Loneliness may increase the risk of heart disease among post-menopausal women, research suggests.
The health implications of being socially isolated are increasingly coming to light.
Heart disease was once mistakenly considered a predominantly male affliction, however, 3.6 million females live with the condition in the UK alone – not far behind the 4 million men.
Prior to the menopause, oestrogen is thought to help keep a woman's blood vessels flexible, which could ward off heart attacks and strokes. With this hormone declining as a woman experiences "the change", her heart disease risk may then rise.
To better understand the relationship between heart disease and loneliness, scientists from the University of California San Diego analysed nearly 60,000 women – aged 73 to 85 – with no history of cardiovascular complications.
Up to four years later, those who were deemed to have had "high levels" of loneliness and social isolation were 29% more likely to have endured a heart attack, stroke or cardiovascular-related death.
This effect was reduced after the scientists accounted for the women's lifestyles, like their smoking status, activity levels and diet.
Loneliness may therefore discourage post-menopausal women from leading a healthy lifestyle, which could be particularly problematic considering the various coronavirus restrictions that have been introduced around the world.
The results were presented at the American Heart Association's (AHA) Epidemiology, Prevention, Lifestyle & Cardiometabolic Health conference and are yet to appear in a peer-reviewed journal.
"Cardiovascular disease is the leading cause of death in women in the US," said lead author Dr Natalie Golaszewski.
"We are learning factors currently not identified in standard care, such as social isolation and loneliness, can impact women’s risk of cardiovascular disease.
"We are social beings. In this time of COVID-19 [the disease caused by the coronavirus], so many people are experiencing social isolation and loneliness, which may spiral into chronic states of social isolation and loneliness.
"It is important to further understand the acute and long-term effects these experiences have on cardiovascular health and overall wellbeing."
Loneliness has long been linked to poor mental health, however, social isolation may also have physical consequences.
In 2010, scientists from Brigham Young University in Utah found people with "adequate social relationships" were 50% more likely to survive over the next seven years than those with "poor or insufficient social relationships" – putting loneliness on par with smoking, and even exceeding obesity and physical inactivity in terms of risk.
More recently, a team from the University of Eastern Finland reported lonely men may have a 10% higher chance of developing cancer.
To better understand how loneliness affects post-menopausal females, the San Diego scientists analysed participants of the Women's Health Initiative Observational Study.
Between 2011 and 2015, the women self-reported their social activities, living and marital status, degree of loneliness and amount of social support.
Loneliness was also assessed via a scale that takes into account an individual's relationship status, living circumstances and social activities – like how often they see friends, eat out or attend events.
Over the next four years, 1,599 heart attacks, strokes or related deaths occurred among the women.
These were 16% higher in those who experienced high levels of social isolation, which can be "quantifiably measured" via the number of interactions a person has within their relationships.
Loneliness – a "perceived" feeling of being isolated, lacking companionship and being left out – was found to raise the risk by 11%.
When social isolation and loneliness were combined, the odds went up by 29%.
Watch: Conquering social isolation in a lonely world
The risk reduced, however, after adjusting for the women's lifestyles.
"People who experience social isolation or loneliness tend to withdraw and don't engage often in healthy behaviours, which may become a cyclical pattern," said Dr Golaszewski.
"Over time, the unhealthy behaviours coupled with social isolation and feeling lonely put them at an increased risk for cardiovascular disease."
The scientists hope future research will address how a woman's needs can be met when it comes to social connections, particularly if she is mourning the loss of a loved one.
"Our results suggest measures of social isolation and loneliness, even with brief questions, should be incorporated into standard care," added Dr Golaszewski.
"We monitor our patients' blood pressure, weight and temperature. It might also be beneficial to capture the social needs women may be lacking to better understand cardiovascular risk and develop solutions."
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