Risk factors of asthma in the Asian population: a systematic review and meta-analysis

Background and objective An increasing trend of asthma prevalence was observed in Asia; however, contributions of environmental and host-related risk factors to the development of this disease remain uncertain. This study aimed to perform a systematic review and meta-analysis for asthma-associated risk factors reported in Asia. Methods We systematically searched three public databases (Web of Science, PubMed, and Scopus) in Feb 2021. We only included articles that reported environmental and host-related risk factors associated with asthma in the Asian population. Random-effect meta-analyses were conducted for frequently reported asthma-associated risk factors to provide an overall risk estimate of asthma development. Results Of 4030 records obtained from public databases, 289 articles were selected for review. The most frequently reported asthma-associated risk factor was the family history of allergy-related conditions. The random-effect asthma risk estimates (pooled odds ratio, OR) were 4.66 (95% confidence interval (CI): 3.73-5.82) for the family history of asthma, 3.50 (95% CI: 2.62-4.67) for the family history of atopy, 3.57 (95% CI: 3.03-4.22) for the family history of any allergic diseases, 1.96 (95% CI: 1.47-2.61) for the family history of allergic rhinitis, and 2.75 (95% CI: 1.12-6.76) for the family history of atopic dermatitis. For housing-related factors, including the presence of mold, mold spots, mold odor, cockroach, water damage, and incense burning, the random-effect pooled OR ranged from 1.43 to 1.73. Other risk factors with significant pooled OR for asthma development included male gender (1.30, 95% CI: 1.23-1.38), cigarette smoke exposure (1.44, 95% CI: 1.30-1.60), cigarette smoking (1.66, 95% CI: 1.44-1.90), body mass index (BMI)-related parameters (pooled OR ranged from 1.06 to 2.02), various types of air pollution (NO2, PM10, and O-3; pooled OR ranged from 1.03 to 1.22), and pre- and perinatal factors (low birth weight, preterm birth, and cesarean section; pooled OR ranged from 1.14 to 1.32). Conclusions The family history of asthma was the most frequently reported risk factor for asthma development in Asia with the highest risk estimate for asthma development. This suggests a major role of the genetic component in asthma pathogenesis. Further study on asthma genetics is required to improve the current understanding of asthma etiology.

Automated summary

This study conducted a systematic review and meta-analysis of asthma-associated risk factors reported in Asia, identifying family history of allergy-related conditions as the most frequently reported risk factor for asthma development with the highest risk estimate. This highlights the significant role of genetic component in the pathogenesis of asthma, suggesting further research on asthma genetics is needed for better understanding of asthma etiology.