Are thyroid peroxidase antibodies associated with cardiovascular disease risk in patients with subclinical hypothyroidism?

OBJECTIVE: Conflicting evidence has been reported about whether subclinical hypothyroidism (SCH) is associated with hyperlipidemia or cardiovascular disease. Thyroid peroxidase antibodies (TPOAb) are more common in persons with SCH. The purpose of this study was to evaluate whether the presence of (TPOAb) in people with SCH is associated with markers of cardiovascular disease.

DESIGN: Cross-sectional study using multivariate regression.

PATIENTS: Adults over age 40 who, in the National Health and Nutrition Examination Survey (NHANES) III, met the criteria for SCH (n = 188).

MEASUREMENTS: Participants were stratified into TPOAb-negative (n = 82) and TPOAb-positive (n = 106) groups. Markers of cardiovascular disease risk were compared between the TPOAb-negative and TPOAb-positive groups. Multivariate regression models were performed to adjust for potential confounders.

RESULTS: In bivariate analyses, individuals with and without TPOAb had similar levels of triglycerides, high-density lipoprotein, low-density lipoprotein, total cholesterol and C-reactive protein. Homocysteine levels were higher in the patients without antibodies (P = 0.01). After adjusting for, age, gender, smoking, hypertension, diabetes and use of a lipid-lowering medication, however, no statistically significant relationships were found between the presence of TPOAb and any of the cardiovascular risk markers.

CONCLUSIONS: The presence of thyroid peroxidase antibodies does not appear to correlate with cardiovascular disease risk in patients with subclinical hypothyroidism. This study does not support the measurement of TPOAb antibodies in SCH as a strategy for guiding treatment or assessment of cardiovascular disease risk.