A general interest article on supercentenarians from the Sacramento Bee: "Avice Nelson Clarke paused in her recollections of her long-ago childhood in England to make a remarkable understatement. 'I've seen lots of life already,' she said. At 111, with memories spanning the horse-and-buggy age, the Space Age and the digital age, she is on the outside edge of the nation's trend toward increasing longevity. The oldest old - supercentenarians, as aging experts refer to them - remain rare: Clarke is one of four Sacramento-region residents who reported their ages as 110 or older in the 2010 U.S. census. ... The census recorded a total of 46 Californians in the supercentenarian category. Another 27 people in the Sacramento region reported their ages as 105 to 109, census figures show. While the number of centenarians has boomed in recent decades 96,000 across the country in 2010, according to the Social Security Administration, up from 37,000 only 20 years ago the nation's population of people 110 and older has remained fairly stable. ... The world's verified oldest person ever, Jeanne Calment, died in France in 1997, age 122 years and 164 days. ... Despite the world's aging population, no one's come close to that since then. That speaks to the limits of the human life span. ... Through blood tests and gene sequencing of the oldest old, scientists want to discover the secret of their extraordinary longevity ... How have they managed to live so long? We think their longevity is inherited. They have virtually nothing else in common. Some are smokers, and some never smoked. Some are drinkers, and some never drank. They don't have the same diets. But they have long-lived parents and siblings. It must be in the DNA. ... The key age is the early 80s for men and 90 for women. If you can get to that age without dementia or major heart disease or stroke, it's the idea of getting over the hump into healthy aging. ... Even so, 40 percent of the oldest old [survive] illnesses that prove fatal to others. ... Maybe they have some kind of functional reserve. The people who live the longest seem better able to deal with illness. They have a propensity to remain independent much longer than the rest of us."