THURSDAY, Jan. 30, 2020 (HealthDay News) -- Discrimination based on age -- ageism -- is widespread throughout the world, and it takes a toll, new research reveals.

The study of more than 7 million people aged 50 and older in 45 countries found that age affected whether or not they got medical treatment and, whether the treatment, its length and frequency were appropriate.

The investigators reviewed 422 published studies, and found that 96% of older people experienced ageism.

According to the new report, ageism led to poor outcomes in depression and physical health, including shorter life expectancy.

"The injurious reach of ageism that our team documented demonstrates the need for initiatives to overcome ageism," said senior author Becca Levy, a professor of psychology at Yale School of Public Health in New Haven, Conn.

In 85% of the studies, her team found that health care was denied to older people, and in 92%, ageism affected medical decisions.

Ageism affects people regardless of age, sex, or race and ethnicity, the researchers noted in a Yale news release.

Study first author E-Shien Chang, a doctoral student in the Yale School of Public Health, said, "Our research highlights the importance of recognizing the influence of ageism on health. Policies to improve older persons' health must take ageism into account."

The study was published online recently in the journal PLOS ONE.

More information

For more on ageism, head to the World Health Organization.