Background: Parkinson's disease (PD) is a complex neurodegenerative condition with a heterogeneous clinical presentation and multifactorial aetiology involving genetic, environmental, and lifestyle factors. The Australian Parkinson's Genetics Study (APGS) is an ongoing nationwide, population-based initiative established to advance understanding of the determinants and progression of PD. Methods: We present a cross-sectional characterisation of 11,986 participants with self-reported PD recruited across Australia through a combination of assisted mailouts, media outreach, and digital engagement. Participants complete comprehensive questionnaires capturing sociodemographic, clinical, environmental, lifestyle, and behavioural data, and provide saliva samples for genetic analysis. A control cohort is currently being recruited and is therefore not reported here. Results: The cohort is 63% male, with a mean age of 71 years and symptom onset at 64 years. Most participants report being diagnosed by a neurologist (79%), and 25% have a family history of PD. Non-motor symptoms such as depression, anxiety, and sleep disturbances are common, and sex-based differences were observed across clinical features, comorbidities, environmental exposures, and impulsive-compulsive behaviours. Previously reported risk factors were notable in the APGS PD cohort, including pesticide exposure (36%), traumatic brain injury (16%), and employment in high-risk industries (33%). COVID-19 vaccination uptake was near-universal (99%), and most infections were mild. Conclusions: APGS is the largest PD cohort in Australia and represents a rich resource for investigating the sociodemographic, genetic, and environmental underpinnings of PD. Its comprehensive design and ongoing expansion, including digital phenotyping and genomic profiling, position it as a transformative platform to inform risk prediction, biomarker discovery, and therapeutic development for PD.

The authors have declared no competing interest.

APGS is supported by the Shake It Up Australia Foundation and the Michael J. Fox Foundation for Parkinson's Research (MJFF-021952). MER thanks the support from the Rebecca L. Cooper Medical Research Foundation (F20231230). KRK is supported by grants from the Medical Research Future Fund, the Lord Mayor's Charitable Fund, and the Ainsworth 4 Foundation (unrelated to the current study).

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The details of the IRB/oversight body that provided approval or exemption for the research described are given below:

The Australian Parkinson's Genetics Study protocol was approved by the Human Research Ethics Committee of the QIMR Berghofer Medical Research Institute (P3711). All participants provided informed consent, including agreement to be recontacted for future related research, with voluntary participation clearly communicated. Data are securely managed in accordance with the Commonwealth Privacy Act (1988) and the National Health and Medical Research Council (NHMRC) Guidelines.

I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals.

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An anonymised version of the data used in this study may be made available to qualified researchers who submit a collaboration proposal to the APGS investigators, are able to sign an institutional data transfer agreement, and agree to comply with all conditions intended to protect participant privacy and confidentiality.