Association between thyroid function and nonalcoholic fatty liver disease in euthyroid elderly Chinese

Objective Thyroid dysfunction commonly occurs in the elderly population and overt thyroid dysfunction is associated with some liver abnormalities. This study aimed to investigate the association of thyroid function with nonalcoholic fatty liver disease (NAFLD) in euthyroid elderly Chinese. Methods A cross-sectional study was performed among 878 euthyroid elderly Chinese who took their annual healthy examination at Zhenhai Lianhua Hospital, Ningbo, China. Results A total of 227 (25.85%) subjects fulfilled the diagnostic criteria of NAFLD. Patients with NAFLD had significantly lower levels of serum-free thyroxine (FT4) than controls (11.12 +/- 1.43 vs 11.58 +/- 1.47 pmol/l; P < 0.001). The prevalence rate of NAFLD decreased along with progressively higher serum FT4 levels (P for trend < 0.001). Age, gender and smoking status-adjusted correlation analysis showed that serum FT4 level was negatively correlated with body mass index, waist circumference, triglyceride and serum uric acid levels (All with P < 0.05). Stepwise logistic regression analysis showed that serum FT4 level was significantly associated with the risk for NAFLD [odds ratio (OR): 0.847, 95% confidence interval (CI): 0.743 - 0.966; P = 0.013]. Conclusion Our findings suggest that thyroid function, even within the reference range, is associated with NAFLD in elderly Chinese.