ABSTRACT
Background:
Females, people with young-onset PD and older individuals, and non-
white populations are historically underrepresented in clinical
Parkinson's disease (PD)
research. Furthermore,
research traditionally focused predominantly on motor symptoms of PD. Including a representative and diverse group of people with PD and also studying non-motor symptoms is warranted to better understand heterogeneity in PD and to generalize
research findings.
Objective:
This project aimed to determine whether, within a consecutive series of PD studies performed within a single center in the
Netherlands (1) the proportion of included
females, mean age and proportion of native Dutch people changed over
time; and 2)
reports of the
ethnicity of participants and the proportion of studies with non-motor outcomes changed over
time.
Methods:
Characteristics of participants and non-motor outcomes were analyzed using a unique
dataset of summary
statistics of studies with a large number of participants conducted at a single center during a 19-year period (2003-2021).
Results:
Results indicate no relationship between calendar
time and proportion of
females (mean 39 %), mean age (66 years), proportion of studies that reported
ethnicity, and proportion of native Dutch people in studies (range 97-100 %). The proportion of participants in whom non-motor symptoms were assessed increased, but this difference was consistent with chance.
Conclusion:
Study participants in this center reflect the PD
population in the
Netherlands in terms of
sex, but older individuals and non-native Dutch individuals are under-represented. We have still a lot to do in ensuring adequate representation and diversity in PD
patients within our
research.
