Loneliness can increase the risk of developing Parkinson’s disease by more than a third, a study has found.
Researchers from Florida State University analysed Biobank data from 491,603 British citizens aged 38 to 73 years from between 2006 and 2021.
Individuals who reported being lonely had a 37 per cent higher risk of developing Parkinson's on their 15-year follow up, an association that remained after accounting for demographic factors, socioeconomic status, social isolation and physical health.
Parkinson's is a condition which causes progressive damage to the brain over a number of years. There are more than 10 million people worldwide living with the disease, according to the Parkinson's Foundation.
Symptoms include involuntary shaking, slow movement and muscle stiffness.
Around 7.1 per cent of people (3.38 million) in the UK experienced chronic loneliness in 2022, meaning they feel lonely "often or always", according to the Campaign to End Loneliness. This has risen from 6 per cent in 2020.
Patients who reported loneliness in the study were more likely to be female and more likely to live in a deprived area, researchers said.
However, the overall risk of developing Parkinson's for patients who reported loneliness was the same for men and women.
The study’s authors said that their findings “complemented other evidence that loneliness is a psychosocial determinant of health associated with increased risk of morbidity and mortality”, noting the results of a previous study which found that loneliness led to a 23 per cent increased risk of dementia.
It is the first study to examine the association between loneliness and the risk of Parkinson's, but the researchers warned that the reasons behind the link were complex and need further investigation.
They cited genetic factors and mental health conditions, particularly depression, as reasons for the link.
The researchers wrote: “Given the observed association and the implications of loneliness for a broad range of health outcomes, effective psychosocial interventions to reduce loneliness are needed.
“In addition to the potential for primary prevention, among patients with Parkinson's, addressing loneliness may be associated with reduced risk of dementia and improved quality of life.”
The study was published on Monday in the American scientific journal JAMA.