Early-Onset Parkinsonism and Early-Onset Parkinson's Disease: A Population-Based Study (2010-2015)

Background: Early-onset Parkinson's disease (EOPD), occurring between ages 40 and 55, carries social, societal, and personal consequences and may progress, with fewer comorbidities than typical, later-onset disease. Objective: To examine the incidence and survival of EOPD and other Parkinsonism occurring before age 55 in the population-based cohort of residents in seven Minnesota counties. Methods: A movement-disorder specialist reviewed all the medical records in a 2010-2015 Parkinsonism-incident cohort to confirm diagnosis and subtypes. Results: We identified 27 patients diagnosed at ≤ 50 years with incident Parkinsonism 2010-15:11 (41%) cases of EOPD, 13 (48%) drug-induced Parkinsonism, and 3 (11%) other Parkinsonism; we also identified 69 incident cases of Parkinsonism ≤ 55 years, of which 28 (41%) were EOPD, 28 (41%) DIP, and 13 (19%) other Parkinsonism. Overall incidence for Parkinsonism ≤ 50 years was 1.98/100,000 person-years, and for EOPD was 0.81/100,000 person-years. In patients ≤ 55 years, Parkinsonism incidence was 5.05/100,000 person-years: in EOPD, 2.05/100,000 person-years. Levodopa-induced dyskinesia was present in 45%of EOPD (both ≤ 50 years and ≤ 55 years). Onset of cardinal motor symptoms was proximate to the diagnosis of EOPD, except for impaired postural reflexes, which occurred later in the course of EOPD. Among the 69 Parkinsonism cases ≤ 55 years, 9 (13%; all male) were deceased (only 1 case of EOPD). Men had a higher mortality risk compared to women (p = 0.049). Conclusion: The incidence of EOPD ≤ 50 years was 0.81/100,000 person-years (1.98 in Parkinsonism all type); prior to ≤ 55 years was 2.05/100,000 person-years (5.05 in Parkinsonism all type) with higher incidence in men than women. Men with Parkinsonism, all type, had higher mortality compared to women.