Having poor gum health and/or gum disease has been demonstrated by a few studies to be associated with a moderate increase in the risk of heart disease, suggesting that gum health and heart disease are interlinked. Many theories have been proposed to explain the mechanism underlying the link between gum disease and heart disease yet how both conditions are connected remains unclear. 

Eager to get to the ‘heart’ of the matter and learn about these theories? Could bacteria be involved? If a moderate link between gum health and heart disease truly exists, can gum disease treatment lessen the adverse consequences of heart disease? All these interesting questions and more will be addressed in this article, so just keep on reading.

Introduction

Gum disease, or periodontal disease as it is widely known, is a chronic disease that results in the inflammation (swelling) of the periodontium, which is a piece of connective tissue that consists of the gingivae (gums), alveolar bone (bone in the jaws), cementum, and periodontal ligament.¹ As a result, the tissues, bones, and ligaments surrounding and holding the teeth together become susceptible to damage in patients with gum disease. 

When the gums become inflamed and damaged, ‘’deep pockets’’ form at the top of the tooth root surface, which make the teeth appear taller.² These ‘’deep pockets’’ create a favourable environment for multiple species of ‘’bad’’ periodontal (periodontopathic) bacteria to proliferate and form biofilms.

If left untreated, these biofilms or sticky and slimy periodontopathic bacterial aggregates may result in the formation of dental plaque and more concerningly, the breakdown of several soft tissues and bones, including the gums and alveolar bone, respectively. In severe cases, gum disease can eventually lead to tooth loss.

The mouth and the gums act as a ‘doorway’ or entry point to many organs and tissues in the body, including the heart. This led scientists to propose a link between gum health and heart disease a century or so ago. However, it has only been just over a decade since scientists have demonstrated a link between gum disease and heart disease.³

Heart disease or cardiovascular disease (CVD) is a severe and chronic disease that is usually accompanied by life-threatening complications including heart attacks and/or strokes (a ‘’heart attack’’ but in the brain), making it the number one cause of death worldwide.^4,5

Shockingly, the global incidence of severe periodontal disease (10-30%)^3,5 appears to be identical to that of heart disease (10-30%)⁵ and it is expected to only increase over the coming years. This makes it absolutely critical to understand how gum health and heart disease are linked and what steps can be taken to optimise gum health and in turn, potentially inhibit the development of disease. 

Understanding gum disease 

Stages, signs, and symptoms 

Although concerning, swollen and bleeding gums do not lead to heart disease right away. Rather, signs and symptoms of gum disease develop in four stages⁶ that may gradually impact the heart. These stages include:

1. Gingivitis: this is considered to be the earliest stage of gum disease. It results in:
   • Red or purplish gums
   • Sore and swollen gums 
   • Bleeding from the gums, especially upon brushing the teeth or flossing 
2. Mild periodontitis: this is the stage where ‘’deep pockets’’ start to form around the gums, resulting in: 
   • Gums pulling away from the teeth (gum recession): this makes it much harder to brush or floss those deeper areas, thus providing periodontopathic bacteria with an optimal ‘hiding’ place where they can happily proliferate and start to ‘seek’ bones, tissues, and ligaments to ‘attack’
3. Moderate periodontitis: at this stage, the periodontopathic bacteria erode or ‘eat away at’ the ligaments, tissues, and bones surrounding the teeth, resulting in signs and symptoms such as:
   • Bad breath (halitosis)
   • Unpleasant taste in the mouth
   • Pain when chewing 
   • Pus or infection around the gum line 
4. Advanced periodontitis: if left untreated, over time, more and more bones that keep the teeth in place fall victim to the periodontopathic bacteria, thus leading to:
   • Loose teeth 
   • Tooth loss: this particularly occurs when the alveolar bone in the jaw breaks down (alveolar bone resorption)²

In contrast to gingivitis, which is associated with no bone loss, and is, therefore, both reversible and treatable, periodontitis, especially in the advanced stages, is irreversible and untreatable.

Factors contributing to gum disease 

This is no surprise, but having poor oral hygiene and not brushing or flossing one’s teeth properly or regularly is the main contributor to gum disease.⁷ After all, tooth health and gum health go hand in hand. 

However, interestingly, there are other factors besides poor oral hygiene that may contribute to gum disease over time including: ⁷ 

• Psychosocial stress: there is some research available that suggests that psychosocial stress may lead to gum disease by potentially causing affected people to:
  • Neglect oral hygiene: this has been demonstrated particularly in medical students under excessive academic stress during the exam period 
  • Change their dietary intake: particularly by causing people to opt for sugary and highly refined carbohydrates instead of healthier low-sugar/high-fibre alternatives 

• Hormones: Interestingly, recent research studies have shown that certain sex hormones such as estrogen and progesterone, the levels of which fluctuate (rise and fall) throughout a female’s life and mainly influence female reproductive health, may cause gum disease by:¹
  • Increasing gingival inflammation (gum inflammation): particularly during puberty, pre-menstruation, and ovulation when estrogen levels are high as well as pregnancy when progesterone levels are high
  • Increasing alveolar bone breakdown: mainly during menopause when estrogen levels are low 
  • Heart disease:⁶ this leads us to the potential factor for gum disease development that will be primarily focused on in this article 

Exploring the link with heart disease

There are some studies available that have established a link or connection between gum health and heart disease. 

One of these studies, published in 2014, showed that patients who had both gum disease and heart disease and received periodontal therapy had 40.9% lower medical/ healthcare costs than those who did not receive periodontal therapy.² These findings suggest that gum health and heart health go hand in hand – when gum health is poor, there is an increased risk in the severity of heart disease and vice versa. They also highlight the importance of integrating proper dental care into heart disease prevention and treatment programmes. 

A study conducted in 2018, with over one million participants who experienced over 65,000 cardiovascular events a 2010 review article, and more recently, a 2023 meta-analysis which gathered and analysed data from over 26 studies, have supported these findings. They showed a moderate 7.2-20% increase in the risk of heart disease development in patients with gum disease.^8,3,5

The link between gum health and heart disease appears to be independent of gender assigned at birth but dependant on age, with gum disease patients assigned male at birth (AMAB) under 45 years of age in particular having a 23.8% versus a 7.5% increased risk of heart disease compared to AMAB gum disease patients aged 45 years and above.⁵

Mechanisms underlying the link

To date, scientists do not know how gum health and heart disease are linked, leading to many theories being proposed to explain the potential mechanisms underlying the link including: 

1. Inflammatory pathways: inflammation is currently the main mechanism proposed to explain the link between gum health and heart disease
2. It is widely theorised that upon periodontal inflammation, pathogenic periodontal bacteria and/or the host’s immune system (immune response) release proinflammatory markers (promote inflammation) into the bloodstream, which may cause systemic inflammation, and thus indirectly lead to heart disease¹ 
3. Bacterial translocation and invasion: rather than ‘attacking’ the heart indirectly via proinflammatory intermediates, it is also thought that the pathogenic periodontal bacteria directly invade the endothelial cells lining blood vessels in the heart, resulting in endothelial dysfunction, and eventually, heart disease³ 
4. Shared risk factors: it has also been theorised that it is not poor gum health that directly causes heart disease, but certain risk factors shared between both conditions⁸

In the 2018 study shared above, with over one million participants who experienced over 65,000 cardiovascular events, the scientists reported a moderate link between gum health and heart disease.⁸ However, when they took certain risk factors such as smoking into consideration, they found that AMAB never-smokers, in particular, had no apparent increase in tooth loss (a marker for gum health) compared to AMAB smokers, hence the direct/causal link between gum health and heart disease disappeared. 

Despite the study’s various strengths including its large size, one of its major weaknesses is that it only measured poor gum health based on tooth loss alone without taking other important indicators of gum health into account such as pocket depth and bleeding on probing. As was discussed above, tooth loss only occurs during the severe stages of gum disease and may occur for other reasons besides gum disease such as trauma.

Therefore, further studies are needed to replicate its findings before a potential direct/causal link between gum health and heart disease is eliminated. 

Summary 

Gum health and heart disease are interlinked, with some recent studies showing a moderate increase in the risk of heart disease development in people with gum disease and/or poor gum health. However, how exactly gum health and heart disease are linked remains unclear to date. 

Most scientists believe that poor gum health contributes to heart disease either: 

Indirectly:

• via release of proinflammatory mediators from the host or periodontopathic bacteria into the bloodstream and to the heart in response to periodontal inflammation (the main theorised mechanism)
• via confounding shared risk factors e.g. smoking 

Directly: via periodontopathic bacterial invasion of endothelial cells lining the heart 

Regardless of how exactly gum health and heart disease are connected, since a link is clearly evident, all people irrespective of gender and age, but particularly those with, or at risk of, heart disease, should be especially consistent with their oral hygiene routine to prevent gum disease and potentially in turn decrease the risk or severity of heart disease.