[Incidence of autonomy and immune hyperthyroidism before and following preventive use of iodized salt in the Berlin-Brandenburg area].

The incidence of hyperthyroidism was observed in the area of Berlin (1.2 million inhabitants) and in a rural district in the geographical region of the "Mark Brandenburg" (48.115 inhabitants) during the period from 1975 und 1989. This area is characterized with a iodine deficiency grade II (WHO). In 1985 an iodine salt supplementation was introduced by law. The period before iodine salt supplementation 1975-1985 was compared to the period after iodine prophylaxis: there was an increase in hyperthyroidism in the Berlin-area by the ratio 1:3.1 and 1:2.8 (1975-83 compared to 1988 and 1989), in the rural district by 1:1.7 (1980-1985 compared to 1986/87). The ratio autonomy (non immunogenic form) to immunogenic etiology was 1:12 (1977-83), and changed to 1:1.45 in 1988 and 1:16.3 in 1989 after iodine supplementation. The sex ratio male:female was 1:10 before, and 1:6.8 after prophylaxis for hyperthyroidism in total, in autonomy the ratio was observed as 1:12 before and 1:7.7 (1988), 1:4.7 (1989) after supplementation, in immunogenic hyperthyroidism 1:10 unchanged in the early and late period of observation. The increase of hyperthyroidism after iodine prophylaxis correlated well with the consumption of thyrostatic drug Thiamazol (Methimazol) for the whole country. The defined daily dose (DDD)/1000 inhabitants/day increased during the observation time from 0.5 (1984), 0.55 (1985), 0.66 (1986), to 1.47 (1987), 1.26 (1988) and 0.81 (1989). The results are compared and discussed with reports from USA, Iceland, Great Britain, Denmark, Italy and Tasmania. During the period of seven years (1980-87) in the rural district a seasonal dependence of onset in hyperthyroidism was observed in spring time between May and June only in immunogenic hyperthyroidism, despite in thyroidal autonomy the disease began throughout the year without a seasonal peak.