Feb. 23, 2010 -- Seniors who have been hospitalized may be more likely to develop dementia and mental decline than seniors who have not been hospitalized, a new study shows.
William J. Ehlenbach, MD, MSc, of the University of Washington in Seattle, and colleagues analyzed data from a study on mental function of older adults. They looked to see whether a history of hospitalization was associated with mental decline and dementia.
The researchers found that older patients who had been hospitalized for a non-critical illness had a 40% higher risk of dementia. Follow-up mental test scores were also lower in participants who had been hospitalized compared to those who had not.
"The mechanism of this association is uncertain," the researchers write. "Hospitalization may be a marker for cognitive decline or dementia that has not been diagnosed. [But] these results also could suggest that factors associated with acute illness, and to a greater degree with critical illness, may be causally related to cognitive decline."
Dementia and Aging
The researchers examined data on 2,929 people 65 and older who were part of a Seattle-area study on aging and dementia from 1994 to 2007. None of the study participants had dementia at the start of the study or were living in a nursing home.
Mental abilities were tested every two years.
After an average follow-up of six years, 1,601 patients had not been hospitalized, 1,287 had been hospitalized for non-critical illness, and 41 had been hospitalized for critical illness.
Researchers found 146 cases of dementia among those not hospitalized. Among those hospitalized for non-critical illness, 228 dementia cases were found. Five cases of dementia were found among people hospitalized for critical illness.
Seniors hospitalized for a critical illness, such as shock or needing a mechanical ventilator to breathe, were also found to be at higher risk of dementia, but this may have been a chance finding due to the small number of participants hospitalized for critical illness.
The researchers write that "an acute or critical illness may cause an abrupt loss of cognitive function rather than steepening the slope of decline or simply being a marker of cognitive decline."
They add that more studies are needed to look into the relationship between hospitalization and mental decline in seniors.