Association between metabolic syndrome and euthyroid nodular goiter: a case-control study

Background: Metabolic syndrome is a cluster of metabolic abnormalities and abdominal obesity; its pathophysiologic basis, insulin resistance, has been shown to act as agent in thyroid cell proliferation. Few studies analyze the relationship between metabolic syndrome and thyroid nodular disease, with a substantial knowledge gap. Objective: Determine the association between metabolic syndrome and nodular thyroid disease in a region with adequate iodine intake. Methods: Case-control study. A total of 182 patients referred to radiology to undergo thyroid ultrasonography due to suspicion of thyroid disease. Cases had at least one thyroid nodule greater than 3 mm (n= 91). Controls did not have evidence of thyroid nodules (n= 91). Results: Bivariate analysis showed a significant association between metabolic syndrome and the presence of thyroid nodule (OR 2.56, 95% CI: 1.41-4.66, p <0.05). Low levels of HDL (OR 2.81, 95% CI: 1.54-5.12, p <0.05) and impaired fasting glucose (OR 2.05, 95%CI 1.10 to 3.78, p <0.05) were significantly associated with the presence of thyroid nodule, independent of the presence of metabolic syndrome. Multivariate analysis maintained the association between metabolic syndrome and thyroid nodule with an OR of 2.96 (95%CI 1.47 to 5.95, p <0.05); similarly, the associations of low levels of HDL (OR 2.77, 95 % CI 1.44 to 5.3, p <0.05) and impaired fasting glucose (OR 2.23, 95%CI 1.14 to 4.34, p<0.05) with thyroid nodule remained significant. Conclusion: The thyroid nodular disease is associated with increased risk of metabolic syndrome, specifically decreased HDL and impaired fasting glucose levels were the factors that increased association was found.