ACE and asthma: Adoption of Mendelian randomization analyses revealed that one unit increment in circulating ACE concentrations was found to be significantly associated with a 1.14-fold increased risk of asthma (95% CI: 1.02 to 4.24).<h4>Conclusion</h4>We provided strong meta-analytical evidence supporting the causal implication of high circulating ACE concentrations in the development of asthma.