According to the World Health Organization, around 25% of people globally aged 60 and over are affected by social isolation and loneliness, deemed “key risk factors for mental health conditions in later life”. These factors are also now being attributed to declines in physical health, according to the findings of a new study by researchers at the Harvard T H Chan School of Public Health.
To reach these conclusions, the researchers used data from the 2006-2018 Health and Retirement Study, involving 12,161 participants aged 50 and over who had never had a stroke.
From 2006-2008, they answered questions on a certified loneliness scale, enabling the scientists to establish precise scores for this risk factor. Four years later, from 2010-2012, 8,936 of the original participants answered the same questions again.
They were then classified into four distinct groups according to their level of loneliness and its evolution over time: “consistently low”, “remitting”, “recent onset”, and “consistently high”.
The experts point out that 1,237 strokes occurred among participants whose loneliness was assessed only at the start of the study, while 601 strokes occurred among participants whose loneliness was assessed twice.
Importantly, they also point out that stroke risk was analysed according to each participant’s experience of loneliness, effectively excluding other risk factors such as depressive symptoms.
Published in the journal eClinicalMedicine, the research shows an association between loneliness and an increased risk of stroke, with chronic loneliness further increasing this risk.
Among those who were only assessed at the start of the study, the risk of stroke was 25% higher in participants who were considered to be lonely than in those who were not. For those who filled out the questionnaire twice, the group with “consistently high” loneliness had a 56% higher risk of stroke than the “consistently low” group.
“Loneliness is increasingly considered a major public health issue. Especially when experienced chronically, our findings suggest that loneliness may play an important role in stroke incidence, which is already one of the leading causes of long-term disability and mortality worldwide,” study lead author Yenee Soh said.
The researchers point out, however, that this association was not significant for participants who experienced loneliness more recently, leading them to believe that its impact on stroke risk occurs over the long term.