Once the harmonica player had hung up, a call came in from an 88-year-old man with an avalanche of memories to share: dogs he had owned, boats he had captained, London during the blitz. Tracey, a former nurse, listened patiently for 30 minutes.  “It can be really fascinating when people talk about things like London during the bombing,” she said after the call ended. “It’s important to remember the rich lives people have led.”  Silver Line workers leave it up to the caller to mention whether they are feeling lonely. Still, the advisers are trained to listen for signs of unhappy isolation, and gently lead the conversation accordingly, perhaps offering to link the caller to a Silver Line Friend, a volunteer who makes weekly phone calls or writes letters to those who request it.  Sophie Andrews, chief executive of The Silver Line, said she was surprised by the explosion of calls shortly after the service began operating nearly three years ago. The Blackpool call center now receives some 1,500 calls a day.  Ms. Andrews said she was most concerned not about those who called The Silver Line, but those who were too depressed by their isolation to pick up the phone. “We need to raise awareness with the people who are the hardest to reach,” she said.  Professor Cacioppo lauds efforts like The Silver Line, yet he warns that the problem of loneliness is nuanced and the solutions not as obvious as they might seem. That is, a call-in line can help reduce feelings of loneliness temporarily, but is not likely to reduce levels of chronic loneliness.  In his research, Professor Cacioppo has shown that loneliness affects several key bodily functions, at least in part through overstimulation of the body’s stress response. Chronic loneliness, his work has shown, is associated with increased levels of cortisol, a major stress hormone, as well as higher vascular resistance, which can raise blood pressure and decrease blood flow to vital organs.  Professor Cacioppo’s research has also shown that the danger signals activated in the brain by loneliness affect the production of white blood cells; this can impair the immune system’s ability to fight infections.  It is only in the past several years that loneliness has been examined through a medical, rather than psychological or sociological, lens. Dr. Perissinotto, the University of California, San Francisco geriatrician, decided to study loneliness when she began to sense there were factors affecting her patients’ health that she was failing to capture.  Using data from a large national survey of older adults, in 2012 Dr. Perissinotto analyzed the relationship between self-reported loneliness and health outcomes in people older than 60. Of 1,604 participants in the study, 43 percent reported feelings of loneliness, and these individuals had significantly higher rates of declining mobility, difficulty in performing routine daily activities, and death during six years of follow-up. The association of loneliness with mortality remained significant even after adjusting for age, economic status, depression and other common health problems.  Dr. Perissinotto is also interested in examining the link between loneliness and suicidal thoughts, as there has been little research in that area. She hopes to study The Friendship Line, a 24-hour, toll-free, loneliness call-in line run by the Institute on Aging in San Francisco that is also a suicide prevention hotline.  Although plenty of research into loneliness takes place in the United States, Britain remains well ahead in addressing the problem.  “In the U.S., there isn’t much recognition in terms of public health initiatives or the average person recognizing that loneliness has to do with health,” said Julianne Holt-Lunstad, a professor of psychology at Brigham Young University, whose studies also link loneliness to deteriorating health.  Age UK, an organization similar to AARP in the United States, oversees an array of programs aimed at decreasing loneliness and coordinates efforts with fire brigades to look for signs of loneliness and isolation in the homes they enter.  Another charity, Open Age, runs some 400 activities each week in Central London — sewing circles, current events discussions, book clubs and exercise and computer classes, held at church halls, sport centers, housing projects — and its employees also visit people in their homes to try to get them out and about.  “We try to work out what it is that’s preventing them from leaving the house,” said Helen Leech, the organization’s director.  Men and women differ greatly in how they grapple with loneliness. Seventy percent of the calls to The Silver Line are from women.  “We have this kind of male pride thing,” said Mike Jenn, 70, a retired charity worker who lives in London. “We say, ‘I can look after myself. I don’t need to talk to anyone,’ and it’s a complete fallacy. Not communicating helps to kill us.”  Mr. Jenn runs a “Men’s Shed” in London’s Camden Town district, which aims to bring older men together in a more familiar and comfortable environment — working side by side in a woodworking shop. The concept began in Australia and has since spread to Britain: There are now more than 300 Men’s Sheds throughout England, Scotland and Ireland.  Keith Pearshouse, 70, a retired school principal, discovered the Men’s Shed near his home after moving to London from Norfolk, England, in 2007 and recognizing he was lonely.  “I was a bit anxious walking into a roomful of people,” said Mr. Pearshouse, chatting amid the din created by a table saw, router and lathe at the Camden Town shed, a 700-square-foot workshop in a local community center. “But I immediately thought, ‘Yeah, this is a place that would work for me.’”  Mr. Pearshouse, who had never worked with wood before he discovered the Men’s Shed, showed a visitor a delicate wooden jar he was finishing. The pieces he produces are gratifying, he said, but not nearly as gratifying as the human connections he has made.  While Mr. Pearshouse is still a long way from sharing every little ache and upset with his friends at the shed, he said his life would now feel much emptier without the shoulder-to-shoulder way of confiding he has come to know. As he spoke, he took the lid off his jar, and it gave a slight pop, signifying a perfect fit.
Social isolation is linked to physical illness and to functional and cognitive decline. Programs to reach out to the elderly are growing, particularly in Britain.