The researchers base their analysis on a systematic review of 422 studies around the world that included over 7 million participants. There was evidence of the adverse effects of ageism on older persons in 96% of the studies.

“The injurious reach of ageism that our team documented demonstrates the need for initiatives to overcome ageism,” says senior author Becca Levy, a professor at the School of Public Health and the psychology department at Yale University. The World Health Organization asked Levy to lead the analysis as part of its newly launched Global Campaign to Combat Ageism, which 194 countries support.

The study is the first systematic review of ageism that simultaneously considered structural-level bias, such as denied access to health care, and individual-level bias, such as the power of stress-inducing negative age stereotypes assimilated from culture to affect the health of older persons.

The researchers found evidence that ageism led to worse outcomes in a number of mental health conditions, including depression, and a number of physical health conditions, including shorter life expectancy.

Ten studies showed that when older persons assimilate negative age stereotypes from the culture, they have a shorter life expectancy. Studies in multiple countries including Australia, Germany, and China made this survival finding, which Levy originally identified in previous research.

Read the full article about ageism by Michael Greenwood at Futurity.