Periodontal disease and cancer risk: A nationwide population-based cohort study

Multifunctional human serum albumin-crosslinked and self-assembling nanoparticles for therapy of periodontitis by anti-oxidation, anti-inflammation and osteogenesis

Periodontitis is a chronic inflammatory disease that can result in the irreversible loss of tooth-supporting tissues and elevate the likelihood and intensity of systemic diseases. The presence of reactive oxygen species (ROS) and associated related oxidative stress is intricately linked to the progression and severity of periodontal inflammation. Targeted removal of local ROS may serve to attenuate inflammation, improve the unfavorable periodontal microenvironment and potentially reverse ensuing pathological cascades. These ROS scavenging nanoparticles, which possess additional characteristics such as anti-inflammation and osteogenic differentiation, are highly sought after for the treatment of periodontitis. In this study, negative charged human serum albumin-crosslinked manganese-doped self-assembling Prussian blue nanoparticles (HSA-MDSPB NPs) were fabricated. These nanoparticles demonstrate the ability to scavenge multiple ROS including superoxide anion, free hydroxyl radicals, singlet oxygen and hydrogen peroxide. Additionally, HSA-MDSPB NPs exhibit the capacity to alleviate inflammation in gingiva and alveolar bone both in vitro and in vivo. Furthermore, HSA-MDSPB NPs have been shown to play a role in promoting the polarization of macrophages from the M1 to M2 phenotype, resulting in reduced production of pro-inflammatory cytokines. More attractively, HSA-MDSPB NPs have been demonstrated to enhance cellular osteogenic differentiation. These properties of HSA-MDSPB NPs contribute to decreased inflammation, extracellular matrix degradation and bone loss in periodontal tissue. In conclusion, the multifunctional nature of HSA-MDSPB NPs provides a promising therapeutic approach for the treatment of periodontitis.

A population-based study on the associations of thyroid cancer with chronic periodontitis

BACKGROUND

Emerging concerns link periodontitis to an array of cancers, notably thyroid cancer, though investigations into these associations are still in the nascent stages. This population-based study aimed to investigate the association of thyroid cancer with chronic periodontitis using Taiwan's Longitudinal Health Insurance Database 2010 (LHID2010).

METHODS

This case-control study utilized LHID2010, selecting 2,775 patients diagnosed with thyroid cancer, matched with 8,325 controls based on age, sex, income, and the presence of diabetes, hypertension, hyperlipidemia, human papillomavirus infection, and tobacco use disorder using propensity-score matching. Multivariate logistic regression models were used to evaluate the association of thyroid cancer with chronic periodontitis.

RESULTS

A chi-squared analysis demonstrated a significant disparity in the prevalence of chronic periodontitis between those diagnosed with thyroid cancer and the controls, with prevalence rates of 38.5% and 24.1% respectively, and a p-value less than 0.001. The odds ratio (OR) for having prior chronic periodontitis among patients with thyroid cancer compared to controls was 1.991, with a 95% confidence interval (CI) of 1.816-2.184 and a p-value less than 0.001. The association was similar between sexes, yielding adjusted ORs of 1.991 (95% CI = 1.816∼2.184) for men and 1.962 (95% CI = 1.765-2.182) for women, indicating a statistically significant higher prevalence of chronic periodontitis in both male and female patients diagnosed with thyroid cancer compared to their control counterparts.

CONCLUSION

The findings highlight chronic periodontitis as a potential risk factor for thyroid cancer, underscoring the importance of integrated health surveillance and preventive strategies that encompass oral health.

PLAIN LANGUAGE SUMMARY

This study aimed to explore the link between thyroid cancer and chronic periodontitis. Using Taiwan's Longitudinal Health Insurance Database 2010 (LHID2010), we selected 2,775 patients with thyroid cancer and matched them with 8,325 individuals without the disease based on age, sex, income, and other health conditions such as diabetes, hypertension, high cholesterol, HPV infection, and smoking habits. The study used statistical models to examine the relationship between thyroid cancer and chronic periodontitis. The findings showed that 38.5% of thyroid cancer patients had chronic periodontitis, compared to 24.1% of the control group. The odds of having chronic periodontitis were nearly twice as high in thyroid cancer patients. This pattern was consistent for both men and women. The study underscores the strong connection between chronic periodontitis and thyroid cancer, emphasizing the importance of raising public awareness about the potential risks of periodontitis.

Epidemiological associations between periodontitis and cancer

There is a postulated association of periodontitis with a number of human cancers. This narrative review provides current epidemiological evidence on the association between periodontitis and cancer. A PubMed search with the relevant keywords (periodontal disease, periodontitis, cancer, and malignancy) was completed to identify relevent articles. We present a narrative review on the association between periodontal disease and a range of cancers, including oral cancer, stomach and esophageal cancer, colorectal cancer, lung cancer, pancreatic cancer, prostate cancer, hematological malignancies, liver cancer, breast cancer, and ovarian cancer. While there is a considerable body of epidemiological evidence that supports the association between periodontal disease and cancer, this is largely from cohort and case-control studies and the association may therefore be circumstantial as little evidence exists in the form of treatment trials that would validate the role of periodontal disease in the process of cancer initiation and development.

Oral health, treatment burden and demographics of elders with care-resistant behavior: A cross-sectional study

AIMS

To assess oral health, treatment burden, mortality risk, and demographics in elders with care-resistant behaviors (CRB) in nursing homes (NH) and compare them with those without CRB.

METHODS AND RESULTS

503 participants from eight NH who received dental treatment through a mobile dental clinic were included. Their medical and dental records were screened regarding oral/dental health, treatment history, general health, demographics, and CRB. Statistical analysis was performed to show correlations between CRB and the measured parameters. Data were verified for normal distribution; a point-biserial correlation model was used (95% CI: α = 0.05). No correlation was found between CRB and Decayed Missing Filled Teeth (DMF-T) (rpb = -0.061, p = .177), as well as periodontal status (rpb = 0.004, p = .946). A negative correlation was observed between CRB and the required number of treatment procedures (rpb = -0.181, p < .0001), time (rpb = -0.118, p = .010), and costs (rpb = -0.100, p = .028). Sex predilection for men regarding CRB was evident (rpb = -0.155, p = .01). No correlation appeared between CRB and vital status (rpb = -0.41, p = .355).

CONCLUSION

Oral health seems to be similar in institutionalized elders with or without CRB. Treatment burden was not elevated, but even reduced in elders with CRB, evincing that few/no treatment procedures were performed in those elders. CRB demonstrated a sex predilection for men. An association between CRB and increased mortality was not evident.

Association between Periodontal Diseases and the Risk of Site-Specific Gastrointestinal Cancers: A Systematic Review and Meta-Analysis

The association between periodontal diseases and the risk of gastrointestinal cancers, especially site-specific gastrointestinal cancers, remains unclear. Here, we comprehensively searched PubMed, EMBASE, Web of Science, and Google Scholar from inception to April 2024 to identify relevant studies. The pooled hazard ratios (HRs) and 95% confidence intervals (CIs) were calculated with a random-effects model. Subgroup analyses and sensitivity analyses were conducted to confirm the robustness of the main findings in different populations. This study was reported according to PRISMA 2020 guidelines. In total, we identified 19 studies, including 16.6 million participants. Individuals with periodontal diseases had an increased risk of overall gastrointestinal cancers compared with those without periodontal diseases (HR 1.31, 95% CI 1.16-1.49). Periodontal diseases significantly increased the risk of esophageal cancer by 39% (HR 1.39, 95% CI 1.15-1.68), gastric cancer by 13% (HR 1.13, 95% CI 1.01-1.26), colorectal cancer by 21% (HR 1.21, 95% CI 1.05-1.39), pancreatic cancer by 35% (HR 1.35, 95% CI 1.00-1.82), and liver cancer by 9% (HR 1.09, 95% CI 1.04-1.13). The risk of gastrointestinal cancers was significantly increased by periodontitis (HR 1.45, 95% CI 1.14-1.85), gingivitis (HR 1.03, 95% CI 1.01-1.04), and periodontitis/gingivitis (HR 1.27, 95% CI 1.07-1.51). Furthermore, severe periodontal diseases showed a significantly increased risk of gastrointestinal cancer (HR 1.79, 95% CI 1.07-2.99). Results of sensitivity analyses for site-specific gastrointestinal cancers were robust with the main findings. In summary, periodontal diseases, especially severe periodontitis, increase the risk of overall and site-specific gastrointestinal cancers. Interventions to prevent and manage periodontal diseases may reduce the risk of developing gastrointestinal cancers.

Bidirectional Association between Periodontitis and Thyroid Disease: A Scoping Review

Periodontitis is a chronic inflammatory disease of the tissues surrounding and supporting the teeth. Due to the development of chronic inflammation, periodontitis can contribute to the development of several systemic diseases, including thyroid disease. Thyroid pathology includes benign, malignant, and autoimmune conditions leading to hypothyroidism, hyperthyroidism, or euthyroidism. Alterations in thyroid hormones, especially hypothyroidism, can reveal significant oral manifestations, including periodontitis. This scoping review aims to explore the probable causal relationship between periodontitis and thyroid disease, in terms of epidemiology, pathogenesis, and treatment. The search strategy follows the PRISMA-ScR guidelines. PubMed, Scopus, Web of Science, and Cochrane were searched from January 2014 to January 2024, entering the MESH terms "periodontitis" and "thyroid". Of 153 initial records, 20 articles were selected and discussed. There is a high prevalence of periodontitis among patients with thyroid disease, including thyroid cancer. The causes at the basis of this association are genetic factors, the oral microbiome, and proinflammatory cytokines. Periodontal treatment, specifically scaling and root planning, can ameliorate thyroid parameters. Although there are a few randomized controlled studies in the literature, this review lays the foundation for a bidirectional relationship between periodontitis and thyroid disease, the link to which is, once again, systemic inflammation.

Periodontitis and the risk of oral, gastric and esophageal cancers: a two-sample Mendelian randomization study

BACKGROUND

Periodontitis is a common oral disease and the chronic inflammation caused by it may influence the development of cancers in the upper gastrointestinal tract. Many observational studies have established a relationship between the two, but the results are not entirely consistent.

METHODS

Two-sample MR was performed using publicly available genome-wide association studies data for periodontitis, oral, gastric and oesophagal cancers. The Inverse Variance Weighting (IVW) method serves as the primary method, with MR Egger, Weighted Median, Simple Model and Weighted Model Algorithm methods as complementary methods to assess genetic causal associations. Cochran Q-test, MR-Egger regression and MR polytropic residuals and outliers were used to assess heterogeneity and horizontal pleiotropy.

RESULTS

IVW results did not support a causal association between periodontitis and oral (OR = 1.00, 95% CI: 1.00, 1.00) and oesophagal cancer (OR = 1.00, 95% CI: 1.00, 1.00). Similarly, there was again no causal association between periodontitis and gastric cancer, which was integrated with an OR of 1.04 (95% CI: 0.97, 1.12). Complementary method results were consistent with IVW and heterogeneity and horizontal pleiotropy were not found in most studies.

CONCLUSIONS

The findings of our MR study do not support a causal relationship between periodontitis and oral, gastric and oesophagal cancers.

Chronic periodontitis and risk of lung cancer: a nationwide cohort study

Background

The impact of long-term chronic periodontal conditions on the risk of lung cancer could not be accurately evaluated. Our aim was to provide more evidence on the connection between chronic periodontitis (CP) and lung cancer using a nationwide dataset.

Methods

This study used data from the Korean National Health Insurance Service National Sample Cohort. We enrolled 72,658 individuals with CP (CP cohort) between 2005 and 2019 and 1:1 age- and sex-matched controls without CP (non-CP cohort).

Results

During the median follow-up period of 5.1 (interquartile range, 2.8-8.0) years, 0.56% (n = 405/72,658) of the CP cohort and 0.29% (n = 212/72,658) of the matched non-CP cohort developed lung cancer, with incidence rates of 8.3 and 4.5 per 10,000 person-years. The risk of incident lung cancer was significantly higher in the CP cohort than in the matched non-CP cohort (adjusted hazard ratio = 2.27, 95% confidence interval = 1.94-2.65). The risk of incident lung cancer was 2.45-fold and 2.10-fold higher in mild and moderate-to-severe CP cohorts than in the matched non-CP control. The risk of incident lung cancer was especially higher in the 40-59 age group, females, and never-smokers than their counterparts.

Conclusion

We demonstrate that the risk of incident lung cancer is higher in individuals with CP than in those without. The risk of lung cancer was especially high in individuals with more severe CP, females, never-smokers, and obese populations.

Two-sample Mendelian randomization analysis of the relationship between periodontitis and risk of upper gastrointestinal cancers

PURPOSE

The aim of the present study is to explore the possible association between periodontitis and upper gastrointestinal (UGI) cancers, including esophageal and gastric cancers, utilizing the Mendelian randomization method.

METHODS

In this research, we utilized the Mendelian randomization method to examine the causal association between periodontitis and UGI cancers. Genome-wide association studies data for periodontitis were obtained from the Gene-Lifestyle Interactions in Dental Endpoints consortium, while UGI cancers' data were accessed from FinnGen's Biobank. After rigorously screening instrumental variables for periodontitis, we analyzed them with UGI cancers primarily using the inverse variance weighted. Finally, to identify outliers, the results were subjected to a leave-one-out sensitivity analysis.

RESULTS

Inverse variance weighted (fixed effect) results revealed that periodontitis is a risk factor for gastric cancer (OR = 1.7735, 95% CI: 1.1576 to 2.7170, P = 0.0085). As for esophageal cancer, no statistically significant correlation was observed. Furthermore, no outliers were detected in any of the results.

CONCLUSION

Our two-sample Mendelian randomization study obviously demonstrates a significant positive association between periodontitis and gastric cancer, while no statistically significant correlation was found for esophageal cancer.

Oral dysbiosis and risk of gastrointestinal cancers: A systematic review and meta-analysis of longitudinal studies

BACKGROUND

Poor oral health and oral dysbiosis were found to be associated with cancers, especially of the gastrointestinal (GI) system. But the cause-and-effect relationship and the effect of the risk are not yet known due to scarcity of literature. Understanding such risk relationship can contribute to an integrated multi-disciplinary approach for GI cancer prevention.

AIM

The aim of the present systematic review and meta-analysis is to assess the role of oral dysbiosis on increasing the risk of digestive system cancers.

OBJECTIVE

To evaluate the effect of poor oral health on increasing the risk of gastrointestinal cancers.

METHODS

We conducted a systematic search following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines in databases PubMed, Elsevier, Wiley's online library and Web of Science from inception to February 2023 to include recent cohort studies that assessed the association between poor oral health and the risk of cancer. We assessed bias using the New Castle Ottawa scale. We used inferential statistics to describe the effect of oral dysbiosis on gastrointestinal cancers. We performed a sub-group analysis to assess the effect of oral conditions on individual cancers.

RESULTS

We included 10 longitudinal studies in the meta-analysis. The overall effect size of poor oral health and GI cancer risk was hazard's ratio (HR) =1.30 (95% CI: [1.14, 1.46]) (p<0.001) (I2 = 68.78). Sub-group analysis indicated that poor oral health increases the risk of esophageal cancer HR=1.61 (95% CI: [1.37, 1.85]), stomach cancer HR=1.33 (95% CI: [1.08, 1.58]), pancreatic cancer HR=1.90 (95% CI; [1.29, 2.50]) and colorectal and hepatocellular carcinoma HR=1.16 (95% CI: [1.08, 1.23]).

CONCLUSION

The meta-analysis indicated that poor oral health was significantly associated with increasing the risk of GI cancers.

Association between Periodontitis and Hematologic Cancer: An NHIRD Cohort Study in Taiwan

BACKGROUND

Chronic periodontitis, an inflammation-related disorder affecting global populations, has been revealed to be linked to diverse cancers. Numerous epidemiological studies have not shown a link between chronic periodontitis and blood cancers in Taiwan.

METHODS

This study included 601,628 patients, diagnosed with newly chronic periodontitis by the ICD-9-CM classification, who were enrolled from 2001 to 2021 in the National Health Insurance Research Database (NHIRD) in Taiwan. In this study, we employed comprehensive statistical analyses to investigate the association between chronic periodontitis and hematologic cancers. Initially, we calculated incidence density and used a Poisson regression to analyze relative risk. Subsequently, we compared the cumulative incidence of hematological cancer in both chronic and non-chronic periodontitis groups using the Kaplan-Meier method.

RESULTS

The results revealed a significantly lower cumulative incidence of hematologic cancer in individuals with non-chronic periodontitis over a 12-year follow-up period. To further explore the risk factors, a Cox proportional hazard regression analysis was conducted. Being male (adjusted hazard ratio [aHR] = 1.21, 95% CI: 1.04 to 1.42; p = 0.014) and having hypertension (aHR = 1.34, 95% CI: 1.06 to 1.69; p = 0.015) were demonstrated to be associated with an increased risk of hematologic cancers, respectively. In addition, in a subtype multivariate analysis for categorizing hematologic cancers into lymphoma and leukemia, the aHR for leukemia was 1.48 (95% CI: 1.13 to 1.93; p = 0.004) and aHR for lymphoma was 1.15 (95% CI: 0.96 to 1.37; p = 0.140).

CONCLUSIONS

This study found that being male and having hypertension were the significant risk factors for hematological malignancies. Moreover, the association between chronic periodontitis and specific subtypes of hematologic cancers was confirmed.

Patients with periodontitis might increase the risk of urologic cancers: a bidirectional two-sample Mendelian randomization study

BACKGROUND

Numerous observational epidemiological studies have reported a bidirectional relationship between periodontitis and urological cancers. However, the causal link between these two phenotypes remains uncertain. This study aimed to examine the bidirectional causal association between periodontitis and four types of urological tumors, specifically kidney cancer (KC), prostate cancer (PC), bladder cancer (BC), and testis cancer (TC).

METHODS

Based on large-scale genome-wide association study (GWAS) data, we utilized the two-sample Mendelian randomization (MR) approach to evaluate causal relationships between periodontitis and urological cancers. Several MR methods covering various consistency assumptions were applied in this study, including contamination mixture and Robust Adjusted Profile Score to obtain robust results. Summary-level data of individuals with European ancestry were extracted from the UK Biobank, the Kaiser GERA cohorts, and the FinnGen consortium.

RESULTS

Our findings revealed significant positive genetic correlations between periodontitis and kidney cancer (OR 1.287; 95% CI 1.04, 1.594; P = 0.020). We did not find a significant association of periodontitis on prostate cancer, bladder cancer, and testis cancer. In reverse MR, no significant results were observed supporting the effect of urologic cancers on periodontitis (all P > 0.05).

CONCLUSION

Our study provides the evidence of a potential causal relationship between periodontitis and kidney cancer. However, large-scale studies are warranted to confirm and elucidate the underlying mechanisms of this association.

Poor oral health was associated with higher risk of gastric cancer: Evidence from 1431677 participants

BACKGROUND

In recent years, the association between oral health and the risk of gastric cancer (GC) has gradually attracted increased interest. However, in terms of GC incidence, the association between oral health and GC incidence remains controversial. Periodontitis is reported to increase the risk of GC. However, some studies have shown that periodontitis has no effect on the risk of GC. Therefore, the present study aimed to assess whether there is a relationship between oral health and the risk of GC.

AIM

To assess whether there was a relationship between oral health and the risk of GC.

METHODS

Five databases were searched to find eligible studies from inception to April 10, 2023. Newcastle-Ottawa Scale score was used to assess the quality of included studies. The quality of cohort studies and case-control studies were evaluated separately in this study. Incidence of GC were described by odds ratio (OR) and 95% confidence interval (CI). Funnel plot was used to represent the publication bias of included studies. We performed the data analysis by StataSE 16.

RESULTS

A total of 1431677 patients from twelve included studies were enrolled for data analysis in this study. According to our analysis, we found that the poor oral health was associated with higher risk of GC (OR = 1.15, 95%CI: 1.02-1.29; I2 = 59.47%, P = 0.00 < 0.01). Moreover, after subgroup analysis, the outcomes showed that whether tooth loss (OR = 1.12, 95%CI: 0.94-1.29; I2 = 6.01%, P > 0.01), gingivitis (OR = 1.19, 95%CI: 0.71-1.67; I2 = 0.00%, P > 0.01), dentures (OR = 1.27, 95%CI: 0.63-1.19; I2 = 68.79%, P > 0.01), or tooth brushing (OR = 1.25, 95%CI: 0.78-1.71; I2 = 88.87%, P > 0.01) had no influence on the risk of GC. However, patients with periodontitis (OR = 1.13, 95%CI: 1.04-1.23; I2 = 0.00%, P < 0.01) had a higher risk of GC.

CONCLUSION

Patients with poor oral health, especially periodontitis, had a higher risk of GC. Patients should be concerned about their oral health. Improving oral health might reduce the risk of GC.

Periodontitis and risk of cancer: Mechanistic evidence

This review aims to critically analyze the pathways of interaction and the pathogenic mechanisms linking periodontitis and oral bacteria with the initiation/progression of cancer at different body compartments. A higher risk of head and neck cancer has been consistently associated with periodontitis. This relationship has been explained by the local promotion of dysbiosis, chronic inflammation, immune evasion, and direct (epi)genetic damage to epithelial cells by periodontal pathobionts and their toxins. Epidemiological reports have also studied a possible link between periodontitis and the incidence of other malignancies at distant sites, such as lung, breast, prostate, and digestive tract cancers. Mechanistically, different pathways have been involved, including the induction of a chronic systemic inflammatory state and the spreading of oral pathobionts with carcinogenic potential. Indeed, periodontitis may promote low-grade systemic inflammation and phenotypic changes in the mononuclear cells, leading to the release of free radicals and cytokines, as well as extracellular matrix degradation, which are all mechanisms involved in carcinogenic and metastatic processes. Moreover, the transient hematogenous spill out or micro-aspiration/swallowing of periodontal bacteria and their virulence factors (i.e., lipopolysaccharides, fimbriae), may lead to non-indigenous bacterial colonization of multiple microenvironments. These events may in turn replenish the tumor-associated microbiome and thus influence the molecular hallmarks of cancer. Particularly, specific strains of oral pathobionts (e.g., Porphyromonas gingivalis and Fusobacterium nucleatum) may translocate through the hematogenous and enteral routes, being implicated in esophageal, gastric, pancreatic, and colorectal tumorigenesis through the modulation of the gastrointestinal antitumor immune system (i.e., tumor-infiltrating T cells) and the increased expression of pro-inflammatory/oncogenic genes. Ultimately, the potential influence of common risk factors, relevant comorbidities, and upstream drivers, such as gerovulnerability to multiple diseases, in explaining the relationship cannot be disregarded. The evidence analyzed here emphasizes the possible relevance of periodontitis in cancer initiation/progression and stimulates future research endeavors.

Real-Time PCR Detection of Candida Species in Biopsy Samples from Non-Smokers with Oral Dysplasia and Oral Squamous Cell Cancer: A Retrospective Archive Study

The impact of Candida sp. in the development of oral cancer remains uncertain and requires sensitive analytical approaches for clarification. Given the invasive capabilities of these microorganisms in penetrating and invading host tissues through hyphal invasion, this study sought to detect the presence of five Candida sp. in oral biopsy tissue samples from non-smoker patients. Samples were obtained from patients at varying stages of oral carcinogenesis, including dysplasia, carcinoma in situ, OSCC, and histologically benign lesions, and analyzed using Real-Time PCR. Oral tissue samples from 80 patients (46 males and 34 females) were included. Significantly higher C. albicans presence was detected in the mild/moderate dysplasia group compared to the healthy (p = 0.001), carcinoma in situ (p = 0.031) and OSCC groups (p = 0.000). Similarly, C. tropicalis carriage was higher in tissues with mild/moderate dysplasia compared to healthy (p = 0.004) and carcinoma in situ (p = 0.019). Our results showed a significant increase in the presence of C. albicans and C. tropicalis within the mild/moderate dysplasia group compared to other cohorts. Coexistence of these two microorganisms was observed, suggesting a potential transition from a commensal state to an opportunistic pathogen, which could be particularly linked to the onset of oral neoplasia.

The Gum-Gut Axis: Periodontitis and the Risk of Gastrointestinal Cancers

Periodontitis has been linked to an increased risk of various chronic non-communicable diseases, including gastrointestinal cancers. Indeed, dysbiosis of the oral microbiome and immune-inflammatory pathways related to periodontitis may impact the pathophysiology of the gastrointestinal tract and its accessory organs through the so-called "gum-gut axis". In addition to the hematogenous spread of periodontal pathogens and inflammatory cytokines, recent research suggests that oral pathobionts may translocate to the gastrointestinal tract through saliva, possibly impacting neoplastic processes in the gastrointestinal, liver, and pancreatic systems. The exact mechanisms by which oral pathogens contribute to the development of digestive tract cancers are not fully understood but may involve dysbiosis of the gut microbiome, chronic inflammation, and immune modulation/evasion, mainly through the interaction with T-helper and monocytic cells. Specifically, keystone periodontal pathogens, including Porphyromonas gingivalis and Fusobacterium nucleatum, are known to interact with the molecular hallmarks of gastrointestinal cancers, inducing genomic mutations, and promote a permissive immune microenvironment by impairing anti-tumor checkpoints. The evidence gathered here suggests a possible role of periodontitis and oral dysbiosis in the carcinogenesis of the enteral tract. The "gum-gut axis" may therefore represent a promising target for the development of strategies for the prevention and treatment of gastrointestinal cancers.

ASSOCIATION OF ORAL MICROBIOTA AND PERIODONTAL DISEASE WITH LUNG CANCER: A SYSTEMATIC REVIEW AND META-ANALYSIS

OBJECTIVES

Evidence of oral microbiota perturbations has been accumulated for lung cancers. This review focused on the oral microbiota alterations in population suffering from lung cancer. In addition, we also discussed conflicting data about the association between oral microbiota dysbiosis and risk of lung cancer.

METHODS

A systematic search was conducted in Medline, Embase, PubMed, and Cochrane Library databases. The studies evaluated diversity and abundance of oral microbes in healthy and lung cancer individuals as well as association of periodontal disease and pathogens with lung cancer. Of 3559 studies, 28 included studies were performed in qualitative analysis, and 25 studies were used in meta-analyses for quantitative assessment. Heterogeneity was analyzed by using I² and chi-squared Q test statistics. Statistical analyses were performed by using the RevMan 5.4 software.

RESULTS

Compared with the control, lung cancer patients had lower alpha diversity (Shannon: SMD = -0.54; 95% CI, -0.90 to -0.19; P < .01, I2 = 71%). In nested case-control studies, individuals with decreased alpha diversity tended to have an increased risk of lung cancer (observed species: HR = 0.90; 95% CI, 0.85-0.96; P < .01, I2 = 0%; Shannon: HR = 0.89; 95% CI, 0.83-0.95; P < .01, I2 = 0%). Overall, no strong evidence of association of relative abundance with specific oral microbes with lung cancers was found because of inconsistent data. No associations were found between periodontal pathogens and lung cancer risk (red complex: HR = 1.12, 95% CI: 0.42-3.02, P = .82, I2 = 62%; orange complex: HR =1.77, 95% CI: 0.78-3.98, P = .17, I2 = 36%), expect for Fusobacterium nucleatum (HR = 2.27, 95% CI: 1.13-4.58, P = .02, I2 = 0%). The positive association of periodontal disease with lung cancer risk was found (HR = 1.58, 95% CI: 1.25-2.00, P < .001, I2= 0%) with increase of periodontal diseases severity (HR = 2.39, 95% CI: 1.57-3.66, P < .001, I2 = 0%). However, such association was not found in never-smoker participants (HR = 1.00, 95% CI: 0.76-1.31, P = .37, I2= 7%).

CONCLUSIONS

Lower alpha diversity of oral microbiome may be associated with a greater risk of lung cancer and might serve as a predictive signal of lung cancer risk. There was no strong evidence of relative abundance of oral microbial taxa and periodontal pathogens in lung cancer patients. Fusobacterium nucleatum might be a potential microbial candidate of biomarkers in lung cancer. Periodontal disease may be positively associated with lung cancer risk by confounding of smoking, but not an independent risk factor.

Composition of subgingival microbiota associated with periodontitis and diagnosis of malignancy-a cross-sectional study

Periodontitis is one of the world's most prevalent infectious conditions, affecting between 25 and 40% of the adult population. It is a consequence of the complex interactions between periodontal pathogens and their products, which trigger the host inflammatory response, chronic inflammation, and tissue destruction. Chronic systemic low-grade inflammation is involved in numerous diseases, and it is also known that long-lasting inflammation and chronic infections predispose one to cancer. Here, we characterized and compared the subgingival microbiota associated with periodontitis and diagnosis of malignancy in a longitudinal 10-year follow-up study. The study was conducted on 50 patients with periodontitis and 40 periodontally healthy individuals. The recorded clinical oral health parameters were periodontal attachment loss (AL), bleeding on probing (BOP), gingival index (GI), probing depth (PD), and plaque index (PI). Subgingival plaque was collected from each participant, from which DNA was extracted, and 16S rRNA gene amplicon sequencing performed. Cancer diagnoses data were collected between the years 2008-2018 from the Swedish Cancer Registry. The participants were categorized based on having cancer at the time of sample collection (CSC), having developed cancer later (DCL), and controls without any cancer. The most abundant phyla across all 90 samples were Actinobacteria, Proteobacteria, Firmicutes, Bacteroidetes, and Fusobacteria. At the genus level, Treponema, Fretibacterium, and Prevotella were significantly more abundant in samples of periodontitis patients compared to non-periodontitis individuals. With regard to samples of cancer patients, Corynebacterium and Streptococcus were more abundant in the CSC group; Prevotella were more abundant in the DCL group; and Rothia, Neisseria, and Capnocytophaga were more abundant in the control group. In the CSC group, we also found that the presence of periodontal inflammation, in terms of BOP, GI, and PLI, significantly correlated with species belonging to the genera Prevotella, Treponema, and Mycoplasma. Our results revealed that several subgingival genera were differentially enriched among the studied groups. These findings underscore the need for further research to fully understand the role that oral pathogens may play in the development of cancer.

Association of vitamin K, fibre intake and progression of periodontal attachment loss in American adults

BACKGROUND

Periodontitis-related attachment loss is accompanied by mucosal bleeding and inflammatory lesions. Dietary vitamin K and fibre intake are known to be correlation factors of haemostasis and anti-inflammation, respectively.

OBJECTIVE

To explore the association between severe periodontal attachment loss and vitamin K or fibre intake in American adults.

METHODS

A cross-sectional analysis was conducted including 2747 males and 2218 females in the National Health and Nutrition Examination Surveys (NHANES) from 2009 to 2014. The number of teeth with severe periodontal attachment loss (above 5 mm attachment loss) was used as the dependent variable. The main independent variables included the intake of vitamin K and dietary fibre. The association among variables was examined using multivariable linear regression models, hierarchical regression, fitted smoothing curves, and generalized additive models.

RESULTS

Based on the indicators of 4965 subjects, we found that severe attachment loss tended to occur in elderly individuals or males and was accompanied by less intake of vitamin K or dietary fibre, as well as lower educational qualification. Vitamin K intake was stably negatively associated with attachment loss progression in each multivariable linear regression model. In subgroup analyses, a negative association between fibre intake and attachment loss progression was identified in all races except blacks (β = 0.0005, 95% CI: -0.0005 to 0.0016). The relationship between fibre intake and attachment loss progression was a broad U-shaped curve (inflection point: 753.4 mg), which especially manifested in males (inflection point: 967.5 mg).

CONCLUSION

There was an inverse association between vitamin K intake and the progression of periodontal attachment loss in American adults, while dietary fibre should be moderate in intake (below 753.4 mg), especially in males (below 967.5 mg).