Seasonal variation of endogenous uveitis in south-western Finland

To evaluate if there is a seasonal pattern to the incidence of endogenous uveitis in south-western Finland with special reference to acute anterior uveitis.

The incidence rates per month of the 414 new uveitis cases from years 1980-82 and 1988 in the district of Turku University Hospital were calculated. The months of the year were grouped into warm (June to September), transitional (April, May, October, November), and cold (December to March) seasons based on the mean air temperature of the months in Turku.

We observed a statistically significant increase in the incidence of all uveitis cases in the warm and transitional seasons compared with the cold season (p=0.030 and p=0.008 respectively). A similar seasonal trend was found among anterior uveitis cases, but not among the intermediate, posterior or panuveitis cases. The incidence of acute anterior uveitis cases was higher in the transitional than in the cold season (p=0.025). No seasonal variation of the incidence was found in the subgroup of acute anterior uveitis where ankylosing spondylitis had been confirmed (p=0.70).

The present data suggests that there is seasonal variation of the incidence of uveitis in south-western Finland.