LONDON, June 19 - Losing teeth at a young age could be an early warning of Alzheimer’s in later life, according to new research which also debunks as myth the theory mental exercise lowers the risk.
WHAT IF YOU DIDN’T ACTUALLY “LOSE” YOUR TEETH, BUT JUST FORGOT WHERE YOU PUT THEM? THAT WOULD BE A BETTER POINTER TO OLDTIMER’S DISEASE WITHOUT HAVING TO PAY FOR ALL THAT RESEARCH! 
A study of identical twins found a strong link between gum disease marked by teeth loss and the brain disease.
Scientists think it is not gum disease as such but the accompanying inflammation which helps to trigger Alzheimer’s.
Early exposure to inflammation quadruples the risk of developing the disease in old age, the research suggests.
Other infections, such as influenza, rheumatic fever and tuberculosis also create inflammation.
However, inherited genes for Alzheimer’s are a much bigger risk factor.
Previous studies have shown that if one of a pair of identical twins has the disease, the other has a 60 per cent chance of developing it as well.
Twins are often used to separate genetic and environmental risk factors.
Because identical twins share all the same genes, they have the same chance of inheriting a genetic susceptibility.
But if a risk factor has an environmental source, for instance an infection, it is likely to affect one twin more than the other. Analysing such patterns can turn the spotlight on a particular environmental hazard.
Researchers used this approach to screen 20,000 people on a Swedish registry of twins.
From the total group, they identified 109 discordant'' pairs with only one twin diagnosed with Alzheimer's or other forms of dementia. Information about participants' education, activities and health history was obtained from surveys conducted in the 1960s when the registry was created. The surveys included questions about loose or missing teeth, which the researchers used as a crude indicator of gum disease. Study leader Professor Margaret Gatz, from the University of Southern California, Los Angeles, said: We’re talking about gum disease, but it was measured by teeth lost or loose.
It's not perfect. Given it's not perfect, it's even more striking that it's such a solid risk factor.'' Prof Gatz was inspired to focus on inflammation by previous work linking today's long life spans to lower rates of childhood infectious diseases. She added: If what we’re indexing with periodontal (gum) disease is some kind of inflammatory burden, then it is probably speaking to general health conditions.
There was in our twins quite a lot of periodontal disease, and at that time in Sweden there was a lot of poverty.'' The study also exposed the theory that mental exercise lowers the risk of Alzheimer's as a myth. People who had more education than their twin partners were at slightly lower risk of developing dementia. But the influence of education on Alzheimer's was statistically negligible. Prof Gatz said it was important not to misunderstand the causes of mental deterioration in later life. Once one controls for genes, the level of education is not a huge risk factor,’’ she said.
We go around saying: `Well, it can't hurt to do crossword puzzles.' There is a way it can hurt. The way it can hurt is if we start blaming the people who are demented for not exercising their brains enough, or overselling activities that could make a difference where it’s really unsubstantiated.
``I think we have got to be real careful in our messages about risk reduction.’’
Prof Gatz was assisted by researchers at the Karolinska Institute in Stockholm. She presented her findings today at the first Alzheimer’s Association International Conference on Prevention of Dementia in Washington DC.