Traffic-related air pollution and eczema in the elderly: Findings from the SALIA cohort.

Childhood eczema results from an interplay of genetic and environmental factors including Traffic-Related Air Pollution (TRAP). In contrast, little is known about eczema in the elderly in general and its association with TRAP in particular. Animal experiments indicate that the arylhydrocarbon receptor (AHR) might link TRAP and eczema. We investigated (i) incidence and prevalence of eczema in elderly women, (ii) its association with long-term TRAP exposure and (iii) the effect modification by AHR polymorphism rs2066853. The study is based on the SALIA cohort. The women's average age was 55 years at baseline (1985-1994) and 74 years at follow-up (2008-2009) examination. Incidence and prevalence of eczema were assessed by an adapted version of the International Study of Asthma and Allergies in Childhood (ISAAC) symptom questionnaire. TRAP was determined using land-use regression models. Adjusted logistic regression models were used. After age 55, the incidence and prevalence of eczema symptoms were 7.9% and 8.8%, respectively. Significant associations (p < 0.05) were found between all parameters of TRAP at the baseline visit and eczema incidence. The risk was higher for minor allele carriers of rs2066853 e.g. NOx: OR = 3.75, p = 0.030 vs. OR = 1.34, p = 0.317 in non-carriers (p(interaction) = 0.122). These results indicate a high incidence for eczema in elderly women, which is associated with chronic exposure to TRAP and possibly mediated by AHR.