Controlling for confounding factors and revealing their interactions in genetic association meta-analyses: a computing method and application for stratification analyses

The association of human leukocyte antigen class II (HLA II) haplotypes with the risk of Latent autoimmune diabetes of adults (LADA): Evidence based on available data

AIMS

Latent autoimmune diabetes in adult (LADA), classified as between type 1 and type 2 diabetes mellitus, has received widespread attention. A number of studies have investigated the association between HLA DQA-DQB, DRB-DQB haplotypes and the onset of LADA. However, the conclusions remained inconsistent. Therefore, this study aims to clarify the impact of these HLA haplotypes on the pathogenesis of LADA.

METHODS

Systematic searches were carried out on the Medline, PubMed, Embase and Wan Fang respectively to investigate the association of LADA with HLA DQA-DQB, DRB-DQB up to June 05, 2020. We performed this retrospective research using meta-analysis.

RESULTS

The pooled results demonstrated that in Chinese, DQA1*05-DQB1*0201, DQA1*03-DQB1*0401, and DQA1*03-DQB1*0303 were statistically significantly associated with increasing the risk of LADA (P < 0.001), while DQA1*0102-DQB1*0602 was statistically significantly correlated with decreasing the susceptibility to the disease (P = 0.003). However, there was no obvious association found between DQA1*0201-DQB1*0201 (P = 0.984), DQA1*03-DQB1*0302 (P = 0.110), DQA1*0601-DQB1*0301 (P = 0.398) and LADA. In Japanese, DRB1*0802-DQB1*0302 (P = 0.003) and DRB1*0901-DQB1*0303 (P = 0.001), but not DRB1*0405-DQB1*0401 (P = 0.136), were found to be a risk factor for LADA. As for Caucasian, both DRB1*03-DQB1*0201 and DRB1*04-DQB1*0302 were predisposed to the development of LADA with a statistical significance (P < 0.001).

CONCLUSION

In all, HLA DQA-DQB, HLA DRB-DQB haplotypes might play a role in the risk of LADA, which could provide an improved understanding of LADA pathogenesis and the detection of susceptible HLA haplotypes in the diagnosis and therapy of this disease.

Advanced stratification analyses in molecular association meta-analysis: methodology and application

Background

Stratification analyses have been widely utilized in molecular association meta-analyses to estimate the interaction between genetic and environmental factors or to control for the confounding variables linked to a disease. Two calculation methods utilized in practical research, which are known as the variants of factorial stratification analysis and confounder-controlling stratification analysis in our nomenclature, have been applied in previous studies, but none of which have presented a methodology and application for these analyses.

Methods

In this paper, these two approaches are integrated and further developed into a standard procedure for stratification analysis. We first propose the advanced statistical methodology and theoretical algorithm of these three types of stratification analysis and then provide two example applications in meta-analyses of molecular association to illustrate the computing processes and interpretation of the results.

Results

The standard stratification analysis synthesizes the advantages of the first two practical methods, including identifying and controlling confounding moderators or revealing and calculating gene-environment interactions, to efficiently classify the real influence of various investigated factors on a disease in the general population. Additional challenges concerning this method and their potential solutions are also discussed, such as the approach to utilizing only the partially stratified data available in meta-research practice.

Conclusions

The standard stratification method will be extensively applicable to rapidly expanding future research on the complex relationships among genetics, environment, disease, and other variables.

The association between nonsteroidal anti-inflammatory drugs and skin cancer: Different responses in American and European populations

OBJECTIVE

To conduct a comprehensive systematic meta-analysis investigating the association of nonsteroidal anti-inflammatory drugs (NSAIDs) and their subtypes with skin cancer (SC) and its subclasses (basal cell carcinoma BCC; squamous cell carcinoma SCC; melanoma; nonmelanoma skin cancer NMSC) in general, American and European populations.

METHODS

PubMed, Embase, the Cochrane Library, the China National Knowledge Infrastructure and ClinicalTrials.gov were searched up to 24 February 2019. Pooled effect sizes and 95% confidence intervals were used to estimate associations.

RESULTS

Results based on 26 original studies including 223,619 cases and 1,398,507 controls showed both NSAIDs and nonselective Cyclooxygenase (COX) inhibitors to be statistically significantly associated with a reduced risk of SC, BCC, SCC and NMSC but not with melanoma. Conversely, no association was observed between selective Cyclooxygenase 2 (COX-2) inhibitors and SC or its subclasses. Further subgroup analysis showed that the results analyzed for American populations were almost the same as those for the general population. For European populations, neither NSAIDs nor its subtypes correlated significantly with susceptibility to SC or its subclasses.

CONCLUSIONS

The use of NSAIDs might reduce the risk of SC, but many factors including study population, drug subtype, and disease subclass affect the significance of the association.