サルコペニア肥満の批判的吟味

サルコペニア肥満のエビデンスを批判的吟味したレビュー論文を紹介します。

Prado CM, Wells JC, Smith SR, Stephan BC, Siervo M. Sarcopenic obesity: A Critical appraisal of the current evidence. Clin Nutr. 2012 Jul 16. [Epub ahead of print]

このレビューの目的は、①サルコペニア肥満が身体機能や心臓・代謝機能に与える影響の評価、②サルコペニア肥満研究の方法論、診断基準、要因、結果の一貫性の評価の2つです。

結果ですが、診断基準や評価に用いた身体組成の選択に、研究間で大きな違いを認めました。この影響もあり、サルコペニア肥満と心臓・代謝機能には一定した関連を認めませんでした。サルコペニア肥満として、脂肪組織と除脂肪組織の割合で評価することを提言しています。

サルコペニアもそうですが、サルコペニア肥満も診断基準がある程度明確にならないと臨床も研究も進みません。サルコペニア＋肥満の合併でなく、脂肪組織と除脂肪組織の割合で評価するのであれば、著明な肥満の場合、筋肉量が若干多めでもサルコペニア肥満と診断するようになるかもしれません。

Abstract
Sarcopenic obesity (SO) is assuming a prominent role as a risk factor because of the double metabolic burden derived from low muscle mass (sarcopenia) and excess adiposity (obesity). The increase in obesity prevalence rates in older subjects is of concern given the associated disease risks and more limited therapeutic options available in this age group. This review has two main objectives. The primary objective is to collate results from studies investigating the effects of SO on physical and cardio-metabolic functions. The secondary objective is to evaluate published studies for consistency in methodology, diagnostic criteria, exposure and outcome selection. Large between-study heterogeneity was observed in the application of diagnostic criteria and choice of body composition components for the assessment of SO, which contributes to the inconsistent associations of SO with cardio-metabolic outcomes. We propose a metabolic load:capacity model of SO given by the ratio between fat mass and fat free mass, and discuss how this could be operationalised. The concept of regional fat distribution could be incorporated into the model and tested in future studies to advance our understanding of SO as a predictor of risk for cardio-metabolic diseases and physical disability.