Objective: Multinodular goitre has been found with a high prevalence in iodine-deficient areas, but less frequently in iodine-replete areas; the iodine intake sufficient to prevent goitre has not been established, however. Methods: We report data from an ultrasonic investigation of the thyroid glands of 2656 randomly selected subjects aged 41 to 71 years in an area with borderline iodine deficiency. Results: Median iodine concentration in spot urine samples was 70 mg/l. Multinodular thyroid structure was found in 23% of the population, increasing in women from 20 to 46% with increasing age, and in men from 7 to 23%. Solitary, scintigraphically cold, thyroid nodules >10 mm were found in 2.4% of the population with the same prevalence in the different age and sex groups. Two years of follow-up of these cold nodules revealed no signs of malignancies. Median thyroid volume was 11.0 ml. Thyroid enlargement (>18 ml for women and >25 ml for men) was found among 13.1% of the women and 6.2% of the men, and the prevalence increased with age. The presence of thyroid nodules was related to positive anti-thyroperoxidase antibody (TPO Ab) titres, whereas thyroid enlargement was associated with iodine excretion <50 mg/day. Conclusions: Thyroid enlargement was associated with low iodine excretion and median thyroid volume was slightly increased compared with iodine-replete areas. Multinodular thyroid structure was found with a high prevalence and was associated with TPO Ab >200 kU/l. Cold thyroid nodules were moderately prevalent, with no cases of detected malignancies during 2 years of follow-up.

Dipyridamole is used for secondary prophylaxis in ischemic stroke and as a vasodilator agent in myocardial scintigraphy. An important side effect to administering dipyridamole is headache. The aim of the current study was to investigate the effects of dipyridamole on cerebral blood flow, large artery diameter, and headache induction. Twelve healthy subjects were included in this single-blind placebo-controlled study in which placebo (0.9% NaCl) and dipyridamole 0.142 mg/kg x min were administered intravenously over 4 minutes 1 hour apart. Blood flow velocity in the middle cerebral artery (Vmax) was recorded by transcranial Doppler and regional cerebral blood flow in the middle cerebral artery (rCBFmca) was measured using single photon emission computed tomography and 133Xenon-inhalation. Blood pressure, heart rate, and pCO2 were measured repeatedly. Headache response was scored every 10 minutes on a verbal scale from 0 to 10 (10 = worst). Dipyridamole caused a decrease in pCO2 (P < 0.001). pCO2 corrected rCBFmca was 41.7 +/- 6.9 mL/100 g x min after placebo versus 41.2 +/- 6.9 after dipyridamole (P > or = 0.05). pCO2 corrected Vmca decreased 8.4% +/- 11.7 (P < 0.001) after dipyridamole, indicating a mean 5.6% +/- 6.7 (P = 0.005) relative increase of the arterial diameter. After dipyridamole the median peak headache score was 2 (range 0 to 7) compared with 0 (range 0 to 3) after placebo (P = 0.02). Dilatation of the middle cerebral artery outlasted the headache response. In conclusion, dipyridamole causes a modest pCO2 independent dilatation of the MCA, which is time-linked to the onset, but not to the cessation, of headache.

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\p=n-\29ml), 18 ml (5\p=n-\47ml), 18 ml (7\p=n-\64 ml) and 18 ml (9-51 ml) in groups I \ p=n-\ IV, respectively. The calculated 24-h iodine excretion was 65 \g=m\g(19\p=n-\365\g=m\g),88 \g=m\g(15-274 \ g=m\ g), 97 \ g=m\ g(40\p=n-\737\g=m\g) and 83 \g=m\g(50\p=n-\999\g=m\g) in groups I\p=n-\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\p=n-\60years 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. Birte Nygaard, Hedebyvej 3, 3650 01stykke, Denmark