New Developments in Biodemography of Aging andLongevity

摘要

Biodemography is a promising scientific approach based on using demographic data and methods for getting insights into biological mechanisms of observed processes. Recently new important developments happened in biodemographic studies of aging and longevity that call into question conventional aging theories and open up new research directions.New studies found that exponential increase of mortality risk with age (the famous Gompertz law) continues even at extreme old ages in humans, rats and mice, thus challenging traditional views about old-age mortality deceleration, mortality leveling-off, and late-life mortality plateaus. This new finding represents a challenge to many aging theories, including the evolutionary theory that explains senescence by declining force of natural selection with age. New ideas are needed to explain why exactly the same exponential pattern of mortality growth is observed not only at reproductive ages, but also at very old post-reproductive ages (up to 106 years), long after the force of natural selection becomes negligible (when there is no room for its further decline).Another important new development is a discovery of long-term ‘memory’ for early-life experiences in longevity determination. Siblings born to young mothers have significantly higher chances to live 100,and this new finding, confirmed by two independent research groups, calls forits explanation. Even the place and season of birth matters for human longevity,as new studies found. Beneficial longevity effects of young maternal age areobserved only when children of the same parents are compared, while the maternalage effect often could not be detected in across-families’ studies,presumably being masked by between-family variation. It was also found that malegender of centenarian has significant positive effect on survival of adult malebiological relatives (brothers and fathers) but not female relatives. Finally,large sex differences are found in longevity determinants for males and females,suggesting higher importance of occupation history for male centenarians, andhigher importance of home environment history for female centenarians.