How your parent's life span determines how long you live.

Although many studies have looked at the family history of disease in relation to the onset of disease, only three major studies have correlated overall longevity trends between parents and their children. The Framingham Study, the "Termite" Study, and the Alameda County Study looked at the age of parental death to determine if it predicted longevity of the offspring. Did the two correlate? Yes, but minimally. Each study showed a minor effect. The Framingham Study, the most comprehensive of the three, found about a 6 percent correlation between life span of the parents and life span of their offspring, meaning that many other factors affect longevity as well. If both your parents lived past the age of seventy-five, the odds that you will live past seventy-five increase to some extent. But to what extent? (Note that we are discussing, for the most part, death related to disease. If a parent dies at age forty in a car accident, for example, that provides little information about how long the child will live, although alcohol-induced accidents are a possible exception.)

If you are a man and both of your parents died before the age of seventy-five, then your RealAge (physiologic age) will be as much as 4.2 years older. If you are a woman, your RealAge will be as much as 3.5 years older. If both parents lived past the age of seventy-five, then your RealAge will be 4.2 years younger if you are man, and 3.5 years younger if you are a woman. If no first-degree relative (parent, brother, sister) had breast, colon, or ovarian cancer diagnosed early, you are an additional 0.2 to eleven years younger than if your siblings or parents had those diagnoses. Some genetic conditions, such as being a carrier of the BRCA-1 breast cancer gene, can make your RealAge as much as 17 years older. This is one of the instances where genetics can make a big difference.

Your parents may largely dictate how long you're going to live. And your mom appears to have most of the control over your "aging gene."

Previous research has linked the length of telomeres -- the tips of chromosomes -- to disease and life span, say researchers. These structures become progressively shorter each time the cell divides, and it is thought that this shortening is one of the critical features of cellular aging and illness. One study showed people with heart disease had shorter telomeres, while other research showed telomere length was a predictor of death.

And while twin studies have indicated that telomere length -- and possibly life span -- is inherited, it's unclear how this is passed from one generation to the next.

So researcher Jan A. Staessen and colleagues sought to determine just where this aging gene might come from. The study is presented in this week's issue of The Lancet. In it they examined DNA from more than 300 parents and offspring of multigenerational families.

They found that sex, age, and smoking were all significant predictors of telomere length. Men have shorter telomeres -- makes sense given their shorter life spans. In addition, telomere length was shorter among smokers. As expected, older people had shorter telomeres.

Moms Hold Most of the Power
But it turns out that dads may not have as much say when it comes to telomere length -- especially when it comes to their sons.

The researchers found a much stronger correlation between the mothers' telomere length and that of the offspring. Dads' telomere length was somewhat predictive of their daughters' life spans.

And since women have two X chromosomes, which are generally longer than those found in men, and men have just one -- to go along with their Y chromosome -- the researchers conclude that this aging gene most likely lives on the X chromosome. This would explain why a mother's telomere length is more predictive of life span.

Pregnancy and Epilepsy-Related Information
To help support this idea, the researchers point to a condition called dyskeratosis congenita, which is due to a mutation on the X chromosome. People with this condition have unstable telomeres and develop diseases at an early age that are normally associated with aging. In addition, they generally suffer premature death.

As to why men -- and smokers -- have shorter telomeres, the researchers suggest that it may be due to a decreased ability to handle damaging by-products in the body. They say that women produce fewer of these "reactive oxygen species" and might be able to metabolize them better. And likewise, the shorter telomere lengths seen in smokers may result from higher amounts of these by-products.

Though further research is needed, Staessen says that the process of aging -- and life span -- may be determined by your mother's X chromosome.

Also CNN gave the following report on how your parent's life span determines how long you live:

 Your parents may have a significant influence on how likely you are to stay healthy later in life.Scientists have long suspected that the lifespan of parents holds clues to how long their own children will live, and now a new study reveals that parents' longevity is linked to their offspring's heart health, too.

 So, long-lived parents may reduce the risk of morbidity and mortality in their kids, according to the study, which was published in the Journal of the American College of Cardiology on Monday.

 "This research is important, as it shows that knowing the age at which your parents died provides information on your own risk of death and disease," said Janice Atkins, a research fellow at the University of Exeter's Medical School in England and lead author of the study.

 "Although people with longer-lived parents are more likely to live longer themselves, there are lots of ways for those with shorter-lived parents to improve their health," she added. "Current public health advice about being physically active, such as going for regular walks, eating well and not smoking are very relevant, and people can really take their health into their own hands."

Parents, longevity linked

The study involved 186,151 non-adopted adults, between 55 and 73 years old, with deceased parents. The researchers analyzed health data on each participant using the UK Biobank, a health resource that collects long-term health information on volunteers.

The data were collected over eight years, and the researchers plotted the relationships between the participants' health and their parents' ages of death.

 It turned out that there was an inverse relationship between the age of a parent's death and the longevity of his or her offspring. When the parents reached about age 70 and older, their offspring's risk of death dropped by about 17%, compared with their counterparts, and continued to fall the longer the parents lived.

 "The risk of death was 17% lower for each decade that at least one parent lived beyond the age of 70 years," Atkins said.

Additionally, participants with longer-lived parents had overall lower incidences of heart disease, heart failure, stroke, hypertension, anemia, high cholesterol and atrial fibrillation compared with their counterparts.

"However, it is important to note that these results are group-level effects, therefore general tendencies, which do not directly apply to individuals," Atkins said. "If people are exposed to the big health risk factors, this will be more important to health than the age at which their parents died."

Such big health risk factors could include smoking, for instance. Atkins added that these findings should also be applicable to people in the United States.

 The Centers for Disease Control and Prevention encourages American adults to document the health history of their family members, as family history is an important risk factor for common chronic diseases such as cancer, heart disease and diabetes.

"The relationship between parental age at death and survival and health in their offspring is complex, with many factors playing a role," Atkins said.

"The association is partly due to the inheritance of genetic risk factors for blood pressure and cholesterol level, among others," she said. "Shared environment and lifestyle choices also play a large role, including diet and smoking habits."

Genetic, environmental or behavioral?

The findings add to growing evidence that there are probably genetic, environmental and behavioral factors "passed down" from parents to children that influence longevity, said Dr. Kenneth Langa, professor of medicine at the University of Michigan, who was not involved in the new study.

 "The relationships between parental longevity and the health of kids are likely quite complicated and overlapping. I don't think that it is 'all genetics,' although it is likely that genetic relationships are certainly part of the story," Langa said.

"The study showed that children of long-lived parents had higher levels of education, income [and] physical activity and lower prevalence of smoking and obesity, suggesting that in addition to genetic links between the generations, there are likely behavioral links resulting from the home, and more general environment, in which one is raised," he added.