Escalating health care costs in retirement could threaten many Americans’ ability to live comfortably in their later years, even if they have Medicare and employer-based supplemental coverage, according to a study released Wednesday.

For women, the odds of maintaining a lifestyle in retirement are worse, because they live 5.2 years longer than men on average and must stretch their resources to support a longer life.

The Employee Benefit Research Institute (EBRI) found that for men and women alike out-of-pocket lifetime health care costs can easily run into six figures; in some estimates, the total jumped by $24,000 or more since last year.

In the best-case scenario for women, the institute found that a 65-year-old with both Medicare and employer-sponsored health coverage would need to use $98,000 in personal savings to have a 50-50 chance of covering her medical costs in retirement. With savings of $164,000, there would be a 90 percent likelihood that her costs would be covered.

A man in the same situation would need $68,000 in savings—$30,000 less than a woman—to have a 50 percent chance of covering health care expenses in retirement. For a 90 percent likelihood, he would require $134,000 in savings.

A married couple would need $165,000 in savings for a 50-50 shot at paying for all their health costs in retirement, or $256,000 for a 90 percent likelihood.

Additional health care costs for women in retirement place a huge burden on their financial stability. In fact, twice as many women at age 75 (13 percent) are poor compared with men (6.7 percent) in that age group, according to the U.S. Census Bureau.

Cindy Hounsell, president of the Women’s Institute for a Secure Retirement in Washington, cites a variety of reasons for the plight of older women. Many outlive their husbands and may no longer receive their company pension. Others who were divorced or never married often earned lower salaries over the years and amassed less retirement income, savings and Social Security benefits. And living longer usually translates into more chronic illness and higher health care costs.

“Very few people get to be in their 80s without some chronic illness,” Hounsell says. “The illnesses and medications are expensive when you live longer.”

She predicts that women’s financial security will become increasingly threatened in the coming years because of a higher divorce rate among boomers than in earlier generations, and because more women are staying single than ever before.

But make no mistake, rising health care costs are a worry for most people. According to the EBRI study, Medicare beneficiaries with Medicare Part D drug coverage and with supplemental insurance like medigap instead of employer-sponsored coverage face the highest out-of-pocket costs.

A man with average drug costs would need $86,000 in savings for a 50-50 shot at paying for health care in retirement, while a woman would need $125,000 and a married couple would require $210,000.

In another look at health care expenses, AARP’s Public Policy Institute examined the out-of-pocket health care expenses for beneficiaries in 2005, a year before Medicare’s Part D drug coverage took effect. A report on the study released this month found that beneficiaries spent an average of $4,394 of their own money on health care that year—about 28 percent of their income.

Women on average spent $4,630, or 32 percent of their income, while men spent $4,105, or 23 percent of their income. Overall, 10 percent of the Medicare population spent more than $8,000 in out-of-pocket costs.

As high as health care costs are, the studies by EBRI and AARP don’t factor in the cost of long-term care expenses or basic living costs. A separate study by the Center for Retirement Research at Boston College earlier this year found that spiraling long-term care costs will prevent many from maintaining their standard of living in retirement.

It said that nearly two-thirds of U.S. households (64 percent) won’t be able to live as well in their retirement years because of the cost of long-term care, even when they’ve spent $3,500 a year on a comprehensive long-term care insurance policy.

Carole Fleck is a senior editor at the AARP Bulletin.