Healthy retirees tend to live longer than sick retirees, and that means they face higher total projected health care costs.

Researchers at the Center for Retirement Research at Boston College are reporting that conclusion in a new study.

The researchers say the results are what they are because:

- People in good health can expect to live significantly longer, and therefore are at risk of incurring health care costs over more years.

- Many retirees who are now free of chronic disease will succumb to one or more chronic diseases later.

- People in healthy households face a higher lifetime risk of requiring nursing home care and other long-term care than people in sick households do.

The researchers found that the expected present value of lifetime health care costs for a couple turning 65 in 2009 in which one or both spouses suffer from a chronic disease is $220,000, including insurance premiums and the cost of nursing home care; and that 5% can expect to spend more than $465,000.

The comparable numbers for couples free of chronic disease at age 65 are substantially higher. For the healthy couples, the expected present value of lifetime health care costs is $260,000, and 5% of those couples can expect to spend $570,000.

Prudential Financial Inc. Newark, N.J. (NYSE: PRU), sponsored the CRR research.