サルコペニアは転倒リスク

サルコペニアは転倒リスクであることを検証したコホート研究を紹介します。

Francesco Landi, et al: Sarcopenia as a Risk Factor for Falls in Elderly Individuals:Results from the ilSIRENTE Study. Clinical Nutrition doi:10.1016/j.clnu.2012.02.007

リサーチクエスチョンは以下の通りです。

P：80歳以上の高齢者で
E：サルコペニアを認めると
C：サルコペニアを認めない場合と比較して
O：2年間で転倒することが多い

サルコペニアはEWGSOPの診断基準で判断しています。筋肉量は上腕筋囲、筋力は握力、身体機能は4m歩行速度で評価して、筋肉量低下＋筋力もしくは身体機能の低下でサルコペニアと診断します。抄録しか読めていないので、上腕筋囲でどのように筋肉量低下を判断したかは不明です。

結果ですが、260人中66人（25.4%）にサルコペニアを認めました。サルコペニアの高齢者では18人（27.3%）、サルコペニアでない高齢者では19人（9.8％）に転倒があり、サルコペニアを認める場合に転倒が有意に多かったです。多変量解析でもサルコペニアの有無は、転倒の独立した危険因子でした。

サルコペニアや低栄養は転倒のリスク因子だと考えていましたが、前者を検証する論文です。サルコペニアや低栄養への介入、つまり栄養（サルコペニア用栄養剤でしょうか）＋運動療法（筋トレ＋歩行でしょうか）で転倒や骨折を少なくすることができるかどうかが、今後の研究課題ですね。

Abstract
Background and aims: Sarcopenia has been indicated as a reliable marker of frailty and poor prognosis among the oldest individuals. We evaluated the relationship between sarcopenia and 2-year risk of falls in a population of persons aged 80 years or older.

Methods: Data are from the baseline and follow-up evaluations of the Aging and Longevity Study in the Sirente Geographic Area (ilSIRENTE Study) (n=260). According to the European Working Group on Sarcopenia in Older People (EWGSOP), sarcopenia was diagnosed in presence of low muscle mass (mid-arm muscle circumference) plus either low muscle strength (hand grip) or low physical performance (4-meter walking speed). The primary outcome measure was the incident falls during the follow-up period of 2 years. The relationship between sarcopenia and incident falls was estimated by deriving hazard ratios (HRs) from multiple logistic regression models considering the dependent variable of interest at least one fall during the follow-up period.

Results: Sixty-six participants (25.4%) were indentified as affected by sarcopenia. Eighteen out of 66 (27.3%) participants with sarcopenia and 19 out of 194 (9.8%) without sarcopenia reported incident falls during the two-year follow-up of the study (p<0.001). After adjusting for age, gender, cognitive impairment, ADL impairment, sensory impairments, BMI, depression, physical activity, cholesterol, stroke, diabetes, number of medications, and C reactive protein, participants with sarcopenia had a higher risk of incident falls compared with non sarcopenic subjects (adjusted hazard ratio [HR], 3.23; 95% confidence interval [CI], 1.25-8.29).

Conclusions: The present study suggests that sarcopenia – assessed using the EWGSOP algorithm – is highly prevalent among elderly persons without gender differences (25%). Sarcopenic participants were over three times more likely to fall during a follow-up period of 2 years relative to non sarcopenic individuals, regardless of age, gender and other confounding factors.