Interleukin gene polymorphisms in chronic periodontitis: A case-control study in the Indian population

Examination of certain single-nucleotide polymorphisms of interleukins 1A and 1B in medication-related osteonecrosis of the jaw - An ambirectional cohort study

AIM

The aim of this study was to examine particular single-nucleotide polymorphisms (IL-1A-889 C/T - rs1800587, IL-1B +3953 C/T - rs 1143634) of interleukins 1A and 1B in the development and prognosis of medication-related osteonecrosis of the jaw.

MATERIALS AND METHODS

DentiGen Parodontitis Tests were applied for collecting samples. This test is suitable for sampling oral mucosa cells in order to detect interleukins 1A and 1B single nucleotide polymorphisms (IL-1A-889, IL-1B+3953). Genetic samples were evaluated in the Istenhegyi Genediagnostic Center using the DNA-hybridization method. Genetic samples were collected in the patient group and the control group. The role of gene polymorphisms in the development of the disease was investigated by comparing the genetic results for the patient and control groups. The investigation of gene polymorphisms in disease prognosis is based on stage improvement, recovery, and relapses following treatment.

RESULTS

In total, 91 patients with MRONJ and 59 healthy controls were included in the study. 51 patients in the patient group and 37 controls had unfavorable allelic variants. No association (Mp = 1.42, SDp = 0.496, Mc = 1.35, SDc = 0.482, p = 0.52) was found between unfavorable polymorphisms and the development of the MRONJ. In the patient group, surgical therapy was required in 79 cases. Stage improvement was detected in 78 cases, recovery in 67 cases, and relapse in 33 cases. No stage improvement was found in one case, recovery in nine cases, or relapse in 34 cases. Of the 79 patients requiring surgical therapy, 49 had unfavorable allelic variants. No connection was found between the polymorphisms examined and stage improvement (Mp = 1.37, SDp = 0.486, Mnp = 2, SDnp = -, p = 0.800) or recovery (Mp = 1.39, SDp = 0.491, Mnp = 1.44, SDnp = 0.527, p = 0.990). However, a significant association (Mp = 1.21, SDp = 0.415, Mnp = 1.58, SDnp = 0.502, p < 0.001) was found between relapses and the presence of unfavorable allelic variants.

CONCLUSION

Within the possible limitations of this study, it can be assumed that the analysis of certain single-nucleotide polymorphisms of interleukin-1 may have the potential to help define the risk stratification of MRONJ after surgical therapy.

Associations among gene polymorphisms, crestal bone loss, and bone mineral density in patients receiving dental implants

Objectives

Interleukin 1 (IL-1) and interleukin 6 (IL-6) gene polymorphisms have been suggested to be responsible for diminished bone mineral density (BMD) and high crestal bone loss (CBL) in some individuals. However, the effects of systemic BMD on variations in peri-implant CBL are unclear. Hence, this study was aimed at investigating the association of IL-1 and IL-6 gene polymorphisms with systemic BMD and CBL around dental implants.

Methods

A total of 190 participants undergoing dental implantation in the mandibular posterior region were selected according to predetermined selection criteria and divided into a normal BMD group (NBD, 93 participants, T-score ≥ -1) and low BMD group (LBD, including both osteoporosis and osteopenia, 97 participants, T-score < -1 standard deviation) according to the BMD of the right femoral neck, measured with dual-energy X-ray absorptiometry. Dental implants were placed through the standard surgical protocol, and CBL was calculated after 6 months with cone beam computed tomography scans before second-stage surgery. Genotyping was performed on all participants for IL-1A-889 A/G, IL-1B-511G/A, IL-1B+3954, and IL-6-572 C/G gene polymorphisms.

Results

The demographic and clinical characteristics of the participants in both groups were compared with t-test and chi-square test (χ2). The associations of NBD and LBD with the different genotypes and CBL was determined with odds ratios, and p < 0.05 was considered statistically significant. The frequency of IL-1B-511AA and IL-6-572 GG genotypes was significantly higher in LBD than in NBD (p < 0.05). In LBD, the IL-1B-511 AA (AA vs GA + GG; p ≤ 0.001) and IL-6-572 GG (GG vs CC + GC; p = 0.001) genotypes were significantly associated with higher peri-implant CBL.

Conclusions

Individuals with the IL-1B-511 AA or IL-6-572 GG genotype had elevated risk of osteoporosis/osteopenia and were more susceptible to CBL around dental implants.

The Role of Interleukin 6 in Periodontitis and Its Complications

Interleukin 6 (IL-6) is a pleomorphic pro-inflammatory cytokine that is strongly associated with local as well as systemic inflammatory processes. Its role in physiological and pathogenic processes throughout the human body has been the subject of numerous studies in recent years. Measurements of the IL-6 levels in gingival crevicular fluid (GFC), as well as in serum, can be important diagnostic and prognostic factors in periodontal diseases (PD) and in assessing their impact on a range of related inflammatory diseases. This narrative review explores the significant role of IL-6 in patients with periodontitis and its association with other widespread inflammatory pathologies.

Molecular mechanism of curcumin on periodontitis: A pharmacological network study

OBJECTIVE

This study aimed to identify the molecular mechanism of curcumin on periodontitis based on a pharmacological network strategy.

METHODS

The potential therapeutic targets of curcumin and differentially expressed genes in periodontitis were identified. Subsequently, we extracted the molecules in common and analyzed them. A metabolic pathway enrichment and gene ontology analysis were performed and the protein-protein interaction network was inferred. These analyses allowed the identification of key proteins. Finally, a molecular docking of the main key proteins was performed with curcumin.

RESULTS

Our results showed that 55 genes are differentially expressed in periodontitis and are potential targets of curcumin. In addition, we observed that these genes participate in cell motility and immune response and are related to chemokine receptors (CXCRs) and enzymatic activity, such as arachidonate 5-lipoxygenase (ALOX5). We identified six key proteins, IL1B, CXCL8, CD44, MMP2, EGFR, and ITGAM; molecular docking revealed that these six proteins spontaneously bind to curcumin.

CONCLUSION

The results of this study helps us understand the molecular mechanism of curcumin in periodontitis. We propose that curcumin affects proinflammatory cytokines, ALOX5, and cell migration through chemokine receptors and acts on the cell membrane. Additionally, we identified six key proteins that are essential in this mechanism, all of which spontaneously bind to curcumin.

Association of interleukin-1, interleukin-6, collagen type I alpha 1, and osteocalcin gene polymorphisms with early crestal bone loss around submerged dental implants: A nested case control study

STATEMENT OF PROBLEM

The reason for variations in peri-implant early crestal bone loss is unclear but may be due to genetic differences among individuals.

PURPOSE

The purpose of this nested case control study was to investigate the association of single-nucleotide polymorphisms of interleukin-1, interleukin-6, collagen type I alpha1, and osteocalcin genes to early crestal bone loss around submerged dental implants.

MATERIAL AND METHODS

Dental implants were placed in the mandibular posterior region (single edentulous space) of 135 participants selected according to predetermined selection criteria. Bone mineral density measurement by using dual energy X-ray absorptiometry, cone beam computed tomography scans at the baseline and after 6 months, and interleukin-1A-889 A/G (rs1800587), interleukin-1B-511 G/A (rs16944), interleukin-1B+3954 (rs1143634), interleukin-6-572 C/G (rs1800796), collagen type I alpha1 A/C (rs1800012), and osteocalcin C/T (rs1800247) genotyping were performed in all participants. Early crestal bone loss measured around dental implants was used to group participants into clinically significant bone loss (BL)>0.5 mm and clinically nonsignificant bone loss (NBL)≤0.5 mm. Early crestal bone loss was calculated as the mean of the difference of bone levels at the baseline and bone levels after 6 months as measured with cone beam computed tomography scans. The obtained data for basic characteristics, early crestal bone loss, and genotyping were tabulated and compared by using a statistical software program (α=.05).

RESULTS

AA genotype and the A allele frequency of interleukin-1B-511 and GG genotype and the G allele frequency of interleukin-6-572 were significantly higher in BL than in NBL (P<.05). Multiple logistic analysis suggested that interleukin-1B-511 AA/GG+AG and interleukin-6-572 GG/CC+CG genotype expression were significantly associated with early crestal bone loss (AA/GG+AG; P=.014, GG/CC+CG; P=.047) around dental implants. Other risk factors were not significantly different (P>.05).

CONCLUSIONS

Of the genes studied, individuals with interleukin-1B-511 AA (rs16944) or interleukin-6-572 GG (rs1800796) genotype had higher susceptibility to early crestal bone loss around dental implants.

Single Nucleotide Polymorphisms in IL-1A RS1800587, IL-1B RS1143634 and Vitamin D Receptor Rs731236 in Stage III Grade B/C Periodontitis

The purpose of the study is to determine the prevalence of interleukin (IL)-1A (rs1800587), IL-1B (rs1143634) and vitamin D receptor (VDR) (TaqI, rs731236) gene polymorphisms in the Turkish population and their association with Stage III Grade B/C periodontitis. Systemically and periodontally healthy individuals (N = 100) and Stage III Grade B/C periodontitis patients (N=100) based on clinical and radiographic examination were included in this research. Clinical attachment level, probing depth, bleeding on probing, plaque and gingival indices of the subjects were measured. Genotyping of IL-1A (rs1800587), IL-1B (rs1143634) and VDR (rs731236) polymorphisms was conducted by Real Time PCR. Allelic and genotypic distributions of IL-1A (rs1800587) gene polymorphism were not associated with periodontitis (p>0.05). In IL-1B (rs1143634) gene polymorphism, the C allele was detected more frequently in healthy individuals compared with the periodontitis patients (p=0.045). CC genotype and C allele in VDR (rs731236) gene polymorphism was higher in periodontitis patients (p=0.031, p=0.034, respectively). In comparison with Grade B periodontitis patients and healthy subjects, CC genotype and C allele were observed more frequently in the Grade B periodontitis in terms of alleles (C/T) and genotypes for VDR (rs731236) polymorphism (p=0.024, p=0.008, respectively). This study presents that the VDR (rs731236) polymorphism are associated with enhanced susceptibility to Stage III periodontitis in the Turkish population. Furthermore, VDR (rs731236) polymorphism may be used as an identification criteria to discriminate Grade B and Grade C in Stage III periodontitis.

A Systematic Review and Meta-Analysis on Multiple Cytokine Gene Polymorphisms in the Pathogenesis of Periodontitis

Aim

Periodontitis is an inflammatory disease that destroys both soft and hard periodontal tissues. However, a complex periodontal cytokine network remains unclear. This systematic review explored multiple cytokine gene polymorphisms in the pathogenesis of periodontitis.

Material and Methods

A systematic search was performed using the databases from previous publications, which indicated the association between cytokine polymorphisms and periodontitis pathogenesis. Meta-analysis was conducted using fixed or randomized models to calculate the significance of multiple cytokine polymorphisms. A total of 147 articles were analyzed with polymorphisms in 12 interleukins [Th1 (IL-2, IFN-γ, and TNF-α), Th2 (IL-4 and IL-13), Th17 (IL-1α, IL-1β, IL-6, and IL-17), and Treg cytokines (IL-10 and TGF-β)]. Doi plot was used to probe the occurrence of publication bias.

Results

The polymorphisms of IL-2 and TNF-α of Th1 cytokine family may be associated with the pathogenesis or the prevention of periodontitis risk, while the polymorphism of IFN-γ is not related to periodontitis risk. The polymorphisms for IL-4 and IL-13 of Th2 cytokine family are not found to be associated with the pathogenesis of periodontitis. For the polymorphisms of the members of Th17 cytokine family, different IL-1α polymorphisms may have inverse actions in the pathogenesis of periodontitis. IL-1β is a noteworthy cytokine biomarker in periodontitis development and progression. IL-6 may have a protective function in the inflammatory responses of periodontitis, and IL-17 has a weak relationship the inflammatory responses. The polymorphisms for the members of Treg cell cytokines may have a protective function against periodontitis risk. LFK indexes show the major asymmetry due to publication bias.

Conclusion

IL-1β is a notable cytokine biomarker in periodontitis risk. Treg cytokines favor an anti-inflammatory and protective environment. Further data are needed to confirm the present conclusion due to publication bias.

Interleukin-1 gene (IL-1) polymorphism in patients with Behçet’s Disease, and its relationship with disease manifestations

Objective

The objective of this study was to investigate whether interleukin-1 (IL-1) gene polymorphisms are associated with susceptibility to Behçet’s disease (BD) and clinical manifestations of the disease.

Methods

In this cross-sectional study, we enrolled 110 patients with BD and age-and gender-matched 120 healthy controls. Five polymorphic regions of the IL-1 gene including rs 1800587 (IL1A-889 C/T), rs 2234650 (IL1R1), rs 16944 (IL1B-511 C/T), rs 315952 (IL1RN), and rs1143634 (IL1B-3954 C/T) were analyzed by using the real-time polymerase chain reaction system. Allele frequencies and genotypes were compared between groups. p ≤ 0.05 was accepted as statistically significant.

Results

The mean age of the patients with BD was 41 ± 12.4 years. The two groups were similar in terms of the age and gender distribution. The vast majority of BD patients had mucocutaneous involvement. The mean disease duration was 83.7 ± 67.8 months among the patients. The frequencies of each polymorphism in the IL-1 gene were similar between patients with BD and healthy controls.

Conclusion

The frequencies of variable IL-1 gene polymorphisms were similar between patients with BD and healthy controls.

Association of IL4 rs2070874, FoxP3 rs3761548 Polymorphisms with Keratoconus in Algeria

Purpose

The aim of this case–control study was to determine the impact of environmental factors on the predisposition to develop keratoconus in a sample of Western Algerian population. Subsequently, we were interested in the implication of two single nucleotide polymorphisms (SNPs) IL4 rs2070874 and FOXP3 rs3761548, previously described as contributing to the occurrence of allergy, in the development of keratoconus.

Methods

The study included 70 unrelated KC cases and 70 controls originating from Western Algeria. DNA genotyping was done using predesigned probe-based allelic discrimination TaqManⓇ assays. Allele and genotype frequencies were compared between the cases and controls by Chi-square test and odds ratios with 95% confidence intervals.

Results

A significant association between risk factors such as family history, atopy, eye rubbing, and the development of keratoconus was found in our sample. Smoking would provide a protective effect against the pathology. No statistically significant differences were found in the allele and genotype frequencies between cases and controls neither for IL4 rs2070874 nor for FOXP3 rs3761548.

Conclusion

Our study provides, for the first time, a clear demonstration of the absence of association of the allergy-associated IL4 and FOXP3 polymorphisms with KC in a sample from Western Algerian population.

The -592C>A Variation of IL-10 Gene and Susceptibility to Chronic Periodontitis: A Genetic Association Study and In-Silico Analysis

OBJECTIVES

Chronic periodontitis (CP) is a common inflammatory disorder with a considerable impact of genetic variations in the interleukin family on predisposition to this disease. This study aimed to investigate the association between the -592C>A polymorphism of the interleukin 10 (IL-10) gene with CP risk in an Iranian population. This experimental study was followed by a meta-analysis and in silico examination.

METHODS

In a case-control study, 270 subjects, including 135 patients with CP and 135 healthy controls, were enrolled. The -592C>A genotyping was performed using the PCR-RFLP method. In the meta-analysis, valid databases were systematically searched to identify relevant studies. Pooled odds ratios (ORs) with 95% confidence intervals (CIs) were computed to examine the association between -592C>A and CP. In silico analysis was conducted using bioinformatics tools to evaluate the impact of the -592C>A polymorphism on IL-10 gene function.

RESULTS

Our case-control study revealed a significant association between polymorphism and CP risk. Overall, we found significant associations between -592C>A genetic variation and CP and stratified meta-analysis. In silico analysis revealed that this polymorphism could change the pattern of the transcription binding site upstream of the IL-10 gene. It may also alter the hsa-miR-101-3p miRNA-targeted sequence upstream of IL-10.

CONCLUSIONS

Based on our results, the -592C>A variation in IL-10 may be a genetic risk factor for susceptibility to chronic periodontitis. However, further studies in different ethnicities and results adjusted for clinical and demographic characteristics are needed to obtain more accurate deductions.

Association between Interleukin-1β Gene Polymorphism and Chronic Periodontitis

Objectives Periodontitis is a pathological condition of the oral cavity, originating from multiple factors, including microbial, environmental and genetic factors. The vulnerability to several pathologies has been studied with the relationship to genetic polymorphisms, and one of the most prominent is the single nucleotide polymorphisms throughout the genome. The study aimed to find out the association of single nucleotide polymorphism (SNP) of interleukin-1β +3954 gene with chronic periodontitis (CP) in Pakistan

Materials and Methods This case–control study was conducted at Dow University of Health Sciences. DNA was extracted from the blood and amplified by using conventional polymerase chain reaction of respective genes followed by sequencing. Mann–Whitney test accessed the difference of clinical parameters between cases and controls, and Fisher’s exact test was applied to access the association of alleles between subjects. Data entered and analyzed using SPSS 21.

Results Significant differences were observed in clinical parameters in cases and controls ( p < 0.001). In the IL-1β +3954 gene, T alleles were significantly higher in cases as compared with controls ( p < 0.001). Genotype CC was significantly dominant in the controls and genotype CT and TT in patients (Chi-square = 19.83, p < 0.001).

Conclusion Within the study’s limits, IL-1β +3954 gene polymorphism is associated with periodontitis and is expected to be among the several causes of respective pathology in Pakistan’s population.

Evaluation of the Genetic Association and Methylation of Immune Response Pathway Genes with the Risk of Chronic Periodontitis in the Uighur Population

Aim: The aim of this study was to explore the possible associations between single nucleotide polymorphisms (SNPs) and DNA methylation levels of seven genes in the inflammatory response pathway with susceptibility to chronic periodontitis (CP) among the Uighur population of the Xinjiang Autonomous Region of China. Methods: A total of 444 eligible subjects (279 CP patients and 165 healthy controls) were enrolled in the study. Genomic DNA was obtained from gingival tissue for genotyping eight SNPs and performing methylation measurements of seven genes. Results: SNP rs2070745 in the formyl peptide receptor 1 (FPR1) gene achieved statistical significance in a standard allelic association analysis for CP (p = 0.02). The frequency of the rs2070745 minor allele G was higher in the cases than in controls (0.367 vs. 0.291). Additionally, rs2070745 was significantly associated with CP under the dominant genetic model (p = 0.03). Using logistic regression analysis, rs2070745 was found to be consistently associated with CP under the additive dominant model, and this association remained significant after covariates were taken into account [odds ratio (OR) = 1.49 (1.09-2.05), p = 0.014; OR = 1.58 (1.04-2.40), p = 0.031, respectively]. No significant gene-gene interactions were identified. Although we did not find a polymorphism in interleukin 6 (IL6) associated with CP in our study, the methylation level of a CpG island region located within the promoter region of IL6 was significantly less in CP patients compared with controls (p < 0.05). Conclusions: The genetic polymorphism rs2070745 in FPR1 and the methylation level of the promoter region of IL6 might be associated with CP in the Uighur population of China.

Association of Interleukin-1α Functional Polymorphism with Risk of Chronic Periodontitis in Han Chinese Population

Chronic periodontitis (CP) is a common inflammatory illness affecting a large proportion of humans. Genetic factors are thought to play important roles in its onset and development. A functional polymorphism (rs1800587) in the promoter of the interleukin-1α gene (−889 C/T) has been found to confer risk of CP primarily in Europeans, but the association between this variant and CP in the Chinese population remains less conclusive. In the current study, we aimed to investigate the association between rs1800587 and CP in case-control samples of Han Chinese origin. A total of 1,777 study subjects, including 884 CP patients and 893 healthy controls, were collected. Genotyping of rs1800587 was performed using the SNAPSHOT method, and statistical analyses were conducted to evaluate the association between rs1800587 and CP. In our sample, rs1800587 was significantly associated with the onset of CP (additive model, T-allele vs. C-allele, p = 0.00359, odds ratio = 1.446, 95% confidence intervals (CIs) = 1.127–1.855; dominant model, (TT + TC) vs. CC, p = 0.00250, odds ratio = 1.502, 95% CIs = 1.152–1.957; overdominant model, TC vs. (TT + CC), p = 0.00264, odds ratio = 1.508, 95% CIs = 1.152–1.976). The T-allele and [TC] genotypes of rs1800587 were significantly overrepresented in CP patients compared with controls. Our data suggest that rs1800587 of IL-1α is significantly associated with the risk of CP in Han Chinese subjects, further confirming its possible involvement in the disease.

The Association between IL2 Genotypes and Risk and Severity of Chronic Periodontitis in a Chinese Han Population: A Case-control Study

Chronic periodontitis (CP) is a kind of multifactorial common oral diseases. Multiple immune molecules including interleukin-2 (IL-2) are involved in the occurrence and development of CP. To investigate the association between the IL2 rs2069762 polymorphism and the risk of CP in Chinese individuals, we recruited 375 CP patients and 443 controls in this case-control study. The PCR-RFLP method was used for genotyping. Data revealed that the GG genotype was related with a decreased risk of CP (GG vs TT: OR, 0.58, 95%CI, 0.37-0.92, P-value = 0.020; GG vs TG+TT: OR, 0.61, 95%CI, 0.39-0.94, P-value = 0.027). Besides, G allele was shown to decrease the risk of CP. In addition, the IL2 rs2069762 polymorphism was related with the severity of CP. To sum up, the IL2 rs2069762 polymorphism is related with a decreased risk and severity of CP in Chinese individuals.

Genetic polymorphisms in interleukin-6 and interleukin-1-beta were associated with dental caries and gingivitis

OBJECTIVE

Evaluate the association between single nucleotide polymorphisms (SNPs) in Interleukin-6 (IL-6) gene (rs1800795) and in Interleukin-1-beta (IL-1β) gene (rs1143627 and rs1143629) with dental caries and gingivitis in Brazilian children.

MATERIAL AND METHODS

Three hundred and fifty-three children aged 8-11 years were included. Visible biofilm and gingival bleeding were evaluated by Community Periodontal Index. The International System for Detection and Assessment of Carious Lesions (ICDAS) was used to investigate dental caries. Real-time PCR evaluated SNPs in the DNA. Chi-square test, haplotype analysis and logistic regression were applied (alpha of 5%).

RESULTS

The GG genotype in rs1800795 (IL-6) decreases the risk of gingivitis in a co-dominant model (p = .05; OR = 0.64). The GG genotype in rs1143627 (IL-1β) reduces the risk of dental caries (Co-dominant model: ICDAS₀ versus ICDAS_1-6: p = .05; OR = 0.55. ICDAS_0-2 versus ICDAS_3-6: p = .02; OR = 0.49. Recessive model: ICDAS₀ versus ICDAS_1-6: p = .005; OR = 0.48. ICDAS_0-2 versus ICDAS_3-6: p = .004; OR = 0.45. Logistic regression: ICDAS_0-2 versus ICDAS_3-6: p = .05; OR = 0.24; CI 95%= 0.05-1.00). The GG genotype in rs1143629 was more frequent in ICDAS₀ (p = .05; OR: 0.60). In the haplotype analysis, IL-1β was associated with gingivitis.

CONCLUSION

The rs1800795 in IL-6 gene was associated with gingivitis. The rs1143627 and rs1143629 in IL-1β were associated with dental caries and gingivitis.

Polymorphisms in the interleukin genes and chronic periodontitis: A field synopsis and revaluation by Bayesian approaches

Periodontitis is a high prevalent disease into the clinical dentistry. Genetic variations in interleukins (IL) genes were associated with chronic periodontitis (CP) and were focus of several meta-analyses. This study aimed to assess the noteworthiness in the meta-analyses by means of a Bayesian approach to determinate possible false report associations. A systematic search was performed for meta-analyses with associations between gene polymorphisms in interleukins and CP. The calculations for the False-Positive Rate Probability (FPRP) and the Bayesian False Discovery Probability (BFDP) were performed to assess the noteworthiness with a statistical power of 1.2 and 1.5 of Odds Ratio at a prior probability of 10^-3 and 10^-6. As results, eight meta-analyses approaching the IL1A/rs1800587, IL1B/rs1143634, IL1RN/rs2234663, IL4/rs2243250, IL6/rs1800795/rs1800796, IL17A/rs2275913 and IL18/rs1946518/rs187238 polymorphisms have been identified. Twenty-two from 270 calculations (8.15%) were noteworthy. Herein, we have identified the IL1A and IL1B polymorphisms as noteworthy biomarkers for CP susceptibility.

Non-significant association between - 330 T/G polymorphism in interleukin-2 gene and chronic periodontitis: findings from a meta-analysis

BACKGROUND

Chronic periodontitis (CP) is an immune-inflammatory disease that promotes tissue damage around the teeth. Among the several inflammatory mediators that orchestrate the periodontitis, there is the interleukin (IL)-2. Genetic variations in IL2 gene may be associated with the risk and severity of the disease. Contrary results are available in the literature with inconclusive findings and none meta-analysis to gather these data.

METHODS

A literature search was performed for studies published before June 11, 2019 in diverse scientific and educational databases. The data was extracted by two investigators and the statistical evaluation was performed by Review Manager statistical program with heterogeneity (I²) and Odds Ratio (OR) with 95% of Confidence Intervals (CI) calculations and a sensitive analysis to assess the accuracy of the obtained results. The publication bias was evaluated by Begg' and Egger's test with Comprehensive meta-analysis software. The value of P < 0.05 was considered as significant.

RESULTS

Five studies were identified in diverse ethnical groups with 1425 participants. The - 330 T/G polymorphism in IL2 gene was not significantly associated with CP in allelic evaluation (P > 0.05) as well as in the genotypic comparisons (P = 0.15). The Begg's test and the linear regression Egger's test did not show any evidence of publication bias risk (P > 0.05) which was corroborated by the absence of obvious asymmetry in Funnel plot graphic.

CONCLUSIONS

This meta-analysis showed a non-significant association between - 330 T/G polymorphism in IL2 gene and CP in any allelic evaluation.

Association between IL-1A (-889C/T) polymorphism and susceptibility of chronic periodontitis: A meta-analysis

OBJECTIVE

The purpose of this study was to investigate the association between IL-1A (-889C/T, rs1800587) polymorphism and susceptibility of chronic periodontitis.

METHODS

A systematic literature search was carried out in the databases updated on July 1, 2019, including PubMed, Embase, Cochrane Library and Web of Science. Through STATA 14.0 software, the association between IL-1A (-889C/T) polymorphism and susceptibility of chronic periodontitis was calculated by pooled odds rations (ORs) and 95% confidence intervals (CIs). Harbord test was used for the publication bias.

RESULTS

The results of overall meta-analysis revealed that IL-1A (-889C/T) polymorphism was associated with the susceptibility of chronic periodontitis among all the genetic models, including allele contrast [T vs. C, OR (95% CI): 1.297 (1.038-1.622), P = 0.022], dominant model [TT + CT vs. CC, OR (95% CI): 1.337 (1.015-1.761), P = 0.039], recessive model [TT vs. CC + CT, OR (95% CI): 1.453 (1.138-1.856), P = 0.003], and codominant model [TT vs. CC, OR (95% CI): 1.555 (1.187-2.038), P = 0.001; CT vs. CC, OR (95% CI): 2.559 (1.245-5.260), P = 0.011]. The results of subgroup analyses indicated that IL-1A (-889C/T) polymorphism was closely related to the susceptibility of chronic periodontitis in African population [T vs. C, OR (95% CI): 1.277 (1.039-1.571), P = 0.020; TT + CT vs. CC, OR (95% CI): 1.357 (1.061-1.735), P = 0.015; TT vs. CC, OR (95% CI): 1.599 (1.115-2.292), P = 0.011], in European population [TT vs. CC + CT, OR (95% CI): 1.645 (1.112-2.435), P = 0.013; TT vs. CC, OR (95% CI): 1.639 (1.044-2.574), P = 0.032] and in American population [CT vs. CC, OR (95% CI): 6.404 (3.000-13.669), P < 0.001].

CONCLUSIONS

IL-1A (-889C/T) polymorphism is associated with the susceptibility of chronic periodontitis in African, European and American populations according to the currently available evidence.