[Periodicity and seasonal variations in the incidence of rheumatism and their relation to various exogenous biorhythms].

The nature of the relationship between rheumatic fever morbidity on some islands in the Estonian SSR and certain heliogeophysical factors was studied over the 25-year period (1958-1983). Altogether 923 patients with rheumatic fever at the active stage were followed up. Periodicity of an increase (every 5-6 yrs) in the number of patients with active rheumatic fever was noted. Changes in the morbidity curve for many years were connected with the frequency of sharp changes of the solar activity. Season and meteorological factors should be regarded as interrelated exogenous factors of risk in rheumatic fever morbidity. Rheumatic fever is a meteotropic disease. The range of meteopathic reactions in patients is associated with certain forms of disease and the presence of chronic infection foci. Meteosensitivity is more typical of familial rheumatic fever.