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NEW YORK (Reuters Health) - Older people who have lost their teeth are at more than three-fold greater risk of memory problems and dementia, UK researchers report.
"This study essentially raises questions rather than answering them," Dr. Robert Stewart of Kings College London, the study's lead author, told Reuters Health. "The measurements were taken at the same time, so we are not able to say what caused what."
It's possible that people with cognitive impairment simply take worse care of their teeth, he added, but there are also mechanisms by which poor dental health itself could harm the brain. "One message still stands regardless of what caused what," he said. "Particular attention may need to be paid to the health and nutrition of people with cognitive impairment because they may also have dental problems."
Stewart and his colleague Vasant Hirani at University College London looked at 2,463 men and women 65 and older who were living independently, as well as 1,569 elderly people residing in nursing homes. Among people living independently, 40 percent had no teeth, compared to 68 percent of those in nursing homes, the investigators report in the Journal of the American Geriatrics Society.
The researchers calculated that people with no teeth were at 3.57 times greater risk of having cognitive impairment than those who had some or all of their teeth. The relationship was only significant for people who lived independently, while there was no similar association among nursing home residents.
There are two possible ways that poor dental health might boost the risk of cognitive problems, Stewart noted.
"Firstly, dental disease often causes prolonged inflammation and infection in the mouth; both of these may alter some factors in the blood which might possibly cause problems in the brain," he explained.
"Secondly, people who lose a lot of teeth tend to alter their diet. There is a lot of interest at the moment in the association between diet and some forms of dementia, like Alzheimer's disease. If people move towards a less-balanced diet as a result of their loss of teeth, then this could result in vitamin deficiencies and other problems which might affect the brain."
More research is needed, Stewart and Hirani conclude, before a causative relationship can be proven or disproven. "However it is certainly a good idea for all sorts of reasons to take care of your teeth as you get older and to make sure that any problems are dealt with promptly by an appropriate specialist," Stewart said. "If you do lose teeth, you may find that you have to change your diet but it is important to make sure that it stays balanced. Your family doctor, dentist or a dietitian can advise on this."
SOURCE: Journal of the American Geriatrics Society, September 2007.