Age-, and gender-specific incidence of vascular parkinsonism, progressive supranuclear palsy, and parkinsonian-type multiple system atrophy in North East Scotland: the PINE study

INTRODUCTION: There have been few incidence studies of vascular parkinsonism (VP), progressive supranuclear palsy (PSP), and parkinsonian-type multiple system atrophy (MSA-P). We measured the age-, gender- and socioeconomic-specific incidence rates for these conditions in north-east Scotland. METHODS: Incident non drug-induced parkinsonian patients were identified prospectively over three years by several overlapping methods from a baseline primary care population of 311,357. Parkinsonism was diagnosed if patients had two or more cardinal motor signs. Patients had yearly follow-up to improve diagnostic accuracy. Incidence rates using the diagnosis by established research criteria at latest follow-up were calculated for each condition by age, gender, and socioeconomic status. RESULTS: Of 377 patients identified at baseline with possible or probable parkinsonism, 363 were confirmed as incident patients after median follow-up of 26 months (mean age 74.8 years, SD 9.8; 61% men). The crude annual incidence was 3.2 per 100,000 (95% confidence interval (CI) 2.2-4.3) for VP, 1.7 per 100,000 (95% CI 1.0-2.4) for PSP, and 1.4 per 100,000 (95% CI 0.8-2.1) for MSA-P. VP and MSA-P were more common in men (age-adjusted male to female ratios 2.58 (95% CI 1.65-3.83) and 8.65 (95% CI 4.73-14.5) respectively). Incidence did not vary with socioeconomic status. DISCUSSION: This is the first community-based, prospective study to report the incidence of vascular parkinsonism and the third to report the incidence of PSP and MSA-P. Further follow-up and comparison with similar studies in different populations will yield valuable prognostic and aetiological information on these conditions.