Epigenome-wide association studies in asthma : a systematic review

Objective: Asthma is a common chronic respiratory airway disease influenced by environmental factors and possibly their interaction with the human genome causing epigenetic changes. Epigenome-wide association studies (EWAS) have mainly investigated DNA methylation and its association with disease or traits, exposure factors or gene expression. This systematic review aimed to identify all EWAS assessing differentially methylated sites associated with asthma in humans. Design: Structured systematic literature search following PRISMA guidelines, Newcastle-Ottawa Scale (NOS) for cohort studies was used for bias assessment. Data Sources: We searched PubMed and Embase databases from 2005 to 2019. Eligibility Criteria: Epigenome-wide association studies testing association between differential methylation and asthma in humans. Results: Overall, we identified 16 EWAS studies complying with our search criteria. Twelve studies were conducted on children, and 10 were conducted on sample sizes