NEW YORK (Reuters Health) - Young adults who lose their teeth to cavities or gum disease may have an increased risk of dying from heart disease later in life, a new study suggests.

The findings, reported in the journal Heart, add to evidence linking oral health to heart health. A number of studies have suggested that gum disease may contribute to heart disease over time -- though it's still not clear that there is a cause-and-effect relationship.

This latest study involved more than 12,000 UK adults who were followed from college onward, for up to 57 years. Researchers found that those with a large number of missing teeth in young adulthood -- nine or more -- were one-third more likely to die of heart disease than their peers with fewer than five missing teeth.

The link remained when the researchers considered factors such as socioeconomic background and smoking, which harms both the teeth and gums and the heart.

Tooth loss is an indicator of poor oral health. Scientists speculate that the bacteria in the mouth that cause cavities and gum disease may enter the bloodstream and either damage the blood vessel lining directly or trigger inflammation in the body that then contributes to heart disease.

The current findings do not prove that this is the case, according to the study authors, led by Dr. Yu-Kang Tu of the University of Leeds. But they do support a relationship between tooth loss and cardiovascular disease, Tu told Reuters Health. Unlike most other studies in this area, the researcher noted, this one looked at oral health early in life rather than in old age.

"Our study adds to the evidence that chronic infection -- oral or elsewhere in the (body) -- may increase the risk of cardiovascular diseases," Tu said.

The findings are based on 12,631 men and women who had medical and dental exams as college students in the 1940s through 1960s. They were then traced through the UK National Health Service until 2005, during which time 1,432 died.

Overall, men and women with the most severe tooth loss as college students were 35 percent more likely to have died from heart disease than those with four or fewer missing teeth.

It's too soon to say that good oral hygiene will lower anyone's risk of heart disease, according to Tu -- particularly since this risk depends on multiple lifestyle and genetic factors. But, Tu added, it also won't hurt people to take better care of their teeth.

SOURCE: Heart, September 2007.