Goitre prevalence and thyroid abnormalities at ultrasonography: a comparative epidemiological study in two regions with slightly different iodine status

OBJECTIVE The association between severe iodine deficiency and endemic goit re is well established, but little information is available on the relation between milder degrees of iodine deficiency and goitre prevalence. SUBJECTS In a comparative epidemiological study performed in two regions in Denmark, we examined 4649 subjects from the general population, women aged 18-65 years and men aged 60-65 years. METHODS Ultrasonography and palpation of the thyroid was performed in all p articipants. Iodine excretion was measured in casual urine samples. Previou s thyroid disease was detected by questionnaires, personal interviews and t racing of records. RESULTS The median iodine excretion was 61 mu g/l (mild iodine deficiency ( ID)) and 45 mu g/l (moderate ID) in the two regions. Median thyroid volume at ultrasonography was 11.9 ml (mild ID) and 13.6 ml (moderate ID), P < 0.0 01, and thyroid enlargement was found in 15.0% (mild ID) and 22.6% (moderat e ID), P < 0.001. Goitre prevalence increased in both regions with age to t he age group 40-45 years, but not after that age. Subjects who had moved fr om the moderate ID to the mild ID area had the same prevalence of thyroid e nlargement as the subjects staying permanently in the mild ID area. Thyroid nodules at ultrasonography were found in 30% in both regions, but nodules were larger and more often palpable in the moderate ID area. Palpable goitr e was found in 9.8% (mild ID) and 14.6% (moderate ID), P < 0.001. The great est regional difference in thyroid abnormalities was found among men. CONCLUSION Marked differences in the prevalence of thyroid abnormalities we re found in these regions with modest differences in iodine excretion.