The results of one of the largest studies ever conducted on loneliness and its health impacts have been published in the scientific journal Nature Mental Health. The lack of social relationships is associated with an increased risk of developing cognitive impairment and a higher chance of getting Alzheimer’s. This has received more attention in the wake of the Covid emergency.
Loneliness, especially later in life, is a risk factor for developing cognitive impairment and dementias. The association between social isolation and certain neurodegenerative diseases isn’t new, but one of the largest studies on the subject now brings further confirmation, providing a better description of its characteristics.
Neurologists and epidemiologists at the University of Florida (United States), led by Italian researcher Martina Luchetti, analysed 21 studies published over recent years (involving around 600,000 people). They investigated the specific role played by social isolation in the onset of cognitive impairment and dementias.
After introducing a number of corrective elements for other possible risk factors like depression, the US researchers published the results of their research in the scientific journal Nature Mental Health.
They found that prolonged loneliness increases the risk of cognitive impairment by 31% in both sexes, regardless of how old the person is when they start to feel lonely. So, people who live alone or have few social relationships for very long periods – years or decades – are much more likely to develop a form of dementia, including Alzheimer's in the most severe of cases, than those with a family to rely on, or even just an efficient and active social support network.
The harm caused by the absence of social relationships builds up over time
“These results are not surprising, given the mounting evidence that links loneliness to poor health,” explained Professor Luchetti. “The neuropathological changes that lead to dementia start decades before clinical onset. And loneliness – the dissatisfaction with social relationships – may impact significantly on how you are functioning cognitively.”
The research by the University of Florida’s team was spurred by the World Health Organization (WHO) and the US authorities (the Surgeon General, to be precise), which declared loneliness a public health crisis in the wake of the Covid-19 pandemic and the related social restrictions. “There has been a lot of interest in the consequences of loneliness for health,” confirmed Martina Luchetti. She added that it is now very “important to understand why and under what circumstances it increases risk for late life dementia.”
Causes of dementia
The percentage (+ 31%) identified by the US researchers is far higher than the one previously indicated by one of the most risk-factor-focused commissions (the commission set up by the journal The Lancet and dedicated specifically to Alzheimer’s dementia). The commission had identified 14 elements that together trigger 50% of dementia cases (such as hypertension, smoking, obesity, depression, hearing loss, physical inactivity, diabetes, and excessive alcohol consumption), and had reported loneliness as playing a smaller role. But these differences are probably due to the different aims of the studies, as the Lancet one is much more focused on Alzheimer’s.
In any case, the conclusions drawn by the researchers are the same: we need to tackle loneliness using every tool we have, including through dedicated public investment aimed at building more facilities that may be used as hubs for socialising with others.
