Psoriasis is associated with an increased risk of parkinsonism: a population-based 5-year follow-up study.

Abstract

Few studies have examined the association between autoimmune diseases and parkinsonism. We sought to investigate the risk for parkinsonism during a 5-year follow-up period after a diagnosis of psoriasis using a population-based data set in Taiwan. We identified 4885 patients with psoriasis for the study cohort and randomly selected 24,425 patients as a control cohort. Each subject was individually followed up for a 5-year period to identify those who subsequently developed parkinsonism. Stratified Cox proportional hazards regression showed that the adjusted hazard ratio for parkinsonism during the 5-year follow-up period for patients with psoriasis was 1.74 (95% confidence interval 1.35-2.20) that of control patients. Furthermore, the adjusted hazard ratios for parkinsonism within the 5-year follow-up period after the index date for subjects with psoriasis were similar between both sexes (1.78 and 1.66 for men and women, respectively). Our data set did not provide detailed information on the severity of psoriasis, or individual factors such as cigarette smoking, alcohol consumption, body mass index, and dietary patterns. Patients with psoriasis were found to be at a significant risk of parkinsonism during a 5-year follow-up.