Association of Subclinical Hypothyroidism with Nonalcoholic Fatty Liver Disease in Patients with Type 2 Diabetes Mellitus: A Cross-Sectional Study

Abstract

Background: Nonalcoholic fatty liver disease (NAFLD) and type 2 diabetes mellitus (T2DM) are recognized as two common health problems. Metabolic diseases, such as dyslipidemia, obesity, and hypertension are known risk factors for NAFLD. In addition to these risk factors, other risk factors have been recently suggested, such as thyroid dysfunction. Materials and Methods: In this study, adult patients with T2DM were recruited. Various clinical and biochemical parameters including thyroid function tests, liver function tests, and liver sonography in all participants were assessed and compared between with and without NAFLD groups. Results: Data from 926 diabetic patients were analyzed; of which, 744 (80.3%) had fatty liver. The prevalence of subclinical hypothyroidism (SCH) in patients with NAFLD was 11.6% and in patients without NAFLD was 6.0% (P = 0.029). Furthermore, the prevalence of overt hypothyroidism was higher in diabetic patients with NAFLD (3.9% vs. 1.6%); this difference was not statistically significant. In univariate logistic regression analysis, hemoglobin A1c (odds ratio [OR]: 8.13); history of insulin consumption (OR: 5.35); duration of diabetes (OR: 2.20); family history of diabetes (OR: 2.85); history of antihypertensive drug use (OR: 2.14) as well as SCH (OR: 2.03) were significant variables for NAFLD. According to the multivariate logistic model, after eliminating the confounding effect of age, sex, and body mass index; the chance of developing NAFLD in patients with SCH was 2.32 times higher than patients without SCH (P = 0.014). Conclusion: NAFLD is extremely common in patients with T2DM. The relationship between hypothyroidism and NAFLD is independent of other risk factors.