INCIDENCE AND PREVALENCE OF MYASTHENIA-GRAVIS IN THE COUNTY OF THE COAST AND GORSKI KOTAR, CROATIA, 1976 THROUGH 1996

For the period 1976 through 1996, we carried out an incidence and prev alence study of myasthenia gravis in the County of the Coast and Gorsk i kotar, Croatia. This was the first epidemiological study of myasthen ia gravis in Croatia. A total of 43 incident cases were identified. Ov erall the average crude annual incidence rate was 6.52 per 1,000,000 p erson-years; 5.59 per 1,000,000 person-years for men and 7.41 per 1,00 0,000 person-years for women. The incidence rate was 6.30 (95% confide nce intervals 4.56-8.51), age-adjusted to the European population and 5.17 (95% confidence intervals 3.74-6.98), age-adjusted to the world p opulation. On 31 December 1996, there were 32 prevalent cases. The cru de prevalence was 99 per 1,000,000 population (95% confidence interval s 67.7-139.6). The prevalence adjusted to the European and world popul ations was 101.9 (95% confidence intervals 69.7-143.7) and 75.9 (95% c onfidence intervals 51.9-107)per 1,000,000 population, respectively. O ur incidence findings are similar to those reported in North-East Ital y but lower than those in the United States. Our prevalence findings w ere generally higher than those in Northern European Countries but low er than those in the United States. Standardization of rates to the Eu ropean or world population could facilitate comparison between differe nt populations.