Late-Life Mortality Plateau

Under the plateau assumption, a 110-year-old's chance of reaching 122.45 is about 0.00018, or 1 in 5,595. The half-life of survival at very advanced ages is 0.693 divided by A. Gerontology Research Group data fitted to a constant post-110 model estimated annual death probability near 0.5. The 1898 U.S. female cohort showed a plateau after age 104, unlike the 1895 cohort before that age. The analysis supports a mortality plateau at extreme ages. U.S. logarithmic mortality trajectories from 1999 to 2007 reached a plateau near age 104. Human mortality plateaus may be difficult to observe because very large cohorts are needed at advanced ages. The central model assumed a constant 50% annual death probability after age 110. The model predicts that mortality becomes constant after the characteristic age delta. At very advanced ages, survival follows first-order decay with rate constant A.