Combined Association of Vitamin D and Sex Hormone Binding Globulin With Nonalcoholic Fatty Liver Disease in Men and Postmenopausal Women: A Cross-Sectional Study

This study aimed to explore the combined associations of 25(OH)-vitamin D and sex hormone binding globulin (SHBG) with nonalcoholic fatty liver disease (NAFLD) in men and postmenopausal women. Our data, which were based on the population, were collected from 16 sites in East China in 2014. There were 2700 men with a mean age of 53 years and 1461 women over 55 who were considered postmenopausal enrolled in the study. Levels of 25(OH)D and SHBG were measured using chemiluminescence assay. NAFLD was measured using liver ultrasound. Multivariable-adjusted logistic regression models examined associations of 25(OH)D and SHBG tertiles with odds of mild and moderate–severe NAFLD. Both the low 25(OH)D and low SHBG groups were significantly associated with higher odds of mild NAFLD (men: OR 1.37, 95% CI 1.05, 1.78 in low 25(OH)D group; OR 1.73, 95% CI 1.23, 2.45 in low SHBG group; women: OR 1.51, 95% CI 1.08, 2.12 in low 25(OH)D group; OR 2.16, 95% CI 1.48, 3.14 in low SHBG group) and moderate–severe NAFLD (men: OR 1.61, 95% CI 1.24, 2.10 in low 25(OH)D group; OR 3.42, 95% CI 2.41, 4.87 in low SHBG group; women: OR 1.66, 95% CI 1.14, 2.42 in low 25(OH)D group; OR 6.84, 95% CI 4.31, 10.84 in low SHBG group). However, the combined association of low 25(OH)D and low SHBG was much larger, especially in moderate–severe NAFLD (men: OR 6.57, 95% CI 3.87, 11.18; women: OR 8.16, 95% CI 3.98, 16.73). The associations were independent of age, total testosterone, abdominal obesity, diabetes, and lipid profile. The negative associations of 25(OH)D and SHBG levels with NAFLD are strongest when viewed in combination in men and postmenopausal women. Further studies should determine the cause–effect relationship and investigate the underlying mechanisms of this finding.