The fat-to-lean mass ratio, a novel anthropometric index, is associated to glucose metabolic disorders

Highlights

• The Fat-to-Muscle ratio mirrors the imbalance between total body fat and lean mass.

• The Fat-to-Muscle index correlates with all glucose metabolic disorders.

• The Fat-to-Muscle ratio is associated to diabetes and all categories of prediabetes.

Abstract

Objective

The aim was to evaluate whether the Fat-to-Lean Mass (FyM) ratio is associated to glucose metabolic disorders (GMD).

Design

Cross-sectional population based study.

Methods

Eligible subjects were healthy men and non-pregnant women with new diagnosis of GMD that were allocated into following groups: 1) Normal Glucose Tolerance (NGT), 2) Diabetes, 3) impaired fasting glucose (IFG) + impaired glucose tolerance (IGT), 4) IGT, and 5) IFG. The FyM index [Total body fat (Kg)/total lean mass (Kg)], and the odds ratio (OR) between FyM index and GMD were estimated.

Results

A total of 875 individuals with average age 41.62 ± 12.3 were enrolled; of them, 645 (73.1%) women and 230 (22.8%) men; 521 (59.5%), 71 (8.1%), 85 (9.7%), 53 (6.0%), and 145 (16.6%) individuals were allocated into groups with NGT, diabetes, IFG + IGT, IGT, and IFG, respectively. The FyM was significantly associated with prediabetes and diabetes in women (OR 4.2; _95%CI 3.0–11.1 and OR = 7.2; _95%CI 2.0–15.2) and men (OR = 2.6; _95%CI 1.1–6.7 and OR = 4.6; _95%CI 1.4–15.1). In the overall population, the OR between FyM index with IGT, IFG, and IFG + IGT was 8.4 (_95%CI 2.6–17.4), 5.2 (_95%CI 2.6–10.6), and 6.1 (_95%CI 1.8–9.5).

Conclusion

The FyM index was strongly associated with all categories of GMD.

Introduction

A strong body of evidence shows that fat and muscle are interconnected in a way that, the imbalance between them may exert a synergistic effect on the risk of developing glucose metabolic disorders (GMD). It is well known that fat infiltration into muscle is associated with lower muscle strength [1,2] and progressive decline in total energy expenditure stemming from decreased physical activity and reduced basal metabolic rate [3]. In addition, it has been reported that fat infiltration into muscle, through activation of inflammatory pathways, is a triggering of insulin resistance [4,5].

Given the role of obesity and/or the fat/muscle imbalance in the pathogenesis of GMD, several anthropometric indexes, such as body mass index (BMI), total body fat, and the waist circumference (WC) have been used for both estimate the obesity status and early recognizing the risk of developing GMD [[6], [7], [8], [9], [10], [11]].

Within this context, we evaluated whether the imbalance between total body fat and total lean mass, measured by the Fat-to-Lean Mass (FyM) ratio, is associated to GMD.