Interleukin-1 genotypes and the association between periodontitis and cardiovascular disease

The Interleukin-1 (IL-1) Superfamily Cytokines and Their Single Nucleotide Polymorphisms (SNPs)

Interleukins (ILs)-which are important members of cytokines-consist of a vast group of molecules, including a wide range of immune mediators that contribute to the immunological responses of many cells and tissues. ILs are immune-glycoproteins, which directly contribute to the growth, activation, adhesion, differentiation, migration, proliferation, and maturation of immune cells; and subsequently, they are involved in the pro and anti-inflammatory responses of the body, by their interaction with a wide range of receptors. Due to the importance of immune system in different organisms, the genes belonging to immune elements, such as ILs, have been studied vigorously. The results of recent investigations showed that the genes pertaining to the immune system undergo progressive evolution with a constant rate. The occurrence of any mutation or polymorphism in IL genes may result in substantial changes in their biology and function and may be associated with a wide range of diseases and disorders. Among these abnormalities, single nucleotide polymorphisms (SNPs) can represent as important disruptive factors. The present review aims at concisely summarizing the current knowledge available on the occurrence, properties, role, and biological consequences of SNPs within the IL-1 family members.

Long term comparison of the prognostic performance of PerioRisk, periodontal risk assessment, periodontal risk calculator, and staging and grading systems

BACKGROUND

Clinicians predominantly use personal judgment for risk assessment. Periodontal risk assessment tools (PRATs) provide an effective and logical system to stratify patients based on their individual treatment needs. This retrospective longitudinal study aimed to validate the association of different risk categories of four PRATs (Staging and grading; Periodontal Risk Assessment (PRA); Periodontal Risk Calculator; and PerioRisk) with periodontal related tooth loss (TLP), and to compare their prognostic performance.

METHODS

Data on medical history, smoking status, and clinical periodontal parameters were retrieved from patients who received surgical and non-surgical periodontal treatment. A comparison of the rate of TLP and non-periodontal related tooth loss (TLO) within the risk tool classes were performed by means of Kruskal-Wallis test followed by post-hoc comparison with the Bonferroni test. Both univariate and multivariate Cox Proportional hazard regression models were built to analyze the prognostic significance for each single risk assessment tool class on TLP.

RESULTS

A total of 167 patients with 4321 teeth followed up for a mean period of 26 years were assigned to four PRATs. PerioRisk class 5 had a hazard ratio of 18.43, Stage 4 had a hazard ratio of 7.99, and PRA class 3 had a hazard ratio of 6.13 compared with class/stage I. With respect to prognostic performance, PerioRisk tool demonstrated the best discrimination and model fit followed by PRA.

CONCLUSION

All PRATs displayed very good predictive capability of TLP. PerioRisk showed the best discrimination and model fit, followed by PRA.

Polymorphism IL-1RN rs419598 reduces the susceptibility to generalized periodontitis in a population of European descent

Interleukin (IL) 1-ra is a potent endogenous competitive inhibitor of IL-α and β and has an anti-inflammatory role. Study objectives were: 1) to assess the associations of IL-1RN genetic single nucleotide polymorphism (SNP) (rs419598) with generalized chronic periodontitis (GCP), generalized aggressive periodontitis (GAgP), and absence of periodontitis and 2) to assess its association with the load of five periodontopathogenic bacteria and periodontal clinical variables. A cross-sectional analytic study was conducted in 123 patients with GCP, 60 patients with GAgP, and 20 controls. Reverse hybridization PCR was used for genotyping analysis to detect SNPs in IL-1A (rs1800587), IL-1B (rs1143634), and IL-1RN (rs419598) genes and for determination of the load of five periodontopathogenic bacteria. The severity and extension of periodontitis were assessed. Multinomial logistic regression and mediated regression analyses were performed. Considering results for GCP and GAgP patients together, the presence of polymorphism in IL-1A and/or IL-1B gene was associated with a higher likelihood of periodontitis, (OR = 8.11; 95%CI [1.85–35.48]), but this likelihood was reduced when IL-1RN polymorphism was also present, (OR = 5.91; 95%CI [1.08–32.27]). IL-1RN polymorphism was significantly associated with lower counts of red complex bacteria, specifically Porphyromona gingivalis, Tannerella forsythia, and Prevotella intermedia, which were associated with improved clinical outcomes. The polymorphic expression of IL-1RN (rs419598) gene may be associated with a reduced susceptibility to GAgP and GCP in populations of European descent. This effect may be mediated by a decreased load of Porphyromona gingivalis, Tannerella forsythia, and Prevotella intermedia.

Association of cytokines polymorphisms with chronic peridontitis and rheumatoid arthritis in a Mexican population

OBJECTIVE

Historically, it has been shown that rheumatoid arthritis (RA) and periodontitis (PE) share pathophysiological similarities and possibly a genetic background. In order to elucidate the genetic background between both diseases, we evaluated the distributions of five SNPs genotypes and all the possible haplotypes composed in subjects with isolated RA, PE, combined diseases and healthy controls.

MATERIALS AND METHODS

The study population consisted of 280 Mexican subjects. Genomic DNA was isolated from buccal epithelial cells collected by cheek scrapings and analyzed for the determination of the following SNPs: IL-1α + 4845 (rs17561), IL-1α -889 (rs1800587), IL-1β + 3954 (rs1143634), IL-1β -511(rs16944) and TNF-α -308 (rs1800629).

RESULTS

After adjustment for age, sex and smoking status, multiple logistic regression analysis revealed a no significant association in the genotype frequencies of TNF-α -308 and IL-1α + 4845 SNPs. Otherwise a significant association was observed in IL-1β + 3954 and IL-1β -511 (p < 0.05) while IL-1α -889 was of borderline statistical significance (p = 0.054). Also, we found three negative associated haplotypes with PE: IL-1α + 4845 G/IL-1β -511 A, IL-1β + 3954 C/IL-1β -511 A and interestingly IL-1α -889 C/IL-1β -511 A also with a positive association with RA.

CONCLUSIONS

Some genotypes and haplotypes are associated with the diseases. But it seems that the genetic background of the association between RA and PE needs to be explored deeper.

Periodontitis: a potential risk factor for Alzheimer's disease

The role of periodontitis as a risk factor for multiple systemic diseases is widely accepted and there is growing evidence of an association between periodontitis and sporadic late onset Alzheimer's disease (SLOAD). Recent epidemiologic, microbiologic and inflammatory findings strengthen this association, indicating that periodontal pathogens are possible contributors to neural inflammation and SLOAD. The aim of this article is to present contemporary evidence of this association.

Interleukin-1β gene variants are associated with QTc interval prolongation following cardiac surgery: a prospective observational study

BACKGROUND

We characterized cardiac surgery-induced dynamic changes of the corrected QT (QTc) interval and tested the hypothesis that genetic factors are associated with perioperative QTc prolongation independent of clinical and procedural factors.

METHODS

All study subjects were ascertained from a prospective study of patients who underwent elective cardiac surgery during August 1999 to April 2002. We defined a prolonged QTc interval as > 440 msec, measured from 24-hr pre- and postoperative 12-lead electrocardiograms. The association of 37 single nucleotide polymorphisms (SNPs) in 21 candidate genes -involved in modulating arrhythmia susceptibility pathways with postoperative QTc changes- was investigated in a two-stage design with a stage I cohort (n = 497) nested within a stage II cohort (n = 957). Empirical P values (Pemp) were obtained by permutation tests with 10,000 repeats.

RESULTS

After adjusting for clinical and procedural risk factors, we selected four SNPs (P value range, 0.03-0.1) in stage I, which we then tested in the stage II cohort. Two functional SNPs in the pro-inflammatory cytokine interleukin-1β (IL1β), rs1143633 (odds ratio [OR], 0.71; 95% confidence interval [CI], 0.53 to 0.95; Pemp = 0.02) and rs16944 (OR, 1.31; 95% CI, 1.01 to 1.70; Pemp = 0.04), remained independent predictors of postoperative QTc prolongation. The ability of a clinico-genetic model incorporating the two IL1B polymorphisms to classify patients at risk for developing prolonged postoperative QTc was superior to a clinical model alone, with a net reclassification improvement of 0.308 (P = 0.0003) and an integrated discrimination improvement of 0.02 (P = 0.000024).

CONCLUSION

The results suggest a contribution of IL1β in modulating susceptibility to postoperative QTc prolongation after cardiac surgery.

Polymorphisms in the interleukin-10 gene and chronic periodontitis in patients with atherosclerotic and aortic aneurysmal vascular diseases

Background

Chronic periodontitis (CP), atherosclerotic and aortic aneurysmal vascular diseases (VD) are chronic inflammatory conditions with multifactorial etiologies, including involvement of predisposing genetic factors. In a previous study, polymorphisms in the gene for the anti-inflammatory interleukin-1 receptor antagonist were associated with CP in patients with VD.

Objective

This study investigates whether polymorphisms in the gene for the anti-inflammatory interleukin-10 (IL10) could be related to CP in the same manner.

Methods

Seventy-two patients with VD of whom 35 had CP were genotyped for single nucleotide polymorphisms (SNPs) in the IL10 −592 (rs1800872), −819 (rs1800871), and −1,082 (rs1800896) gene by Taqman rtPCR method and by DNA sequencing.

Results

The C alleles and C/C genotypes of IL10 −592 and IL10 −819 frequencies were significantly higher, while the frequencies of the IL10 −592 (C/A) and IL10 −819 (C/T) heterozygote genotypes were significantly lower in the VD group with CP compared to those without CP. The IL10 haplotype ATA frequency (−1,082, −819, −592) showed a trend to a significant difference between the two groups indicating protection against CP.

Conclusions

Taken together, our findings suggest an independent association of genetic polymorphisms in the IL-10 gene locus with CP in patients with VD. Development of CP and the implications on vascular disease emphasize the importance of early detection and adequate treatment of periodontitis among these patients.

The Role of Interleukin-1 Genotype in the Association between Coronary Heart Disease and Periodontitis in a Syrian Population

Objective. To determine whether differences exist between periodontitis subjects with and without Coronary Heart Disease (CHD) in a Syrian population in the distribution of IL-1 alleles at positions IL-1α+4845, IL-1β+3954, IL-1β−511, and IL-1RN VNTR. Background. The role of Interleukin-1 genes in the association between periodontitis and CHD has been demonstrated in previous studies. No study has been carried out on the Syrian population to asses for such a role. Methods. 200 Syrian Arab periodontitis patients (184 males, 16 females; mean age 52.61) were divided into two groups: cases group 100 subjects with CHD (92 males, 8 females; mean age 52.06); controls group 100 subjects without CHD (92 males, 8 females; mean age 53.16). Probing depth (PD), clinical attachment loss (CAL), and alveolar bone loss (ABL) were performed for patients. Blood samples were collected for genotyping analysis of IL-1α+4845, IL-1β+3954, and IL-1β−511 using PCR-RFLP technique and IL-1RN VNTR using normal PCR. Results. An association between both (CAL and ABL) and CHD was shown after adjustment for other confounders (OR: 7.659, P = 0.001; OR: 3.645, P = 0.006, resp.). Also, an association between allele 2 of IL-1α+4845, IL-1β+3954, and IL-1β−511 and ABL was shown. Allele 2 of IL-1α+4845 and IL-1β−511 was associated with ABL among individuals with and without CHD. But after adjustment for other confounders, the association remained only between allele 2 of IL-11α+4845 and both CHD and severe ABL (OR: 0.189, P < 0.001). Conclusion. Allele 2 of IL-11α+4845 may be considered a risk indicator for having both CHD and severe ABL in the investigated Syrian population.

Associations between interleukin-1 gene polymorphisms and coronary heart disease risk: a meta-analysis

Objective

A great number of studies regarding the associations between IL-1B-511, IL-1B+3954 and IL-1RN VNTR polymorphisms within the IL-1gene cluster and coronary heart disease (CHD) have been published. However, results have been inconsistent. In this study, a meta-analysis was performed to investigate the associations.

Methods

Published literature from PubMed and Embase databases were searched for eligible publications. Pooled odds ratios (ORs) with 95% confidence intervals (CIs) were calculated using random- or fixed- effect model.

Results

Thirteen studies (3,219 cases/2,445 controls) for IL-1B-511 polymorphism, nine studies (1,828 cases/1,818 controls) for IL-1B+3954 polymorphism and twelve studies (2,987 cases/ 2,208 controls) for IL-1RN VNTR polymorphism were included in this meta analysis. The results indicated that both IL-1B-511 and IL-1B+3954 polymorphisms were not associated with CHD risk (IL-1B-511 T vs. C: OR = 0.98, 95%CI 0.87–1.09; IL-1B+3954 T vs. C: OR = 1.06, 95%CI 0.95–1.19). Similarly, there was no association between IL-1RN VNTR polymorphism and CHD risk (*2 vs. L: OR = 1.00, 95%CI 0.85–1.17).

Conclusions

This meta-analysis suggested that there were no associations between IL-1 gene cluster polymorphisms and CHD.

Do genetic factors explain the association between poor oral health and cardiovascular disease? A prospective study among Swedish twins

Epidemiologic studies suggest positive associations between poor oral health and cardiovascular disease. The authors undertook a prospective study among 15,273 Swedish twins (1963-2000) to examine whether genetic factors underlying the 2 diseases could explain previous associations. They estimated hazard ratios and 95% confidence intervals controlling for individual factors and stratifying on twin pairs to control for familial effects. Quantitative genetic analyses estimated genetic correlations between oral diseases and cardiovascular disease outcomes. Tooth loss (hazard ratio (HR) = 1.2, 95% confidence interval (CI): 1.1, 1.4) and periodontal disease (HR = 1.3, 95% CI: 1.0, 1.4) were associated with small excess risks of cardiovascular disease; periodontal disease was also associated with coronary heart disease (HR = 1.4, 95% CI: 1.1, 1.6). Adjustment for genetic factors in co-twin analyses did not appreciably change estimates. In contrast, tooth loss was more strongly associated with coronary heart disease in twin models (HR = 2.1, 95% CI: 1.2, 3.8) compared with adjusting for individual factors alone (HR = 1.3, 95% CI: 1.1, 1.4). There was evidence of shared genetic factors between cardiovascular disease and tooth loss (r(G) = 0.18) and periodontal disease (r(G) = 0.29). Oral disease was associated with excess cardiovascular disease risk, independent of genetic factors. There appear to be common pathogenetic mechanisms between poor oral health and cardiovascular disease.

Relationship between the gingival sulcus depth and interleukin-1 isoform concentrations within the adjacent gingival tissue

BACKGROUND AND OBJECTIVE

While there is substantial information concerning the concentrations of interleukin-1 isoforms within gingival crevicular fluid, there is little information concerning their concentrations within either normal or diseased gingival tissues. Therefore, the aim of this study was to evaluate the relationship between the concentrations of gingival interleukin-1 isoforms and the adjacent sulcular depth.

MATERIAL AND METHODS

Interdental gingival papillae were excised and grouped based on adjacent pocket depth and the presence of bleeding on probing. Gingiva adjacent to a sulcus of < or = 3 mm without bleeding on probing were classified as 'normal'; gingiva adjacent to a 3-mm sulcus with bleeding on probing were classified as 'diseased-slight'; gingiva adjacent to a 4-6-mm sulcus featuring bleeding on probing were classified as 'diseased-moderate'; and gingiva adjacent to a sulcus of > 6 mm featuring bleeding on probing were classified as 'diseased-severe'. Tissues were solublized and the concentrations of interleukin-1beta, interleukin-1alpha, interleukin-1 receptor antagonist and interleukin-6 were assessed by enzyme-linked immunosorbent assay. Data were compared by factorial analysis of variance, the post-hoc Tukey test and the Pearson's correlation test.

RESULTS

Gingival concentrations of interleukin-6, interleukin-1 receptor antagonist, interleukin-1alpha- and interleukin-1beta were significantly greater at diseased-severe sites than at normal, diseased-slight, or diseased-moderate sites (p < 0.05); the gingival concentrations of interleukin-1 receptor antagonist and interleukin-1alpha were significantly greater at diseased-severe than at diseased-moderate sites (p < 0.05). Interleukin-1 receptor antagonist concentrations were significantly correlated with both interleukin-1alpha and interleukin-1beta concentrations. The ratios of concentrations of the interleukin-1 isoforms were different at the various stages of inflammation.

CONCLUSION

Our data indicated a progressive increase in gingival concentrations of interleukin-1 isoforms with increased adjacent sulcular depth. However, within 'diseased' tissues, the proportional concentrations of interleukin-1alpha and -beta to interleukin-1 receptor antagonist were lowest within diseased-severe tissues.

Inflammation as a potential mediator for the association between periodontal disease and Alzheimer's disease

Periodontal disease (PDD) is associated with increased risk of cardiovascular disease, cerebrovascular disease, and mortality in many studies, while other studies have begun to suggest an association of PDD with Alzheimer's disease (AD). This paper discusses how infectious pathogens and systemic infection may play a role in AD. The roles of infection and inflammation are addressed specifically with regard to known AD pathologic lesions including senile plaques, neuron death, neurofibrillary tangles, and cerebrovascular changes. A testable model of proposed pathways between periodontal infection and AD is presented including three possible mechanisms: a) direct effects of infectious pathogens, b) inflammatory response to pathogens, and c) the effects on vascular integrity. The role of gene polymorphisms is discussed, including apolipoprotein (APOE) varepsilon4 as a pro-inflammatory and pro-infection genotype.

Association of pesticide exposure, vaccination response, and interleukin-1 gene polymorphisms

We performed a cross-sectional study involving workers from four European countries in which exposure to pesticides and immune parameters were evaluated over a short period of time. The total study population consisted of 238 workers occupationally exposed to pesticides and 198 nonoccupationally exposed workers. The study showed that pesticide exposure at levels encountered by workers under different conditions in Europe did not affect the ability of the immune system to respond to vaccination. We could, however, identify individuals within the group of pesticide exposed workers who were genetically characterized by the 2.2 IL-1α polymorphism and who showed a lower antibody response, pointing out the importance of the understanding of genetic variability and the interaction between genetic and environmental factors in the identification of high-risk individuals, which may eventually lead to preventive measures.

Association of interleukin-1 receptor antagonist +2018 gene polymorphism with Japanese chronic periodontitis patients using a novel genotyping method

Genetic variants at multiple loci have been shown to be associated with periodontitis risk. In this study, we have focused on nine functional gene polymorphisms encoding immunoregulation-related molecules such as cytokines (interleukin-1 (IL-1), transforming growth factor-beta1 (TGF-beta1)) and cell surface receptors (immunoglobulin G and A Fc receptors (Fc gamma R and Fc alpha R)). In total, 113 Japanese patients with chronic periodontitis (CP) and 108 race-matched healthy controls were genotyped with the modified serial invasive signal amplification reaction. There was a significant difference in the distribution of IL-1 receptor antagonist (RN) +2018 T/C allele between the patient and control groups, with enrichment of the +2018 C in controls (P = 0.021, odds ratio = 0.38). An increased frequency of the IL-1 haplotype comprising IL-1A +4845 G, IL-1B -31 C, and IL-1RN +2018 C was observed in controls (P = 0.004). Moreover, a multivariate logistic regression analysis revealed that subjects with IL-1RN +2018 C allele were less likely to have CP (P = 0.016, odds ratio = 0.29). These findings document the association of IL-1RN +2018 C with reduced susceptibility to CP in the Japanese.

Patients with a history of stable or unstable coronary heart disease have different acute phase responses to an inflammatory stimulus

Increased levels of acute phase proteins (APP) in serum are associated with vulnerability of atherosclerotic plaques and acute manifestations of coronary heart disease (CHD). APP have been viewed as indexes of active vascular inflammation or as mediators of atherothrombosis. In the present study we tested the hypothesis that individuals who develop stable or unstable forms of CHD might have different innate responses to an inflammatory stimulus. We compared changes in plasma C-reactive protein (CRP) and serum amyloid A (SAA) concentrations 48 h after a standardized inflammatory stimulus (adjuvanted influenza vaccination) in patients with quiescent CHD that had been manifested at onset as inducible myocardial ischemia (Group 1, n=26) or as acute coronary syndromes (ACS) (Group 2, n=34). Selected patients were free from inflammatory or other conditions that might affect the immune response. CRP concentration increased significantly after vaccination in both groups (Group 1: 0.47 [0.21-0.86] to 0.56 [0.32-1.17]mg/L, p=0.005; Group 2: 0.64 [0.21-1.09] to 0.75 [0.33-1.48]mg/L, p=0.003), without significant differences between groups in absolute or percentage changes. By contrast, SAA did not change after vaccination in Group 1 (14.4 [8.9-19.5] to 14.8 [10.3-18.8]mg/L, p=0.88) but increased significantly in Group 2 (16.9 [10.0-21.5] to 19.2 [11.3-29.1]mg/L, p=0.002), with significant differences between the groups in absolute and percentage terms (p=0.015 and 0.019, respectively). Changes in CRP and SAA, both absolute and percentage, were significantly correlated in Group 2 (r=0.60 and 0.66, both p<0.001). The responsiveness of plasma SAA to an inflammatory stimulus in Group 2 alone suggests a pro-inflammatory status in patients prone to acute coronary syndrome but not in those with inducible myocardial ischemia.

The genetics of cerebrovascular atherosclerosis

Ischemic stroke attributable to atherosclerosis remains a major public health problem. Genetic factors are increasingly recognized as influencing risk for atherosclerosis directly and indirectly. Genetic makeup may influence the development of major vascular risk factors or alter susceptibility of the cerebral vasculature to these risk factors. More recently, newly identified risk factors for atherosclerosis, such as plasma homocysteine and infection, have also been reported to be influenced by important genetic determinants. This article reviews the current nature on genetics of cerebral and precerebral atherosclerosis and seeks to identify areas of promise for future clinical application.

Cardiovascular and oral disease interactions: what is the evidence?

This paper reviews the evidence for the interaction of oral disease (more specifically, periodontal infections) with cardiovascular disease. Cardiovascular disease is a major cause of death worldwide, with atherosclerosis as the underlying aetiology in the vast majority of cases. The importance of the role of infection and inflammation in atherosclerosis is now widely accepted, and there has been increasing awareness that immune responses are central to atherogenesis. Chronic inflammatory periodontal diseases are among the most common chronic infections, and a number of studies have shown an association between periodontal disease and an increased risk of stroke and coronary heart disease. Although it is recognised that large-scale intervention studies are required, pathogenic mechanism studies are nevertheless required so as to establish the biological rationale. In this context, a number of hypotheses have been put forward; these include common susceptibility, inflammation via increased circulating cytokines and inflammatory mediators, direct infection of the blood vessels, and the possibility of cross-reactivity or molecular mimicry between bacterial and self-antigens. In this latter hypothesis, the progression of atherosclerosis can be explained in terms of the immune response to bacterial heat shock proteins (HSPs). Because the immune system may not be able to differentiate between self-HSP and bacterial HSP, an immune response generated by the host directed at pathogenic HSP may result in an autoimmune response to similar sequences in the host. Furthermore, endothelial cells express HSPs in atherosclerosis, and cross-reactive T cells exist in the arteries and peripheral blood of patients with atherosclerosis. Each of these hypotheses is reviewed in light of current research. It is concluded that although atherosclerotic cardiovascular disease is almost certainly a multifactorial disease, there is now strong evidence that infection and inflammation are important risk factors. As the oral cavity is one potential source of infection, it is wise to try to ensure that any oral disease is minimised. This may be of significant benefit to cardiovascular health and enables members of the oral health team to contribute to their patients' general health.

Polymorphisms within the IL-1 gene cluster: effects on cytokine profiles in peripheral blood and whole blood cell cultures of patients with aggressive periodontitis, juvenile idiopathic arthritis, and rheumatoid arthritis

BACKGROUND

Genetic polymorphisms of cytokines have been associated with the susceptibility, severity, and clinical outcome of inflammatory diseases, such as periodontitis and chronic arthritis. An important question to address is how interleukin (IL)-1 polymorphisms affect the cytokine profiles of patients with such diseases.

METHODS

The study population consisted of Danish white adults, <35 years of age, who were diagnosed with localized aggressive periodontitis (LAgP, n = 18), generalized aggressive periodontitis (GAgP, n = 27), juvenile idiopathic arthritis (JIA, n = 10), and rheumatoid arthritis (RA, n = 23) and healthy individuals with no systemic or oral diseases (n = 25). Genotypes of IL-1A-889, IL-1A+4845, IL-1B-511, and IL-1B+3954 were determined by polymerase chain reaction (PCR)-restriction fragment length polymorphism, and IL-1RN variable number tandem repeat (VNTR) was detected by PCR amplification and fragment size analysis. Analysis of variance was used to evaluate the effects of IL-1 genotypes on the levels of IL-1alpha, -1beta, -1 receptor antagonist, -6, and -10; tumor necrosis factor-alpha (TNF-alpha); and lymphotoxin-alpha in peripheral blood (plasma) and in unstimulated and stimulated whole blood cell cultures from the same blood collection.

RESULTS

The frequencies of IL-1 genotypes investigated did not differ significantly between diseased and control individuals. In LAgP patients, allele 2 of IL-1RN VNTR was associated with significantly higher levels of IL-1alpha, -6, and -10 and TNF-alpha, whereas allele 2 of IL-1B+3954 was associated with significantly lower levels of the same cytokines. In GAgP patients, a general lack of association was found. In JIA and RA patients, IL-1RN VNTR also influenced the cytokine levels.

CONCLUSIONS

IL-1 genotypes were associated with cytokine levels in patients with aggressive periodontitis and chronic arthritis. No associations were observed in control individuals.

The association of the composite IL-1 genotype with periodontitis progression and/or treatment outcomes: a systematic review

BACKGROUND

Genetically transmitted traits such as cytokine gene polymorphisms may accentuate the host inflammatory response to the bacterial challenge and influence susceptibility to periodontitis.

OBJECTIVE

To systematically review the evidence of an association between the interleukin-1 (IL-1) composite genotype, i.e. presence of the allele 2 in the gene clusters IL-1A-889 and in IL-1B +3953, and periodontitis progression and/or treatment outcomes.

MATERIAL AND METHODS

Based on the focused question, a search was conducted for longitudinal clinical trials comparing progression of periodontitis and/or treatment outcomes in IL-1 genotype-positive (carrying allele 2) and IL-1 genotype-negative (not carrying allele 2) subjects. A search in the National Library of Medicine computerized bibliographic database MEDLINE and a manual search were performed. Selection of publications, extraction of data and validity assessment were made independently by two reviewers.

RESULTS

The search provided 122 titles of which 11 longitudinal publications were included. The heterogeneity of the data prevented the performance of a meta-analysis. While findings from some publications rejected a possible role of IL-1 composite genotype on progression of periodontitis after various therapies, other reported a prognostic value for disease progression of the positive IL-1 genotype status. When assessed on a multivariate risk assessment model, several publications concluded that the assessment of the IL-1 composite genotype in conjunction with other covariates (e.g. smoking and presence of specific bacteria) may provide additional information on disease progression. The small sample size of the available publications, however, requires caution in the interpretation of the results.

CONCLUSION

Based on these findings, (i) there is insufficient evidence to establish if a positive IL-1 genotype status contributes to progression of periodontitis and/or treatment outcomes. Therefore, (ii) results obtained with commercially available tests should be interpreted with caution.

IL1RN VNTR polymorphism in ischemic stroke: analysis in 3 populations

BACKGROUND AND PURPOSE

Genetic factors influence risk for ischemic stroke and likely do so at multiple steps in the pathogenic process. Variants in genes related to inflammation contribute to risk of stroke. The purpose of this study was to confirm our earlier finding of an association between allele 2 of a variable number tandem repeat of the IL-1 receptor antagonist gene (IL1RN) and cerebrovascular disease.

METHODS

An association study of the variable number tandem repeat genotype with ischemic stroke and stroke subtypes was performed on samples from a North American study of affected sibling pairs concordant for ischemic stroke and 2 North American cohorts of prospectively ascertained ischemic stroke cases and unrelated controls. DNA analysis was performed on cases and controls, stratified by race.

RESULTS

After adjustment for age, sex, and stroke risk factors, the odds ratio for association of allele 2 and ischemic stroke was 2.80 (95% confidence interval, 1.29 to 6.11; P=0.03) for the white participants. The effect of allele 2 of IL1RN on stroke risk most closely fits a recessive genetic model (P=0.009). For the smaller sample of nonwhite participants, the results were not significant.

CONCLUSIONS

Allele 2 of IL1RN, present in nearly one-quarter of stroke patients, may contribute to genetic risk for ischemic stroke and confirm the previously identified association with cerebrovascular disease. These results are driven by the association in the white participants. Further exploration in a larger nonwhite sample is warranted.

Tissue destruction induced by Porphyromonas gingivalis infection in a mouse chamber model is associated with host tumor necrosis factor generation

Intrachamber challenge with Porphyromonas gingivalis strain 381 in a mouse subcutaneous chamber model results in a local infection that progresses to exfoliation of the chambers within 15 days. This study was designed to elucidate the contribution of host reactions to tissue destruction manifested by chamber exfoliation in animals infected with P. gingivalis. Chamber fluids showed increasing levels of prostaglandin E(2) with infection, and the levels of tumor necrosis factor (TNF) in chamber fluids peaked just before chamber exfoliation. Intraperitoneal injection of a TNF inhibitor, thalidomide (TH), reduced the number of exfoliated chambers, while indomethacin had no effect. Exogenous TNF in chambers without bacterial infection did not cause chamber exfoliation but induced neutrophil infiltration. In a dual-chamber model, two chambers were implanted in the same mouse. One chamber was infected with P. gingivalis, and 9 days later exogenous TNF was added to the other chamber. Altogether, 66.67% of uninfected chambers were exfoliated between day 11 and day 16, although no bacteria were recovered from uninfected chambers. TH treatment alleviated both infected and uninfected chamber exfoliation. In this study, tissue destruction caused by P. gingivalis 381 infection was due to the elevation of the TNF levels and not due to local bacterial activities. Our results further indicate that local infection by P. gingivalis 381, a nondisseminating strain, actually has systemic effects on the host pathological outcome.

Pharmacogenomics and cardiovascular drugs: need for integrated biological system with phenotypes and proteomic markers

Personalized medicine is based on a better knowledge of biological variability, considering the important part due to genetics. When trying to identify involved genes and their products in differential cardiovascular drug responses, a five-step strategy is to be followed: 1) Pharmacokinetic-related genes and phenotypes (2) Pharmacodynamic targets, genes and products (3) Cardiovascular diseases and risks depending on specific or large metabolic cycles (4) Physiological variations of previously identified genes and proteins (5) Environment influences on them. After summarizing the most well-known genes involved in drug metabolism, we will take as example of drugs, the statins, considered as very important drugs from a Public-Health standpoint, but also for economical reasons. These drugs respond differently in human depending on multiple polymorphisms. We will give examples with common ApoE polymorphisms influencing the hypolipemic effects of statins. These drugs also have pleiotropic effects and decrease inflammatory markers. This illustrates the need to separate clinical diseases phenotypes in specific metabolic pathways, which could propose other classifications, of diseases and related genes. Hypertension is also a good example of clinical phenotype which should be followed after various therapeutic approaches by genes polymorphisms and proteins markers. Gene products are under clear environmental expression variations such as age, body mass index and obesity, alcohol, tobacco and dietary interventions which are the first therapeutical actions taken in cardiovascular diseases. But at each of the five steps, within a pharmacoproteomic strategy, we also need to use available information from peptides, proteins and metabolites, which usually are the gene products. A profiling approach, i.e., dealing with genomics, but now also with proteomics, is to be used. In conclusion, the profiling, as well as the large amount of data, will more than before render necessary an organized interpretation of DNA, RNA as well as proteins variations, both at individual and population level.

A candidate gene approach of immune mediators effecting the susceptibility to and severity of upper gastrointestinal tract diseases in relation to Helicobacter pylori and Epstein-Barr virus infections

This review focuses on immunogenetic aspects of diseases of the upper gastrointestinal tract in which infectious agents may play a role in the aetiopathogenesis, such as Helicobacter pylori, Epstein-Barr virus (EBV) and HIV. Gastric adenocarcinoma is a common cancer all around the world, with declining incidences in Europe and high incidences in Asia and central and south America. Together with gastric atrophy and peptic ulcer disease, gastric adenocarcinoma belongs to the commonest upper gastrointestinal tract diseases. These diseases are multifactorial and factors such as smoking and dietary habits contribute to the pathogenesis. More recently, scientists have turned their eyes on the host. Functional polymorphisms in the genes regulating the host immune system may contribute to the susceptibility to and progression of disease. In multifactorial and polygenetic diseases, candidate gene studies of single nucleotide polymorphisms (SNPs) detect small to moderate relative risks. Unfortunately, only a few functional SNPs have been identified. The candidate gene approach can be seen as a useful first step in exploring causal pathways between genetic determinants and complex diseases such as those mentioned above. To date, little is known about the immunogenetics of upper gastrointestinal tract diseases. We review the literature on H. pylori, EBV and gene polymorphisms that affect key immune mediators influencing the pathogenesis of the inflammatory response, such as the genes that code for the IL-1 family, TNF-alpha, lymphotoxin alpha, and IL-10. IL-1, IL-10, lymphotoxin alpha and TNF-alpha polymorphisms increase the risk of upper gastrointestinal pathogenesis in H. pylori-infected patients, whereas IL-1 and TNF-alpha polymorphisms confer risk in EBV-infected patients.

Environmental and heritable factors in the etiology of oral diseases--a population-based study of Swedish twins

A population-based twin study is a useful design for quantification of the effects of genes and environmental factors in disease etiology. We used data from 10,000 Swedish twin pairs to quantify genetic and environmental contributions to tooth loss and periodontal health. Oral health information was obtained from telephone interviews. Structural equation models measured the relative importance of genetic and environmental factors. Genetic factors contributed to 14% of variation in tooth loss among women, and 39% among men. Non-shared environmental factors accounted for one-quarter of risk; environmental factors shared by twins comprised the remainder. Heritability estimates of periodontal disease were 39% and 33% for women and men, respectively, while non-shared environmental factors accounted for the remaining variation. Heritability for both conditions varied as a function of age and smoking status. Analysis of data from this large, population-based study demonstrates a moderate role of genetic factors in oral diseases, and suggests potential gene-environment interactions.

Interleukin-1 gene cluster polymorphisms predict risk of ESRD

BACKGROUND

Patients with chronic kidney disease manifest an inflammatory state relative to healthy individuals. Inflammation is regulated in part by genes of the interleukin-1 (IL-1) gene cluster. We hypothesized that polymorphisms in this gene cluster may be associated with risk of end-stage renal disease (ESRD).

METHODS

Polymorphisms in the IL-1 gene cluster were examined in a cohort of 239 racially diverse hemodialysis (HD) patients and 252 controls. These individuals were genotyped for 3 single nucleotide polymorphisms (SNPs) in the IL-1alpha and beta genes, and a variable-number-of-tandem-repeats polymorphism in the IL-1 receptor antagonist gene (IL-1RN). Polymorphisms were analyzed by logistic regression for their independent associations with ESRD, and the effect of allele dose of IL-1RN on risk for ESRD was examined. The interaction between race and genotype was also investigated.

RESULTS

A logistic regression model demonstrated that homozygosity for allele 2 of the IL-1RN variable-number-of-tandem-repeats (VNTR) polymorphism was associated with ESRD independent of race (P < 0.0005). The IL-1alpha-889 promoter SNP was associated with ESRD independent of race and of the IL-1RN polymorphism (P= 0.04). The IL-1beta-511 promoter SNP is associated with ESRD, but this is accounted for by race (P= 0.04).

CONCLUSION

Two polymorphisms within the IL-1 gene cluster are associated with ESRD independent of race. This finding is one of the strongest associations between genotype and ESRD reported, and suggests that polymorphisms in the IL-1 gene cluster affect the risk of development of ESRD.

Association between the interleukin-1beta C(-511)T polymorphism and blood pressure in a Chinese hypertensive population

The interleukin-1beta (IL-1beta) is an important pro-inflammatory cytokine in a broad spectrum of physiological processes. Previous investigations have observed that levels of the IL-1beta were higher in essential hypertensive patients and the IL-1beta gene polymorphism has been shown to be related to IL-1 production. We hypothesized that genetically determined differences in activity or responsiveness of cytokine(s) might contribute to hypertension. In this report, we utilized a family-based design to test the association between the IL-1beta C(-511)T polymorphism and blood pressure levels in hypertensive patients chosen from rural communities in Anhui, China. In men, carriers of the IL-1beta (-511)*C allele were found to have lower systolic (P = 0.049) blood pressure levels compared with T homozygotes, which conforms to an additive effect model. By contrast, no significant association between the IL-1beta gene and blood pressure levels was revealed in women. Our results suggested a significant role of the IL-1beta C(-511)T polymorphism in the control of blood pressure in Chinese hypertensives.

Periodontitis and atherogenesis: causal association or simple coincidence?

OBJECTIVES

The aim of this study was to assess the systemic effects of treating severe widespread periodontitis in a population of otherwise healthy individuals by examining treatment associated changes in markers of inflammation that are also implicated in cardiovascular atherosclerotic diseases. The potential impact of specific polymorphisms in cytokine genes known to influence both periodontitis and cardiovascular diseases was also examined.

MATERIALS AND METHODS

A convenience sample of patients affected with severe generalised periodontitis was enrolled into a prospective single blind longitudinal intervention trial with a 6 months follow-up. Serum C-reactive protein (CRP) and interleukin-6 (IL-6) levels were assessed by high-sensitivity assays. Serological and clinical periodontal parameters were evaluated at baseline, 2 and 6 months after completion of non-surgical periodontal therapy.

RESULTS

In the 94 subjects that completed this pilot trial improvements in all clinical periodontal parameters were achieved. These were accompanied with significant reductions in serum IL-6 and CRP concentrations. In a multivariate model, serum CRP levels were significantly associated with the outcome of periodontal treatment after correcting for potential covariates (age, body mass index, gender, smoking) and polymorphisms in the IL-6 (-174 C/G) and IL-1A (-889) genes. A median decrease in serum CRP of 0.5 mg/l (95% CI 0.4-0.7 mg/l) was observed 6 months after completion of periodontal therapy in this population. Subjects with above average response to periodontal therapy (<30 residual pockets and <30% of sites bleeding on probing) accounted for the observed improvement in serum CRP.

CONCLUSIONS

Control of periodontitis, achieved with non-surgical periodontal therapy, significantly decreased serum mediators and markers of acute phase response. The significance of the serum response was associated with the half of the population that responded better to non-surgical periodontal therapy. The results of this pilot study indicate that severe generalised periodontitis causes systemic inflammation. This is consistent with a causative role of periodontitis in atherogenesis.

Single nucleotide polymorphisms associated with aggressive periodontitis and severe chronic periodontitis in Japanese

Periodontitis is a common inflammatory disease causing destruction of periodontal tissues. It is a multifactor disease involving genetic factors and oral environmental factors. To determine genetic risk factors associated with aggressive periodontitis or severe chronic periodontitis, single nucleotide polymorphisms (SNPs) in multiple candidate genes were investigated in Japanese. We studied 134 patients with aggressive periodontitis, 117 patients with severe chronic periodontitis, and 125 healthy volunteers without periodontitis, under case-control setting, and 310 SNPs in 125 candidate genes were genotyped. Association evaluation by Fisher's exact test (p < 0.01) revealed statistically significant SNPs in multiple genes, not only in inflammatory mediators (IL6ST and PTGDS, associated with aggressive periodontitis; and CTSD, associated with severe chronic periodontitis), but also in structural factors of periodontal tissues (COL4A1, COL1A1, and KRT23, associated with aggressive periodontitis; and HSPG2, COL17A1, and EGF, associated with severe chronic periodontitis). These appear to be good candidates as genetic factors for future study.

Oral infection with a periodontal pathogen accelerates early atherosclerosis in apolipoprotein E-null mice

OBJECTIVE

Because recent epidemiologic evidence suggests that periodontal infections may increase the risk of atherosclerosis and related events in humans, we assessed the impact of oral inoculation with the periodontal pathogen Porphyromonas gingivalis on atherogenesis in hypercholesterolemic apolipoprotein E-null mice.

METHODS AND RESULTS

In the absence of alterations in distinct risk factors, P gingivalis infection exacerbated the early stages of atherogenesis in this model. Infected animals displayed evidence of local periodontal infection, as the severity of alveolar bone loss, the hallmark of periodontitis, was increased. Generalized activation of host inflammatory responses was evident in infected mice, as demonstrated by serum IgG response to P gingivalis and elevated levels of interleukin-6. P gingivalis DNA was localized in the aortic tissue from a limited number of infected mice but not in any noninfected controls. Infected mice displayed enhanced vascular activation, as suggested by increased aortic expression of vascular cell adhesion molecule-1 and tissue factor.

CONCLUSIONS

Oral infection with P gingivalis accelerates early atherosclerosis. Thus, uncovering the underlying mechanisms is critical for the design of preventive and therapeutic strategies targeting atherosclerotic vascular disease and its sequelae.

Cardiovascular diseases and periodontology

BACKGROUND

Cardiovascular diseases represent a widespread heterogeneous group of conditions that have significant morbidity and mortality. The various diseases and their treatments can have an impact upon the periodontium and the delivery of periodontal care.

AIM

In this paper we consider three main topics and explore their relationship to the periodontist and the provision of periodontal treatment.

METHOD

The areas reviewed include the effect of cardiovascular drugs on the periodontium and management of patients with periodontal diseases; the risk of infective endocarditis arising from periodontal procedures; the inter-relationship between periodontal disease and coronary artery disease.

RESULTS AND CONCLUSIONS

Calcium-channel blockers and beta-adrenoceptor blockers cause gingival overgrowth and tooth demineralisation, respectively. Evidence suggests that stopping anticoagulant therapy prior to periodontal procedures is putting patients at a greater risk of thromboembolic disorders compared to the risk of prolonged bleeding. The relationship between dentistry and infective endocarditis remains a controversial issue. It would appear that spontaneous bacteraemia arising from a patient's oral hygiene practices is more likely to be the cause of endocarditis than one-off periodontal procedures. The efficacy of antibiotic prophylaxis is uncertain (and unlikely to be proven), and the risk of death from penicillin appears to be greater than the risk of death arising from infective endocarditis. Finally, the association between periodontal disease and coronary artery disease has been explored and there seem to be many issues with respect to data handling interpretation. Many putative mechanisms have been suggested; however, these only further highlight the need for intervention studies.

Interleukin-1 receptor antagonist gene polymorphisms in carotid atherosclerosis

BACKGROUND AND PURPOSE

Inflammation plays an important role in the development of atherosclerosis. The gene for the counterinflammatory cytokine interleukin-1 receptor antagonist (IL-1ra) is polymorphic, and high frequencies of allele 2 have been found to be associated with other inflammatory diseases. This study examined the association of allele and carrier frequencies of the IL-1ra gene with the presence of carotid atherosclerosis and plaque symptomaticity.

METHODS

A total of 328 subjects identified as having carotid atherosclerosis or no atherosclerosis (controls) participated. Blood was obtained for DNA determination.

RESULTS

Frequency of allele 2 was significantly greater in patients with atherosclerosis compared with nonatherosclerotic subjects. No difference was seen between symptomatic and asymptomatic atherosclerosis patients. Noncarriage of allele 2 was associated with reduced likelihood of atherosclerosis (odds ratio [OR], 0.44; 95% CI, 0.27 to 0.71). The homozygous carrier state for allele 2 was associated with greater likelihood of atherosclerosis (unadjusted OR, 7.30; 95% CI, 2.31 to 22.94; adjusted OR, 13.78; 95% CI, 1.94 to 97.9). A gene-dose effect was detected.

CONCLUSIONS

These data suggest that allele 2 of the IL-1ra gene represents a susceptibility factor in the development of carotid atherosclerosis. Further investigation appears warranted.

Science review: Genetic variability in the systemic inflammatory response

The present review discusses recent studies that have identified genetic differences in inflammatory proteins associated with different phenotypic presentations of systemic inflammation. Basic genetic terminology is defined. Implications of genetic influences on the inflammatory response are discussed. The published associations of specific polymorphisms in antigen recognition pathways, proinflammatory cytokines, anti-inflammatory cytokines, and effector molecules are reviewed. The strongest and most consistent associations thus far have been with the tumor necrosis factor, lymphotoxin-alpha, and IL-1 receptor antagonist polymorphisms. However, large, phenotypically detailed studies are required to address all of the other potential polymorphisms in inflammatory molecule genes and their interactions.

HLA-A, B, Cw, DRB1, DRB3/4/5, DQB1 in German patients suffering from rapidly progressive periodontitis (RPP) and adult periodontitis (AP)

BACKGROUND/AIM

There is growing indication that differences in host response determine susceptibility and resistance to periodontal disease. Particularly, the effect of histocompatibility antigens (HLA) on early onset periodontitis (EOP) has been studied. As most of the results are not conclusive and to date no report has been done on German patients, the aim of this study was to investigate the distribution of HLA alleles in a group of 50 German RPP patients and 102 German AP patients and to compare them to 102 control probands without periodontitis.

METHODS

Diagnosis was established according to standardised clinical criteria. HLA typing was performed using serologic and molecular biologic (PCR-SSP) techniques.

RESULTS

Compared to the controls, RPP patients had a significantly higher frequency of HLA-DRB1*13 and a significantly lower frequency of HLA-DRBblank*(non-DRB3/4/5). AP patients showed a significantly increased occurrence of HLA-B*14 and -Cw*08 as well as a significantly decreased frequency of HLA-A*03. In both patient groups HLA-A*11 and -A*29 had an increased frequency and HLA-A*31 and -A*30/31 were decreased. These differences were statistical significant in the whole patient group (RPP + AP).

CONCLUSIONS

Based on modern DNA techniques the present study shows an association of HLA to both RPP and AP. Certain HLA alleles seem to be associated with susceptibility or resistance to periodontitis in general. However, before this knowledge can be used for differential diagnosis or prognosis, further investigations are necessary.

Investigation of the association between angiographically defined coronary artery disease and periodontal disease

BACKGROUND

The association between periodontal disease and coronary artery disease (CAD) has been investigated in numerous studies with inconsistent results. Resolving these differences is complicated by the use of varying definitions of CAD. The aim of this study was to investigate the association between angiographically-defined CAD and periodontal disease.

METHODS

Non-smoking, non-diabetic patients, over 40 years of age, with no history of a myocardial infarction in the previous 6 months and who had undergone cardiac catheterization within the previous 12 months were enrolled in this study. Subjects were classified as having CAD (CAD+) if they had 50% stenosis in at least one major epicardial artery and classified as CAD negative (CAD-) if they had <50% stenosis in all identified arteries. Periodontal disease severity was measured through bleeding on probing, probing depth, clinical attachment level (CAL), gingival recession, number of missing teeth, and radiographic bone loss.

RESULTS

One hundred (53 = CAD+; 47 = CAD-) patients were examined. CAD+ patients were more likely to be male (CAD+ 83.0% male; CAD- 40.4% male; P= 0.001), and were older (CAD+ 65.3 years; CAD- 60.8 years; P= 0.0138). Although all patients reported they were currently non-smokers and had not smoked for at least 5 years, the fraction who were former smokers was greater for CAD+ patients (66% versus 24.4%; P = 0.0001) and mean pack/year history of smoking was higher for CAD+ patients (15.8 versus 4.5; P = 0.0003). Mean CAL (3.13 mm versus 2.78 mm; P 0.0227), number of sites with CAL > or = 6 mm (6.85 versus 3.32; P = 0.0242), radiographic bone loss (3.60 mm versus 3.18 mm; P = 0.0142) were greater for CAD+ patients than for CAD- patients. However, after adjustment for age and previous smoking history, factors common to both diseases, the associations of CAD and periodontal disease were reduced and were not statistically significant (odds ratio [OR]: mean CAL OR = 1.06; number of sites with CAL > or = 6 mm OR = 1.03; mean radiographic bone loss OR = 1.31; P > or = 0.2055).

CONCLUSIONS

After accounting for factors common to both periodontal disease and CAD, there was no significant association between periodontal disease and chronic CAD as assessed angiographically. Further investigations into the relationship between periodontal disease and CAD should clearly separate chronic CAD and acute coronary events.

Oral health and heart disease

Over the past ten years, a body of evidence has accumulated to suggest that aspects of oral health, particularly the extent and severity of periodontal disease, may be associated with an increased risk of coronary heart disease (CHD). This evidence should be seen against the background of a more general interest in the role of chronic infections in vascular disease. There have, for example, been suggestions of associations between CHD and a range of bacterial and viral agents, including H. pylori, C. pneumoniae, and cytomegalovirus, which are involved in persistent infections at various sites around the body. Reviews of the evidence for the causality of these relationships between CHD and specific organisms have been inconclusive. By comparison, periodontal disease is related to a wide and complex range of organisms rather than a single species and although the nature of the relationship is still inconclusive, the evidence for its validity still persists to some degree. A brief synopsis of the epidemiological studies to date and their outcomes is shown in Table 1.

The Role of Cigarette Smoking in the Association Between Periodontal Disease and Coronary Heart Disease

BACKGROUND

Cigarette smoking is a significant risk factor for both coronary heart disease and periodontal disease. The goal of this study was to better understand the role of smoking in the relationship between periodontal disease and heart attack history.

METHODS

The study population consisted of 5,285 participants in the Third National Health and Nutrition Examination Survey (NHANES) during 1988-1994 and who were age 40 years or older when examined. The data analysis employed logistic regression models and accounted for the complex sampling design used in NHANES.

RESULTS

After adjustment for potential confounders, we only found significant associations between periodontal loss of attachment (LOA) and heart attack history for smokers, with odds ratios and 95% confidence interval (CI) of 2.64 (1.48 to 4.71), 3.84 (1.22 to 12.10) and 5.87 (1.91 to 18.00) for those with 2.0 to 2.99, 3.0 to 3.99, and 4 mm or more mean LOA, respectively. When the analysis was stratified by smoking status and tertile of age at heart attack, the statistically significant associations were limited to smokers who had a heart attack between the ages of 25 and 50 years, with odds ratios and 95% Cl associated with increasing mean LOA for this group of 3.29 (1.35 to 8.04), 7.32 (1.60 to 33.51), and 8.04 (1.91 to 18.00), respectively.

CONCLUSIONS

These results suggest that cigarette smoking is a necessary cofactor in the relationship between periodontal disease and coronary heart disease, and the increase in risk appears to be age dependent. However, the key role played by smoking in the etiology of both periodontal and heart diseases makes it difficult to determine how much of the observed association resulted from periodontal disease.