Lifetime data analysis of disease and aging by the Weibull probability distribution.

We applied the Weibull distribution to the life-table and age-patterns of diseases in Japan. The life-table follows a composite Weibull distribution composed of initial failure and two stage wear-out failure periods. The extension of lifespan during the past century is manifested as increases in the scale parameters in all three periods and the shape parameters in the wear-out periods with female predominancy. The shape parameters of diseases show time-independent sex-dependent specific values. When consistent changes are observed, such as increases in the shape parameters of tuberculosis and pneumonia, legitimate causes such as prevention and repair at the societal and medical level are present. Cancer and arteriosclerosis share a common range of shape parameters suggesting analogous underlying biological processes. An analysis of the epidemiology of human aging and disease by the Weibull distribution discloses intrinsic properties of man as a biological organization as well as a societal presence.