Endogenous sex hormones and nonalcoholic fatty liver disease in US adults

Background and Aims: Sex steroid hormones and sex hormone-binding globulin (SHBG) have a role in predisposing individuals to nonalcoholic fatty liver disease (NAFLD), but their effects are known to differ between men and women. The testosterone-to-estradiol ratio (T/E2 ratio) and free androgen index (FAI) were known biomarkers for the hormonal milieu. We investigated whether sex steroid hormones, T/E2 ratio, FAI, and SHBG were associated with NAFLD in US adults.Methods: A cross-sectional analysis using the 2013-2016 National Health and Nutrition Examination Survey (NHANES) was performed. NAFLD was defined by utilizing the Hepatic Steatosis Index (HSI) and the US fatty liver index (USFLI) without other causes of chronic liver disease.Results: Out of 8687 subjects (49.5% male), low total testosterone levels were associated with progressively higher odds of NAFLD in men. Increasing T/E2 ratio was inversely associated with higher odds of NAFLD in men. Low serum SHBG levels were independently associated with an increased risk of NAFLD regardless of sex and menopausal status. Increasing FAI was independently associated with NAFLD. When we additionally adjusted for SHBG, T/E2 ratio, not total testosterone, was inversely associated with NAFLD in a dose-dependent manner. Increasing FAI was associated with higher odds of NAFLD in premenopausal women and marginally associated with NAFLD in postmenopausal women.Conclusion: The T/E2 ratio and SHBG were inversely associated with an increased risk of NAFLD in men. In women, increasing FAI was associated with NAFLD, whereas SHBG was inversely associated with NAFLD.