Negative association between chitinase 3-Like-1 C-131G polymorphism and asthma-from a meta-analysis

The CHI3L1 gene has been widely regarded as a genetic candidate for asthma. Since the identification of functional polymorphism, CHI3L1 gene -131C/G (rs4950928), numbers of studies have been performed to estimate the relationship between it and asthma, but the results remain inconclusive. The present meta-analysis was conducted to evaluate the real association of CHI3L1 C-131G polymorphism on risk of asthma on 3,777 asthma cases and 7,844 controls from 10 published studies by searching PubMed, EMBASE and CNKI databases and reference lists of relevant articles. A random-effects or fixed-effects model was used to estimate the overall and stratification effect sizes on CHI3L1 C-131G polymorphism on the risk of asthma as appropriate. However, we failed to find any significant association between the CHI3L1 C-131G polymorphism and the risk of asthma for different genetic models (recessive model: OR=1.18, 95% CI: 0.91-1.53 and dominant model: OR=0.94, 95% CI: 0.72-1.21, respectively). In stratified analysis by ethnicity and age, we still did not detect any significant associations in different subgroup for all genetic models. Our study suggested that the CHI3L1 C-131G polymorphism alone may not contribute to asthma development of asthma risk.