The long-term health effects of broken families can often be devastating for children’s health, according to a new book on how long people in the US live.

‘The Longevity Project’, which looks at the secret of long life, says that parental divorce during childhood is the single strongest predictor of early death in adulthood.

The findings tally with a range of studies which show that divorce is linked to a higher likelihood of poor physical and mental health.

A survey, carried out by London law firm Mishcon de Reya in 2009, found that nearly 10 percent of children from broken families say that the process has left them suicidal, while other children involved in the process said they later sought solace in drink, drugs or crime.

And a 2009 major study by researchers from the University of Chicago and Johns Hopkins University showed that the divorced or widowed have 20 per cent more chronic health conditions such as heart disease, diabetes or cancer than married people.

They also have 23 per cent more mobility problems including trouble climbing stairs or walking short distances.

Furthermore, those who have remarried still have 12 per cent more chronic conditions and 19 per cent more mobility problems than those who have been continuously married.

According to this latest study, grown children of divorced parents died almost five years earlier, on average, than children from intact families.

The causes of death ranged from accidents and violence to cancer, heart attack and stroke. Parental break-ups remain, the authors say, among the most traumatic and harmful events for children.

The authors Howard S. Friedman and Leslie R. Martin, looked at eight decades worth of research in the course of writing the book.

The book is the culmination of a study launched in 1921 by Stanford University psychologist Lewis Terman, who asked San Francisco teachers to pick out their brightest students—most were about 10 years old—to help him try to identify early glimmers of high potential.

His interviews were so detailed that the results could be used as a basis for studying the respondents’ lives in follow-up interviews across the years. Terman himself died in 1956, just shy of 80; after his death his work was picked up by others, with Mr. Friedman and Ms. Martin launching their portion of the project in 1990.

Having a high IQ didn’t seem to play a direct role in longevity. Neither did going on to an advanced degree. According to the authors suggest that persistence and the ability to navigate life’s challenges were better predictors of longevity.

The early death of a parent had no measurable effect on children’s life spans or mortality risk, according to the research.