183 Association of atopic dermatitis, ultraviolet radiation and climate factors: a systematic review and ecological meta-analysis

Abstract

Previous studies found conflicting results about the relationship of ultraviolet radiation (UVR) and climate with atopic dermatitis (AD) prevalence. We examined the relationship of UVR and climate with lifetime and point AD prevalences globally. A systematic review was performed of all published observational studies in MEDLINE, EMBASE, LILACS, Scopus, Cochrane library and GREAT that analyzed AD prevalence. Mean UVR dose exposure was determined from the Tropospheric Emission Monitoring Internet Service. Mean daily temperature and total precipitation were obtained from the Intergovernmental Panel on Climate Change Data Distribution center. Linear and nonlinear associations (penalized spline term) of AD prevalence with mean and maximum UV dose exposures, temperature and precipitation were assessed using generalized linear mixed-effects regression models. Overall, 284 studies met inclusion criteria. The pooled global lifetime and point prevalences (95% confidence interval [CI]) of AD were 13.8% (12.6, 14.9%) and 9.4% (7.6, 11.3%), respectively. Lifetime prevalence of AD was inversely and non-linearly associated with mean UVR dose exposure (P=0.003) and temperature (P=0.01). Point prevalence of AD was inversely and non-linearly associated with mean UVR dose exposure (P=0.04) and linearly associated with mean temperature (beta [95% CI]: -0.19 [-0.34, -0.05], P=0.01). Lifetime and point prevalence of AD were not associated with precipitation levels. Snowy climate was associated with higher lifetime (beta [95% CI]: 4.79 [1.34, 8.25]) and point (6.13 [1.43, 10.83]) prevalences of AD compared to equatorial climate. Similar results were seen in studies of children and/or adults. The results of this ecological study support a role for UVR, temperature and climate type in global AD prevalence.