Abstract
BACKGROUND/AIMS: Metabolic dysfunction-associated steatotic liver disease (MASLD) is associated with various metabolic disorders; however, its relationship with thyroid cancer remains unclear. This study investigated the association between MASLD and the risk of thyroid cancer. METHODS: This retrospective cohort study used data from the Korean National Health Insurance Service database on individuals who underwent three or more health examinations between January 2002 and December 2015. MASLD was diagnosed using the Hepatic Steatosis Index. Participants were followed up until December 31, 2019, to assess the incidence of newly diagnosed thyroid cancer. RESULTS: A total of 121,479 individuals were included in this study. In the age- and sex-adjusted analysis, the risk of thyroid cancer was significantly higher in the MASLD group than in the normal group (HR 1.19, 95% CI 1.11-1.29, p < 0.001). Age was a significant effect modifier of the relationship between MASLD and thyroid cancer (p for interaction < 0.05). Among individuals aged 65 years or older, the risk of thyroid cancer was higher in the MASLD group than in the normal group (HR 1.31, 95% CI 1.00-1.72, p = 0.05), whereas in individuals younger than 65 years, MASLD was not associated with thyroid cancer (HR 0.97, 95% CI 0.89-1.04, p = 0.37). CONCLUSION: This study suggests an association between MASLD and an increased risk of thyroid cancer in older adults. However, further research is needed to determine whether lifestyle modifications, such as weight management, influence thyroid cancer risk in this population.