People who don't brush their teeth every day have a higher chance of developing heart disease, researchers have found. Lack of brushing can lead to constant, low-level gum infections, which researchers think could cause inflammation in the body and play a part in causing heart disease.

What do we know already?

It may seem strange that brushing your teeth could be linked to the health of your heart and blood vessels. The link could be explained by an increasingly influential theory: that inflammation is responsible for many of the things that can go wrong in your body. Inflammation is one of your body's responses to illness. According to the theory, inflammation prompts the release of chemicals in your blood that increase your risk of high blood pressure or heart disease.

Getting infections can play a part in causing inflammation. Doctors think that even mild infections could increase your risk of heart problems, especially if they're long lasting or you get them often. Gum disease is one possible culprit.

To investigate how gum disease might affect people's risk of heart problems, researchers asked nearly 12,000 Scottish people about how often they brushed their teeth or visited the dentist. They then used hospital records to see which people developed heart problems.

What does the new study say?

People who brushed their teeth less often were more likely to get heart or circulation problems. During the eight-year study, 11 percent of people who brushed their teeth less than once a day developed heart problems, compared with 7 percent of people who brushed once a day, and just 4 percent of people who brushed twice a day.

Of course, lots of things can affect your risk of heart problems, such as whether you smoke, a family history of heart problems, and the amount of exercise you do. After accounting for as many contributing factors as possible, the researchers concluded that brushing just once a day rather than twice increases a person's risk of heart disease by 30 percent. Brushing less often than once a day increases the risk by 70 percent.

Some of the people in the study were given blood tests. People who brushed their teeth less often had higher levels of chemicals called C-reactive protein and fibrinogen, which tend to rise in response to inflammation in the body.

The average age of the people in the study was 50. Overall, about 5 percent of people got some kind of heart or circulation problem. The most common problem was coronary heart disease.

How reliable is the research?

This is a large and well-run study. However, it's hard to know whether lack of brushing actually causes heart problems. It is possible that brushing regularly reduces the inflammation caused by gum disease. Or there could be other factors involved. Maybe people who don't brush their teeth take less care of themselves in other ways, so don't eat healthily, or forget to take medicines they've been prescribed. It's impossible to take every last influence into account, which means we can't be sure that the link is one of cause and effect.

Where does the study come from?

The study was published by the BMJ (British Medical Journal), which is owned by the British Medical Association.

What does this mean for me?

There's more and more research suggesting that inflammation might play an important part in the health of people's heart and blood vessels. If, as the researchers suspect, brushing your teeth cuts heart disease by preventing infections, we can add this study to the evidence. It's still early days when it comes to translating this knowledge into new treatments, but in the future, drugs to control inflammation might have an important role to play in keeping people healthy. For now, we can try to remember to brush our teeth regularly.

What should I do now?

If you don't already brush your teeth twice a day, it makes sense to start doing so. There's no guarantee that it will cut your risk of heart problems, but it's unlikely to do you any harm. The British Dental Association recommends brushing your teeth twice a day with a fluoride toothpaste in order to prevent tooth decay, gum disease, and bad breath.

You can definitely cut your risk of heart disease by watching your blood pressure and cholesterol levels, taking some exercise, not smoking, and eating a healthy diet.

From:

de Oliveira C, Watt R, Hamer M. Toothbrushing, inflammation, and risk of cardiovascular disease: results from Scottish Health Survey. BMJ. 2010; 340: 2451.

© BMJ Publishing Group Limited ("BMJ Group") 2010