Prevalence of thyroid antibodies in Shiraz, Iran, an area with iodine deficiency.

The prevalence of thyroid antibodies was 2% among 53 healthy Shirazi volunteers, 3% among 30 consecutive patients with goitre, 41% among 17 patients with thyrotoxicosis and 67% among 18 consecutive patients with myxoedema. A surprising finding was that in a sub-group of 9 of the latter, a high incidence of diabetes (55%) was found and when both diseases co-existed, the prevalence of thyroid antibodies was 80% compared with 67% with myxoedema alone. Serum cholesterol was marginally lower in the goitre than the control group (P, 0.05-0.025) but when females alone were compared there was no significant difference. It was also lower in the thyrotoxic group (P, 0.0025) and higher in the myxoedema group (P, 0.0025). Serum triiodothyronine was lower in the goitre group than the controls (P, 0.0005) but again, when females alone were considered, this difference lessened (P, 0.025-0.0125). Serum thyroxine and thyroid stimulating hormone levels showed no significant differences in the goitre and control groups.