Association between hypothyroidism and non-alcoholic fatty liver disease

Introduction and Objectives

Association between hypothyroidism and non-alcoholic fatty liver disease (NAFLD) is controversial. The aim of the study was to evaluate the association between levels of thyroid stimulating hormone (TSH) and NAFLD.

Material and Methods

This is a cross-sectional study of patients who attended at check-up unit. NAFLD was evaluated by the controlled attenuation parameter (CAP). Also, patients were classified by metabolic dysfunction-associated fatty liver disease (MAFLD) criteria. TSH levels were divided into three different cut-off points (>4.5, >3.1 y >2.5). Associations between THS, NAFLD and MAFLD were evaluated by univariate and multivariate logistic regression analysis.

Results

Three thousand seven hundred forty-one patients were included, 59% (n=2211) were male, mean of age and body mass index were 48 [43-55] years and 25.9 [23.6-28.6] kg/m2.44.5% (n=1664) of patients were diagnosed with NAFLD meanwhile, 1% (n=37) presented significant liver fibrosis. In multivariate analysis, TSH levels did not show an independent association with the presence of NAFLD or MAFLD (Table). According to different cut-off points, patients with high levels of TSH presented similar risks for NAFLD to the general population (presence of metabolic syndrome and high-fat percentage).

Discussion

There is evidence of an association between hypothyroidism and NAFLD. However, liver steatosis is diagnosed by abdominal ultrasound. This is the first study that evaluates steatosis by CAP.

Conclusion

TSH levels are not associated with NAFLD or MAFLD; patients with high TSH levels have the same risk for NAFLD as the general population.

Funding

The resources used in this study were from the hospital without any additional financing

Declaration of interest

The authors declare no potential conflicts of interest.

Table. Association between TSH and NAFLD/MAFLD.

	NAFLD				MAFLD
Characteristic	Univariate		Multivariate		Univariate		Multivariate
	OR (IC 95%)	p	OR(IC 95%)	p	OR (IC 95%)	p	OR (IC 95%)	p
Male	2.1 (1.8-2.4)	**			1.5 (1.2-1.82)	**
MetS	5.1 (4.2-6.1)	**	1.6 (1.2-2.1)	**	3.1 (2.5-3.8)	**	1.6 (1.2-2.1)	**
TSH >4.5	1.2 (0.9-1.5)	0.11			1.3 (0.9-1.8)	0.09
TSH >2.5	1.1 (1.0-1.3)	0.01			1.2 (1.0-1.4)	0.03
TSH >3.1	1.2 (1.0-1.4)	0.002			1.2 (1.0-1.5)	0.01
% fat >29.8	2.2 (1.9-2.6)	**	2.2 (1.6-2.9)	**	1.8 (1.5-2.1)	**	2.0 (1.4-2.8)	**

** p≤0.001; NAFLD non-alcoholic fatty liver disease; MAFLD metabolic dysfunction-associated fatty liver disease; MetS metabolic syndrome; TSH thyroid stimulating hormone.