New study tracks factors leading to physical decline in older adults

A study by Yale School of Medicine researchers reveals that the illnesses and injuries that can restrict the activity of older adults or land them in the hospital are linked to worsening functional ability, especially among those who are physically frail. The report appears in JAMA's November 3 theme issue on aging.

Thomas M. Gill, M.D., the Humana Foundation Professor of internal medicine (geriatrics), investigative medicine and epidemiology and public health at Yale, will present the findings at a JAMA media briefing today.

"We now have a much better understanding of the complex and highly dynamic disabling process," said Gill, who is also an attending physician at Yale-New Haven Hospital.

Among older adults, disability in essential activities of daily living, such as bathing, and dressing, is common and associated with an increased rate of death, institutionalization, and greater use of formal and informal home services. But many older adults also recover from disabilities. Gill points to high rates of recovery and frequent transitions between states of disability, but he said the role of intervening illnesses and injuries on these transitions was little understood until this study shed some light on it.

Gill and his co-authors followed 754 adults age 70 and older living in the Greater New Haven area, with monthly phone interviews for over 10 years starting in 1998. The team assessed disability and ascertained exposure to intervening illnesses and injuries. Physical frailty—slow walking speed—was assessed every 18 months for nine years. The team evaluated the relationship between two types of intervening events—hospitalization and restricted activity, and transitions between no disability, mild disability, severe disability and death.

The team found that among the 637 participants, who had at least one functional transition, 90.7 percent had at least one hospital admission and 94.3 percent had at least one month of restricted activity. Hospitalization was associated with disability for eight of the nine transitions.

Among the possible reasons for hospitalization or restricted activity, fall-related injury led to the highest likelihood of developing new or worsening disability.

Gill notes that despite the reductions observed in the prevalence of disability over the past two decades, the number of disabled older Americans could increase substantially in the coming years with the aging of the baby boom generation. "To address this increase, more aggressive efforts will be needed to prevent and manage intervening illnesses and injuries, given their apparent role in precipitating and perpetuating the disabling process," said Gill.