Clean Teeth Again Linked to Healthy Heart|
"Low-grade inflammation appeared to be playing a role.....the risk of a fatal or nonfatal event was 40% greater for those who brushed once rather than twice a day and 2.3-fold higher for those who brushed less than once a day....They also had increased concentrations of both C reactive protein [inflammation marker] (ß 0.04, 0.01 to 0.08) and fibrinogen (0.08, -0.01 to 0.18).....The literature clearly shows that raised pro-inflammatory cytokines are present in both cardiovascular disease and periodontal disease"
Published: May 28, 2010
Regular toothbrushing could help stave off cardiovascular disease, according to a nationally-representative study in Scotland.
Action Points Explain to interested patients that poor dental hygiene -- brushing less than twice daily -- is thought to be a major cause of periodontal disease and may also impair cardiovascular health.
Individuals who rarely or never brushed were 70% more likely to have a heart attack or other cardiovascular disease event (P<0.001) even after controlling for many other factors, found researchers led by Richard Watt, MSc, PhD, of University College London.
Even brushing once a day rather than twice a day was associated with a significant 30% increase in the risk of these fatal or nonfatal events.
Low-grade inflammation appeared to be playing a role, although whether it is a causal role remains uncertain, Watt's group reported online in BMJ.
These increases in risk could have a "profound public health impact," they wrote in the study.
Nearly 40% of the population has some degree of periodontal disease, a complex chronic inflammatory condition largely caused by poor oral hygiene, the investigators noted.
Its link to cardiovascular disease has been extensively studied with results affirmed and strengthened by the new population-level data.
The researchers used self-reported frequency of toothbrushing as a proxy for periodontal disease, which wouldn't have been feasible for a large-scale population study, they said.
The analysis included 11,869 men and women ages 35 and older (mean 50) who retained their natural teeth and were without preexisting cardiovascular disease in the 1995, 1998, and 2003 iterations of the Scottish Health Survey of the general population.
Overall, their oral health was good. Regular visits to a dentist at least every six months were reported by 62% of respondents and 71% reported brushing twice a day.
More frequent toothbrushing appeared to be dose-dependently protective against cardiovascular disease events -- fatal or nonfatal, including cardiovascular disease-related hospitalization, acute MI, coronary artery bypass surgery, percutaneous coronary angioplasty, stroke, and heart failure.
In the analysis adjusted only for age and sex, the risk of a fatal or nonfatal event was 40% greater for those who brushed once rather than twice a day and 2.3-fold higher for those who brushed less than once a day (P=0.001 for trend).
Further adjustment for socioeconomic status, smoking, physical activity, and visits to the dentist attenuated the link. Additional controls for body mass index, family history of cardiovascular disease, hypertension, and physician-diagnosed diabetes also reduced the relationship but not to the point where significance was lost.
For cardiovascular disease-related death alone, similar trends were seen with a 10% elevated risk with once-a-day brushing and 50% elevated risk with less than once-a-day brushing compared with twice daily. However, this relationship lost significance with multivariate adjustment.
The other independent predictors of fatal and nonfatal cardiovascular disease events combined included:
* Smoking (hazard ratio 2.4, 95% confidence interval 1.9 to 2.9)
* Hypertension (HR 1.7, 95% CI 1.4 to 2.0)
* Diabetes (HR 1.9, 95% CI 1.4 to 2.7)
A subgroup of 4,830 study participants gave blood samples from which markers of inflammation (C reactive protein) and coagulation (fibrinogen) were measured.
Among them, less frequent toothbrushing appeared to have an effect that remained significant after multiple adjustments (P=0.46 for trend in C reactive protein levels and P=0.015 for trend in fibrinogen levels).
Inclusion of inflammatory markers partly attenuated the point estimates for the link between toothbrushing and cardiovascular disease "thus suggesting a possible mediating role," Watt's group wrote in BMJ.
They cautioned that residual confounding may have played a role as well.
Even though the study could not prove that inflammation from poor dental hygiene was causing the increase in cardiovascular events, Watt and colleagues concluded that "educating patients in improving personal oral hygiene is beneficial to their oral health regardless of the relation with systemic disease."
BMJ, 27 May 2010
"Toothbrushing, inflammation, and risk of cardiovascular disease: results from Scottish Health Survey"
Toothbrushing 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. Our results largely confirm those of previous studies.20 21 We examined the association between toothbrushing behaviour and cardiovascular disease and whether markers of low grade inflammation/coagulation were associated with low frequency of toothbrushing. Our results also suggest that toothbrushing is associated with concentrations of C reactive protein and fibrinogen. To the best of our knowledge, this is the first study to show an association between a single item self reported measure of toothbrushing and incident cardiovascular disease in a large representative sample of adults without overt cardiovascular disease. As self reported measures of oral hygiene have been associated with clinically confirmed periodontal disease,13 a simple self report measure of toothbrushing could therefore be associated with future risk for cardiovascular disease.
Oral health and cardiovascular disease
The role of oral health in the aetiology of cardiovascular disease has received considerable attention. Periodontal disease is a complex chronic inflammatory disease, resulting in a loss of connective tissue and bone support of the teeth.22 It is a major cause of tooth loss in adults aged over 40, and, according to the World Health Organization, affects people worldwide at prevalence rates of up to 10-20% for the most severe forms.23 Periodontal disease is highly prevalent, especially in late middle age when coronary artery disease is also most common,24 and it is caused mostly by poor oral hygiene.
In our study, participants who brushed their teeth less often had a 70% increased risk of a cardiovascular disease event in fully adjusted models. These results confirm findings from several observational epidemiological studies that showed that poor periodontal health status is associated with an increased risk of cardiovascular disease.1 In a study of 15 year follow-up data from the First National Health and Nutritional Examination Survey (NHANES I) Epidemiologic Follow-up Study, DeStefano et al found that people with periodontal disease had a 25% increased risk for coronary heart disease relative to those with minimal periodontal disease, after adjustment for age, sex, race, education, poverty index, marital status, systolic blood pressure, total cholesterol concentration, diabetes, BMI, and alcohol consumption.25 In a longitudinal study, Beck et al found that the odds ratios were 1.5 for total coronary heart disease and 1.9 for fatal coronary heart disease among people with periodontal bone loss compared with those without bone loss, after adjustment for several risk factors for cardiovascular disease.26
One meta-analysis concluded that periodontal disease and poor oral health overall indeed contribute to the pathogenesis of cardiovascular disease.27 Another meta-analysis, by Bahekar et al, confirmed that having periodontal disease might enhance the risk for cardiovascular disease but concluded that this risk was not robust.20
Periodontal disease seems to be associated with a 19% increase in the risk of future cardiovascular disease. This increase in relative risk is more prominent (44%) in people aged under 65. The increment of risk between people with or without periodontal disease in the general population is modest, at around 20%, because nearly 40% of the population have periodontal disease. This modest increase might, however, have a profound public health impact.28
In our study, less frequent toothbrushing was associated with increased concentrations of both C reactive protein and fibrinogen, and these associations remained significant after multiple adjustments including acute infections such as influenza. The work on serum markers of inflammation in both cardiovascular and periodontal research is extensive. The literature clearly shows that raised pro-inflammatory cytokines are present in both cardiovascular disease and periodontal disease. As a result, accumulating evidence has associated severe periodontal disease with increased odds of future cardiovascular disease events.3 Our study suggests a possible role of poor oral hygiene in the risk of cardiovascular disease via systemic inflammation. Raised inflammatory and homoeostatic responses as well as lipid metabolism disturbance caused by periodontal infection might be possible pathways underlying the observed association between periodontal disease and the increased risk for cardiovascular disease.29 Few studies, however, have examined these potential pathways. If these biological mechanisms are responsible for a slight increase in the risk of cardiovascular disease, better controlled and larger studies will be needed to identify them. Such efforts would be important because of the relatively high prevalence of periodontal disease.
Strengths and limitations
The Scottish Health Survey is nationally representative, with a rigorous design and data linked to a patient based database of hospital admissions and deaths with follow-up. The Scottish population is relatively homogeneous, with a high incidence of cardiovascular disease and poor indicators of oral health, thus our findings have high relevance to this population.
Though clinical data regarding the periodontal disease status of the participants might have strengthened our findings, previous research has also shown a good correlation between self report and clinical evaluation of periodontal disease.13 We had no follow-up data on toothbrushing behaviour. There is, however, evidence showing stability of oral health related behaviour such as toothbrushing and dental flossing,30 thus small changes in oral health behaviour are unlikely to affect the present findings. Both residual confounding and potential influence of effect modifiers could be responsible for a substantial attenuation of the relative risk in fully adjusted models. In addition, misclassification of both the exposure and the outcome could have played a role.
Our results confirmed and further strengthened the suggested association between oral hygiene and the risk of cardiovascular disease. Furthermore, inflammatory markers were significantly associated with poor oral health behaviour. Future experimental studies will be needed to confirm whether the observed association between oral health behaviour and cardiovascular disease is in fact causal or merely a risk marker. Nevertheless, use of a simple one item measure of self reported toothbrushing could be a useful and cost effective marker of future health risk in large scale population studies.
Given the high prevalence of oral infections in the population, doctors should be alert to the possible oral source of an increased inflammatory burden. In addition, educating patients in improving personal oral hygiene is beneficial to their oral health regardless of the relation with systemic disease.