Fatty liver index is associated with the risk of testosterone deficiency in aging men without metabolic syndrome.

OBJECTIVES Non-alcoholic fatty liver disease (NAFLD) is suggested to be a precursor of metabolic syndrome (MetS) and could influence the risk of testosterone deficiency (TD). Fatty liver index (FLI) is a simple and useful screening tool for NAFLD. We determined the association between the risk of NAFLD assessed by FLI and TD in aging Taiwanese men, especially those without MetS. MATERIALS AND METHODS A free health screening program was conducted for men (age: >40 years) in a medical center in Kaohsiung, Taiwan. All participants underwent a physical examination; answered a questionnaire assessing demographics, medical history, and clinical symptoms of TD; and provided 20-mL whole blood samples for biochemical, adipocytokine, and hormonal evaluations. The risk of NAFLD was evaluated using FLI. The presence of NAFLD was ruled out if FLI value was <25 and ruled in if FLI value was ≥35. RESULTS A total of 552 men (mean age: 54.7 ± 7.7 years) were enrolled. The prevalence rates of TD and MetS were significantly higher among men with NAFLD than those without NAFLD (both p < 0.001). FLI was significantly correlated with total testosterone (TT) and adipocytokines associated with insulin resistance, such as adiponectin, leptin, and retinol-binding protein-4 (RBP-4) levels, respectively (all p < 0.001). Among men without MetS, those at risk of and with NAFLD had a 3.82 and 8.50 times higher risk of TD, respectively, than those without NAFLD after adjusting for potential covariates. CONCLUSION The FLI is associated with the risk of TD in aging Taiwanese men, especially in those without MetS. Our findings also suggest that insulin resistance may be an important link among the inter-relationships of NAFLD, MetS, and TD. Further population-based studies with larger sample sizes of different ethnicities are warranted to confirm these preliminary results.