Endocrine Abstracts

It has been claimed that an increased level of thyroid autoantibodies in serum is associated with a higher risk for coronary heart disease (CHD). We explored whether this risk was mediated by subclinical hypothyroidism and hypercholesterolemia. We evaluated 945 consecutive hospital patients (mean age 59 years) according to strict electrocardiographic and clinical criteria for the presence of CHD. Serum cholesterol, LDL and HDL cholesterol and sensitive TSH were measured in all patients. In 245 patients antithyroglobulin and thyroid peroxidase antibodies were also determined. Patients were divided into group I (normal TSH, i.e. below 4 mU/l), group II (borderline TSH, i.e. 4.0 to 5.9 mU/l) and group III (high TSH, i.e. 6.0 mU/l or more). There were 398, 45 and 22 women and 410, 50 and 20 men in group I, II and III respectively. Patients of group III were randomly age- and sex-matched with patients of group I and II combined as controls. Alternately the groups II and III were randomly age- and sex- matched with group I as controls. Both procedures gave on identical prevalence of CHD in control and index groups in both sexes. Cholesterol was significantly lower in group III compared to matched controls. The prevalence of thyroid antibodies was 8.3, 14.3 and 48% in women and 4.5, 2 and 4.8% in men of group I, II and III respectively. In women with antibodies mean cholesterol was lower than in age-matched controls without antibodies (P<0.05) irrespective of whether they belonged to group I, II or III and the presence of antibodies was not associated with the prevalence of CHD. In men the prevalence of antibodies was too low to permit analysis of their contribution to CHD. We conclude that neither subclinical hypothyroidism nor thyroid antibodies are risk factors for CHD.