A centenarian is a person who has reached the age of 100 years. Because life expectancies worldwide are below 100, the term is invariably associated with longevity. The United Nations estimated that there were 316,600 living centenarians worldwide in 2012,[1] and 573,000 in 2020, almost quadruple the 2000 estimate of 151,000.[2]
As world population and life expectancy continue to increase, the number of centenarians is expected to increase substantially in the 21st century.[3] According to the Office of National Statistics in the United Kingdom, one-third of babies born in the country in 2013 are expected to live to 100.[4]
According to a 1998 United Nations demographic survey, Japan is expected to have 272,000 centenarians by 2050;[5] other sources suggest that the number could be closer to 1 million.[6] The incidence of centenarians in Japan was one per 3,522 people in 2008.[7]
In Japan, the number of centenarians is highly skewed towards females. Japan in fiscal year 2016 had 57,525 female centenarians, while there were 8,167 males, a ratio of 7:1. The increase of centenarians was even more skewed at 11.6:1.[8]