Association between thyroid function and metabolic associated fatty liver disease: a systemic review and meta-analysis

Background: Metabolic dysfunction-associated fatty liver disease (MAFLD) is one of the most common chronic liver diseases. The relationship between MAFLD and thyroid function parameters remains controversial. Aim: This study aimed to explore the influence of metabolic parameters and thyroid dysfunction on the development of MAFLD and examine the relationship between them in different age groups. Methods: The PubMed, Embase, Web of Science, China National Knowledge Infrastructure(CNKI), and Cochrane Library databases were searched. Standardized mean difference (SMD) and odds ratio with a 95% confidence interval (CI) were calculated. Results: A total of 36 studies involving 198,254 participants were eligible. Compared with controls, the patients with MAFLD had significantly higher thyroid-stimulating hormone (TSH) levels (MAFLD vs controls: SMD = 0.02, 95% CI = 0.01-0.03); significantly higher free triiodothyronine levels (MAFLD vs controls: SMD = 0.19, 95% CI = 0.18-0.20); significantly lower free thyroxine levels (MAFLD vs controls: SMD = -0.41, 95% CI = -0.42 to -0.40); significantly higher total triiodothyronine levels (MAFLD vs controls: SMD = 0.26, 95% CI = 0.23-0.29); and significantly lower total thyroxine levels (MAFLD vs controls: SMD = -0.10, 95% CI = -0.13 to -0.07). Conclusions: The TSH level may be an important risk factor for the occurrence and development of MAFLD. The relationship between them is influenced by age.