Background Patients with cystic fibrosis (CF) have a higher prevalence of asthma than the background population, however, it is unclear whether heterozygous CF carriers are susceptible to asthma. Given this, a meta-analysis is necessary to determine the veracity of the association of CF heterozygosity with asthma. 

Methods We screened the medical literature from 1966 to 2015 and performed a meta-analysis to determine the risk of asthma in CF heterozygotes vs. non-carriers. 

Results Aggregating data from 15 studies, the odds ratio for asthma in CF heterozygotes compared with non-carriers was significantly elevated at 1.61 (95% CI: 1.18–2.21). When analyzing the studies considered of high quality in which asthma was diagnosed by a physician, the patients were > 18 years, or study size was ≥ 500, the trend remained the same, that heterozygous carriers of CF had elevated risk for asthma. 

Conclusions The results show that heterozygous carriers for CF have a higher risk of asthma than non-carriers.