Studies on Mortality Rates

As a group of people gets older, a higher percentage of them will die in any given time period. Benjamin Gompertz was a British mathematician from 19th-century created a law of mortality that says each additional period brings a constant increase in mortality rates. 20th century researchers found his research to be true. Around 80, mortality increases, but at a slower rate. More 100-year olds will die by 101 than 80-year-olds who will die by 81, but the difference was not as great as Gompertz predicted.

A study published last year may prove Gompertz right after all though. Leonid Gavrilov and Natalia Gavrilova are a husband and wife team at the Center on Aging at the University of Chicago. They posit a reliability theory of aging that suggests that the body amasses more flaws as it ages. Past a certain point, layers of protection on the body fall away and mortality comes at a constant rate. Their studies have found, however, that death rates among Americans born between 1875 and 1895 have grown steadily as they aged all the way through age 106.

Their new observations call into question their idea that there would be a slowdown in mortality increases with age, so they are now trying to reconcile their theory with those findings. The pair is waiting to see whether the pattern that they discovered will be applied to another set of aging populations, but they will have to wait until those born after the 1940s continue to age.

See Death Gets in the Way of Old-Age Gains, The Wall Street Journal, Mar. 2, 2012. 

Special thanks to Joel Dobris (Professor of Law, UC Davis School of Law) for bringing this to my attention.