Can tooth loss predict the development of dementia later in life?

Past studies have shown that patients with dementia are more likely than patients without the condition to have poor oral health, but few researchers have examined the relationship to determine whether poor oral health actually may contribute to the development of dementia.

According to research published in The Journal of the American Dental Association, a team from the University of Kentucky College of Medicine and College of Dentistry (Lexington, Ky.) has investigated a possible link.

The researchers examined data from 144 participants in the Nun Study, a study of aging and Alzheimer's disease among Catholic sisters of the School Sisters of Notre Dame.

Using dental records and results of annual cognitive examinations, they studied participants from the order's Milwaukee province who were 75 to 98 years old, finding that: "Of the participants who did not have dementia at the first examination, those with few teeth (zero to nine) had an increased risk of developing dementia during the study compared with those who had 10 or more teeth."

Researchers proposed several possible reasons for the association between tooth loss and dementia: not only periodontal disease but also early-life nutritional deficiencies, infections or chronic diseases that may result simultaneously in tooth loss and damage to the brain.

However, they added, whether the tooth loss has any real role in bringing about the dementia is impossible to say on the basis of this study. "It is not clear from our findings whether the association is causal or casual," they write, urging further study.