LONDON People who don't brush their teeth twice a day have an increased risk of heart disease, scientists said on Friday, adding scientific weight to 19th century theories about oral health and chronic disease.
British researchers studied nearly 12,000 adults in Scotland and found those with poor oral hygiene had a 70 percent extra risk of heart disease compared with those who brushed twice a day and who were less likely to have unhealthy gums.
People with gum disease are more likely to develop heart disease and diabetes because inflammation in the body, including in the mouth and gums, plays a role in the build up of clogged arteries, said Richard Watt from University College London, who led the study.
The 70 percent extra risk compares to a 135 percent extra risk of heart disease in those who smoke, he said.
Although the overall risk was low -- with a total of 555 heart attacks or other serious coronary problems among 11,869 people -- the effect of regular teeth brushing was significant.
"Compared to things like smoking and poor diet, which are obviously the main risk factors for heart disease, we are not claiming this is in the same league," Watt said.
"But ... even after controlling for all those things there is a still a relationship between this very simple measure of tooth brushing and heart condition," he told Reuters.
"In a way, it's really quite an old story, because back in the early 19th century there was a theory called focal sepsis, and people believed that infections in the mouth caused disease in the whole body," Watt said.
"As a result, they used to take everyone's teeth out."
Watt said such a response was "a bit dramatic," but his findings did suggest that twice-a-day brushing was a good idea.
Gum or periodontal disease is an infection of the tissues surrounding and supporting the teeth and is more likely to occur in people who do not brush their teeth regularly.
Heart disease is the leading killer of men and women in Europe, the United States and many other rich nations and together with diabetes, accounted for almost a third of all deaths around the world in 2005, according to the World Health Organization.
The teeth brushing study published on Friday in the British Medical Journal was the first to investigate whether the simple number of times someone brushes their teeth daily has any bearing on the risk of heart disease.
The results showed oral health behaviors were generally good, with 62 percent of participants saying they visited the dentist every six months and 71 percent reporting they brushed their teeth twice a day.
Once the data were adjusted for other known heart risk factors such as social class, obesity, smoking and family history of heart disease, those who reported less frequent teeth brushing had a 70 percent extra risk of heart disease compared to those who brushed twice a day.
Blood tests on those with poor oral hygiene were also positive for two factors called C-reactive protein and fibrinogen -- both of which signal inflammation in the body.
(Editing by Matthew Jones)