Thyroid volume and morphology and urinary iodine excretion in a Danish municipality

In order to throw light upon the eventual need for iodine supplementation in Denmark, four age groups of women (15, 30, 45 and 60 years) from the Holbaek municipality were invited for a clinical and ultrasound study of thyroid volume, structure and function. Of the 570 women invited, 391 accepted and were divided into the following groups: group I: 15 years, N = 113; group II: 30 years, N = 100; group III: 45 years, N = 98; group IV: 60 years, N = 80. The results were as follows the thyroid gland was palpable in 39% and visible in 16% of the entire group; 19% had a family history of thyroid disorders and 7.6% had a previous thyroid disorder. Thyroid volumes (median (range)) as measured by ultrasound were 12 ml (4-29 ml), 18 ml (5-47 ml), 18 ml (7-64 ml) and 18 ml (9-51 ml) in groups I-IV, respectively. The calculated 24-h iodine excretion was 65 micrograms (19-365 micrograms), 88 micrograms (15-274 micrograms), 97 micrograms (40-737 micrograms) and 83 micrograms (50-999 micrograms) in groups I-IV, respectively. An abnormal echo structure was present in 3, 10, 21 and 30%, respectively. Defining a goitre as a thyroid volume above 28 ml indicated a goitre prevalence of 17% in females aged 30-60 years in the Holbaek area of Denmark. Among the 60-year-old women, 3% had a clinically significant goitre (WHO grade III). Thyroid volume did not correlate with iodine excretion. The benefit of iodine supplementation is discussed.