Numerous studies have evaluated the association between polymorphisms of a disintegrin and metalloproteinase 33 (ADAM33) gene and chronic obstructive pulmonary disease (COPD) risk; however, the results remain conflicting. The aim of this study was to investigate whether ADAM33S2 and -T1 polymorphisms are associated with susceptibility to COPD risk in the Chinese population. Publications addressing the association between ADAM33S2 or T1 polymorphisms and COPD risk were selected from the PubMed, Cochrane Library, Embase, CNKI, and Wanfang databases.
Vitamin D deficiency and insufficiency are increasingly being recognized in the general population over the last few decades. However, a number of other disorders have now been linked to vitamin D deficiency and insufficiency, including asthma and COPD. The aim of this study was to evaluate the evidence on the effect of vitamin D on asthma and COPD. We searched electronic databases including SCI, EMBASE, Ovid, and PubMed. Reviewers working independently and in duplicate extracted study characteristics, quality, and the outcomes.