Low serum sex hormone‐binding globulin is associated with nonalcoholic fatty liver disease in type 2 diabetic patients

Abstract

Studies have indicated that low serum sex hormone-binding globulin (SHBG) and testosterone levels are associated with nonalcoholic fatty liver disease (NAFLD). However, it remains unclear whether an association exists between SHBG and NAFLD independent of testosterone. This study was aimed to investigate the relationship between SHBG and both total and free testosterone levels with NAFLD. One hundred and twenty patients with NAFLD and 120 age-, sex- and BMI-matched patients with non-NAFLD were enrolled into a case-control study. Serums SHBG, total testosterone (TT), liver enzymes, lipids, insulin, C-peptide and plasma glucose were measured. Free testosterone (FT) and fatty liver index were calculated. Serum SHBG levels were significantly lower in NAFLD group than in non-NAFLD group (24·5 ± 11·0 vs 37·6 ± 14·4 nm, P < 0·001). After adjustment for age, smoking status, alcohol use, duration of diabetes, BMI and fasting C-peptide, serum SHBG levels in men and women were inversely associated with NAFLD, with odds ratio (OR) and 95% confidence interval (CI) in the forth quartile as 0·05 (0·01-0·30) and 0·25 (0·08-0·77) compared with the first quartile (OR = 1·00). Additional adjustment for TT in men and FT in women did not materially alter the association. The relationship between serum TT (for men) and FT (for women) with NAFLD was attenuated and even diminished after multivariable adjustment for known risk factors and SHBG. Low serum SHBG levels, but not TT or FT, are associated with NAFLD in type 2 diabetic patients.