The availability of employer-sponsored retiree health benefits from large companies has declined since 1991, according to a new study conducted for the Kaiser Family Foundation by Hewitt Associates LLC. The study also shows that the number of big businesses charging premiums, tightening eligibility requirements, encouraging use of managed care, and placing dollar caps on coverage increased. In addition, the report concluded that potential changes in the Medicare program, such as a higher eligibility age, could accelerate the decline in retiree benefits by shifting additional health care coststo employers and retirees and thus encouraging companies to scale back or eliminate retiree plans.