Active smoking and passive exposure to smoke are associated with increased atopic dermatitis (AD) prevalence, a recent study found. Researchers performed a systematic review and meta-analysis of 86 studies, including 680,176 patients from 39 countries. They found:

• Overall, 17,969 (12.9%) of the active smokers, 33,200 (15.3%) of those passively exposed to tobacco smoke in the home, and 14,004 (15.4%) of children born to mothers who smoked during pregnancy, respectively, had a previous and/or current history of AD.

• AD was associated with higher odds of active smoking and exposure to passive smoke, but not maternal smoking during pregnancy.

• In sensitivity analyses, the association between active smoking and AD remained significant in children and adults, in all continents studied and study sizes, but all studies were cross-sectional designs.