LOS ANGELES. — Traveling the country over the years I came to think that the great American malady was a social disease that had nothing to do with blood pressure, doctors or such. The disease was ''aloneness,'' the flip side of all the things that make American life unique: freedom, individualism, mobility.
The ties that bind are not very tight in the United States -- and most of us like it that way most of the time. We raise our children to leave the nest. We expect our old people to take care of themselves, and when they grow older than either they or we ever imagined, we ship them off to one of the less inviting of American innovations, nursing homes.
We are a nomad people, always have been, leaving almost everything behind when we move on -- place, family, job, religion, friends. That is the way we have always been. The Anglo-Saxons who crossed the Atlantic Ocean to get to the East Coast of America, and then the Easterners who went west in wagons never, or almost never, looked back -- or went back. (Some emigrants did go back in large numbers, particularly Italians and Greeks in the 20th century, who made some money here and then headed back to the pleasures of Southern Europe.)
Now, with divorce and drugs and life-extending medical technology separating families as covered wagons once did, there are, according to the 1990 census, more than 22 million Americans living alone. That is about 12 percent of all adults, compared with 7 percent only 10 years ago. And, reports the new issue of the Journal of the American Medical Association, many of those Americans alone are dying of isolation. Being alone, according to the journal, actually is for many a medical condition.
The doctors are not talking about the pain of loneliness, a principal subject of much American literature, drama and music (one of the latest examples is the film ''Grand Canyon''); they are reporting on a life-threatening condition. The report covers studies done by physicians in New York and North Carolina who studied the lives of men and women after heart attacks.
People alone, according to the New York study at Columbia University and St. Luke's-Roosevelt Hospital, are twice as likely to have second heart attacks and to die from them than people living with family or friends. The other study, at Duke University Medical Center, found that unmarried heart-attack patients with no close friends were much more likely to die within five years than similar people with close attachments to family or friends.
I suppose all that is common sense, but it is one thing to guess something and quite another to realize that it is part of a predictable pattern. ''A major independent risk factor,'' was the term of art in the studies. People alone, it seems, literally die of broken hearts. This is apparently as much a part of health as cholesterol, as much a part of modern life in our country as pollution. Many people alone are dying the saddest of deaths in this society that tends more than others to push people away from each other.
''What's particularly significant is the magnitude of the effect,'' said one of the New York researchers, Nan Case, a clinical psychologist. ''We know that emotions and [social] integration have an effect, but we never knew it would come close to the physiological factors in heart disease.''
But this is much more than a physiological problem, something physicians should be worrying about. This goes to a different heart, the heart of the American experience, of the quality of life here at the end of the 20th century. People are living longer, but to what end? What are we doing to ourselves, sentencing each other to live and die alone?
The nature of the times dictates that life in America is going to be quite different a few years or a couple of decades from now. Among the big questions on the American table will be the choice and balance between community and individuals. Is each of us out there on our own, buddy, or are we all in this together?
Few people, I imagine, want to die alone. But, according to our physicians, we are headed for something like that -- or, rather, a mass of ''I's'' and ''you's'' are going to end up all alone.
Richard Reeves is a syndicated columnist.