Is atopic dermatitis associated with obesity? A systematic review of observational studies.

Obesity has been associated with atopic dermatitis (AD); however, the results have been conflicting. Our aim was to provide an update on current knowledge from observational studies addressing the possible association between obesity and AD. Systematic literature review was performed by identifying studies addressing a possible link between AD and overweight/obesity from PubMed, EMBASE and the Cochrane Library in accordance with the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guidelines. The quality of the included studies was assessed using the Newcastle-Ottawa Scale. A total of 45 studies (comprising more than 90 000 individuals with AD) fulfilled the criteria and were included in the present review. The available studies revealed inconsistencies, but the majority indicated that obesity is associated with AD. Studies addressing obesity in infancy or early childhood (age < 2 years) and AD reported a positive association. From childhood into adulthood, there is a discrepancy in the observations, as the more recent prospective studies found a positive association, whereas this was not observed in older cross-sectional studies. The inconsistency might be explained by the difference in study design, the diagnostic criteria of AD, regional differences, and by the varied definitions of overweight and obesity used in the studies. In Conclusion, overweight/obesity is associated with an increased risk of AD. Large prospective cohort studies are required to confirm the association between AD and obesity and the possibility that weight control in childhood may help to mitigate or reverse AD symptoms.