Bundled in an aqua-colored sweater and waiting for her morning tea in the Placerville nursing home where she lives, 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, though she's likely the only one to receive a birthday card each year from the queen.
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.
"They really are at the very edge of the human life span," said Dr. Thomas Perls, director of the New England Centenarian Project, which has enrolled 107 supercentenarians in its research.
The world's verified oldest person ever, Jeanne Calmont, 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," said Perls. "That speaks to the limits of the human life span."
Because of concerns about the lack of accuracy of records from more than a century ago, researchers caution that many claims of extreme old age are exaggerated.
UCLA's Gerontology Research Group turns birth certificates and other documents over to teams of researchers to authenticate. The group has verified Avice Clarke's age, along with that of another Northern California supercentenarian named Elsie Rich, 110, who fled Austria in World War II and lives in Santa Rosa.
Through blood tests and gene sequencing of the oldest old, scientists want to discover the secret of their extraordinary longevity, said Dr. Stephen Coles, Gerontology Research Group co-founder.
"How have they managed to live so long?" he said. "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."
Alda Curry lived on her own until well past 100. Now, at 106, she lives in nursing care at Sacramento's Eskaton Greenhaven facility.
"She says she's lived so long because she's a vegetarian and she loves God," said her daughter Ardele Watkins, 82. "I think it's because she's peaceful. She doesn't let anything stress her out. She'll take it to the Lord in prayer."
Curry doesn't hear well any more, but she watches what's going on around her with a bright smile on her face. And she likes to tell people her date of birth.
"July 25, 1905!" she said.
One of her siblings lived to age 99, another to 89 and her mother, Della Mae Cummings, lived to almost 102, Watkins said.
Beyond the common thread of family longevity, researchers know that the typical centenarian is female and the firstborn of a large family, likely to have been raised in the American West, with a birthday in October or November.
But for those born in 1900, life could be quick and brutal. One-quarter of children died before they reached the age of 4. The average life expectancy was 47, compared with 78 now. The great public health advances of the 20th century, which made old age possible, were still far in the future.
Today's oldest old not only lived through the epidemics and disasters of their childhood; they also survived two world wars. And perhaps most significant to scientists, they managed to navigate the chronic diseases of earlier old age.
"The key age is the early 80s for men and 90 for women," Perls said. "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 including Curry, who had breast cancer in her late 60s survive illnesses that prove fatal to others.
"Maybe they have some kind of functional reserve," Perls said. "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."
Avice Clarke, the oldest of five siblings born in a small industrial town near Liverpool, left school at age 12 to work in a cotton mill. At 16, in the thick of World War I, she and her co-workers stood silently in their factory while German zeppelins floated overhead, only to drop their bombs in a nearby canal by mistake.
Her family left England in 1920 and moved to Gilroy, where friends had said they could find work. Clarke met her husband, George Ramos, working in a cannery. The couple divorced in 1948, and Clarke, who never remarried, spent several decades after that working in both California and England.
Her son Norman Ramos is 88 and lives in Camino. Until a year ago, Clarke lived with him.
"When she was 99, she wanted to go to England again," he said. "I drove her to the British Airways terminal in San Francisco. Mom takes the cart for her luggage and says, 'I'll see you.'
"She's independent today, too. I kid you not."
With her morning cup of tea, Gold Country Health Center nurse supervisor Carol Reis brought Clarke her daily medication: a blood pressure pill and a Tums.
"It takes a while to get them down," Clarke said. "Are you going to bring me a couple of biscuits? I think I'm short on biscuits."