Loneliness can be twice as unhealthy as obesity, according to researchers who found that feelings of isolation can have a devastating impact on the elderly.
The scientists tracked more than 2,000 people aged 50 and over and found that the loneliest were nearly twice as likely to die during the six-year study than the least lonely.
Compared with the average person in the study, those who reported being lonely had a 14 per cent greater risk of dying.
The figure means that loneliness has around twice the impact on an early death as obesity. Poverty increased the risk of an early death by 19 per cent.
The findings point to a coming crisis in Britain as the population there ages and people increasingly live alone or far from their families.
A major study of loneliness in older Britons in 2012 found that more than one-fifth felt lonely all the time, and a quarter became more lonely over five years. Half of those who took part in the survey said their loneliness was worse at weekends.
Previous studies have linked loneliness to a range of health problems, from high blood pressure and a weakened immune system to a greater risk of depression, heart attack and strokes.
In his recent book, Loneliness, John Cacioppo, a psychologist at the University of Chicago, says that the pain of loneliness is akin to physical pain.
Cacioppo said the world was experiencing a "silver tsunami" as baby boomers reached retirement age.
"People have to think about how to protect themselves from depression, low subjective well-being and early mortality."
Cacioppo added that people approaching retirement age should think twice about pulling up their roots and heading to new pastures to live.
"We have mythic notions of retirement. We think that retirement means leaving friends and family and buying a place down in Florida where it is warm and living happily ever after. But that's probably not the best idea."