Research Centre on Aging, CIUSSS de l'Estrie-CHUS, Sherbrooke, QC, Canada.
Faculty of Physical Activity Sciences, University of Sherbrooke, Sherbrooke, QC, Canada.
J Cachexia Sarcopenia Muscle. 2022 Feb;13(1):377-385. doi: 10.1002/jcsm.12856. Epub 2021 Nov 25.
It is well established that body composition influences metabolic health, but emerging data are conflicting with the largely purported idea that a large fat-free mass (FFM) has a protective effect on health. A potential explanation for these discrepancies is the way FFM is represented. The first objective is to determine the association between the metabolic syndrome (MetS) and FFM when the latter was represented in three different ways: 1-absolute FFM; 2-relative to squared height (FFMi); and 3-relative to body weight (FFM%). The second objective is to assess the impact of FFM on the relative risk of having the MetS after taking fat mass, physical activity, and sociodemographic variables into account.
A total of 5274 individuals from the National Health and Nutrition Examination Survey database were studied. Age-specific and sex-specific quartiles of the three representations of FFM were defined, and the prevalence of MetS was determined in each of them. Quartiles of FFMi (kg/m ) were used to calculate the odds ratios of having the MetS independently of FM, physical activity levels, and sociodemographic variables.
The prevalence of MetS decreased with increasing quartiles of whole-body FFM% (Q1: 40%; Q4: 10%) but grew with increasing quartiles of absolute FFM (Q1: 13%; Q4: 40%) and FFMi (Q1: 10%; Q4: 44%). Similar results were observed for appendicular and truncal FFM. The odds ratios of having the MetS, independently of fat mass, physical activity, and sociodemographic variables, were significantly greater in the fourth quartile of FFMi when compared with the first quartiles of each specific subgroup [Q4 vs. Q1: younger men: 4.16 (1.99-8.68); younger women: 5.74 (2.46-13.39); older men: 1.98 (1.22-3.22); older women: 2.88 (1.69-4.90); all P ≤ 0.01].
These results support the notion that the representation of FFM significantly influences its association with MetS and that a larger FFM, whether absolute or relative to height, is associated with alterations in cardiometabolic health.
众所周知，身体成分会影响代谢健康，但新出现的一些数据与普遍认为的大脂肪-free mass (FFM) 对健康有保护作用的观点相矛盾。造成这些差异的一个潜在解释是 FFM 的表示方式。本研究的主要目的是确定当 FFM 以三种不同方式表示时，即 1-绝对 FFM；2-相对于身高的平方（FFMi）；3-相对于体重（FFM%），与代谢综合征（MetS）之间的关联。第二个目的是评估在考虑脂肪量、身体活动和社会人口统计学变量后，FFM 对患有 MetS 的相对风险的影响。
本研究共纳入了来自国家健康和营养调查数据库的 5274 名个体。定义了三种 FFM 表示方式的年龄和性别特异性四分位数，并确定了每个四分位数中 MetS 的患病率。使用 FFMi（kg/m ）四分位数来计算独立于 FM、身体活动水平和社会人口统计学变量的 MetS 的比值比。
随着全身 FFM%的四分位数增加（Q1：40%；Q4：10%），MetS 的患病率降低，但随着绝对 FFM（Q1：13%；Q4：40%）和 FFMi（Q1：10%；Q4：44%）的四分位数增加而升高。四肢和躯干 FFM 也观察到了类似的结果。在独立于脂肪量、身体活动和社会人口统计学变量的情况下，FFMi 四分位数与每个特定亚组的第一四分位数相比，MetS 的比值比显著更高[Q4 与 Q1：年轻男性：4.16（1.99-8.68）；年轻女性：5.74（2.46-13.39）；老年男性：1.98（1.22-3.22）；老年女性：2.88（1.69-4.90）；所有 P 值均≤0.01]。
这些结果支持了这样一种观点，即 FFM 的表示方式显著影响其与 MetS 的关联，并且无论绝对大小还是相对于身高的大小，更大的 FFM 都与心血管代谢健康的改变有关。
