Oral health and systemic disease

Johnson & Johnson is delighted to bring you this article, with the aim of supporting the ongoing CPD needs of dental healthcare professionals in improving and maintaining the oral health of their patients.

This article is equivalent to one hour of Enhanced CPD. To provide feedback on this article, please contact

Learning outcomes


Aims and objectives

The aim of this article is to consider the current evidence linking periodontal disease to other non-communicable conditions and offer advice on its usefulness in dental practice.

On completing this Enhanced CPD session, the reader will:

• Understand the historical link between periodontal disease and systemic health, and how it has developed over time

• Understand that loss of periodontal tissue is a common manifestation of certain systemic disorders, which could have important diagnostic value and therapeutic implications

• Understand the quality of the evidence linking periodontal disease with diabetes mellitus, obesity, cardiovascular disease and cancer

• Understand why there are limitations on what can be concluded from the body of evidence investigating the link between periodontal diseases and other chronic inflammatory conditions, and how ‘confounding’ and ‘causality’ fit in

• Understand how to communicate the possible link with patients in an effort to further support their oral health efforts between appointments.

Oral health and systemic disease

This article considers the current evidence linking periodontal disease to other non-communicable conditions and offers advice on its usefulness in dental practice.

A link between oral infection and systemic health was first suggested in the literature in the 1800s, and was followed around 1900 by the focal-infection theory, which linked oral sepsis and the disease of organs but was later discarded.1,2 In the late 1980s, Matilla and colleagues suggested a possible link between oral health and cardiovascular disease, introducing a topic that is still of great interest to the dental profession.1

More recently, at the 2017 World Workshop on the classification of periodontal and peri-implant diseases and conditions, it was stated that: ‘Periodontal diseases and certain systemic disorders share similar genetic and/or environmental etiological factors and, therefore, affected individuals may show manifestations of both diseases. Hence, loss of periodontal tissue is a common manifestation of certain systemic disorders, which could have important diagnostic value and therapeutic implications.’3

With this in mind, it may be worth further exploring the evidence linking periodontal disease with some of the other common diseases affecting the global population, such as diabetes mellitus, obesity, strokes and cancer.4

Diabetes mellitus

Among the disorders that have been investigated for a link with periodontal disease is diabetes mellitus. Over the last few years, evidence has emerged suggesting diabetes mellitus is a risk factor for periodontal disease and is associated with a higher prevalence and severity of periodontitis. There is also growing evidence that periodontal inflammation may play a part in triggering hyperglycaemia, and its continuance.

However, offering a notable caution to all of this, Albandar and colleagues (2018) wrote: ‘[…] interpretation of these findings may be confounded by the effects of comorbidities often seen in individuals with metabolic syndrome, including obesity and hypertension.’3


Obesity is a growing problem, with adult obesity in England rising from 15% in 1993 to 26% in 2016.5


Studies indicate that obesity increases a person’s susceptibility to viral and bacterial infections.3

In terms of periodontal disease, meta-analyses support, ‘[…] an epidemiological association between obesity and periodontitis, suggesting a 50% to 80% higher likelihood of periodontitis in individuals who are obese compared with individuals who are not. It has been estimated in longitudinal follow-up studies that individuals who are obese have a 35% increased risk of developing periodontitis compared with normal‐weight individuals, and the risk may be higher among women who are obese compared with men who are obese.’3

However, it should be noted that there is no difference in the preventive / treatment protocol to be provided to obese patients with periodontal disease versus those who are a healthier weight.3


In 2018, Sen and colleagues reported on their Atherosclerosis Risk in Communities (ARIC) study, during which participants were divided into seven periodontal disease levels and monitored for 15 years. They found that the more severe the periodontal disease, the higher the risk of stroke. It was also found that patients who underwent regular dental care demonstrated a negative association with stroke.6

They wrote: ‘Observational studies have shown that poor periodontal health status is associated with an increased stroke risk. Poor oral hygiene is a major contributor to periodontal disease and thus a potentially modifiable stroke risk factor. An increase in tooth-brushing frequency decreases the concentrations of systemic inflammatory markers levels in the serum.’6

This suggests that dental treatment may act as a preventive tool in reducing the risk of cardiovascular diseases. However, prospective studies are needed to confirm this theory, as Sen and colleagues (2018) research did have limitations, including, ‘[…] reliance on single periodontal disease assessment, a limited number of incident stroke subtypes, and owing to the observational nature of our investigation, the possibility of residual confounding cannot be eliminated.’6,7


Cancer is another disease that has been discussed in the literature as perhaps having an association with periodontal disease. In a separate, supplementary study to the above-mentioned ARIC, the same cohort was examined for cancer risk factors. Following up after an average of 7.9 years, it was found that the ‘[…] hazard ratios for a diagnosis of malignancy was significantly higher (24%;HR-1.24) among patients with severe periodontitis as compared to those who had mild disease or a healthy mouth. The strongest associations were found for lung and colorectal cancer and were observed mostly in men. A correlation of cancer mortality with severe PD [periodontal disease] was also identified.’7

Further research is required in this area, as explained by Michaud and colleagues (2018): ‘Future studies should evaluate and report periodontitis using clinical dental measurements whenever possible and consider different classification of periodontal disease severity. Additional research, both observational and experimental, is needed to evaluate whether periodontal disease prevention and treatment can alleviate cancer burden.’8

Evidential limitations

Whilst each new study adds to the body of evidence linking periodontal disease with systemic health, there are limitations to what can be concluded.6 Not all studies are created equal as suggested by Sen et al (2018), who wrote: ‘Individual studies have limitations, including the use of many differing definitions of periodontal disease, consideration of potential cofounders such as socioeconomic status, and low statistical power.’6

As mentioned above, there are also the issues of ‘confounding’, as well as ‘causality’, to consider. Confounding factors encompass risk factors that may overlap between systemic diseases such as age, gender, smoking, obesity and socio-economic status.2

Because of this, Winning and Linden (2015) suggested, ‘[…] when we describe links between periodontitis and systemic disease to patients we should bear possible confounding factors in mind so we do not imply that periodontal disease is the only reason they might have a particular condition. A further difficulty is that most research cannot identify cause and effect relationships.’2

With this in mind, unless and until there is sufficiently robust evidence of causality, ‘[…] when we discuss links between periodontitis and systemic disease with patients it is better to describe ‘association’ rather than ‘causation’.’2

Offering a further practical perspective in line with this caveat, Bartold and Mariotti (2017) stated: ‘Traditionally, periodontal treatment has focused on preserving or restoring the structure, function, and esthetics of the dentition; however, with the emergence of how periodontal inflammation and infection may impact overall health and well being, focus is turning towards preventing untoward effects of periodontal disease on overall health. As the possible relationships between oral and systemic health gain coverage in the public, we must not raise false hopes of treatment resulting from inappropriate studies containing irrelevant or trivial associations.’9

Practical aspects

This article has provided a snapshot of some of the systemic conditions that have been associated with periodontal disease, with varying levels of evidence supporting any such link. An extensive list of the conditions thought to be connected in some way was created at the 2017 World Workshop by Albandar and colleagues (2017) and is available at

Dental professionals may also find the European Federation of Periodontology’s (EFP) manifesto on perio and general health useful, as it provides a consensus of the outcomes reached by experts at the 9th European Workshop in Periodontology and was updated in 2018.

The advice offered in this manifesto for periodontal care in relation to a number of systemic diseases is based upon ‘[…] rigorous scientific analysis of the evidence base for reported links between periodontal and systemic diseases […]’.10

Given that that the evidence base is of varying quality, Borgnakke and colleagues (2013) offered dental professionals the following practical advice: ‘While waiting for definitive evidence, it may be wise to make efforts to prevent – and treat to resolution any existing – periodontal disease, in order to ensure good health.’11

As a final note, Winning and Linden (2015) had the following to offer on the topic: ‘Whilst there is now good evidence for periodontitis associating with various systemic diseases (particularly atherosclerotic cardiovascular disease and diabetes), evidence for a causative role is still lacking. Many of the reviews in this area report that ‘further studies are needed’, but that should not prevent us taking a pragmatic approach in promoting a patient’s good oral health benefiting their general health. Treating periodontal disease, where we also address shared modifiable risk factors such as smoking, diabetes control, and diet can only have a positive effect on related systemic disease and as dental professionals we are ideally situated as front line health staff to do this. It is acknowledged that the gaps in our knowledge remain large.’2



  1. Kjellström B et al. Periodontal disease – important to consider in cardiovascular disease prevention. Expert Review of Cardiovascular Therapy 2016; 14(9): 987-989

  2. Winning L, Linden JG. Periodontitis and systemic disease. BDJ Team 2015; 2(15163)

  3. Albandar JM et al. Manifestations of systemic diseases and conditions that affect the periodontal attachment apparatus: Case definitions and diagnostic considerations. J Clin Periodontol. 2018; 45(Supp 20): S171-S189

  4. Global Burden of Disease: Massive shifts reshape the health landscape worldwide. The Institute for Health Metrics and Evaluation (IHME) 2012. Available at: Accessed 7 February 2019

  5. Baker C. Obesity Statistics. Briefing paper no. 3336. House of Commons Library, March 2018

  6. Sen S et al. Periodontal disease, regular dental care use, and incident ischemic stroke. Stroke 2018; 49(2): 355-362

  7. Barasch A. Oral disease and systemic implications. Accessed 6 February 2019

  8. Michaud DS et al. Periodontal disease assessed using clinical dental measurements and cancer risk in the ARIC study. JNCI J Natl Cancer Inst (2018) 110(8): 843-854

  9. Bartold PM, Mariotti A. The future of periodontal-systemic associations: raising the standards. Curr Oral Health Rep 2017; 4: 258-262

  10. EFP Manifesto. Perio and general health. European Federation of Periodontology, updated 2018

  11. Borgnakke WS. Effect of periodontal disease on diabetes: systematic review of epidemiologic observational evidence. J Clin Periodontol 2013; 40 (Supp. 14): S135–S152