A simple but illuminating new study shows that people who don’t brush their teeth enough have significantly increased risk for cardiovascular disease.

Richard Watt of University College, London and his team asked almost 12,000 participants a simple question: How often do you brush your teeth? They followed the group for an average period of eight years and tracked how many cardiovascular events occurred, among them heart attack and stroke, and which were fatal or nonfatal.

Overall, the team found that '[p]articipants who reported less frequent toothbrushing had a 70% increased risk of a cardiovascular disease...compared with participants who brushed their teeth twice a day.'

The researchers also wished to measure the level of systemic inflammation the participants experienced – inflammation is a known culprit in cardiovascular disease and could be the link between oral hygiene and heart health.

Overall, the team found that “[p]articipants who reported less frequent toothbrushing had a 70% increased risk of a cardiovascular disease...compared with participants who brushed their teeth twice a day.” Even after many variables were adjusted for (that is, essentially removed from the equation), the researchers found that “[t]oothbrushing is associated with cardiovascular disease, even after adjustment for age, sex, socioeconomic group, smoking, visits to dentist, BMI, family history of cardiovascular disease, hypertension, and diagnosis of diabetes.” The study was published in the May 27, 2010 issue of BMJ.

Interestingly, Watt and colleagues also found that people who did not brush their teeth twice daily had higher levels of C-reactive protein and fibrinogen, both of which are known to be associated with systemic inflammation. One reason that inflammation is thought to contribute to cardiovascular disease is that it leads to the build-up of plaques in the arteries.

The authors conclude by saying that the “study suggests a possible role of poor oral hygiene in the risk of cardiovascular disease via systemic inflammation.”

They do point out the need for future studies to determine whether “the observed association between oral health behaviour and cardiovascular disease is in fact causal or merely a risk marker.” In other words, because the study only pointed to a correlation between the variables, there is no “proof” that one actually causes the other. However, the new piece of evidence that inflammation is higher in people who do not brush their teeth often enough makes the relationship more clear – and future studies will likely identify exactly how the rest of the pieces of the puzzle fit together.