New data reveals striking sex differences and widespread non-motor burden.
Australia’s largest-ever study of people living with Parkinson’s disease is offering new insight into how the condition develops and presents, revealing marked sex differences, a heavy burden of non-motor symptoms and widespread exposure to environmental risk factors.
Researchers analysing baseline data from the Australian Parkinson’s Genetics Study have characterised 10,929 Australians with self-reported Parkinson’s disease, making it the largest active Parkinson’s cohort globally.
Their findings, published in The Lancet Regional Health Western Pacific, provide a detailed snapshot of clinical features, lifestyle factors and comorbidities in people with the disease and are expected to inform future genetic research, biomarker discovery and precision approaches to care.
“This study strengthens the evidence base for understanding PD within the Australian and broader Asia–Pacific context, where demographic, environmental, and healthcare system differences may shape disease risk, presentation, and progression,” the researchers wrote.
“By integrating comprehensive self-reported phenotypes with ongoing genomic profiling, the APGS cohort is uniquely positioned to support prevention strategy, biomarker discovery, and precision medicine both regionally and globally.
“Our findings reinforce the need for greater clinical attention to non-motor symptoms and sex-related variations in PD management. More broadly, establishing inclusive and scalable data collection frameworks is essential to advance research, enhance clinical care, and guide public health planning for PD.”
The APGS is an ongoing nationwide, population-based initiative established to advance understanding of PD determinants and progression.
Participants in the latest study had a mean age of 71 years, with symptoms beginning at an average age of 64 years.
Nearly four in five reported receiving their diagnosis from a neurologist, while one in four said they had a family history of Parkinson’s disease, reinforcing the importance of genetic susceptibility alongside environmental exposures.
The data highlight how far Parkinson’s extends beyond motor symptoms.
Sleep disturbances were reported by almost all participants, while cognitive changes, depression and other neuropsychiatric symptoms were also common.
Pain, orthostatic symptoms and falls were frequently reported, underscoring the complex, multisystem nature of the disease that clinicians must manage alongside classical motor features such as tremor, rigidity and bradykinesia.
Environmental and lifestyle risk factors were also prominent.
More than one third of participants reported exposure to pesticides or herbicides, and one in three had worked in occupations considered high risk for toxic exposures, including agriculture, petrochemical industries and metal processing.
Sixteen per cent reported a history of major traumatic brain injury, often involving loss of consciousness. These findings add to evidence suggesting environmental toxicants and head trauma may contribute to Parkinson’s risk or earlier disease onset.
Sex differences emerged across several domains of the disease. Women were more likely to report unilateral symptom onset, falls and pain, while men more frequently reported memory changes and had higher exposure to environmental risk factors such as pesticides and hazardous occupations.
Men were also more likely to report impulse-control behaviours, particularly those related to sexual behaviour, which can occur as a complication of dopaminergic therapy.
Comorbidity was widespread across the cohort. Participants frequently reported conditions affecting neurological, cardiovascular, gastrointestinal and musculoskeletal systems, including hypertension, constipation, osteoarthritis and vision problems. Mental health conditions were also common, with depression affecting nearly one third of participants and anxiety reported by around one in five.
Sleep disorders were particularly prevalent, with conditions such as restless legs syndrome, sleep apnoea and REM sleep behaviour disorder reported by a substantial proportion of patients. Some of these disorders are known to precede motor symptoms and may represent early markers of neurodegeneration.
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The researchers said the scale of the cohort was a key strength of the study. The APGS was established to better understand how genetic susceptibility interacts with environmental exposures to shape disease risk, symptom profiles and progression.
Participants were recruited nationwide through government-assisted mail-outs, media outreach and digital campaigns, demonstrating that large-scale remote enrolment in neurological research is feasible.
The study forms part of a global effort to unravel the complex causes of Parkinson’s disease, which affects more than 10 million people worldwide and over 150,000 Australians.
Current treatments, including levodopa therapy and deep brain stimulation, help control symptoms but do not halt the underlying neurodegeneration.
By combining detailed clinical and lifestyle data with ongoing genomic profiling, researchers hope the cohort will help identify new biological pathways involved in Parkinson’s disease and accelerate the search for disease-modifying therapies.
The data may also help clinicians better recognise sex-specific patterns of disease and manage the significant non-motor symptom burden that many patients experience.
The researchers said the findings reinforced the need for clinicians to look beyond motor symptoms when assessing and treating Parkinson’s disease, particularly given the high prevalence of sleep disorders, psychiatric conditions and other systemic comorbidities in the population.
The study is ongoing, with recruitment of a control cohort underway and plans to incorporate digital monitoring tools such as wearable devices and smartphone-based assessments.
The researchers said they hoped the expanding dataset would support improved risk prediction, earlier diagnosis and more personalised treatment strategies for people living with Parkinson’s disease.
They noted their study has several limitations, including the modest response rate (∼10,000 of 186,000 invitations), which may have introduced self-selection bias, and restricting analyses to non-missing observations could bias a small number of variables if data were not missing completely at random.
Secondly, while the remote design enabled national reach, “it may compromise data accuracy and limit the depth of clinical phenotyping,” they wrote.
“Future study phases will incorporate digital biomarkers from smartphones and wearables, alongside electronic patient-reported outcomes, to support objective, longitudinal, and patient-centred data collection.
“Third, the cohort is predominantly of European ancestry, which may limit the generalisability of findings to more diverse populations.
“Lastly, the findings are limited by the study’s descriptive nature and absence of an age- and sex-matched control group, with recruitment still underway.”
Despite this, as the largest active PD cohort, the APGS offered an “unprecedented opportunity to uncover the sociodemographic, genetic, and environmental drivers of disease susceptibility, presentation, and progression” the researchers said.
“Here, we provided a comprehensive profile of the PD cohort, forming a critical foundation for transformative research,” they concluded.
“By contributing to national and global efforts, APGS is poised to expedite the discovery of novel biomarkers and therapeutic targets, ultimately accelerating the development of strategies to prevent, slow, or modify the course of PD.”
National advocacy and patient group Parkinson’s Australia is currently seeking input to a national survey from Australians living with PD and their unpaid carers, including friends, family, spouses and partners who provide daily support. The survey closes on 10 March and can be accessed here.
