May 13, 2011 -- Husbands and wives who care for a spouse with Alzheimer's disease or another kind of dementia may face an increased risk of mental decline themselves, a new research review shows.
"It is incredibly ironic, but also, it makes sense," says study researcher Peter P. Vitaliano, PhD, an adjunct professor and director of the Stress and Coping Project at the University of Washington, Seattle.
Spousal caregivers of dementia patients "have been married for, on average, 30 years in the studies," he says, "So there is all of that shared lifestyle. And then on top of it, you have all the things that happen after you become a caregiver."
The study is published in the Journal of the American Geriatrics Society.
The burdens of caregiving include many things that have been shown to increase the risk of cognitive decline, including chronic stress, social isolation, depression, decreased physical activity, and a shift in eating habits toward more fast food and processed foods.
Studies have shown, for example, that caregivers of Alzheimer's disease patients had lower scores on tests that measure attention, visual processing speeds, and memory than adults of the same age who were not caregivers. Studies also show that greater distress -- including disturbed sleep and lack of positive experiences -- appeared to account for those differences.
In 2004, Harvard researchers reported that older women who took care of a disabled or ill spouse were 31% more likely to have a low score on a standard test for cognitive function compared to women of the same age who were not caregivers.
And a study published in 2010, which followed more than 1,200 older married couples in rural Utah for 12 years, found that spouses of husbands or wives that developed dementia had a 600% greater risk of developing dementia themselves.
"It's terrifying," says Leah Eskenazi, a social worker who is director of operations and planning for the nonprofit Family Caregiver Alliance in San Francisco. "People put their lives on hold to care for somebody else, to care for a spouse. And to think that doing that puts them at risk for being in the same situation, and they see the person declining -- especially with dementia -- it's a scary disease."
Experts stress, however, that many of the lifestyle factors that have been shown to lead to cognitive decline can be changed and that doing so may help to reduce the risks of dementia and other ailments linked to caregiving, like heart disease and depression.
"We don't know anything about causality at this point," says Vitaliano. For example, he says, researchers can't say whether depression pushes caregivers into cognitive decline or whether dementia that's already there, but perhaps not as advanced as in a diagnosed spouse, may be contributing to depression.
"Like in a lot of epidemiology, these are associations and we need to understand them because they have great implications."