According to a study presented in Dublin on Saturday, feeling lonely is a strong predictor of premature death.
The team of Danish researchers found that loneliness was linked to a doubled mortality risk in women and nearly double in men.
"Loneliness is more common today than ever before, and more people live alone," said lead author Anne Vinggaard Christensen, PhD student at Copenhagen University Hospital in Denmark.
"Previous research has shown that loneliness and social isolation are linked with coronary heart disease and stroke, but this has not been investigated in patients with different types of cardiovascular disease."
The study also revealed that people who felt lonely were three times as likely to report symptoms of of anxiety and depression - this was true for both men and women.
These people also reported a much lower quality of life in general.
The study was presented at EuroHeart 2018, the European Society of Cardiology's annual nursing conference.
It involved data from 13,463 patients who had either ischaemic heart disease, arrhythmia (abnormal heart rhythm), heart failure or heart valve disease.
The quality of their social network was rated via linking data from national registers with the results from the DenHeart survey, which was given to all patients discharged from five heart centres in Denmark between April 2013 and April 2014.
In the survey, patients were asked to answer questions regarding their physical and mental health in addition to stating their levels of social support.
Measures of loneliness were examined via two questions: "Do you have someone to talk to when you need it?" and "Do you feel alone sometimes even though you want to be with someone?".
Vinggaard Christensen added that it was crucial to gather data on patients who lived alone and those who did not because living alone may not always lead to loneliness and neither does living with others necessarily immunise you from social isolation.
"Loneliness is a strong predictor of premature death, worse mental health, and lower quality of life in patients with cardiovascular disease, and a much stronger predictor than living alone, in both men and women," she said.
"We live in a time when loneliness is more present and health providers should take this into account when assessing risk. Our study shows that asking two questions about social support provides a lot of information about the likelihood of having poor health outcomes."
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