Background: Numerous studies have investigated the relationship between COX-2 8473 T > C polymorphism and cancer susceptibility, however, the results remain controversial. Therefore, we carried out the present meta-analysis to obtain a more accurate assessment of this potential association. Methods: In this meta-analysis, 79 case-control studies were included with a total of 38,634 cases and 55,206 controls. We searched all relevant articles published in PubMed, EMBASE, OVID, Web of Science, CNKI and Wanfang Data, till September 29, 2017. The pooled odds ratios (ORs) with 95% confidence intervals (CIs) were used to evaluate the strength of the association. We performed subgroup analysis according to ethnicity, source of controls, genotyping method and cancer type. Moreover, Trial sequential analysis (TSA) was implemented to decrease the risk of type I error and estimate whether the current evidence of the results was sufficient and conclusive. Results: Overall, our results indicated that 8473 T > C polymorphism was not associated with cancer susceptibility. However, stratified analysis showed that the polymorphism was associated with a statistically significant decreased risk for nasopharyngeal cancer and bladder cancer, but an increased risk for esophageal cancer and skin cancer. Interestingly, TSA demonstrated that the evidence of the result was sufficient in this study. Conclusion: No significant association between COX-2 8473 T > C polymorphism and cancer risk was detected.
BackgroundPeriodontitis is a major oral health problem and it is considered as one of the reasons for tooth loss in developing and developed nations. The objective of the current review was to investigate the association between IL10 polymorphisms -1082 A>G (rs1800896), -819C>T (rs1800871), -592 A>C (rs1800872) and the risk of either chronic periodontitis or aggressive periodontitis.MethodsThis is a meta- analysis study, following the preferred reporting items for systematic reviews and meta- analyses (PRISMA). Relevant studies were searched in the health related electronic databases. Methodological quality of the included studies were assessed using the Newcastle-Ottawa Scale. For individual studies, odds ratio (OR) and its 95%confidence interval (CI) were calculated to assess the strength of association between IL10 polymorphisms (-1082 A>G, -819C>T, -592 A>C) and the risk of periodontitis. For pooling of the estimates across studies included, the summary OR and its 95% CIs were calculated with random-effects model. The pooled estimates were done under four genetic models such as the allelic contrast model, the recessive model, the dominant model and the additive model. Trial sequential analysis (TSA) was done for estimation of the required information size for this meta-analysis study.ResultsSixteen studies were identified for this review. The included studies were assessed to be of moderate to good methodological quality. A significant association between polymorphism of IL10-1082 A>G polymorphism and the risk of chronic periodontitis in the non-Asian populations was observed only in the recessive model (OR,1.42; 95% CI:1.11, 1.8,I-2: 43%). The significant associations between -592 A>C polymorphism and the risk of aggressive periodontitis in the non-Asian populations were observed in particular genetic models such as allele contrast (OR, 4.34; 95%CI:1.87,10.07,I-2: 65%) and recessive models (OR, 2.1; 95% CI:1.16, 3.82,I-2: 0%). The TSA plot revealed that the required information size for evidence of effect was sufficient to draw a conclusion.ConclusionsThis meta-analysis suggested that the IL10-1082 A>G polymorphism was associated with chronic periodontitis CP risk in non-Asians. Thus, in order to further establish the associations between IL10 (-819 C>T, -592 A>C) in Asian populations, future studies should include larger sample sizes with multi-ethnic groups.
Significant energy flows embodied in international trade have evolved into a complex interconnected flow network. Therefore, this study applies a variety of complex network analysis tools to uncover the structure of embodied energy flow network (EEFN) at global, regional and national level, based on environmentally extended input–output analysis (EEIOA). At global level, small-world nature has been found, implying the economies are highly connected through embodied energy transfer. EEFN is proved to be a heterogeneous network due to the scale-free power-law distribution of degree/strength. At regional level, 4 communities are detected and members in the same regional cooperative organizations, such as EU, ASEAN, NAFTA and AU, tend to be classified into the same community, indicating that EEFN embodies the characteristics of regionalization and multi-polarization. At national level, some key economies, such as USA, China and Germany, are always at the forefront of network-based centrality measures and EEIOA-based accountings. Furthermore, the security of embodied energy supply is evaluated for each economy. Consequently, policy implications of the results are discussed, which could provide additional insights for policy formulation to enhance energy security.