Association Between Albumin-to-Globulin Ratio and Hashimoto's Thyroiditis: A Cross-Sectional Study Based on NHANES 2007-2012.

Background: The albumin-to-globulin ratio (AGR) is an inexpensive and routinely available laboratory index that may reflect nutritional status and systemic immune activity. However, its association with Hashimoto's thyroiditis (HT) and thyroid autoantibodies has not been well characterized in population-based samples. We investigated the associations of AGR with HT and thyroid autoantibody levels in US adults. Methods: We analyzed 10,423 participants from the 2007-2012 National Health and Nutrition Examination Survey (NHANES). Multivariable logistic regression was used to evaluate the association between AGR and HT. Smooth curve fitting was applied to assess the shape of the associations. We examined relationships between AGR and thyroid autoantibodies and performed sensitivity and subgroup analyses to assess robustness. Results: In fully adjusted models, each one-unit increase in AGR was associated with a lower likelihood of HT (OR = 0.70; 95% CI: 0.54-0.91; Conclusion: Lower AGR was associated with higher odds of HT and higher TPOAb levels in a nationally representative US sample. As a routinely available composite index, AGR may be useful for HT risk assessment and early identification at the population level. These findings are observational and hypothesis-generating; prospective and mechanistic studies are warranted to confirm temporality and clarify underlying pathways.