The importance of assessing confounding and effect modification in research involving periodontal disease and systemic diseases

The Oral Health Statistics Guidelines for Reporting Observational Studies and Clinical Trials in Oral Health Research: Explanation and Elaboration

Adequate and transparent reporting is necessary for critically appraising research. Yet, evidence suggests that the design, conduct, analysis, interpretation, and reporting of oral health research could be greatly improved. Accordingly, the Task Force on Design and Analysis in Oral Health Research-statisticians and trialists from academia and industry-empaneled a group of authors to develop methodological and statistical reporting guidelines identifying the minimum information needed to document and evaluate observational studies and clinical trials in oral health: the Oral Health Statistics Guidelines. Drafts were circulated to the editors of 85 oral health journals and to task force members and sponsors and discussed at a December 2020 workshop attended by 49 researchers. The final version was subsequently approved by the task force in September 2021, submitted for journal review in 2022, and revised in 2023. The checklist consists of 48 guidelines: 5 for introductory information, 17 for methods, 13 for statistical analysis, 6 for results, and 7 for interpretation; 7 are specific to clinical trials. Each of these guidelines identifies relevant information, explains its importance, and often describes best practices. The checklist was published in multiple journals. The article was published simultaneously in Journal of Dental Research Clinical and Translational Research, the Journal of the American Dental Association, and the Journal of Oral and Maxillofacial Surgery. Completed checklists should accompany manuscripts submitted for publication to these and other oral health journals to help authors, journal editors, and reviewers verify that the manuscript provides the information necessary to adequately document and evaluate the research.

The OHStat Guidelines for Reporting Observational Studies and Clinical Trials in Oral Health Research: explanation and elaboration

Adequate and transparent reporting is necessary for critically appraising research. Yet, evidence suggests that the design, conduct, analysis, interpretation, and reporting of oral health research could be greatly improved. Accordingly, the Task Force on Design and Analysis in Oral Health Research-statisticians and trialists from academia and industry-empaneled a group of authors to develop methodological and statistical reporting guidelines identifying the minimum information needed to document and evaluate observational studies and clinical trials in oral health: the OHstat Guidelines. Drafts were circulated to the editors of 85 oral health journals and to Task Force members and sponsors and discussed at a December 2020 workshop attended by 49 researchers. The final version was subsequently approved by the Task Force in September 2021, submitted for journal review in 2022, and revised in 2023. The checklist consists of 48 guidelines: 5 for introductory information, 17 for methods, 13 for statistical analysis, 6 for results, and 7 for interpretation; 7 are specific to clinical trials. Each of these guidelines identifies relevant information, explains its importance, and often describes best practices. The checklist was published in multiple journals. The article was published simultaneously in JDR Clinical and Translational Research, the Journal of the American Dental Association, and the Journal of Oral and Maxillofacial Surgery. Completed checklists should accompany manuscripts submitted for publication to these and other oral health journals to help authors, journal editors, and reviewers verify that the manuscript provides the information necessary to adequately document and evaluate the research.

The OHStat Guidelines for Reporting Observational Studies and Clinical Trials in Oral Health Research: Explanation and Elaboration

Adequate and transparent reporting is necessary for critically appraising research. Yet, evidence suggests that the design, conduct, analysis, interpretation, and reporting of oral health research could be greatly improved. Accordingly, the Task Force on Design and Analysis in Oral Health Research-statisticians and trialists from academia and industry-empaneled a group of authors to develop methodological and statistical reporting guidelines identifying the minimum information needed to document and evaluate observational studies and clinical trials in oral health: the OHstat Guidelines. Drafts were circulated to the editors of 85 oral health journals and to Task Force members and sponsors and discussed at a December 2020 workshop attended by 49 researchers. The final version was subsequently approved by the Task Force in September 2021, submitted for journal review in 2022, and revised in 2023. The checklist consists of 48 guidelines: 5 for introductory information, 17 for methods, 13 for statistical analysis, 6 for results, and 7 for interpretation; 7 are specific to clinical trials. Each of these guidelines identifies relevant information, explains its importance, and often describes best practices. The checklist was published in multiple journals. The article was published simultaneously in JDR Clinical and Translational Research, the Journal of the American Dental Association, and the Journal of Oral and Maxillofacial Surgery. Completed checklists should accompany manuscripts submitted for publication to these and other oral health journals to help authors, journal editors, and reviewers verify that the manuscript provides the information necessary to adequately document and evaluate the research.

Periodontitis Is Associated With Risk of Conventional Stent Restenosis: Pilot Case-Control Study

Objectives: Percutaneous coronary angioplasty with stent implantation has been established as the main form of treatment of atherosclerosis. However, 16 to 44% of patients may evolve with stent restenosis. Periodontitis is an inflammatory condition associated with bacterial infection, that may lead to periodontal tissue destruction and tooth loss. This study aimed to evaluate the association between stent restenosis and periodontitis.

Materials and Methods: Coronary angiography exams presenting stent imaging with and without restenosis were analyzed. Patients meeting the inclusion and exclusion criteria were selected and allocated in 2 groups: case (restenosis) and control (without restenosis). We evaluated if systemic and periodontal variables were predictors of restenosis (primary outcome) using a multivariable stepwise logistic regression. Additionally, we compared clinical and periodontal conditions between the control and case groups (secondary outcomes) using Chi-square test and ANOVA test.

Results: Data from 49 patients (case n = 15; control n = 34) were analyzed. The results showed that stages III and IV periodontitis and lack of physical activity were significant predictors of stent restenosis (OR 5.82 and 5.98, respectively). Comparisons regarding the diagnosis of periodontal conditions between control and case groups did not present significant differences in the incidence of periodontitis and alveolar bone loss.

Conclusion: Stages III and IV periodontitis increased the incidence of stent restenosis. These findings suggest that advanced stages of periodontal disease might lead to the occurrence of negative outcomes after coronary angioplasty with stent placement.

Interaction between beta-3 adrenergic receptor genotype and environmental factors on periodontal progression

OBJECTIVES

The purpose of this longitudinal study was to evaluate the relationship between beta-3 adrenergic receptor polymorphism and environmental factors such as smoking on periodontal disease by considering effect modification.

MATERIALS AND METHODS

A total of 294 subjects who participated in all follow-up surveys over the 6-year study period were analysed. After dividing subjects into tertiles according to the number of years exposed to smoking, we conducted Poisson regression analysis to compare the incidence rate ratio (IRR) for periodontal disease events during the 6-year study period with beta-3 adrenergic receptor genotype (1: Arg allele carriers, 2: Arg allele non-carriers) for each tertile adjusted for other four variables.

RESULTS

The number of years exposed to smoking (mean ± standard deviation) for the 1st, 2nd and 3rd tertiles was 0 ± 0, 20.1 ± 9.1 and 45.3 ± 7.7 years, respectively. The IRRs ± SE were 0.89 ± 0.08 (p = 0.218) for the 1st tertile, 1.93 ± 0.36 (p < 0.001) for the 2nd tertile and 2.56 ± 0.23 (p < 0.001) for the 3rd tertile.

CONCLUSION

There was a clear dose-response relationship between beta-3 adrenergic receptor genotype and periodontal disease progression based on the number of years exposed to smoking.

Impact of Periodontitis Case Criteria: A Cross-Sectional Study of Lifestyle

BACKGROUND

Associations of risk factors/indicators with periodontitis may depend on the included case criterion. The objective of the current study is to evaluate differences in outcome by applying five periodontitis case definitions for cross-sectional associations with lifestyle factors among participants of the Danish Health Examination Survey (DANHES).

METHODS

A total of 4,402 adults aged 18 to 96 years from the general health examination of DANHES had a periodontal examination consisting of half-mouth registration at six sites per tooth including probing depth (PD) and clinical attachment level (CAL). Periodontitis was defined according to severe periodontitis, European Workshop of Periodontology (EWP)-specific, meanCAL ≥2.55 mm, CAL-tertile, and PD-CAL definitions. Multivariable logistic regression models fitted the association of age, sex, smoking status, diabetes mellitus, educational level, alcohol consumption, body mass index, physical activity, body fat percentage, waist circumference, triglycerides, total cholesterol, and C-reactive protein with periodontitis.

RESULTS

Number of cases captured by the five periodontitis case definitions ranged from 337 (9.2%) to 1,136 (31.0%). A total of 224 participants were defined as periodontitis cases by all five criteria. Analyses on 3,665 participants with complete data revealed statistically significant associations of age and smoking with all periodontitis case definitions and of male sex with severe periodontitis and EWP-specific definitions. Educational level (two lowest groups) was related to three periodontitis criteria. Among obesity and hyperlipidemia measures no factors were related to periodontitis.

CONCLUSION

Regression analyses showed little difference in odds ratio across the five periodontitis case definitions; however, the level of significance did show some variation.

The Infection Hypothesis Revisited: Oral Infection and Cardiovascular Disease

Background. The pathophysiology of cardiovascular disease (CVD) includes inflammation in the development of atherosclerosis and thrombosis. Increasing evidence supports oral infections, and in particular the common periodontal disease, to be associated with CVD development. Periodontal infection is present in populations worldwide and in the moderate to mild form in about 35% of populations according to the World Health Organization. Objective. This review of the literature aims to present cross evidence from medical research disciplines that explore how oral infections can contribute to increase the risk for CVDs and how treatment of oral infections can reduce the risk for CVDs. Design. Review article. Results. Long-term exposure to active nontreated infections of the oral cavity presents an opportunity for bacteria, bacterial products, and viruses to enter the circulation. Toxic bacterial products enter the circulation, affecting atherosclerosis, causing platelet adhesiveness that results in clot formation, and establishing cardiac vegetation. Pathological observations have identified oral bacteria in heart valves, aortic aneurysms, and arterial walls. Clinical intervention studies on periodontal disease reduce the risk level of serological predictors for CVDs. Conclusions. This paper presents evidence across medical research disciplines for oral infections to be considered as one of the risk factors for CVDs.

Obesity and periodontitis: systematic review and meta-analysis

The scope of this study was to conduct a systematic review of the studies on the association between obesity and periodontitis. The methods applied included a literature search strategy and selection of studies using inclusion and exclusion in accordance with the criteria for characteristics of the studies and meta-analysis. The research was conducted in the PubMed, Embase and Lilacs databases through 2010. Selected papers were on studies on humans investigating whether or not obesity is a risk factor for periodontitis. Of the 822 studies identified, 31 studies met the inclusion criteria and were included in this meta-analysis. The risk of periodontitis was associated with obesity (or had a tendency for this) in 25 studies, though it was not associated in 6 studies. The meta-analysis showed a significant association with obesity and periodontitis (OR = 1.30 [95% Confidence Interval (CI), 1.25 - 1.35]) and with mean Body Mass Index (BMI) and periodontal disease (mean difference = 2.75). Obesity was associated with periodontitis, however the risk factors that aggravate these diseases should be better clarified to elucidate the direction of this association. Working with paired samples and avoiding confusion factors may contribute to homogeneity between the studies.

Is obesity a possible modifier of periodontal disease as a chronic inflammatory process? A case-control study

BACKGROUND AND OBJECTIVE

This cross-sectional case-control study was conducted to provide a comparative evaluation of clinical periodontal measurements, together with serum levels of certain bioactive peptides and inflammatory cytokines, in relation to obesity. For this purpose, clinical periodontal measurements and the levels of serum leptin, adiponectin, interleukin-6 (IL-6), C-reactive protein and soluble intercellular adhesion molecule-1 of obese female individuals and their nonobese counterparts were compared.

MATERIAL AND METHODS

Sixty obese (body mass index (BMI) > 30) and 31 nonobese (BMI < 30) female subjects were recruited for the present study. Before any periodontal intervention, serum samples were obtained and full-mouth clinical periodontal measurements were recorded at six sites per tooth. ELISA was used for the biochemical analysis. Data were tested statistically.

RESULTS

Clinical attachment level was significantly higher in the obese group compared with the nonobese control group (p < 0.05). Serum levels of leptin and IL-6 were significantly higher in the obese group (p < 0.05). BMI correlated with the serum levels of inflammatory molecules (p < 0.05), but not with clinical periodontal parameters, in the obese group.

CONCLUSION

In conclusion, obesity does not seem to have a prominent effect on clinical periodontal parameters but it does have many correlations with circulating inflammatory molecules. As suggested in the literature, increased levels of leptin and IL-6 in the obese group might be one explanation for a possible relationship between obesity and periodontal disease. A prospective study is warranted to clarify, in greater detail, the effects of obesity on periodontal health.

Oral infection, regular alcohol drinking pattern, and myocardial infarction

Oral infections have been associated with an increased risk for myocardial infarction (MI) and other cardiovascular diseases (CVD). Conversely, low, regular alcohol consumption is associated with a lower association of CVD. The objective was to test the novel hypothesis that oral infections are modified by regular alcohol drinking which has the effect of lowering the incidence of MI's. The effect has been observed where tooth extractions where carried out due to infections and compared with extractions unconnected to infections. Oral infections and in particular periodontal infections impose an infectious load on the health in many people. In its advanced forms (periodontal pockets ≥ 6mm) periodontitis affects ∼10-15% of adults. The infection runs a chronic course with exacerbations. The bacteria cause local infection destructive to the supporting tissues of the teeth and have been detected in systemic diseases through bacterial products and bacteria entering the circulation. The often persistent, long term history of chronic periodontal infection in individuals is a challenge to the immune system. Over 700 oral bacteria and other microorganisms have been identified, many of which are virulent. Control of the level of oral microbiota is through well known oral hygiene measures. Alcohol by being bactericidal is a factor that may reduce the bacterial level in the oral cavity. If this effect truly exists, it should be observed through reduction of infections in the mouth. Tooth extraction is the ultimate consequence of periodontal and dental infections and a reduction of tooth extraction due to infections should therefore be observed. The hypothesis was tested using the screening data of the Oslo II-study in a cross sectional analysis. The Oslo-study included men aged 48-67 years. The main finding was that the effect of a drinking pattern of 2-7 times per week reduced the risk of MI among men who had a history of tooth extractions due to infections versus tooth extraction for other causes or no extractions. This hypothesis supports an explanation as to why oral infection is a weaker independent risk factor for CVD in some studies. It also gives an indication of the reason for an added benefit by a regular drinking pattern as part of the Mediterranean diet. The important consequence of this hypothesis is the added importance of optimal oral hygiene for the prevention of CVD as well as for the benefit of good oral health.

Periodontal disease and atherosclerotic vascular disease: does the evidence support an independent association?: a scientific statement from the American Heart Association

A link between oral health and cardiovascular disease has been proposed for more than a century. Recently, concern about possible links between periodontal disease (PD) and atherosclerotic vascular disease (ASVD) has intensified and is driving an active field of investigation into possible association and causality. The 2 disorders share several common risk factors, including cigarette smoking, age, and diabetes mellitus. Patients and providers are increasingly presented with claims that PD treatment strategies offer ASVD protection; these claims are often endorsed by professional and industrial stakeholders. The focus of this review is to assess whether available data support an independent association between ASVD and PD and whether PD treatment might modify ASVD risks or outcomes. It also presents mechanistic details of both PD and ASVD relevant to this topic. The correlation of PD with ASVD outcomes and surrogate markers is discussed, as well as the correlation of response to PD therapy with ASVD event rates. Methodological issues that complicate studies of this association are outlined, with an emphasis on the terms and metrics that would be applicable in future studies. Observational studies to date support an association between PD and ASVD independent of known confounders. They do not, however, support a causative relationship. Although periodontal interventions result in a reduction in systemic inflammation and endothelial dysfunction in short-term studies, there is no evidence that they prevent ASVD or modify its outcomes.

Oral health behavior and metabolic syndrome and its components in adults

Inflammation has been strongly related to metabolic syndrome (MetS). Periodontal disease is the most common chronic infection in adults. We investigated a cross-sectional (n = 925) and 3-year longitudinal (n = 685) relationship between the daily frequency of toothbrushing and MetS. In the cross-sectional analysis, the prevalence of MetS was 15.7%. After adjustment for potential confounding factors (including all lifestyle factors), the odds ratios (95% confidence interval [CI]) of having MetS in those who brushed 2 times/day and ≥ 3 times/day were 0.71 (0.48-1.05) and 0.47 (0.24-0.92), respectively, as compared with ratios in those with a toothbrushing frequency of ≤ 1 time/day. Increasing toothbrushing frequency tended to relate inversely to hypertriglyceridemia and high-sensitivity C-reactive protein. In the longitudinal analysis, 99 participants were newly diagnosed with MetS. The adjusted odds ratios (95% CI) of the MetS in participants who brushed 2 times/day and ≥ 3 times/day as compared with participants who brushed ≤ 1 time/day were 0.80 (0.49-1.31) and 0.43 (0.19-0.97), respectively. The frequency of toothbrushing was related inversely only to hypertriglyceridemia, consistent with the cross-sectional analysis. This study found that more frequent toothbrushing is related to a lower prevalence and incidence of MetS. These results suggest that more frequent toothbrushing may contribute to the prevention of MetS due to the inflammation/triglyceride pathway.

Oral hygiene, periodontal health and chronic obstructive pulmonary disease exacerbations

AIM

To assess the associations of oral hygiene and periodontal health with chronic obstructive pulmonary disease (COPD) exacerbations.

MATERIAL AND METHODS

In total, 392 COPD patients were divided into frequent and infrequent exacerbation (≥2 times and <2 times in last 12 months) groups. Their lung function and periodontal status were examined. Information on oral hygiene behaviours was obtained by interview.

RESULTS

In the univariate analysis, fewer remaining teeth, high plaque index (PLI) scores, low tooth brushing times, and low regular supra-gingival scaling were significantly associated with COPD exacerbations (all p-values <0.05). After adjustment for age, gender, body mass index, COPD severity and dyspnoea severity, the associations with fewer remaining teeth (p = 0.02), high PLI scores (p = 0.02) and low tooth brushing times (p = 0.008) remained statistically significant. When stratified by smoking, fewer remaining teeth (OR = 2.05, 95% CI: 1.04-4.02) and low tooth brushing times (OR = 4.90, 95% CI: 1.26-19.1) among past smokers and high PLI scores (OR = 3.43, 95% CI: 1.19-9.94) among never smokers were significantly associated with COPD exacerbations.

CONCLUSIONS

Fewer remaining teeth, high PLI scores, and low tooth brushing times are significant correlates of COPD exacerbations, indicating that improving periodontal health and oral hygiene may be a potentially preventive strategy against COPD exacerbations.

Periodontal disease: a new factor associated with the presence of multiple complex coronary lesions

BACKGROUND AND AIM

Periodontal disease, including bone loss, is thought to be involved in coronary artery disease. Multiple complex coronary lesions relate to multifocal destabilization of coronary plaques. We investigated whether bone loss could be associated with the presence of multiple complex coronary lesions.

METHODS

This cross-sectional study included 150 patients with recent myocardial infarction (<1 month). Multiple complex coronary lesions were determined at coronary angiography. A panoramic dental X-ray including bone loss >50% was performed. Patients with no or simple complex lesions were compared to patients with multiple complex lesions.

RESULTS

Over 20% of patients had multiple complex coronary lesions. Patients with multiple complex lesion were less likely to be women and more likely to have multivessel disease or elevated C-reactive protein (CRP) than patients with no or single complex lesion. Bone loss >50% tended to be more frequent in patients with multiple complex lesions (p = 0.063). In multivariate analysis, multivessel disease, gender and CRP were associated with multiple complex lesion. Bone loss >50% increased the risk of multiple complex lesion.

CONCLUSION

Bone loss was associated with complex multiple coronary lesions, beyond systemic inflammation. These findings may bear important clinical implications for the prevention and treatment of coronary artery disease.

The association between self-reported tooth loss and cognitive function in the REasons for Geographic And Racial Differences in Stroke study: an assessment of potential pathways

BACKGROUND

Several mechanisms may associate tooth loss and related oral inflammation with cognitive impairment. The authors studied the relationship between tooth loss and cognitive function.

METHODS

The REasons for Geographic And Racial Differences in Stroke study is a national longitudinal study of more than 30,000 African American and white adults 45 years or older. Data for tooth loss, cognitive function and potential confounding variables were available for 9,853 participants at the time of analysis. The authors used incremental linear regression modeling to investigate the cross-sectional association between self-reported tooth loss and cognitive function.

RESULTS

In unadjusted analysis (mean learning followed by recall; α level of significance of .05), the loss of six to 16 teeth and the loss of more than 16 teeth were associated with poorer cognitive function compared with the loss of no teeth. Attenuated associations persisted after the authors adjusted for demographic and systemic risk factors. The full model, which was adjusted for socioeconomic status (SES), revealed no association between tooth loss and cognitive function.

CONCLUSION

Tooth loss may be associated with cognitive function; however, this association is mediated by age and SES.

CLINICAL IMPLICATIONS

Tooth loss due to periodontal disease may be a marker for low SES, and the interplay of these factors with advanced age may confer risk of having poorer cognitive function. Further studies are needed to clarify these associations.

Association between volatile sulfur compounds and periodontal disease progression in elderly non-smokers

BACKGROUND

Periodontal pathogenic microorganisms produce volatile sulfur compounds (VSCs), such as hydrogen sulfide, methyl mercaptan, and dimethyl sulfide. VSCs are toxic to periodontal tissue. Therefore, there is a relationship between periodontitis and the VSC level of mouth air. However, the association between VSC and periodontal disease progression has not been investigated in a longitudinal study. The purpose of this study is to evaluate the association between VSCs in mouth air and periodontal disease progression among elderly dentulous non-smokers.

METHODS

Two hundred forty-one dentulous non-smokers (103 males and 138 females; all 70 years old) had their VSC levels examined with a portable sulfide monitor, and their periodontal status was assessed. Periodontal examinations were performed at baseline and once a year for 3 years to investigate the clinical attachment levels of all teeth. Participants were classified by membership in tertile groups (lowest, middle, and highest) according to the value of baseline VSC measurements.

RESULTS

In negative binomial regression analysis, the number of teeth with periodontal disease progression for participants in the highest tertile of VSC measurement was greater (incidence rate ratio of 1.33, P = 0.011) than for the reference group (lowest tertile of VSC measurement) after simultaneously adjusting for sex, number of remaining teeth, and maximum clinical attachment level.

CONCLUSIONS

VSC measurements were significantly associated with periodontal disease progression in a non-smoking dentulous elderly population. This suggests that VSC measurements are useful for the diagnosis of periodontal disease progression.

Relationship between Saturated Fatty Acids and Periodontal Disease

Saturated fatty acids (SFAs) produce an inflammatory response. Hyperinflammation is now recognized as one of the key underlying etiologic factors in periodontal disease. The longitudinal relationship between dietary SFAs and periodontal disease in 264 Japanese individuals, aged 75 years, for whom data were available for the years 2003-2004, was investigated. SFA intake was assessed with a brief self-administered diet history questionnaire. Participants were classified by quartiles of SFA intake. Full-mouth periodontal status, measured as the clinical attachment level (CAL), was recorded at baseline and follow-up examinations. The number of teeth with a loss of CAL ≥ 3 mm at any site over a year was calculated as ‘periodontal disease events’. Poisson regression analysis was conducted, with dietary SFAs as the primary predictor of interest, to estimate their influence on periodontal disease events. High dietary SFA intake was significantly associated with a greater number of periodontal disease events among non-smokers. The multivariate adjusted relative risk (95% confidence intervals) in the 1st, 2nd, 3rd, and 4th quartiles of dietary SFAs was 1.00, 1.19 (0.72-1.97), 1.55 (0.95-2.52), and 1.92 (1.19-3.11), respectively. These findings suggest an independent association of dietary SFA intake to the progression of periodontal disease in older Japanese non-smokers.Abbreviations: saturated fatty acid (SFA); clinical attachment level (CAL); Toll-like receptor (TLR); lipopolysaccharide (LPS); brief self-administered diet history questionnaire (BDHQ); decayed, missing, and filled teeth (DMFT); clinical attachment level (CAL); body mass index (BMI); relative risk (RR); confidence intervals (CI); nuclear factor-kappa B (NF-κB).

Inter-generational continuity in periodontal health: findings from the Dunedin family history study

OBJECTIVE

To determine whether parental periodontal disease history is a risk factor for periodontal disease in adult offspring.

METHODS

Proband periodontal examination [combined attachment loss (CAL) at age 32, and incidence of CAL from ages 26 to 32] and interview data were collected during the age-32 assessments in the Dunedin Study. Parental data were also collected. The sample was divided into two familial-risk groups for periodontal disease (high- and low-risk) based on parents' self-reported periodontal disease.

RESULTS

Periodontal risk analysis involved 625 proband-parent(s) groups. After controlling for confounding factors, the high-familial-risk periodontal group was more likely to have 1+ sites with 4+mm CAL [relative risk (RR) 1.45; 95% confidence interval (CI) 1.11-1.88], 2+ sites with 4+mm CAL (RR 1.45; 95% CI 1.03-2.05), 1+ sites with 5+mm CAL (RR 1.60; 95% CI 1.02-2.50), and 1+ sites with 3+mm incident CAL (RR 1.64; 95% CI 1.01-2.66) than the low-familial-risk group. Predictive validity was enhanced when information was available from both parents.

CONCLUSIONS

Parents with poor periodontal health tend to have offspring with poor periodontal health. Family/parental history of oral health is a valid representation of the shared genetic and environmental factors that contribute to an individual's periodontal status, and may help to predict patient prognosis and preventive treatment need.

"Gum bug, leave my heart alone!"--epidemiologic and mechanistic evidence linking periodontal infections and atherosclerosis

Evidence from epidemiologic studies suggests that periodontal infections are independently associated with subclinical and clinical atherosclerotic vascular disease. Although the strength of the reported associations is modest, the consistency of the data across diverse populations and a variety of exposure and outcome variables suggests that the findings are not spurious or attributable only to the effects of confounders. Analysis of limited data from interventional studies suggests that periodontal treatment generally results in favorable effects on subclinical markers of atherosclerosis, although such analysis also indicates considerable heterogeneity in responses. Experimental mechanistic in vitro and in vivo studies have established the plausibility of a link between periodontal infections and atherogenesis, and have identified biological pathways by which these effects may be mediated. However, the utilized models are mostly mono-infections of host cells by a limited number of 'model' periodontal pathogens, and therefore may not adequately portray human periodontitis as a polymicrobial, biofilm-mediated disease. Future research must identify in vivo pathways in humans that may (i) lead to periodontitis-induced atherogenesis, or (ii) result in treatment-induced reduction of atherosclerosis risk. Data from these studies will be essential for determining whether periodontal interventions have a role in the primary or secondary prevention of atherosclerosis.

Design, Operation, and Interpretation of Clinical Trials

Randomized controlled clinical trials offer the best evidence for changing clinical practice and informing public health policy. Using examples from the literature, this paper reviews clinical trials for those who may be unfamiliar with their design, operation, and interpretation. In the design of a clinical trial, the question to be answered and a clinically meaningful outcome must be clearly defined. Ethics must be considered, sample size carefully estimated, and use of biomarkers and surrogate outcomes understood. Prominent issues in trial implementation include developing a manual of operations, trial registration, subject recruitment and retention, use of a data coordinating center, and data and safety monitoring. Interpretation of clinical trials requires understanding differences between efficacy and effectiveness; superiority, equivalence, and non-inferiority; intent-to-treat; primary and secondary analyses; and limitations of unregistered small clinical trials compared with large multi-center Phase III trials that are more likely to be representative of a population and change clinical practice or public health policy.

Clinical periodontal and microbiologic parameters in patients with acute myocardial infarction

BACKGROUND

The aim of this study was to evaluate the impact of clinical periodontal parameters and the presence of periodontal pathogens in patients with acute myocardial infarction (AMI).

METHODS

A total of 104 subjects (54 patients with AMI and 50 healthy controls) were included. Subgingival plaque samples were analyzed for periodontal pathogens Aggregatibacter actinomycetemcomitans (Aa; previously Actinobacillus actinomycetemcomitans), Porphyromonas gingivalis (Pg), Tannerella forsythia (Tf; previously T. forsythensis), and Prevotella intermedia (Pi) using dot-blot hybridization.

RESULTS

Patients with AMI had a significantly higher frequency of probing depths (PDs) >or=4 mm than controls (39.2% versus 14.9%; P <0.0001). Among different cutoff levels, the frequency of >50% sites with PDs >or=4 mm showed the highest discrepancy between both groups (33% versus 0%; P <0.001). All periodontal pathogens were overrepresented in patients with AMI and positively correlated with increased periodontal PD and clinical attachment level (CAL). After adjustment for age, gender, smoking, body mass index, hypertension, plaque index, statin intake, and ratio of cholesterol to high-density lipoprotein, Pg remained a significant predictor for AMI (odds ratio [OR]: 13.6; 95% confidence interval [CI]: 3.1 to 59.8; P = 0.0005). Furthermore, the simultaneous presence of Aa + Pg (P = 0.0005) and Aa + Pg + Tf (P = 0.0018) were found with significantly higher frequency in patients with AMI than controls.

CONCLUSIONS

The results of our study confirm an association between periodontitis and AMI in which periodontal destruction was correlated with the presence of periodontal pathogens. In particular, Pg might be considered a potential risk indicator for AMI.

Tooth loss and cognitive impairment

OBJECTIVES

Chronic subclinical inflammation may elevate the risk of cognitive impairment. Periodontitis is associated with subclinical inflammation and accounts in part for tooth loss. The hypothesis was tested that periodontitis and tooth loss as a proxy of chronic periodontitis is associated with cognitive impairment in the elderly.

SUBJECTS AND METHODS

The population-based Study of Health in Pomerania comprises 1336 subjects (60-79 years). Cognitive impairment was assessed with the Mini-Mental Status Examination (MMSE). Tobit regression analyses were adjusted for potential confounders.

RESULTS

A decreased number of teeth was associated with lower MMSE scores in females (p<0.001) and males (p=0.007) in age-adjusted models. In the fully adjusted models, tooth loss was associated with cognitive impairment in females (p=0.002) but not in males (p=0.825).

CONCLUSIONS

A significant association between tooth loss and cognitive impairment was found in females that was not accounted for by potential confounders. Former periodontitis may account for this association as periodontitis was frequently the cause for tooth extractions.

The relationship between serum lipids and periodontitis in elderly non-smokers

BACKGROUND

There are common risk factors for periodontal disease and cardiovascular disease in elderly patients. Some studies reported that a low total cholesterol (TC) serum level is associated with a higher level of death in the elderly. The purpose of this study was to investigate the relationship between serum lipids and periodontal disease in non-smoking elderly patients.

METHODS

Two hundred thirty-four non-smokers (63 males and 171 females) participated in this study. Multiple regression analysis was performed to evaluate the relationship between serum lipids and periodontitis and between serum lipids and inflammatory factors. The percentage of sites with probing depth (PD) > or =4 mm, clinical attachment level (CAL) > or =4 mm, and bleeding on probing (BOP) were used as dependent variables. TC, high-density lipoprotein cholesterol (HDL-C), gender, and the number of teeth present were included in the model as independent variables in the first analysis. TC, HDL-C, and low-density lipoprotein cholesterol (LDL-C) were used as dependent variables. Albumin, inorganic phosphorus, calcium, and C-reactive protein were used as independent variables in the second analysis.

RESULTS

According to the results of the multiple linear regression analysis, TC was associated with the percentage of sites with PD > or =4 mm (P <0.01; beta = -0.19), CAL > or =4 mm (P <0.01; beta = -0.20), and BOP (P = 0.03; beta = -0.16). HDL-C and LDL-C have a significant association with inflammatory markers and inorganic phosphorus and calcium, respectively.

CONCLUSION

Higher TC is associated with a lower prevalence of periodontitis in non-smoking elderly patients.

Association between periodontitis and anti-cardiolipin antibodies in Buerger disease

AIM

Anti-cardiolipin (CL) antibodies can be induced in Buerger disease (BD), an inflammatory occlusive disorder affecting peripheral blood vessels, in response to bacteria bearing homology to the TLRVYK peptide of a phospholipid-binding plasma protein beta-2-glycoprotein I. TLRVYK homologies are present in Porphyromonas gingivalis (TLRIYT) and Treponema denticola (TLALYK). This study investigated the association between periodontal infection and anti-CL antibodies in BD patients.

MATERIAL AND METHODS

Periodontal conditions were examined in 19 BD patients and 25 systemically healthy control subjects. All subjects were heavy smokers. Serum anti-CL, anti-TLRVYK, anti-TLRIYT, and anti-TLALYK antibodies were assessed using the enzyme-linked immunosorbent assay.

RESULTS

BD patients had a significantly higher prevalence of periodontitis, more severe periodontal destruction and increased titres of serum anti-CL, anti-TLRVYK, anti-TLRIYT, and anti-TLALYK antibodies compared with healthy subjects. The levels of anti-CL antibodies positively correlated with those of the three anti-peptide antibodies. Anti-CL antibody titres were significantly associated with the percentage of sites with clinical attachment level >or=4 mm in BD patients.

CONCLUSION

Elevated anti-CL antibody levels were associated with periodontal destruction in BD patients. Periodontopathic bacteria may serve as exogenous antigens that stimulate the anti-CL antibody production through molecular mimicry between the bacterial peptides and a host plasma protein.

Periodontal health, oral health behaviours, and chronic obstructive pulmonary disease

AIM

To evaluate the associations of periodontal health status and oral health behaviours with chronic obstructive pulmonary disease (COPD).

MATERIALS AND METHODS

We conducted a case-control study of 306 COPD patients and 328 controls with normal pulmonary function. Their periodontal status and respiratory function were clinically examined and information on oral health behaviours was obtained using a validated questionnaire.

RESULTS

Patients with COPD had fewer teeth and a higher plaque index than the controls. Univariate analysis showed that tooth brushing times and method, experience of dental floss use, dental visit and regular supra-gingival scaling, and oral health knowledge were significantly related to the risk of COPD. After adjusting for age, sex, and body mass index and stratifying by smoking status, inappropriate tooth brushing method (p=0.025 among non-smokers), lower regular supra-gingival scaling (p=0.027 among non-smokers and p<0.0001 among former smokers), and poorer oral health knowledge (p<0.0001 among non-smokers and p=0.019 among former smokers and p=0.044 among current smokers) remained significantly associated with COPD.

CONCLUSIONS

Poor periodontal health, dental care, and oral health knowledge were significantly associated with an increased risk of COPD. Our findings indicate the importance of promoting dental care and oral health knowledge that can be integrated into the prevention and treatment of COPD.

Maternal periodontal disease and risk of preeclampsia: a case-control study

BACKGROUND

We examined whether pregnant women with periodontal disease have an increased risk of preeclampsia, and we empirically evaluated the extent to which associations between periodontal disease and preeclampsia are dependent upon diagnostic criteria used to define periodontal disease operationally.

METHODS

One hundred and fifty preeclampsia cases and one-fifty normotensive controls who delivered a singleton infant at term were enrolled. Periodontal examinations were performed within 48 h after delivery. Participants' periodontal health status was classified, a priori, into four categories according to the extent and severity of periodontal disease. Putative risk factors for periodontal disease and preeclampsia were ascertained during in-person postpartum interviews using a structured questionnaire and by medical record abstraction. Logistic regression was used to estimate odds ratios (ORs) and 95% confidence intervals (95% CIs).

RESULTS

No clinically meaningful differences were observed between cases and controls with regard to periodontal parameters. After controlling for known confounders, severe clinical periodontal disease was not associated with an increased risk of preeclampsia (OR = 0.92, 95% CI: 0.26-3.28). In addition, there was no evidence of a linear increase in risk of preeclampsia with increasing severity of periodontal disease (P for trend = 0.65). When different diagnostic criteria previously used in other studies were used, the prevalence of periodontal disease varied substantially. However, the magnitude and direction of associations between periodontal disease and preeclampsia were largely similar regardless of the diagnostic criteria used to define periodontal disease.

CONCLUSIONS

This study provides no convincing evidence that periodontal disease is associated with preeclampsia risk among Thai women.

Is maternal periodontal disease a risk factor for preterm delivery?

Several studies have suggested an association between maternal periodontal disease and preterm delivery, but this has not been a consistent finding. In 2006-2007, the authors examined the relation between maternal periodontal disease and preterm delivery among 467 pregnant Thai women who delivered a preterm singleton infant (<37 weeks' gestation) and 467 controls who delivered a singleton infant at term (> or =37 weeks' gestation). Periodontal examinations were performed within 48 hours after delivery. Participants' periodontal health status was classified into 4 categories according to the extent and severity of periodontal disease. Logistic regression was used to estimate odds ratios and 95% confidence intervals. Preterm delivery cases and controls were similar with regard to mean probing depth, mean clinical attachment loss, and mean percentage of sites exhibiting bleeding on probing. After controlling for known confounders, the authors found that severe clinical periodontal disease was not associated with an increased risk of preterm delivery (odds ratio = 1.20, 95% confidence interval: 0.67, 2.16). In addition, there was no evidence of a linear increase in risk of preterm delivery or its subtypes associated with increasing severity of periodontal disease (P(trend) > 0.05). The results of this case-control study do not provide convincing evidence that periodontal disease is associated with preterm delivery or its subtypes among Thai women.

Amount and type of alcohol and periodontitis in the Copenhagen City Heart Study

AIM

The aim of this study was to study the association between alcohol consumption and periodontitis assessed as clinical attachment loss (CAL) and bleeding on probing (BOP) in a cross-sectional design.

MATERIAL AND METHODS

The study included 1,521 adults aged 20-95 years, who underwent an oral examination including full-mouth registration of CAL and BOP. Alcohol was ascertained using a food-frequency questionnaire. The association between total and type-specific alcohol and periodontitis was assessed by means of multivariate logistic regression.

RESULTS

A lower odds ratio (OR) for CAL (defined as mean >or=3 mm) was observed in men consuming 21-34 [OR=0.51, 95% confidence interval (CI), 0.27-0.95] and 35+ drinks/week (OR=0.34, 95% CI, 0.15-0.79) compared with men drinking 1-13 drinks/week. Also, men with a weekly wine consumption of more than 14 drinks compared with men who reported no wine intake had lower OR for CAL (OR=0.24; 95% CI, 0.09-0.62). A higher OR for BOP (defined as >or=25%) among male abstainers was observed (OR=1.79, 95% CI, 1.03-3.12) compared with men in the light-drinking group (1-13 drinks/week). No significant association was observed for either CAL or BOP in women.

CONCLUSIONS

The results indicate that higher alcohol consumption, particularly intake of wine, is inversely associated with CAL in men. Such an association is not found in women.

A critical assessment of adverse pregnancy outcome and periodontal disease

BACKGROUND

Pre-term birth is a major cause of infant mortality and morbidity that has considerable societal, medical, and economic costs. The rate of pre-term birth appears to be increasing world-wide and efforts to prevent or reduce its prevalence have been largely unsuccessful.

AIM

To review the literature for studies investigating periodontal disease as a possible risk factor for pre-term birth and adverse pregnancy outcomes.

MAIN FINDINGS AND CONCLUSION

Variability among studies in definitions of periodontal disease and adverse pregnancy outcomes as well as widespread inadequate control for confounding factors and possible effect modification make it difficult to base meaningful conclusions on published data. However, while there are indications of an association between periodontal disease and increased risk of adverse pregnancy outcome in some populations, there is no conclusive evidence that treating periodontal disease improves birth outcome. Based on a critical qualitative review, available evidence from clinical trials indicates that, although non-surgical mechanical periodontal treatment in the second trimester of pregnancy is safe and effective in reducing signs of maternal periodontal disease, it does not reduce the rate of pre-term birth. Clinical trials currently underway will further clarify the potential role of periodontal therapy in preventing adverse birth outcomes. Regardless of the outcomes of these trials, it is recommended that large, prospective cohort studies be conducted to assess risk for adverse pregnancy outcome in populations with periodontal disease. It is critical that periodontal exposure and adverse birth outcomes be clearly defined and the many potential confounding factors and possible effect modifiers for adverse pregnancy outcome be controlled in these studies. If periodontal disease is associated with higher risk of adverse pregnancy outcome in these specific populations, large multicenter randomized-controlled trials will be needed to determine if prevention or treatment of periodontal disease, perhaps combined with other interventions, has an effect on adverse pregnancy outcome in these women.

Association of cortisol and dehydroepiandrosterone sulphate levels in serum with periodontal status in older Japanese adults

BACKGROUND AND AIM

The associations between periodontitis and stress-related steroid hormone levels released by the hypothalamic-pituitary-adrenal axis are poorly understood. In this study, we examined the association between levels of the stress-related steroid hormones cortisol and dehydroepiandrosterone-sulphate (DHEAS) and periodontitis in elderly subjects.

METHODS

A total of 467 subjects participated in this study. Serum cortisol and DHEAS levels were determined, and a medical questionnaire regarding medical conditions and lifestyle was administered. In addition, clinical examinations including probing depth (PD), bleeding on probing (BOP), and clinical attachment loss (CAL) were conducted.

RESULTS

The subjects were divided into tertiles on the basis of periodontitis severity. When the analysis was stratified by smoking status, we found that cortisol levels were significantly higher in those with severe CAL among subjects who had never smoked. Furthermore, multiple regression analysis showed that a higher level of cortisol was significantly associated with greater numbers of sites with severe CAL only in those who had never smoked, while a somewhat weaker association was also observed regarding cortisol/DHEAS ratio. In contrast, the level of DHEAS in serum was not associated with periodontitis.

CONCLUSION

There were significant associations between serum cortisol level, including cortisol/DHEAS ratio, and periodontitis severity in elderly subjects who had never smoked.

Evaluation of logistic regression reporting in current obstetrics and gynecology literature

OBJECTIVE

To evaluate the quality of logistic regression reporting in the obstetrics and gynecology literature.

METHODS

All original papers published in 2005 and 2006 in four leading obstetrics and gynecology journals were manually searched for the use of logistic regression. One hundred four articles that used logistic regression were randomly selected (13 from each journal and each year) and evaluated according to previously established criteria for reporting logistic regression analyses. Rates of compliance with these criteria were calculated separately for each journal and weighted according to the number of articles using logistic regression in each of the journals in the same period to obtain an overall estimate.

RESULTS

Logistic regression was used in 34.2% of all original research articles (724 of 2,234) in the four journals for the study period. Statistical significance of estimates was reported in 96% of examined articles. Criteria of variable selection for the logistic regression model were reported in 76% of articles, and coding of variables was described in 83%. Overfitting (models with too many variables for the number of outcome events) occurred in 57% of studies. The majority of examined articles insufficiently reported information for the remaining criteria-testing for interactions (18%), conformity to a linear gradient of continuous variables (9%), goodness of fit (3.6%), assessment of multi-collinearity (0.46%), and validation of the model (0%).

CONCLUSION

Logistic regression has become a standard statistical method in obstetrics and gynecology literature. Although some standards are mostly fulfilled, there is still considerable room for improvement.

LEVEL OF EVIDENCE

III.

Relationship between betel quid additives and established periodontitis among Bangladeshi subjects

AIM

To determine the relationship between betel quid chewing additives and established periodontitis in Bangladeshi subjects.

MATERIAL AND METHODS

A total of 864 subjects participated in this study. Among them, 140 pairs of sex- and age-matched case subjects and control subjects were selected. A case was defined as a person who had at least two sites with a clinical attachment level (CAL)> or =6 mm and at least one site with probing depth (PD)> or =5 mm. Subjects who did not fulfill these criteria were considered as controls. Information on sociodemographic variables, psychological stress, dental health behaviour, smoking and betel quid chewing habits was obtained.

RESULTS

Multiple logistic regression analysis showed that current betel quid chewers had greater probabilities of having established periodontal disease than did non-chewers (odds ratio=3.97, p<0.05). Mean PD, mean CAL, mean percentage of bleeding on probing and number of missing teeth were significantly higher in chewers of betel quid with tobacco and masala than in chewers of betel quid without such additives adjusting for age, sex, smoking habit, body mass index, dental visit pattern, stress and plaque index. Higher frequency and longer duration of betel quid chewing showed a significant relation to an increase in periodontal parameters.

CONCLUSION

The results indicate that betel quid additives might significantly enhance periodontitis in the population studied.