English summary: Psoriasis in the ageing population in Finland

Background

Psoriasis is a chronic immune-mediated inflammatory skin disease. In this study, which was part of the GOAL programme, we assessed the prevalence and phenotype of psoriasis in the aging 55-75-year-old Finnish population (n= 39421) in the Päijät-Häme Hospital District, Finland on the basis of a randomly sampled population based cohort (n=4272).

Methods

The study was a cross-sectional study and included a general health questionnaire also asking about psoriasis. A dermatologist (J.L.) examined those patients reporting that they had psoriasis. Psoriasis was either confirmed at the visit, or had been confirmed earlier by a doctor. The age of onset was recorded, and the severity of psoriasis was assessed using the Psoriasis Area and Severity Index (PASI) and the Psoriasis Global Assessment (PGA) scorings.

Results

Altogether 66% (2815/4272) of the cohort participated in the study. The reported prevalence of psoriasis was 2.6% (n=72), 2.3% for females (n=33), and 2.9% for males (n=39). The dermatologist/doctor-confirmed annual prevalence of psoriasis was 1.8% (n=51) and the point prevalence 1.4% (n=40). Psoriasis was in general mild or very mild, the median PASI was 2.9 (range 0-12.8). Using the PGA, 22% were symptom free, 4% showed very mild, 69% mild and 6 % moderately severe psoriasis. Five patients with psoriasis reported having had doctor-confirmed psoriatic arthritis; this was 9,8% of psoriatic patients in the study, giving a 0.2% prevalence in this population.

Conclusions

The annual and point prevalences of psoriasis in Finland of 1.8% and 1.4% were slightly lower than we expected. In most participants psoriasis was mild.