Wei-Dong Leng

Periodontal Disease and Risk of Head and Neck Cancer: A Meta-Analysis of Observational Studies

Background Many epidemiological studies have found a positive association of periodontal disease (PD) with risk of head and neck cancer (HNC), but the findings are varied or even contradictory. In this work, we performed a meta-analysis to ascertain the relationship between PD and HNC risk. Methods We searched the PubMed, Embase, and Cochrane Library databases for relevant observational studies on the association between PD and HNC risk published up to March 23, 2013. Data from the included studies were extracted and analyzed independently by two authors. Meta-analysis was performed using RevMan 5.2 software. Results We obtained seven observational studies involving two cohort and six case-control studies. Random-effects meta-analysis indicated a significant association between PD and HNC risk (odds ratio = 2.63, 95% confidence interval = 1.1.68 - 4.14; p < 0.001), with sensitivity analysis showing that the result was robust. Subgroup analyses based on adjustment for covariates, study design, PD assessment, tumor site, and ethnicity also revealed a significant association. Conclusions Based on currently evidence, PD is probably a significant and independent risk factor of HNC.

Meta-analysis on the association between toothbrushing and head and neck cancer

BACKGROUND Epidemiological studies have focused on the association between toothbrushing and head and neck cancer (HNC). However, the question of whether toothbrushing is associated with decreased risk of HNC remains unanswered. Since there is currently no systematic review or meta-analysis available to provide quantitative findings on this important clinical question; we consequently performed this meta-analysis to investigate the association between toothbrushing and HNC risk. METHODS We searched PubMed and Embase up to January 13 (updated on October 20), 2014 to identify observational studies that investigated the association between toothbrushing and HNC. After study section and data extraction, the meta-analysis was conducted using RevMan 5.2 software. RESULTS A total of 18 case-control studies involving 7068 cases and 9990 controls were included. The meta-analysis showed that compared with highest toothbrushing frequency, lowest level was significantly increased risk of HNC 2.08 times (odds ratio=2.08, 95% confidence interval=1.65-2.62). This significant association remained consistent after adjusting for smoking status and alcohol consumption. No publication bias was detected. CONCLUSIONS This meta-analysis found frequency of toothbrushing was significantly associated with HNC risk. Effective toothbrushing may be potentially important for the prevention of HNC and we suggest that the frequency be twice per day (morning and night).

Meta-Analysis of Association Between Interleukin-1β C-511T Polymorphism and Chronic Periodontitis Susceptibility.

BACKGROUND Many studies have been conducted to explore the association between interleukin (IL)-1β C-511T polymorphism and risk of chronic periodontitis (CP) but with different or even contradictory results. A meta-analysis was performed to further explore their association. METHODS PubMed, Chinese National Knowledge Infrastructure, and EMBASE were searched up to September 30, 2014 for relevant case-control studies. Two authors (D-YL and L-YX) independently selected studies and extracted data from included studies. The meta-analysis was performed using comprehensive meta-analysis software. RESULTS Nineteen case-control studies involving 2,173 patients with CP and 3,900 healthy controls were included. Using a random-effects meta-analysis model, a non-significant association between IL-1β C-511T polymorphism and CP was identified (T versus C: odds ratio [OR] = 1.03, 95% confidence interval [CI] = 0.85 to 1.25; TT versus CC: OR = 1.03, 95% CI = 0.72 to 1.46; CT versus CC: OR = 0.96, 95% CI = 0.71 to 1.30; CT + TT versus CC: OR = 1.00, 95% CI = 0.74 to 1.34; TT versus CT + CC: OR = 1.05, 95% CI = 0.81 to 1.38), and sensitivity analysis indicated that the results were robust. Subgroup analyses also revealed a non-significant association. No publication bias was detected. CONCLUSIONS Based on currently available evidence, IL-1β C-511T polymorphism is not associated with the risk of developing CP. Additional research is warranted to further explore and confirm the association of genetic polymorphism and CP.

Periodontal Disease and Incident Lung Cancer Risk: A Meta-Analysis of Cohort Studies.

BACKGROUND Periodontal disease is linked to a number of systemic diseases such as cardiovascular diseases and diabetes mellitus. Recent evidence has suggested periodontal disease might be associated with lung cancer. However, their precise relationship is yet to be explored. Hence, this study aims to investigate the association of periodontal disease and risk of incident lung cancer using a meta-analytic approach. METHODS PubMed, Scopus, and ScienceDirect were searched up to June 10, 2015. Cohort and nested case-control studies investigating risk of lung cancer in patients with periodontal disease were included. Hazard ratios (HRs) were calculated, as were their 95% confidence intervals (CIs) using a fixed-effect inverse-variance model. Statistical heterogeneity was explored using the Q test as well as the I(2) statistic. Publication bias was assessed by visual inspection of funnel plots symmetry and Eggers test. RESULTS Five cohort studies were included, involving 321,420 participants in this meta-analysis. Summary estimates based on adjusted data showed that periodontal disease was associated with a significant risk of lung cancer (HR = 1.24, 95% CI = 1.13 to 1.36; I(2) = 30%). No publication bias was detected. Subgroup analysis indicated that the association of periodontal disease and lung cancer remained significant in the female population. CONCLUSION Evidence from cohort studies suggests that patients with periodontal disease are at increased risk of developing lung cancer.

Association between the TP53 codon 72 polymorphism and risk of oral squamous cell carcinoma in Asians: a meta-analysis

BackgroundSeveral epidemiological studies have previously investigated the association between the TP53 codon 72 polymorphism and oral squamous cell carcinoma (OSCC) susceptibility; however, current results are inconsistent. We therefore performed this meta-analysis to thoroughly investigate any association among Asian patients.MethodsA comprehensive search of PubMed and Embase databases was performed up to December 2013. We only considered studies consisting of patients diagnosed with OSCC by pathological methods. Statistical analyses were performed using Review Manager (RevMan) 5.2 software and odds ratios (ORs) with 95% confidence intervals (CIs) were used to assess the association.ResultsA total of 11 case–control studies involving 2,298 OSCC patients and 2,111 controls were included. We found no association between the TP53 codon 72 polymorphism and OSCC susceptibility [(OR = 0.77, 95% CI = 0.48–1.22) for Arg vs. Pro; (OR = 0.67, 95% CI = 0.31–1.43) ArgArg vs. ProPro; (OR = 1.14, 95% CI = 0.97–1.35) ArgPro vs. ProPro; (OR = 0.85, 95% CI = 0.53–1.34) (ArgPro + ArgArg) vs. ProPro; or (OR = 0.34, 95% CI = 0.34–1.23) for ArgArg vs. (ProPro + ArgPro)]. However, subgroup analysis demonstrated an association between the TP53 codon 72 polymorphism and human papillomavirus (HPV)-related OSCC patients. Although statistical heterogeneity was detected, there was no evidence of publication bias.ConclusionsCurrent results suggest that the TP53 codon 72 polymorphism is not associated with OSCC in Asians without the presence of HPV infection. Further research is necessary to determine if such a relationship exists in HPV-related OSCC patients.

Tooth Loss and Head and Neck Cancer: A Meta-Analysis of Observational Studies

Backgroud Epidemiological studies have shown that tooth loss is associated with risk of head and neck cancer (HNC); however, the results were inconsistent. Therefore, we conducted a meta-analysis to ascertain the relationship between tooth loss and HNC. Methods We searched for relevant observational studies that tested the association between tooth loss and risk of HNC from PubMed and were conducted up to January 30, 2013. Data from the eligible studies were independently extracted by two authors. The meta-analysis was performed using the Comprehensive Meta-Analysis 2.2 software. Sensitivity and subgroup analyses were conducted to evaluate the influence of various inclusions. Publication bias was also detected. Results Ten articles involving one cohort and ten case-control studies were yielded. Based on random-effects meta-analysis, an association between tooth loss and HNC risk was identified [increased risk of 29% for 1 to 6 teeth loss (OR = 1.29, 95% CI = 0.52–3.20, p = 0.59), 58% for 6 to 15 teeth loss (OR = 1.58, 95% CI = 1.08–2.32, p = 0.02), 63% for 11+ teeth loss (OR = 1.63, 95% CI = 1.23–2.14, p<0.001), 72% for 15+ teeth loss (OR = 1.72, 95% CI = 1.26–2.36, p<0.001), and 89% for 20+ teeth loss (OR = 1.89, 95% CI = 1.27–2.80, p<0.001)]. The sensitivity analysis shows that the result was robust, and publication bias was not detected. Conclusions Based on the current evidence, tooth loss is probably a significant and dependent risk factor of HNC, which may have a dose-response effect. People who lost six or more teeth should pay attention to symptoms of HNC, and losing 11 teeth or 15 teeth may be the threshold.

CYP1A1 Ile462Val polymorphism contributes to colorectal cancer risk: A meta-analysis

AIM To study the relation between CYP1A1 Ile462Val polymorphism and colorectal cancer risk by meta-analysis. METHODS A meta-analysis was performed to investigate the relation between CYP1A1 Ile462Val polymorphism and colorectal cancer risk by reviewing the related studies until September 2010. Data were extracted and analyzed. Crude odds ratio (OR) with 95% confidence interval (CI) was used to assess the strength of relation between CYP1A1 Ile462Val polymorphism and colorectal cancer risk. RESULTS Thirteen published case-control studies including 5336 cases and 6226 controls were acquired. The pooled OR with 95% CI indicated that CYP1A1 Ile462Val polymorphism was significantly related with colorectal cancer risk (Val/Val vs Ile/Ile: OR = 1.47, 95% CI: 1.16-1.86, P = 0.002; dominant model: OR = 1.33, 95% CI: 1.01-1.75, P = 0.04; recessive model: OR = 1.49, 95% CI: 1.18-1.88, P = 0.0009). Subgroup ethnicity analysis showed that CYP1A1 Ile462Val polymorphism was also significantly related with colorectal cancer risk in Europeans (Ile/Val vs Ile/Ile: OR = 1.22, 95% CI: 1.05-1.42, P = 0.008; dominant model: OR = 1.24, 95% CI: 1.07-1.43, P = 0.004) and Asians (Val/Val vs Ile/Ile: OR = 1.40, 95% CI: 1.07-1.82, P = 0.01; recessive model: OR = 1.46, 95% CI: 1.12-1.89, P = 0.005). CONCLUSION CYP1A1 Ile462Val may be an increased risk factor for colorectal cancer.

AlloDerm implants for prevention of Frey syndrome after parotidectomy: A systematic review and meta-analysis

Although Frey syndrome is not life-threatening, it is identified as the most serious and widely recognized sequela of parotidectomy and has significant potential negative social and psychological implications. Several studies have investigated whether AlloDerm® implants prevent Frey syndrome effectively and safely, however, the conclusions are inconsistent. We aimed to evaluate the precise effectiveness of AlloDerm implants for preventing Frey syndrome after parotidectomy, using a systematic review and meta-analysis. We searched randomized and quis-randomized controlled trials in which AlloDerm implants were compared to blank controls for preventing Frey syndrome after parotidectomy, from the PubMed, Embase, the Cochrane Library and the ISI Web of Knowledge databases, without any language restriction. Two reviewers independently searched, identified, extracted data and assessed methodological quality. Relative risks with 95% confidence intervals were calculated and pooled. Five articles involving 409 patients met the inclusion criteria. Meta-analyses showed a significant 85% relative risk reduction in objective incidence (RR=0.15, 95% CI 0.08–0.30; P<0.00001) and 68% in subjective incidence (RR=0.32, 95% CI 0.19–0.57; P<0.00001) of Frey syndrome with AlloDerm implants; there was a significant 91% relative risk reduction in salivary fistula (RR=0.09, 95% CI 0.01–0.66; P=0.02); there was no statistical significance for the incidence of facial nerve paralysis (RR=0.96, 95% CI 0.84–1.09; P=0.51); there was no statistical significance for the incidence of seroma/sialocele (RR=1.36, 95% CI 0.66–2.80; P=0.40); there was a trend for a small effect in improving facial contour. Adverse events related to AlloDerm implants were not found. There is evidence that AlloDerm reduces the incidence of Frey syndrome effectively and safely, and also has the potential to improve facial contour and decrease salivary fistula. However, it is unclear whether AlloDerm implants improve facial contour and decrease other complications. Thus, further controlled evaluative studies incorporating more precise measures are required.

Cytochrome P450 2E1 RsaI/PstI polymorphism and risk of esophageal cancer: A meta-analysis of 17 case-control studies

The aim of this study was to explore the cytochrome P450 2E1 (CYP2E1) RsaI/PstI polymorphism and risk of esophageal cancer (EC) in mainland Chinese populations. A systematic search of PubMed, EMBASE, Web of Science, CBM, CNKI and VIP databases for publications on the CYP2E1 RsaI/PstI polymorphism and risk of EC was performed. and the genotype data were analyzed in a meta-analysis. Odds ratios (ORs) with relevant 95% confidence intervals (CIs) were estimated to assess the association. Sensitivity analysis, test of heterogeneity and assessment of publication bias were performed. The search yielded 17 studies including 18 trails involving 1,663 cases and 2,603 controls. The meta-analyses showed a significant association between the CYP2E1 RsaI/PstI polymorphism and risk of EC in the mainland Chinese population (c2 vs. c1: OR=0.64; 95% CI, 0.50–0.81; P<0.001; c2/c2 vs. c1/c1: OR=0.73; 95% CI, 0.57–0.93; c2/c2 vs. c1/c1+c1/c2: OR=0.76; 95% CI, 0.60–0.96; P=0.02; c1/c2 vs. c1/c1: OR=0.54; 95% CI, 0.38–0.75; P<0.001; c1/c2+c2/c2 vs. c1/c1: OR=0.48; 95% CI, 0.34–0.70; P<0.001). An increased cancer risk in all genetic models was identified following stratification by ethnicity, source of controls and tumor type. In conclusion, in all genetic models, the association between the CYP2E1 RsaI/PstI polymorphism and risk of EC in the mainland Chinese population was significant. This meta-analysis suggests that the CYP2E1 RsaI/PstI polymorphism is a risk factor for EC, and the c2 allele is a factor that lowers the possibility of EC in the mainland Chinese population and this association did not change due to ethnic differences in genetic backgrounds and the environment.

No Association Between MTHFR A1298C Gene Polymorphism and Head and Neck Cancer Risk: A Meta-analysis Based on 9,952 Subjects

OBJECTIVE Findings for associations between the methylenetetrahydrofolate reductase (MTHFR) A1298C gene polymorphism and head and neck cancer risk have been conflicting. We therefore performed a meta-analysis to derive a more precise relationship. METHODS Ten published case-control studies were collected and odds ratios (ORs) with 95% confidence intervals (CIs) were used to assess the association between MTHFR A1298C polymorphism and head and neck cancer risk. Sensitivity analysis and publication bias assessment also were performed to guarantee the statistical power. RESULTS Overall, no significant association between MTHFR A1298C polymorphism and head and neck cancer risk was found in this meta-analysis (C vs. A: OR=1.04, 95%CI=0.87- 1.25, P=0.668, P heterogeneity<0.001; CC vs. AA: OR=1.07, 95%CI=0.70-1.65, P=0.748, P heterogeneity<0.001; AC vs. AA: OR=1.06, 95%CI=0.88-1.27, P=0.565, P heterogeneity<0.001; CC+AC vs. AA: OR=1.06, 95%CI=0.86-1.30, P=0.571, P heterogeneity<0.001; CC vs. AA+AC: OR=1.02, 95%CI=0.69-1.52, P=0.910, P heterogeneity<0.001). Similar results were also been found in succeeding analysis of HWE and stratified analysis of ethnicity. CONCLUSIONS In conclusion, our meta-analysis demonstrates that MTHFR A1298C polymorphism may not be a risk factor for developing head and neck cancer.