Key messages:
- Improving flossing behaviour may have an additional benefit in preventing cardiovascular disease events.
- Medical practitioners should advise their patients to improve their oral self-care practices, in addition to the standard diet and exercise advice.
Introduction
There is growing evidence of an independent association between periodontal disease (PD) and cardiovascular disease (CVD). PD is initiated by the accumulation of pathogenic bacterial plaque, resulting in a host-mediated inflammatory response that can progressively damage the tooth-supporting structures. As the sixth most common disease affecting humans, PD is a significant public health concern due to its associated complications that can impair quality of life and systemic health.
CVDs, mainly coronary heart disease, cerebrovascular disease, and peripheral vascular disease, account for one-third of all-cause mortality and significantly burden global health care systems. Population-based studies and systematic reviews have consistently shown a modest increase in the risk of developing CVD among individuals with PD. Consensus reports from 2020 and 2023 cite a robust body of evidence to support independent associations between PD and CVD. Transient bacteremia, chronic inflammation, and endothelial dysfunction induced by PD are the possible mechanisms contributing to the underlying atherogenesis and subsequent thrombotic events.
PD and CVD share several common risk factors, including advanced age, male sex, smoking, obesity, dyslipidemia, and diabetes, along with similar genetic predispositions. Factors associated with atherothrombosis development, such as inflammatory mediators (e.g., C-reactive protein [CRP] and interleukin 6 [IL-6]), prothrombotic factors (e.g., fibrinogen), and dyslipidemia, have been reported to be significantly higher in individuals with PD. Additionally, individuals with both CVD and PD exhibit elevated levels of these factors compared to those with either condition alone.
Research suggests treating PD may reduce the risk of CVD events and improve atherosclerotic profiles and vascular function. There is moderate evidence that PD therapy can reduce levels of CVD-related biomarkers, such as CRP, IL-6, and fibrinogen. However, PD therapy does not appear to significantly affect lipid levels, oxidative stress, or coagulation markers.
Daily oral self-care is essential to prevent PD. As the association between PD and CVD becomes more evident, it has been suggested that poor oral hygiene should be considered a risk factor for CVD. Consistent observational evidence across various population groups indicates that oral self-care practices, such as toothbrushing and flossing, are associated with a lower risk of CVD-related events, mortality, and improved CVD-associated biomarkers. However, most of these studies focused on the relationship between toothbrushing and CVD events or the associations between toothbrushing and changes in CVD risk markers (e.g., dyslipidemia, CRP, fibrinogen, vascular function, hypertension). There is comparatively limited evidence regarding the additional benefits of flossing in reducing CVD-related events, risk markers, or mortality.
Objectives
This population-based study assessed the impact of self-reported dental flossing on the prevalence of CVD and the risk of experiencing CVD-associated mortality. The study also evaluated whether daily flossing can lower levels of CVD-associated inflammatory risk markers (e.g., CRP).
Methods
Data from 18,801 adult participants in the 2009 to 2016 National Health and Nutrition Examination Surveys were analyzed to examine flossing behaviour, the prevalence of CVD events, causes of mortality, and levels of CRP. Mortality information was obtained from the U.S. mortality registry. Participants who responded to the flossing question were categorized into four groups based on their flossing frequency: non-flossers (0 days per week), occasional flossers (1-3 days per week), frequent flossers (4-6 days per week), and daily flossers (7 days per week). Multiple logistic regression and Cox proportional hazards regression analyses were performed to analyze the data.
Results
Daily flossing was associated with a lower prevalence of CVD events after adjusting for age, sex, sociodemographic factors, and lifestyle habits (model 2). The odds ratio for CVD prevalence in the daily flossing group compared with the non-flossing group was 0.71. For each extra day of flossing, the odds ratio for CVD prevalence was 0.95 in model 2, and this finding remained statistically significant after further adjusting for metabolic syndrome.
Daily flossing compared with not flossing was associated with a lower risk of experiencing CVD mortality in model 2. The hazard ratio of CVD mortality for each additional day of flossing was 0.94 in model 2. Participants who did not floss exhibited significantly higher levels of CRP, even after adjusting for various factors.
Conclusions
Even after adjusting for sociodemographic factors and lifestyle habits, this large-scale analysis revealed that poor flossing habits were associated with a higher prevalence of CVD events, increased risk of CVD-related mortality, and elevated CRP levels.
