Is Subclinical Thyroid Dysfunction Associated with Coronary Heart Disease?

Introduction: Previous cohort studies reported contradictory data on the association between subclinical thyroid dysfunction and coronary heart disease (CHD). Regarding this, the present study was conducted to illuminate this relationship. Material and Methods: For the purpose of the study, 3,066 participants employed in a study conducted by Azizi et al. aged ≥ 20 years were subjected to thyroid function tests every 3 years over a mean follow-up of 10 years. After the exclusion of the subjects with CHD and those consumed thyroid, anti-thyroid, or corticosteroid preparations, 2,144 subjects remained for analysis and followed up for CHD events in the next 10 years. Results: At the baseline, 1929, 139, and 76 subjects had euthyroid, subclinical hyperthyroid, and subclinical hypothyroid, respectively. No CHD event occurred in the subclinical hypothyroid group. After the adjustment of all confounders, the subclinical hyperthyroid group had the hazard ratio of 1.01 for CHD with a 95% confidence interval of 0.36-2.85. Conclusion: The 10 year follow-up of subjects with subclinical thyroid disease revealed no relationship between CHD and subclinical thyroid disorders.