:: By Lydialyle Gibson

Investigations ::

Birthright

It’s not just that centenarians are tougher than everybody else. Turns out they’ve got statistics on their side. According to a study by Leonid A. Gavrilov, PhD’98, and wife Natalia S. Gavrilova, SM’04, both researchers on aging at Chicago’s National Opinion Research Center, people raised on farms out West are more likely to live to 100 than urbanites back East. October and November babies might expect to outlast those born between April and June. Up to age 110, men’s mortality outpaces women’s, and the life expectancies of both increase for those born of young parents less likely to have age-damaged sperm and eggs. But the predictor that most struck researchers, who sifted through 75 million U.S. genealogical records to find centenarians born between 1875 and 1899, was birth order. First-born daughters were three times more likely to survive to 100 than their youngest sisters. Twice as many first-born sons reached 100 than boys born fourth or sixth. The odds rebounded, however, for sons born ninth or later. The study posits that younger siblings might suffer from diluted family resources, less parental attention, and their mothers’ “biological depletion.”

Graphic by Allen Carroll