An international study has found that children of parents who live to an older-than-average age are more likely to live longer themselves, as well as 24 percent less likely to develop cancer.

The study was conducted by researchers at the University of Exeter, University of Michigan, University of Iowa, and the National Institute for Health and Medical Research in France. It was carried out in preparation for a much larger study, which will analyze factors explaining why some people seem to age more slowly than others.

The researchers analyzed data from interviews of over 9,764 people who took part in the Health and Retirement study, based in the U.S. The study interviewed people every two years from 1992 to 2010, including questions about the age of their parents when they died. Most participants were over 70 years old by the end of the study.

They defined long-lived mothers and long-lived fathers as parents who survived past 91 years and 87 years old respectively. Average-aged mothers and average-aged fathers were considered parents who reached an age of 77 to 91 years and 65 to 87 years, respectively. Participants whose mothers died before 61 and whose fathers who died before 46 were not analyzed in the study.

They found that mortality rates dropped by as much as 19 percent for every decade that at least one of the parents lived past 65 years old. For mothers who lived past 85, mortality rates were 40 percent lower. The reduction in mortality rates of children for long-lived fathers, however, were much lower, at 14 percent. Researchers hypothesized that adverse lifestyle factors more common in fathers, such as smoking, could have accounted for this difference. During the 18 years, there were 938 new cases of cancer.

But, remarkably, chidren of long-lived parents were less likely to be diagnosed with cancer and other diseases associated with old age.

"Previous studies have shown that the children of centenarians tend to live longer with less heart disease, but this is the first robust evidence that the children of longer-lived parents are also less likely to get cancer," said William Henley, professor at the University of Exeter Medical School. "We also found that they are less prone to diabetes or suffering a stroke. These protective effects are passed on from parents who live beyond 65 — far younger than shown in previous studies, which have looked at those over the age of 80."

Henley acknowledged that children of older parents aren't immune to contracting cancer or any other diseases from ageing. He believes that the evidence shows that rates are lower and that the "inherited resistance to age-related diseases gets stronger the older their parents lived."

The team also made adjustments for factors such as sex, race, smoking, wealth, education, body mass index, and childhood socioeconomic status. They also examined the effect on daughters- and sons-in-law of long-lived parents.

"Interestingly, from a nature versus nurture perspective, we found no evidence that these health advantages are passed on from parents-in-law," Ambarish Dutta, a researcher at the Asian Institute of Public Health at the Ravenshaw University in India, said. "Despite being likely to share the same environment and lifestyle in their married lives, spouses had no health benefit from their parents-in-law reaching a ripe old age. If the findings resulted from cultural or lifestyle factors, you might have expected these effects to extend to husbands and wives in at least some cases, but there was no impact whatsoever."

The study was published in the Journals of Gerontology: Series A.

Source: Dutta A, Henley W, Robine J.-M., et al. Longer Lived Parents: Protective Associations With Cancer Incidence and Overall Mortality. The Journals of Gerontology: Series A. May 2013.