They said a study of the GP health records of more than a million east Londoners indicated a link, in addition to the well-known symptom of tremor.
The research, in JAMA Neurology, examined the healthcare records of people who lived in east London between 1990 and 2018 – the most diverse study to explore early symptoms and risk factors for Parkinson’s.
Parkinson’s is a progressive neurological disease that affects about 145,000 people in the UK. It is caused by a loss of nerve cells and limits movement. Drugs can be used to slow its progression.
Researchers from Queen Mary University of London, funded by Barts Charity, discovered that tremor appeared up to 10 years, and memory problems five years, before diagnosis.
Conditions such as hypertension (high blood pressure) and Type 2 diabetes, both more prevalent in Asian communities, were associated with increased odds of developing Parkinson’s, the study found.
Lead study author Dr Cristina Simonet, neurologist and PhD student at QMUL, said: “People from minority ethnic groups and deprived areas have largely been under-represented in Parkinson’s research up till now.
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“Our results uncovered novel risk factors and early symptoms: epilepsy and hearing loss.
“Whilst previous research has hinted at the association, such as epilepsy being more prevalent in Parkinson’s patients than in the general population, more research is now needed for us to fully understand the relationship.
“It’s important that primary care practitioners are aware of these links and understand how early the symptoms of Parkinson’s can appear.”
Dr Alastair Noyce, reader in neurology and neuroepidemiology at QMUL, said: “If we’re able to diagnose Parkinson’s earlier, we have a real opportunity to intervene early and offer treatments that could improve quality of life for patients.”
“This study confirms that many of the symptoms and early features of Parkinson’s can occur long before a diagnosis.”
The researchers are aiming to recruit 10,000 people aged 60 to 80 to take part in online tests to identify those at high risk of developing Parkinson’s.
The PREDICT-PD project, funded by Parkinson’s UK, wants people from all backgrounds who do not have Parkinson’s to take part in a simple set of online tests that screen for factors linked to increased risk of the condition.
Dr Noyce said: “Through our ongoing PREDICT-PD research, we’re hoping to identify people at high risk of Parkinson’s even before obvious symptoms appear – which means that we could do more than just improve quality of life for patients, and perhaps be in the position to slow down or cure Parkinson’s in the future.”