About one-third of U.S. adults age 45 and older report feeling lonely — and, due to an increased number of aging adults, the number is growing.

A survey by AARP Foundation finds that those who have low income are especially vulnerable. Nearly half of midlife and older adults with annual incomes of less than $25,000 report being lonely. A full 10 million people over the age of 50 live in poverty in the United States.

People who are lonely and socially isolated are more likely to have health problems, which can have serious financial implications. Social isolation among midlife and older adults is associated with an estimated $6.7 billion in additional Medicare spending annually.

More information and resources on AARP’s recent research into social isolation is available here.