Older married adults whose spouse has dementia are at significantly higher risk of developing dementia themselves, compared to similar older married adults whose spouse never develops dementia. This is the key finding of a study published yesterday in the Journal of the American Geriatrics Society.
Informal dementia caregiving is difficult, requiring time, energy and usually physical exertion. Dementia caregivers have been shown to provide more assistance, and to report more personal sacrifices and stress, than those who care for physically-impaired elderly without dementia.
2,442 individuals (1,221 married couples) aged 65 and older from Northern Utah, USA, without dementia at onset were studied for up to 12 years to monitor for onset of dementia in husbands, wives or both. During this time, 125 cases of dementia only in the husband were diagnosed, 70 only in the wife, and 30 where both spouses were diagnosed (60 people). The researchers, led by Dr. Maria Norton of Utah State University, USA, adjusted for socioeconomic status, a significant predictor of many health-related outcomes including dementia to control for shared environmental exposures that might influence risk for dementia in both spouses.
The results showed that incident dementia was significantly associated with older age, and having a spouse with dementia. Participants with a spouse who developed dementia were at a six times increased risk of developing dementia, net of the effect of age, gender, APOE genotype, and socioeconomic status, with higher risk in men (11.9) than women (3.7).
“Future studies are needed to determine how much of this association is due to caregiver stress compared to a shared environment,” said Norton.
Likewise, here in Britain, the Alzheimer's Society stressed the need for further investigation. "Two people living the same lifestyle may be exposed to the same risk factors so it could be possible that spouses both develop dementia. However there has been limited research in this area and more is needed to determine which people are the most vulnerable" said Professor Clive Ballard, Director of Research.