Despite the high cost, 40 percent of Americans over age 70, regardless of income, have modified their homes with grab bars, bathroom railings, wheelchair ramps and other aids, reports a Cornell University housing economist.

"We had no idea that so many elderly have modified their homes to function better," says Nandinee Kutty, assistant professor of policy analysis and management at Cornell. "The modifications become such a necessity that older Americans invest in them regardless of financial situation. Yet, the cost of these modifications is not covered by Medicare or other insurance."

In one of the first studies to look at the demand for home modification by the elderly, Kutty found that 6.4 million homes in which older Americans live have some modification. Almost half the homes with a person over age 80, and 60 percent of homes with someone age 90 or older have some type of home modification. Her study will be published in a forthcoming issue of Applied Economics.

The most common types of home modification are bathroom grab bars or shower seats, installed by more than one-fourth of those over 70. About 12 percent modify their homes for indoor wheelchair use, the second most common modification. Call buttons to summon help are installed by 10 percent, the same percentage that put in railings. Wheelchair ramps go in 8 percent of homes.

About 40 percent of the elderly who live in non-institutionalized settings have some physical limitation caused by chronic conditions, says Kutty, who studies housing economics and other economic issues among the elderly. The most common limitations are difficulty in walking, bathing and getting outside, in that order.

In her analysis, Kutty used the Survey of Asset and Health Dynamics Among the Oldest-Old, a nationally representative data set acquired in 1993-1994 of 7,500 people age 70 or over, 2,500 of whom were age 80 or older.

The study suggests that the elderly sacrifice other needs in order to install essential modifications. Kutty proposes that Medicare cover the cost of home modifications both to enhance the well-being of the elderly and to help avoid high nursing home costs by allowing the elderly to live at home longer.

Kutty's other findings:

• Older people living alone are more likely to modify their homes because they find hired personal care expensive and may use the modifications as a substitute.
• Home modifications become more likely the higher a person's education.
• Francine Moccio, director, Cornell Institute for Women and Work, moderator.
• Home modifications are less likely to be found among minority groups.
• About 43 percent of women modify their homes, compared with 33 percent of men.
• Of all modified homes, 60 percent are single-family; 28 percent are apartments or condominiums; the rest are mobile homes, duplexes or townhouses.

Kutty points out that the study uses an innovative adaptation of what is called the Household Production Function Model an economic model that at looks at how households invest in areas such as nutrition, education and health. "In this case, we are adapting the model to look at how households invest in home modification to produce human functionality," Kutty says.

The study was funded, in part, by the Bronfenbrenner Life Course Center at Cornell.