May 5, 2010 -- Older men living with wives who have dementia have an almost 12-fold increased risk for developing dementia themselves, a new study shows.
Elderly women in the study whose husbands developed dementia had a fourfold increase in dementia risk.
The new study shows greater intellectual declines among the spouses of men and women with Alzheimer's or other age-related dementias, study researcher Maria Norton, PhD, of Utah State University tells WebMD.
"The association was strong for both men and women, but the good news is that most people in the study did not develop dementia even when their spouse did," she says.
Dementia Risk Among Married Couples
The investigation included 1,221 married couples residing in Cashe County, Utah, who were participants in a large, ongoing study of memory, health, and aging.
All the participants were 65 years old or older at enrollment and none showed evidence of dementia.
Up to 12 years later, however, dementia had been diagnosed in the husband alone in 125 couples and in the wife alone in 70 couples. In 30 couples, both the husband and wife had developed dementia.
After taking into account well-known risk factors for Alzheimer's disease, including age, sex, genetic predisposition, and socioeconomic status, having a spouse with dementia was associated with a sixfold increase in dementia risk (11.9-fold increase in risk among men and 3.7-fold increase among women).
The study participants were not asked if they were the caregivers for a spouse with dementia, but most lived in the same home with these spouses after they were diagnosed.
The findings are published in the Journal of the American Geriatrics Society. The National Institute on Aging funded the research.
Manage Stress, Reduce Risk
Norton says more research is needed to determine if certain elderly caregivers are more vulnerable than others and to identify interventions that may reduce the risk.
University of Washington professor of psychiatry Peter P. Vitaliano, PhD, agrees. Vitaliano has studied the physical and psychological impact of caring for chronically ill loved ones for many years.
He says study after study shows that spouse caregivers are more likely than noncaregivers to be depressed, socially isolated, and neglect their own health.
His own research suggests that the stress hormone cortisol plays a major role in dementia by increasing insulin levels. There is evidence that excess circulating insulin in the brain causes lesions similar to those believed to cause Alzheimer's disease.
"It amazes me that caregivers often think that denying their own needs makes them better caregivers," Vitaliano says. "In reality, the complete opposite is true."