INDIANAPOLIS (AP) — Aetna Inc. said Monday it will buy the Medicare supplement business of Genworth Financial Inc. for about $290 million, as it becomes the latest health insurer to announce a plan that capitalizes on the aging baby boomer population.

Aetna has about 10,000 Medicare supplement customers and will add roughly 145,000 members with its acquisition of Continental Life Insurance Co. of Brentwood, Tenn. Medicare supplement insurance covers deductibles, co-payments and other expenses not covered by Medicare, the federal health insurance program for the elderly and disabled.

Aetna CEO Mark Bertolini said in a statement from the insurer Medicare supplement coverage is expected to grow fast in the coming years as baby boomers — the generation of Americans born in the years after World War II ended — reach age 65 and become eligible for Medicare.