Lack of social connections can lead to unhealthy lifestyle choices, decreased memory and depression. Apart from the toll it has on mental health, a new study reveals that loneliness might increase the risk of developing Parkinson's disease.

Loneliness, a lack of meaningful social relationships or a sense of belonging, can raise the chances of a Parkinson's diagnosis by 37%, according to the latest study, published in Jama Network.

However, it does not mean that loneliness causes Parkinson's.

"We show that there is an association between loneliness and the development of Parkinson's disease, not that loneliness causes Parkinson's disease," said senior researcher Angelina Sutin, from Florida State University's College of Medicine in Tallahassee.

"This study adds to the body of evidence for the poor outcomes associated with loneliness, particularly neurodegenerative diseases. Loneliness has been associated with Alzheimer's disease and other types of dementia. The present research indicates that it is a risk factor for Parkinson's disease as well," she added.

The researchers studied data from 491,603 adults from the U.K. Biobank, a large health registry of U.K. residents. The participants, who were between 38 and 73, did not have Parkinson's at the start of the study.

They were first assessed from 2006 to 2010 and later followed up until 2021. When the participants were asked to answer "Do you often feel lonely?", 18.51% responded positively to feelings of loneliness.

After an average follow-up of 15.58 years, there were 2,822 cases of Parkinson's diagnosis – 549 of them had reported feeling lonely. Overall, individuals who reported loneliness were 1.37 times more likely to develop Parkinson's.

Although the researchers expected an increased risk of Parkinson's during the first five years of loneliness, the study showed the link in the next 10 years.

Those who received the Parkinson's diagnosis were more likely to be older men, those who smoked and had higher body mass index, diabetes, blood pressure, heart attack or stroke. They were also more prone to anxiety or depression and had a higher polygenetic risk score for Parkinson's, which measures their genetic predisposition to developing the condition.

After adjusting these variables, researchers still found a link between loneliness and Parkinson's, revealing a 25% greater risk among people who reported feelings of loneliness.