HALIFAX - Researchers have discovered that frailty is a key risk factor for dementia.

A study by Halifax's Dalhousie University and Chicago's Rush University found frailty aggravates the effects of plaques and tangles -- the jumbled strands of proteins that accumulates in some brains.

It found frailty may even be a risk factor on its own, and resilience may be the most important protection against Alzheimer's disease and dementia.

The first-of-its-kind study, published in Lancet Neurology, looked at autopsy and clinical data from 456 people.

The subjects were part of Rush University's Memory and Aging Project, and their frailty was measured on an index developed at Dalhousie that ranks physical health deficits and the ability to function.

The researchers say seniors' homes are key for promoting preventive measures like social interaction, physical activity and healthy eating.