The study shows the majority of people enjoy good or excellent health, even past age 85. Later life is not necessarily defined by a steady decline in health, but rather by more healthy years followed by a much shorter period of ill health immediately before death.

The results of the study will be published in the February 2006 issue of the Journal of the American Geriatrics Society. The study was funded by the National Institute on Aging, part of the National Institutes of Health.

"Older people are healthy, and it is important for health providers to keep this optimistic perspective and share it with their elderly clients," said Truls Ostbye, M.D., Ph.D., lead study author and professor in Duke's Department of Community and Family Medicine. "We hear a lot about disease and disability among the elderly, but the quality of life in older individuals is actually, by most measures used, high up to the oldest of age."

These findings, Ostbye said, contradict the generally held perceptions among the public that elderly individuals begin a slow decline into ill health decades before they actually do.

Participants were all residents of the same county in Northern Utah and were involved in the "Cache County Memory Study," a larger, four-institution epidemiological study of aging and dementia. The participants in this very long-lived population, many living beyond age 80, self-reported their overall health on 10 measures, including their ability to carry out activities of daily living (ADLs), such as dressing or bathing; the presence of any major illness, such as cardiovascular disease, diabetes or cancer; and their level of social activity. The researchers said that few previous studies have included data on as many health dimensions.

The study included nearly 3,500 men and women over age 65. Between 80 percent and 90 percent of participants ages 65 to 75 reported excellent or good health, and approximately 60 percent of those over age 85 did so. The participants were asked to describe their overall health as excellent, good, fair and poor. Participant cognition was also tested with the Mini-Mental Status Examination, a widely used 20-question test of reasoning and memory.

According to the researchers' analysis of the data, nearly 90 percent of participants were healthy enough to live at home, including those age 85 and over. More than 90 percent of men and women ages 65 to 84 were independent in all ADLs, and more than two-thirds over age 85 could complete these tasks alone. The 2004 National Health Interview Survey indicates that individuals of the same age perform similarly nationwide.

While up to 50 percent of participants were free from any major disease, the rest were living with at least one physical ailment. According to researchers, most continued to report at least fair health and the ability to perform most ADLs and other physical activities despite the chronic conditions. The percentage of participants without chronic illness fell slightly as individuals aged, but 40 percent of men age 85 and older and 42 percent of women in the same age group still did not suffer from any major disease.

"Many people in this study with chronic diseases were not in bad overall health," Katrina Krause, a co-author of the study, said. "And as they got older, a chronic disease did not necessarily mean they were disabled."

Many of the problems older individuals listed as impairing their overall health and quality of life could potentially be modified, said Krause. The three most common factors affecting self-reported health – poor vision, hearing loss and mood – can often be treated with clinical interventions, such as prescriptive lenses, hearing aids or antidepressive therapy. The occurrence of depression, however, in this study was low – less than 10 percent of participants were affected. Individuals over age 85 reported the most cases of depression, perhaps, Ostbye said, because they had fewer opportunities for social participation.

During data analysis, researchers discovered that gender did play a role in the level of self-reported good health as individuals got older. Women over age 85 were more likely to be frail and less likely to be able to perform certain activities of daily living.

Co-authors are Maria C. Norton, Ph.D., Utah State University, JoAnn Tschanz, Ph.D., Utah State University, Linda Sanders, MPH, Duke University Medical Center, Kathleen Hayden, Ph.D., Duke University Medical Center, Carl Pieper, DrPH, Duke University Medical Center, Kathleen A. Welsh-Bohmer, Ph.D., Duke University Medical Center, Katrina M. Krause, Duke University Medical Center. Investigators from Johns Hopkins Medical Center and the University of Washington are also involved in the Cache County study.