[The mode of onset of rheumatoid arthritis and seasonal variations]

The aim of the study was to establish age and sex distribution, seasonal variations, and mode, of onset in a sample of patients with rheumatoid arthritis. One hundred eighty nine patients (146 women and 43 men), whose age ranged from 18 to 77 yrs. (mean age 49.1, SD 12.93) were included in the survey. In majority of patients the disease started between 31-50 years, whereas in the age group from 21-30 it occurred more frequent in women, and in the age group from 51-60 in men. The onset of rheumatoid arthritis was in almost equal proportions acute or insidious, regardless sex. No difference was found concerning onset of the disease and seasonal variations. However there was a statistically significant correlation between mode of the onset and seasonal variations (P < 0.05). Rheumatoid arthritis started abruptly more often in springtime, and more insidiously in autumn, whereas in summer and winter there was an equal number of patients with acute or insidious onset of the disease.