Subclinical hypothyroidism represents an additional risk factor for coronary artery calcification, especially in subjects with intermediate and high cardiovascular risk scores

Abstract

ObjectiveSeveral studies have suggested an association between subclinical hypothyroidism (SCH) and increased cardiovascular risk. The aim of this study was to evaluate the presence of coronary artery disease (CAD) in asymptomatic patients with SCH by measuring the coronary artery calcium score (CACS).DesignA total of 222 asymptomatic subjects (103 SCH and 119 euthyroid (EU)), who were between the ages of 35 and 65 years and had no previous history of CAD, were enrolled for this cross-sectional analysis.MethodsThe criteria for SCH included a confirmed normal serum free thyroxine and high TSH levels. Lipid profile, Framingham risk score (FRS) and CACS analyses were performed for all subjects.ResultsThe SCH and EU groups were comparable with respect to age, gender, BMI and frequency of diabetes, systemic arterial hypertension, hypercholesterolaemia and smoking. There was no difference in the median CACS between the SCH and EU groups. However, in the subgroup of subjects with intermediate/high FRS (AR10y≥10%), CACS was higher in the SCH subjects compared with EU subjects (EU vs SCH, 0.0 (57.0) vs 23.0 (161.5);P=0.045). Multivariate analysis revealed that the risk for CACS >100 was independently associated with male gender, age >55 years, and the presence of simultaneous SCH and AR10y≥10% (OR=87.5 (CI=2.1–3500);P=0.001). Serum TSH was positively correlated with CACS, especially in intermediate/high FRS subjects (rs=0.301,P=0.045).ConclusionsIt was demonstrated that SCH represents an additional risk factor for CAD, notably in intermediate and high FRS subjects.