筋肉量と腰椎と大腿骨頸部の骨量に有意な相関を認めました（相関係数はそれぞれ0.197と0.274なので弱い相関です）。腰椎と大腿骨頸部の骨量は年齢と有意な負の相関を認めましたが、筋肉量は有意な相関を認めませんでした。

腰椎の骨量で評価した場合のサルコペニアの有病割合は、正常10.4％、骨量減少16.8％、骨粗鬆症20.4％でした。大腿骨頸部の骨量で評価した場合のサルコペニアの有病割合は、正常9.0％、骨量減少17.8％、骨粗鬆症29.7％でした。

サルコペニアと骨量減少、骨粗鬆症には独立した有意な関連を認めました。以上より、日本女性ではサルコペニアは骨量減少、骨粗鬆症と関連するという結論です。

サルコペニアと骨量減少、骨粗鬆症に関しては有意な関連を認めるという報告が多く、日本女性でも当てはまりそうです。年齢と筋肉量に有意な相関を認めなかったというのは気になりますが…。

Abstract

Sarcopenia and osteoporosis are both significant health burdens among postmenopausal women. This study examined associations between sarcopenia and osteopenia/osteoporosis in Japanese women and evaluated the prevalence of sarcopenia in women with osteopenia and osteoporosis. A total of 2400 Japanese women aged 40-88 years underwent dual-energy x-ray absorptiometry (DXA) scans of the whole body, lumbar spine, and total hip. Osteopenia and osteoporosis were defined according to World Health Organization criteria using bone mineral density (BMD) of the lumbar spine or hip. Sarcopenia was defined as a relative skeletal muscle index (RSMI) more than 2 standard deviations below the mean for a young adult reference population, calculated as the appendicular skeletal muscle mass (ASM) obtained from whole-body DXA divided by height in meters squared (RSMI = ASM/height²). Significant and marginal/moderate positive correlations were observed between RSMI and lumbar spine/total hip BMDs (r = 0.197 and r = 0.274, respectively; p < 0.0001 each). The BMDs of the lumbar spine and total hip showed significant moderate negative correlations with age (r = -0.270 and r = -0.375, respectively; p < 0.0001 each), but RSMI showed no association with age in this population (r = 0.056). When osteopenia/osteoporosis was defined using lumbar spine BMD, prevalences of sarcopenia in subjects with normal BMD, osteopenia and osteoporosis were 10.4, 16.8, and 20.4 %, respectively. When osteopenia/osteoporosis was defined using total hip BMD, the prevalences of sarcopenia in these subjects were 9.0, 17.8, and 29.7 %, respectively. A Chi-square test for independence showed a significant association between sarcopenia and osteopenia/osteoporosis (p < 0.0001). These results indicate that sarcopenia is significantly associated with osteopenia and osteoporosis in Japanese women.