Is there any relationship between low B12 level (deficiency) and asthma?

Asthma and vit B12. No clear cut connection, or causal relationship, hope your asthma is controlled, kindly check this link which I found written in simple scientific language http://www.sharecare.com/health/vitamin-b12/will-b12-help-childs-asthma.
B12. May help to bind sulphites that cause asthma flare ups. It may help if your level is low. All the best.