The chances of reaching the ripe old age of 110 are within reach - if you survive the perilous 90s and make it to 105 when death rates level out, according to a study of extremely old Italians led by UC Berkeley and Sapienza University of Rome."Our data tell us that there is no fixed limit to the human lifespan yet in sight," said senior author Kenneth Watcher, a professor of demography and statistics at the University of California, Berkeley. "Very few of us are going to reach those kinds of ages, but the fact that mortality rates are not getting worse forever and ever tells us there may well be more progress to be made improving survival past the ages of 80 to 90. This is a valuable, encouraging discovery."
The findings showed that the chances of survival for the longevity warriors plateaued once they made it past 105, challenging previous research that claims the human lifespan has a final cut-off point. Once you hit 80, your immediate death risk starts to decline, according to the study of 4,000 people by researchers in the US and Italy.
Specifically, the study showed people at age 110 had the same continued chances of survival as those between the ages of 105 and 109: a 50/50 chance of dying within the year and an expected further lifespan of 1.5 years. The world is getting older, with an estimated 100,000 centenarians.
Researchers have long debated whether humans have an upper age limit. If the oldest old tell us how long we could live, then many centenarians could, in principle, get even older.
As human lives into their 80s and 90s, mortality rate surge due to frailty and a higher risk of such ailments as heart disease, dementia, stroke, cancer and pneumonia. "If mortality rates kept rising at the rates they rise from age 40 to age 90, then there would be a strong barrier to progress at extreme ages—great diminishing returns to behavioural change or to new medical advances," Wachter said. "The fact these rates ultimately level out gives hope there's more leeway for those advances."
Some scientists have examined demographic data and concluded that there is a fixed, natural shelf life for our species and that mortality rates keep increasing. The current record for the longest human lifespan was set 21 years ago, when Jeanne Calment, a Frenchwoman, died at the age of 122.
Life expectancy at present is about 75 for most western countries but is already increasing owing to better housing, diet and health care. According to researchers, those who survive do so because of demographic selection and natural selection.