Thyroid microsomal and thyroglobulin antibodies are more common in women than in men at all ages and are most common in post-menopausal women (Fig. 15.25). Raised TSH values show a similar age and sex distribution, and there is a close correlation with thyroid antibodies.
Patients with thyroid antibodies may maintain normal thyroid function for their lifetime. Up to fifty per cent of people with thyroid antibodies, however, also have raised TSH levels, and such patients progress to overt hypothyroidism at the rate of approximately five per cent per annum. Prophylactic T4 replacement therapy merits consideration in individuals with evidence of underlying autoimmune thyroiditis and compensated hypothyroidism. Replacement therapy is used in patients with overt hypothyroidism and may also decrease goitre size.
