Relationship between fat-free mass and metabolic syndrome in obese females

OBJECTIVE: A greater fat-free mass (FFM) could be negatively or positively associated with metabolic syndrome (MS). The objective of this work was to evaluate the relationship of FFM with MS, through three determinations; absolute FFM, relative to body weight FFM% and relative to squared height (FFMi). PATIENTS AND METHODS: We conducted a cross-sectional study on 1,008 obese Caucasian females. Fat-free mass index (FFMi) was calculated by dividing FFM by squared height [FFM (kg)/height (m(2))]. Fat-free mass percentage (FFM%) was calculated (absolute FFM/body weight) x100. RESULTS: The odds ratio adjusted by age of having MS per tertiles were significantly higher in tertile 3 of FFM (OR=1.74, 95% CI=1.26-2.41; p=0.01) and FFMi (OR=3.38, 95% CI=2.42-3.72; p=0.001) and tertile 2 of FFM (OR=1.45, 95% CI=1.08-1.94; p=0.02) and FFMi (OR=2.37, 95% CI=1.75-3.20; p=0.01) compared with its reference (tertile-1). In contrast, odds ratio adjusted by age of having MS per tertiles were significantly lower in tertile-3 of FFM% (OR=0.29, 95% CI=0.20-0.41; p=0.01) and tertile-2 of FFM% (OR= 0.68, 95% CI=0.51-0.91; p=0.01) compared with its reference (tertile-1). CONCLUSIONS: The prevalence of MS relative to FFM varies depending on the method used to represent it.