A team of Newcastle researchers has found loneliness in middle age has a strong link with developing dementia later in life.
The University of Newcastle research on 1968 Hunter residents over the age of 55 showed dementia risk almost trebled with persistent feelings of loneliness and doubled with transient loneliness.
The findings, based on data from the decade-long Hunter Community Study, suggested exposure to loneliness before the age of 70 could quadruple the risk of dementia.
"These results suggest that promoting coping strategies for loneliness, especially in persons 70 years and younger, may play a role in preventing dementia," the study concludes.
"Feeling lonely in middle age and young late adulthood appears to be a critical exposure period."
The results, published on Saturday in the International Journal of Geriatric Psychiatry, come as the NSW government launches a parliamentary inquiry into loneliness.
The inquiry will examine the extent, causes and impacts of loneliness; review how other regions address loneliness; help identify those most at risk of social isolation; and identify steps to reduce its impact.
Minister for Mental Health Rose Jackson said loneliness had profound impacts on mental and physical wellbeing.
"With this NSW government inquiry, we aim to delve deeper into loneliness, which has emerged as a significant public health issue following the COVID-19 pandemic," she said.
Dementia is the second leading cause of death in Australia and affects 421,000 Australians.
About one in six Australians experienced loneliness in 2022, and 17 per cent of the Hunter research subjects experienced loneliness when the study began.
Previous studies have linked loneliness with physical changes, including vascular disease, inflammation in the nervous system and neurodegeneration, along with unhealthy behaviours such as drinking, smoking and lack of physical activity.
The chairman of mental health group Groundswell Foundation, Martin Blake, said a growing body of evidence showed the harmful effects of loneliness.
"The impacts of loneliness are equivalent to smoking 15 cigarettes or having six alcoholic drinks per day," he said.
The NSW chief executive officer of Relationships Australia, Elisabeth Shaw, said intimate and family relationships, friends, neighbourhoods, workplaces and interest groups all played a part in making people feel connected with others.
"You can be lonely due to lack of social connections, and you can be surrounded by others and feel deeply lonely," she said.
"The ramifications of loneliness can be life-threatening.
"Loneliness is an experience we all have from time to time.
"When it becomes chronic it can lead to further impoverishment in terms of identity, life experience, confidence, and can even shorten your lifespan."
The University of Newcastle School of Medicine and Public Health study was co-authored by Dr Kay Khaing, Dr Xenia Dolja-Gore, Emeritus Professor Kichu Nair, Emeritus Professor Julie Byles and Laureate Professor John Attia.
