S2697 Higher TSH Within the Normal Range Is Linked to Increased Risk of NAFLD/MASLD in Euthyroid Individuals: A Meta-Analysis

Introduction: Thyroid function may influence liver fat metabolism, even within the normal (euthyroid) range. However, the link between serum thyroid-stimulating hormone (TSH) levels and the risk of non-alcoholic fatty liver disease (NAFLD), now termed metabolic dysfunction-associated steatotic liver disease (MASLD), remains unclear in euthyroid adults. This meta-analysis aimed to assess this association using both continuous and categorical TSH levels. Methods: A systematic review was conducted in accordance with PRISMA guidelines. PubMed, Embase, Scopus, and Google Scholar databases were searched through May 2025 using terms including “euthyroid,” “TSH,” “thyroid-stimulating hormone,” “NAFLD,” and “MASLD.” Studies were eligible if they evaluated the association between serum TSH and NAFLD/MASLD among euthyroid adults. Two independent reviewers performed data extraction and quality assessment using the Newcastle-Ottawa Scale. Meta-analyses were performed using a random-effects model, with pooled odds ratios (ORs) and 95% confidence intervals (CIs). Continuous and categorical TSH levels were analyzed separately. Heterogeneity was assessed using I² statistics, and leave-one-out sensitivity analysis was conducted. Results: The meta-analysis included 7 studies, comprising 37,625 euthyroid individuals. In the categorical analysis, higher serum TSH levels were significantly associated with increased odds of NAFLD/MASLD (pooled OR: 1.33, 95% CI: 1.15–1.53, I² = 31.8%, P = 0.22). Effect estimates ranged from 1.29 to 1.46 in leave-one-out sensitivity analysis, indicating no single study unduly influenced the overall result. In the continuous analysis, each unit increase in TSH was associated with higher odds of NAFLD/MASLD (pooled OR: 1.52, 95% CI: 0.89–2.59), though substantial heterogeneity was observed (I² = 85.2%, P < 0.01). Sensitivity analysis showed that excluding Berg et al. increased the pooled estimate (OR: 1.95, 95% CI: 1.38–2.76), suggesting this study may have moderated the overall association. Together, these findings indicate a positive association between higher TSH levels and NAFLD/MASLD risk in euthyroid individuals, with more consistent results in the categorical analysis. Conclusion: Higher TSH levels within the normal range are associated with increased NAFLD/MASLD risk in euthyroid adults, especially in biopsy-based studies. TSH may aid early risk detection. Further research is needed to clarify mechanisms and clinical relevance.