This article discusses the research that shows not only has life expectancy increased considerably over the years, but the extended years also are high quality years for most people. Disability now occurs much later in life than in the past, and the rates of disability are down. But the article also argues that the rate of improvement is about to slow down and perhaps the improvements might stop. He argues that the main causes of the improvements have had their full effects, and there aren’t new catalysts in site.
A recent study by University of Southern California gerontologist Eileen Crimmins and her colleagues looked at the change in disability-free life expectancy—the average number of years that we would expect someone to live free of major limitations due to long-term illness. From 1970 to 2010 American males gained about 7.7 years of life expectancy at birth, of which nearly half (3.2) could be expected to be disability free. Perhaps more immediately relevant, Americans aged 65 saw their remaining life expectancy increase from 15 to 19 years, with 2.5 of the 4 extra years being disability-free. (This averages the results for men and women; women gained fewer years overall than men, but the relative gains between disability-free and disabled years are similar.) The largest increase in healthy years after age 65 came in the last decade. Americans in 2010 could expect to live 80 percent of their lives without major disability, including well over half of their years after age 65.
Perhaps most striking, a new study has discovered that over the past two decades the incidence of new dementia cases has dropped by 20 percent.3 Men in the United Kingdom develop dementia today at the same rate as men five years younger in the 1990s; for women the improvements have been more modest.