Department of Internal Medicine, Division of Geriatrics, Istanbul Medical School, Istanbul University, Capa, 34390, Istanbul, Turkey.
Department of Internal Medicine, Division of Geriatrics, Istanbul Medical School, Istanbul University, Capa, 34390, Istanbul, Turkey.
Clin Nutr. 2021 May;40(5):2851-2859. doi: 10.1016/j.clnu.2021.04.002. Epub 2021 Apr 12.
BACKGROUND & AIMS: There have been several attempts to come up with a global operational definition of sarcopenia (S), and consequently, a definition of S has been established, to some extent. That said, the definition of sarcopenic obesity (SO), which is defined as the presence of obesity + sarcopenia, remains obscure, hindering evaluations of the prevalence and relevance of SO. It has yet to be elucidated whether SO is associated with worse functionality when compared to S alone (S without obesity). In the present study, we compare SO and S alone in terms of their associations with functional measures through the application of alternative definitions of SO. As a secondary output, we document the prevalence of SO based on alternative definitions.
This retrospective cross-sectional study included community-dwelling adults over 60 years of age who presented as outpatients to a university hospital between 2012 and 2020. All were evaluated for body composition (bioimpedance analysis), handgrip strength (Jamar hand dynamometer) and functional health status [activities of daily living (ADL), instrumental activities of daily living (IADL)]. The fat percentile method was used to define the obesity component of SO. Low muscle mass (LMM) was defined using two different adjustment methods of skeletal muscle mass (LMM adjusted by height or LMM adjusted by BMI). S was defined based on the EWGSOP2 definition, as probable S (low muscle strength) or confirmed S (low muscle strength + LMM). Accordingly, three alternative definitions of SO were applied based on three alternative definitions of S, i.e., "obesity + sarcopenia (probable)", "obesity + sarcopenia (confirmed, LMM adjusted by height)" and "obesity + sarcopenia (confirmed, LMM adjusted by BMI)". The associations of SO and S alone with functional measures were examined with univariate analyses and adjusted multivariate analyses.
Included in the study were 1468 older adults (median age 75; 68.8% female). The prevalence of SO was very low (0.2%) based on the SO definition "obesity + sarcopenia (confirmed, LMM adjusted by height), but it was present at a considerable and comparable rate based on SO definition "obesity + sarcopenia (probable)" and SO definition "obesity + sarcopenia (confirmed, LMM adjusted by BMI)" (4.1%, 4.0%; respectively). As SO by "obesity + sarcopenia (confirmed, LMM adjusted by height)" had an ignorable prevalence, this definition of SO was excluded from further analyses. Multivariate analyses revealed that, when compared to the Non-S Non-Obese group, S alone definitions had odds ratio (OR) of 5.4 and 3.4 while SO definitions had an OR of 3.2 and 2.7 for impaired ADL, and an OR of 7.9 and 6.4, while SO definitions had an OR of 3.0 and 2.7 for impaired IADL. SO was thus found to be associated with a lower prevalence of impaired functional measures than that of S alone.
Our results suggest that the SO definition confirmed, LMM adjusted by height has an ignorable prevalence in populations in which underweight or malnutrition is uncommon. Among sarcopenic older individuals, obesity may have a protective effect against the limitations of some functional measures, providing evidence of the possible protective effect of obesity in sarcopenic individuals.
人们曾多次尝试提出全球肌少症（Sarcopenia）的操作性定义，因此，在某种程度上已经建立了肌少症的定义。也就是说，肌少症合并肥胖（Sarcopenic Obesity，SO）的定义仍然模糊不清，这阻碍了对 SO 患病率和相关性的评估。目前还不清楚与单纯肌少症（无肥胖的 S）相比，SO 是否与更差的功能状态相关。在本研究中，我们通过应用 SO 的替代定义来比较 SO 和单纯 S 在与功能测量相关方面的关联。作为次要结果，我们根据替代定义记录 SO 的患病率。
这是一项回顾性的横断面研究，纳入了 2012 年至 2020 年期间在一所大学医院就诊的 60 岁以上的社区居住成年人。所有参与者均接受了身体成分（生物电阻抗分析）、握力（Jamar 手持测力计）和功能健康状况（日常生活活动 [ADL]、工具性日常生活活动 [IADL]）评估。肥胖成分的 SO 采用脂肪百分位数法定义。低肌肉量（Low Muscle Mass，LMM）使用两种不同的骨骼肌质量调整方法（通过身高调整的 LMM 或通过 BMI 调整的 LMM）来定义。S 根据 EWGSOP2 定义，定义为可能的 S（低肌肉力量）或确诊的 S（低肌肉力量+LMM）。因此，根据 S 的三种替代定义，应用了三种替代的 SO 定义，即“肥胖+肌少症（可能）”、“肥胖+肌少症（确诊，通过身高调整的 LMM）”和“肥胖+肌少症（确诊，通过 BMI 调整的 LMM）”。使用单变量分析和调整后的多变量分析检查 SO 和单纯 S 与功能测量的关联。
本研究纳入了 1468 名老年人（中位数年龄 75 岁；68.8%为女性）。根据 SO 定义“肥胖+肌少症（确诊，通过身高调整的 LMM）”，SO 的患病率非常低（0.2%），但根据 SO 定义“肥胖+肌少症（可能）”和 SO 定义“肥胖+肌少症（确诊，通过 BMI 调整的 LMM）”，SO 的患病率相当且相近（分别为 4.1%和 4.0%）。由于 SO 定义“肥胖+肌少症（确诊，通过身高调整的 LMM）”的患病率可以忽略不计，因此从进一步的分析中排除了该 SO 定义。多变量分析显示，与非 S 非肥胖组相比，S 单独的定义有 5.4 和 3.4 的比值比（OR），而 SO 的定义有 3.2 和 2.7 的 OR 用于评估 ADL 受损，有 7.9 和 6.4 的 OR 用于评估 IADL 受损，而 SO 的定义有 3.0 和 2.7 的 OR 用于评估 IADL 受损。因此，与单纯 S 相比，SO 被发现与较低的功能测量受损患病率相关。
我们的结果表明，在消瘦或营养不良不常见的人群中，通过身高调整的 LMM 确认的 SO 定义的患病率可以忽略不计。在肌少症的老年人中，肥胖可能对某些功能测量的限制具有保护作用，这为肌少症个体中肥胖的可能保护作用提供了证据。
