Loneliness and social isolation have been linked to a 30% increase in the risk of having a stroke or coronary artery disease, the two major causes of death and illness in wealthy societies.
In findings which compared the effects of loneliness with recognised risk factors, such as anxiety and a stressful job, researchers said that their analysis backed up public health concerns about the importance of social contacts for health and wellbeing.
Loneliness had already been linked to a compromised immune system, high blood pressure and premature death, but its potential effect on heart disease and stroke risk has remained unclear.
Previous studies involving more than 181,000 adults were scrutinised by the researchers, whose findings have been published online in the journal Heart.
The pooled data showed that loneliness and social isolation was associated with a 29% increased risk of a heart or angina attack and a 32% heightened risk of having a stroke.
The researchers, from the universities of York, Liverpool and Newcastle, stress that their study was observational and that firm conclusions cannot be drawn about cause and effect, as well as pointing out that it wasn’t possible to exclude the potential effect of other unmeasured factors.
However, they state: “Our work suggests that addressing loneliness and social isolation may have an important role in the prevention of two of the leading causes of morbidity in high-income countries.”
They noting that a variety of interventions directed at loneliness and social isolation have already been been developed, ranging from group initiatives such as educational programmes and social activities, to one-to-one approaches including befriending and cognitive-behavioural therapy.
“These have primarily focused on secondary prevention, targeting people identified as isolated or lonely, but their effectiveness is unclear. Evaluative research is needed to investigate their impact on a range of health outcomes,” they add.
Reacting to the study, the British Heart Foundation (BHF) said that while it suggested a physiological link between loneliness and heart health problems, it was not a clear one and much more research was needed to understand if there truly was a relationship between the two.
Christopher Allen, a senior cardiac nurse for the BHF, said: “Social isolation is a serious issue that affects many thousands of people across the UK. We know that loneliness, and having few social contacts, can lead to poor lifestyle habits such as smoking, which can increase your risk of heart disease and stroke.
He added earlier research, which the BHF had funded, had shown an association between social isolation and increased risk of dying.
A linked editorial which is also published in Heart argued for the inclusion of social factors in medical education, individual risk assessment, and in guidelines and policies applied to populations and the delivery of health services.
Its authors, Dr Julianne Holt-Lunstad and Dr Timothy Smith of Brigham Young University, Utah, US, said that one of the greatest challenges would be how to design effective interventions to boost social connections, taking account of technology.
“With such rapid changes in the way people are interacting socially, empirical research is needed to address several important questions,” they write. “Does interacting socially via technology reduce or replace face to face social interaction and/or alter social skills?”