Are Older Adults More Vulnerable to Oral Systemic Link?

This blog is part of the Geriatric Dentistry Program weekly special – updates in Advancement and Oral Health in Geriatric Dentistry.

The link between oral and systemic diseases has been under intense investigation in recent years.  This is certainly an exciting and necessary advance for dentistry because it finally brings awareness to all healthcare practitioners and the public on the importance of oral health.

This topic is more important in older adults than in any other age group because of significantly higher prevalence of systemic diseases and decreased physiologic reserve as well as functional capacity in this group.

As people age, they may experience more changes in their oral health, such as teeth loss, periodontal disease, dry mouth, and caries. These oral health issues can have significant impacts on overall health as they may contribute to various systemic conditions and diseases.

The main purpose of this blog post is to briefly examine current evidence of the link between oral health and various systemic diseases in an attempt to increase awareness among clinical and non-clinical oral health practitioners/staff on the crucial importance of oral health in older adults. 

Periodontal disease has been extensively studied in terms of its link to systemic health. A hematogenous (bacteria, toxins, and inflammatory cytokines in the systemic circulation) route had been considered as a main mechanism in the impact of periodontal disease on systemic diseases.   However, in recent years, the entire oral microbiome consisting of bacteria, fungi, and viruses, has been implicated in disrupting the gut microbiome through the digestive route thereby inducing a negative impact on systemic diseases.  Much evidence available today suggests that maintaining optimal oral health is crucial to maintaining good overall health [1].

Here are current findings on how oral health affects other systemic diseases.

Cardiovascular Diseases (CVD):

It is estimated that 70% of people over 70 years old will develop CVD and that more than two-thirds will also have associated non-cardiovascular comorbidities [2].

Ngamdu and coworkers investigated the relation between cardiovascular diseases (CVD) and periodontal disease and found that patients with stage 3 and 4 periodontal disease were 3 and a half times more likely to have CVD than those with stage 1 periodontal disease [3].

Furthermore, it was found that oral bacteria, specifically Streptococcus mutans (implicated in caries) and Porphyromonas gingivalis  (implicated in periodontitis) induce platelet aggregation, leading to thrombus formation [4].

The most probably causative mechanism behind this is the influx of bacteria and/or bacterial products (endotoxin) and inflammatory cytokines into the systemic circulation [5].

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Diabetes Mellitus:

The percentage of adults with diabetes, both diagnosed and undiagnosed, increased with age, reaching 26.8% among those aged 65 years or older in the U.S. in 2013-16 [6]. The prevalence of diabetes will likely double from 2010 (14%) to 2050 (25 -28%) in the U.S. in part due to the aging of the population, increase in diabetes incidence, and lower diabetes-related mortality [7]. Other projections suggest that the number of cases of diagnosed diabetes in those aged ≥75 years will increase by 4.5-fold (compared to 3-fold in the total population) between 2005 and 2050.  46.6% of older adults over 65 years of age were estimated to have prediabetes in 2013-16 [8].

Patients with diabetes have twice the risk for periodontal disease when compared to those without [9]. Patients with periodontal infections display worse glycemic control and have greater difficulty managing their diabetes.  Treatment of periodontitis appears to improve glycemic control. A bidirectional relationship has been described as existing between diabetes and periodontal disease [10].

Aspiration Pneumonia:

Today, many older adults retain their natural teeth much longer while others become edentulous and resort to wearing complete dentures.  Oral and denture hygiene presents an important factor in aspiration pneumonia for older adults.  Poorly cleaned dentures can become reservoirs for many bacterial, viral, and fungal microorganisms [11]. Considering many older adults develop dysphagia (difficulty swallowing), poor oral and denture hygiene, coupled with many denture wearers sleeping with dentures in the mouth, can increase the risk of aspiration pneumonia for frail elderly [12].

Alzheimer’s Disease:

Borsa’s systematic review of 5 studies found increases in F. nucleatum and P. gingivalis (periodontal pathogens) in Alzheimer’s disease patients.  In addition, the presence of periodontitis at baseline was associated with a nearly 6-fold increase in the rate of cognitive decline over 6 months follow up, which highly suggests an association between periodontal disease and Alzheimer’s disease [13].

In addition, a community based prospective study in Japan revealed that the number of remaining natural teeth was significantly associated with cognitive function. They also found that the use of artificial teeth was associated with the preservation of cognitive function [14].

Yamazaki K., Oral-gut axis as a novel biologic. al mechanism linking periodontal disease and systemic diseases: A review. Jpn Dent Sci Rev. 2023 Dec:59:273-280

Problems older adults face and possible solutions:

• Many older adults avoid dental visits because they are without any dental insurance and may have a limited budget [15]:  Improvements in access for to dental care for older adult by providing easier financing and in-office discount membership plan which includes examinations, x-rays and prophylaxis at nominal or no cost.
• Many older adults avoid dental visits simply because they are not aware how oral health can significantly impact their general overall health:  Our local, state and national level dental organizations should jointly create and disseminate education on importance of oral systemic link in general overall health especially for older adults.  Individual oral health practitioners should also provide patient education as well as prevention and management strategies.
• Undiagnosed/untreated periodontal disease and caries:   Provide thorough examination during frequent maintenance visits for early detection of periodontal disease and caries and provide timely and appropriate treatment to prevent inflammation, infection and teeth loss.
• Frail immunocompromised older adults with swallowing difficulty (dysphagia) may be more vulnerable to aspiration pneumonia:  Educate dentate patients on importance of home care before sleep.  If patient wears prosthesis, educate patients on proper denture hygiene and to avoid sleeping with dentures in the mouth.
• Older patients with uncontrolled diabetes:  Place them on more frequent maintenance intervals and close monitoring and appropriately treat periodontal disease if present.
• Compromised home care in patients with dementia:  Involve caregiver/family member to improve home care and aggressively prevent and treat periodontal disease and teeth loss.

Conclusion:

A substantial amount of evidence has become available in the last decade on the topic of various links between oral and systemic health.  Since older adults are the segment which is most impacted by this connection due to the higher prevalence of various systemic and oral diseases, dentists must focus closely on prevention, early diagnosis, and timely treatment of oral diseases in older patients.

Because of the complex health status of many older patients, it is of utmost importance for oral health and medical practitioners to work closely together for the benefit of older patients to achieve optimal care and outcomes.

It is so exciting to know that we as oral health practitioners can have an enormous impact on improving the overall health and quality of life of our older patients!

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References:

1. Lee Y. et al. Progress in Oral Microbiome Related to Oral and Systemic Diseases: An Update. Diagnostics (Basel). 2021 6;11(7):1283. 
2. Dunlay SM, Chamberlain AM. Multimorbidity in older patients with cardiovascular disease. Curr Cardiovasc Risk Rep. 2016;10:3.
3. Ngamdu K et al. Association Between Periodontal Disease and Cardiovascular Disease (from the NHANES). Am J Cardiol. 2022 Sep 1:178:163-168.
4. Nomura R, Otsugu M, Naka S, et al. Contribution of the interaction of Streptococcus mutans serotype k strains with fibrinogen to the pathogenicity of infective endocarditis. Infect Immun. 2014;82:5223–34
5. Yamazaki K., Oral-gut axis as a novel biologic. al mechanism linking periodontal disease and systemic diseases: A review. Jpn Dent Sci Rev. 2023 Dec:59:273-280
6. National Diabetes Statistics Report, 2020: Estimates of Diabetes and Its Burden in the United States. Centers for Disease Control and Prevention, U.S. Dept of Health and Human Services. Published 2020. https://www.cdc.gov/diabetes/pdfs/data/statistics/national-diabetes-statistics-report.pdf
7. Boyle JP et al. Projection of the year 2050 burden of diabetes in the US adult population: Dynamic modeling of incidence, mortality, and prediabetes prevalence. Popul Health Metr. 2010;8:1-12.
8. Narayan KMV et al. Impact of recent increase in incidence on future diabetes burden: U.S., 2005-2050. Diabetes Care. 2006;29(9):2114-2116.
9. National Diabetes Statistics Report. Centers for disease control and prevention website. 2014. Available at: www.cdc.gov/diabetes/pubs/statsreport14/national-diabetes-report-web.pdf.
10. Taylor GW, Burt BA, Becker MP, et al. Severe periodontitis and risk for poor glycemic control in patients with non-insulin-dependent diabetes mellitus. J Periodontol. 1996;67(10 suppl):1085–93.
11. O’Donnell L. et al, Dentures are a Reservoir for Respiratory Pathogens J Prosthodont. 2016 Feb;25(2):99-104.
12. Iinuma T. et al. Denture wearing during sleep doubles the risk of pneumonia in the very elderly. J Dent Res. 2015 Mar;94(3 Suppl):28S-36S.
13. Borsa et al. Analysis the Link between Periodontal Diseases and Alzheimer’s Disease: A Systematic Review. Int J Environ Res Public Health. 2021 Sep 3;18(17):9312.  
14. Kato H. et al. Tooth Loss-associated Cognitive Impairment in the Elderly: A Community-based Study in Japan. Intern Med. 2019 May 15;58(10):1411-1416.
15. https://www.nidcr.nih.gov/research/oralhealthinamerica/section-3b-summary