Department of Eating and Weight Disorders, Villa Garda Hospital, Via Montebaldo, 89, I-37016 Garda, Verona, Italy.
Institute of Human Nutrition and Food Science, Christian-Albrechts University, Kiel, Germany.
Clin Nutr. 2017 Feb;36(1):170-178. doi: 10.1016/j.clnu.2015.10.006. Epub 2015 Oct 28.
BACKGROUND & AIMS: Data on the deficits in lean body mass (LBM) and total body skeletal muscle mass (SM) in anorexia nervosa (AN) is scarce and inconsistent. Furthermore, the usefulness of the reported body mass index (BMI) severity cut-off for AN has not been tested with respect to these important parameters. The study had two aims, namely to study LBM patterns and SM in adult females with AN before and after weight restoration, and to examine the clinical usefulness of the 16.5 kg/m BMI cut-off for assessing the protein status in terms of LBM and SM in AN patients.
Body composition was measured by dual-energy X-ray absorptiometry (DXA) before and after weight gain in 90 adult female inpatients with AN, and 90 controls matched by post-treatment BMI and age. Patients were stratified into two groups using BMI 16.5 kg/m as a cut-off.
Before weight restoration, patients in the BMI≤16.5 kg/m subgroup (n = 65) had lower LBM, SM and lean extremity mass percentage, but higher %LBM and lean trunk-to-extremity ratio on average than controls. However, those with BMI >16.5 kg/m (n = 25) displayed lower lean extremity mass percentage and higher %LBM, but no significant differences in LBM and SM with respect to controls. Moreover the time × subgroup interaction was significant in terms of LBM and SM, meaning that, changes occur in different manner over time in the two AN subgroups. However no differences were found between the two AN subgroups in either demographic or other eating disorder characteristics. After weight gain, normalization of LBM, %LBM, lean extremity mass percentage and SM was achieved across the entire AN sample, and the BMI≤16.5 kg/m subgroup. The fat mass was the major determinant of gain in LBM; the higher the FM at baseline, the greater the increase in LBM.
Our results suggest a BMI cut-off ≤16.5 kg/m as a clinical threshold for determining AN severity. As short-term weight restoration is associated with a normalization in LBM and SM, it appears that biological regulation of weight gain remains intact in AN, i.e., unaffected by the severity of malnutrition.
Changes in lean and skeletal muscle body mass in adult females with anorexia nervosa before and after weight restoration (ISRCTN168721194).
关于神经性厌食症（AN）患者瘦体质量（LBM）和全身骨骼肌质量（SM）的缺失数据非常有限且不一致。此外，目前尚未针对这些重要参数对报告的身体质量指数（BMI）严重程度截止值在 AN 中的有用性进行测试。本研究有两个目的，即研究 AN 成年女性在体重恢复前后的 LBM 模式和 SM，并检查 BMI 16.5kg/m 截止值用于评估 AN 患者 LBM 和 SM 中蛋白质状态的临床有用性。
通过双能 X 射线吸收法（DXA）在 90 名 AN 成年女性住院患者体重增加前后测量身体成分，并按治疗后 BMI 和年龄与 90 名对照匹配。使用 BMI 16.5kg/m 作为截止值将患者分为两组。
在体重恢复之前，BMI≤16.5kg/m 亚组（n=65）的患者 LBM、SM 和瘦体肢质量百分比较低，但平均 LBM 和瘦体躯干-肢体比例较高，而 BMI＞16.5kg/m 组（n=25）的患者则表现出较低的瘦体肢质量百分比和较高的 LBM，但与对照组相比，LBM 和 SM 无明显差异。此外，LBM 和 SM 的时间×亚组交互作用显著，这意味着在两个 AN 亚组中，随着时间的推移，变化的方式不同。然而，在两个 AN 亚组中，在人口统计学或其他饮食失调特征方面均无差异。体重增加后，整个 AN 样本和 BMI≤16.5kg/m 亚组的 LBM、%LBM、瘦体肢质量百分比和 SM 均恢复正常。脂肪质量是 LBM 增加的主要决定因素；基线时 FM 越高，LBM 的增加越大。
我们的结果表明，BMI 截止值≤16.5kg/m 作为确定 AN 严重程度的临床阈值。由于短期体重恢复与 LBM 和 SM 正常化相关，因此似乎 AN 中的体重增加的生物学调节仍然完好，即不受营养不良严重程度的影响。
神经性厌食症成年女性体重恢复前后瘦体和骨骼肌体质量的变化（ISRCTN86552644）。
