Objective: To describe the incidence of Parkinson’s disease (PD); to investigate whether the male:female ratio of incident PD varies with age; and to set up a pooled incidence cohort of PD with low risk of bias.

Background: There is dramatic heterogeneity in estimates of the incidence of PD in previous studies with estimates from 1.5 to 36 new cases per year per 100,000 population. Two important causes of this heterogeneity are methodological differences in intensity of case finding and variation in diagnostic accuracy. Some previous studies have suggested that the male:female ratio in the incidence of PD varies by age, but there remains uncertainty.

Methods: From a systematic review of PD incidence studies we identified six whole-population incidence studies with long-term follow-up of identified incident patients. These studies are all in Northern Europe with recruitment between 2000 and 2011 (CamPaIGN, ICICLE-PD, NYPUM, ParkWest PICNICS, and PINE). We have initiated a collaborative project to pool data from these studies (the Parkinson’s Incidence Cohorts Collaboration). Each study has similar comprehensive methods with multiple sources of case ascertainment to identify all new cases in a defined incidence period and geographical area. In each study diagnoses were revised at regular intervals during follow-up, guided by the UK PD Brain Bank criteria. For this analysis we have calculated pooled incidence rates, stratified to the standard European population, stratified by age and sex, with the benefit of diagnostic revision over several years in those consenting to follow-up. We examined whether the male:female ratio in incidence varied by age by comparing odds of being female in 10-year age strata and looking for evidence of a trend (chi-squared test for trend).

Results: There was heterogeneity in incidence rates between individual studies (incidence rates ranging from 13.0 to 19.7 cases per 100,000 population per year). Overall pooled crude incidence rate was 15.3 per 100,000 per year (95% confidence interval 14.2 to 16.3). There was no evidence that the male:female ratio changed with age (p=0.53). 1004 patients (75% of incident cases) have consented to long-term follow-up.

Conclusions: We have defined the incidence of PD in a pooled analysis of six high-quality incidence studies with long-term follow-up for diagnostic confirmation. There was no evidence of an interaction between sex and age. Follow-up of these cohorts provides a cohort for the study of prognosis in PD with low risk of selection bias.

« Back to 2018 International Congress

MDS Abstracts - https://www.mdsabstracts.org/abstract/incidence-of-parkinsons-disease-pooled-analysis-of-six-high-quality-incidence-studies-with-long-term-follow-up/