Cohort profile: The Australian Parkinson’s Genetics Study (APGS) - pilot (N = 1,532)

Abstract Purpose Parkinson’s disease (PD) is a neurodegenerative disorder associated with progressive disability. While the precise aetiology is unknown, there is evidence of significant genetic and environmental influences on individual risk. The Australian Parkinson’s Genetics Study (APGS) seeks to study genetic and patient-reported data from a large cohort of individuals with PD in Australia to understand the sociodemographic, genetic, and environmental basis of PD susceptibility, symptoms and progression. Participants In the pilot phase reported here, 1,819 participants were recruited through assisted mailouts facilitated by Services Australia based on having three or more prescriptions for anti-PD medications in their Pharmaceutical Benefits Scheme (PBS) records. The average age at the time of the questionnaire was 64 ± 6 years. We collected patient-reported PD information and socio-demographic variables via an online (93% of the cohort) or paper-based (7%) questionnaire. One thousand five hundred thirty-two participants (84.2%) met all inclusion criteria and 1,499 provided a DNA sample via traditional post. Findings to date 65% of participants were male, and 92% identified as being of European descent. A previous traumatic brain injury was reported by 16% of participants and was correlated with a younger age of symptom onset. At the time of the questionnaire, constipation (36% of participants), depression (34%), anxiety (17%), melanoma (16%) and diabetes (10%) were the most commonly reported comorbid conditions. Future plans We plan to recruit sex- and age-matched unaffected controls, genotype all participants, and collect non-motor symptoms and cognitive function data. Future work will explore the role of genetic and environmental factors in the aetiology of PD susceptibility, onset, symptoms and progression, including as part of international PD research consortia. Article summary Strengths and limitations of this study We showed that recruiting Australian participants for PD research through the PBS database is a feasible and highly efficient method that enables us to reach people all over Australia who have been prescribed medications used to treat Parkinson’s symptoms. The Australian Parkinson’s Genetics Study (APGS) is the most extensive nationwide genetic and epidemiological study of Parkinson’s disease (PD) in Australia. It will serve as a platform for advancing PD research in the country. The pilot study questionnaire covered patient-reported outcomes and variables relevant to disease onset, diagnosis, symptoms, medical comorbidities and family history. Information on environmental exposures, lifestyle factors, ethnicity and socio-demographic variables were also included. A significant limitation is that with a 9% response rate, the sample may be prone to self-selection bias. For instance, patient characteristics reflect a younger group of patients with a younger age of onset and higher educational attainment than expected for the larger population of individuals with PD in Australia. Future recruitment efforts will investigate the extent of those biases by recruiting via movement disorders clinics, patient support groups and a public communications campaign.