A systematic review and meta-analysis of risk factors associated with atopic dermatitis in Asia

BACKGROUND: Atopic dermatitis (AD) is a chronic, inflammatory skin disorder characterised by intense itch and eczematous lesions. Rising prevalence of AD has been observed worldwide including in Asia. Understanding the risk factors associated with AD may explain its pathogenicity and identify new preventive strategies and treatments. However, AD-associated risk factors and comorbidities specific to Asia have not been systematically reviewed. METHODS: We performed a systematic review in accordance with the Preferred Reporting Item for Systematic Review and Meta-Analyses (PRISMA) guidelines and summarised epidemiological studies investigating personal, family, and environmental factors and comorbidities associated with AD in Asia. Significant factors were assessed if they can be altered through lifestyle practices and further classified into non-modifiable and modifiable factors. Meta-analysis using the random-effect model was also conducted to provide an overall estimate for several significant factors. RESULTS: We identified a total of 162 epidemiological studies conducted in Asia. Among non-modifiable factors, a family history of atopic diseases was the most reported, suggesting the involvement of genetics in AD pathogenesis. Among modifiable factors, the results of meta-analyses revealed maternal smoking as the strongest risk factor with a pooled odds ratio (OR) of 2.95 (95% CI, 2.43–3.60), followed by active smoking (pooled OR, 1.91, 95% CI, 1.41–2.59). CONCLUSION: While a family history may aid clinicians in identifying high-risk individuals, literature has long suggested the importance of gene-environment interaction. This review identified several modifiable factors including medical treatments, indoor and outdoor environmental exposure, and personal and family lifestyle specific to Asia. Based on the meta-analyses performed, prevention strategies against AD may start from changing personal and family lifestyle choices, especially smoking habits.