title: Mortality increase in late-middle and early-old age: heterogeneity in death processes as a new explanation.
abstract: Deviations from the Gompertz law of exponential mortality increases in late-middle and early-old age are commonly neglected in overall mortality analyses. In this study, we examined mortality increase patterns between ages 40 and 85 in 16 low-mortality countries and demonstrated sex differences in these patterns, which also changed across period and cohort. These results suggest that the interaction between aging and death is more complicated than what is usually assumed from the Gompertz law and also challenge existing biodemographic hypotheses about the origin and mechanisms of sex differences in mortality. We propose a two-mortality model that explains these patterns as the change in the composition of intrinsic and extrinsic death rates with age. We show that the age pattern of overall mortality and the population heterogeneity therein are possibly generated by multiple dynamics specified by a two-mortality model instead of a uniform process throughout most adult ages.
authors.affiliation: Center for Population and Development Studies, Renmin University of China, No. 59 Zhongguancun Street, Haidian District, Beijing, 100872, China, tingli@email.unc.edu.
authors.forename: Ting
authors.initials: T
authors.lastname: Li
authors.forename: Yang Claire
authors.initials: YC
authors.lastname: Yang
authors.forename: James J
authors.initials: JJ
authors.lastname: Anderson
mesh_terms: D000328:Adult; D017677:Age Distribution; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging; D015331:Cohort Studies; D019049:Developed Countries / Q000706:statistics & numerical data*; D005260:Female; D006801:Humans; D015993:Life Tables; D008297:Male; D008875:Middle Aged; D008962:Models, Theoretical; D009026:Mortality / Q000639:trends*; D017678:Sex Distribution