Washington: Women who have babies in their forties and fifties tend to live longer than other women, according to a new study.
The study shows their brothers also live longer, but their wives don't. This suggests the same genes prolong lifespan and female fertility, more than social and environmental factors.
"If women in your family give birth at older ages, you may well have a chance of living longer than you would otherwise," said the study's lead author, Ken R Smith, professor at the University of Utah.
"If you have a female relative who had children after age 45, then there may be some genetic benefit in your family that will enhance your longevity."
The researchers examined high-quality genealogical records from the Utah Population Database.
They also used the University of Montreal's Programme on Demographic History Research.
Specifically, the study involved the records of 11,604 Utah men who were born between 1800 and 1869 and who had at least one sister who lived at least to age 50; and the records of 6,206 Quebec men who lived between 1670 and 1750, and had at least one sister who lived to 50 or older.
The key findings included: Women who had "late fertility", a birth at age 45 or older were 14 percent to 17 percent less likely to die during any year after age 50 than women who did not deliver a child after age 40.
Brothers who had at least three sisters, including at least one sister who gave birth at age 45 or later, were 20 percent to 22 percent less likely to die during any year after age 50 than brothers who had no "late fertile" sisters, said a Utah release.
This indicates what earlier studies did not, namely, the same genes may influence the lifespan of both sexes and women's ability to give birth at older ages.
These findings are slated for publication in the June issue of the Journal of Gerontology: Biological Sciences.