The authors examined the incidence of IDDM in 1369 child diabetics in Slovakia recorded between 1985 and 1997. The initial incidence was 6.75 per 100 000 children, within 12 years an increase to 11.40/10 5 was recorded. By chronobiometric analysis a general rising trend of IDDM was found (linear regression coefficient b = +0.43/year), with a prediction of 13.5/10 5 for the year 2000. The distribution of the IDDM incidence throughout the year was seasonal with cumulation of new patients in autumn and winter and a minimum during the summer months. The seasonality was apparent in all age groups. In 66 children with manifest IDDM in 1985 - 1989 we found a significantly (58%) higher presence of coxsackie virus infection than in 218 healthy controls (6%). The relationship between IDDM incidence and serologically assessed coxsackie infection was therefore investigated. From a group of 179 diabetics in 1990 - 1994 in 77 anticoxsackie positive ones a maximum incidence of diabetes in autumn and winter was found, while 102 anticoxsackie negative patients had the peak incidence in spring. In 554 healthy children in 1985 - 1989 the anticoxsackie serological positivity had its peak most frequently in summer and autumn, i.e. 3 months earlier than the incidence of IDDM in our anticoxsackie positive patients.

        Key words: incidence of diabetes type 1, secular trend of diabetes, seasonal character of IDDM incidence, seasonal character of coxsackie infection