Tooth loss may predict the development of dementia late in life, according to research published Wednesday in the October issue of The Journal of the American Dental Association.

Numerous past studies have shown that people with dementia have a high incidence of poor oral health. Few researchers, however, have examined the relationship from the opposite direction, to determine whether poor oral health actually may contribute to the development of dementia.

To that end, researchers from the University of Kentucky studied data from 144 participants in the study. They used dental records and results of annual cognitive examinations to study participants who were 75 to 98 years old.

"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," the authors wrote.

They propose 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 note, whether the tooth loss has any real role in bringing about 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 wrote, urging further study.

(Agencies via Xinhua News Agency October 11, 2007)