INCREASED INCIDENCE OF THYROTOXICOSIS IN MALMO DURING THE YEARS 1988-1990 AS COMPARED TO THE YEARS 1970-1974

Objective and design. To compare the total and age-specific incidence of thyrotoxicosis, as well as the incidence of the individual types of thyrotoxicosis [i.e. thyrotoxicosis of Graves' type (GD), toxic nodul ar goitre (TNG) and solitary toxic adenoma (STA)] in Malmo during the years 1988-1990 to those of a previous study in 1970-1974. Setting. Th e town of Malmo in southern Sweden. Subjects. All patients from the Ma lmo population treated for thyrotoxicosis (GD, TNG and STA) for the fi rst time during the 3-year period 1988-1990 were included. Results. Ov erall, 299 (263 females and 36 males) new cases of thyrotoxicosis were diagnosed in 1988-1990, corresponding to a mean annual incidence of t hyrotoxicosis of 43.0 per 100 000 inhabitants, The incidence of GD was 22.3, of TNG 16.0 and of STA 4.8 per 100000 per year. Comparing age- and sex-standardized incidences to the results in 1970-1974, there was a significant increase (P < 0.001) in the mean annual incidence of th yrotoxicosis in the total material as well as in TNG. In addition, the re was an increase in GD in females younger than 50 years (P < 0.01), whereas in TNG/STA, an increase was seen in females of 50 years or old er (P < 0.001). The incidence figures in males were not significantly changed. There was a higher proportion of smokers in females with GD c ompared to females with TNG (P < 0.001) and STA (P < 0.05). Conclusion s. The total incidence of thyrotoxicosis, as well as the incidence of GD in females younger than 50 years and the incidence of TNG/STA in fe males of 50 years or older, has increased in Malmo during the period f rom 1970 to 1990. The increase was probably caused by several factors such as more sensitive diagnostic tools and GD changes in smoking habi ts, but additional unknown factors might also be of importance.