435 The association between tobacco smoke exposure during childhood and adolescence and atopic dermatitis activity and severity

Abstract

Atopic dermatitis (AD) is the most common chronic inflammatory skin disease worldwide, yet the triggers of disease activity and persistence are still not completely understood. Tobacco smoke exposure (TSE) is an environmental factor that deserves particular attention because of its known effects on humoral and cellular immunity. The objective of our study was to investigate the extent to which TSE during childhood and adolescence is associated with AD activity and severity. Data were obtained from the Avon Longitudinal Study of Parents and Children, a longitudinal population-based cohort from the UK with 10,518 individuals followed from birth through adolescence. AD was based on a validated measure of maternal-reported flexural dermatitis activity at 10 time points and severity at 9 time points between the ages of 2.5 and 18 years. TSE was measured using a standardized maternal-reported measure at 8 time points between the ages of 6 months and 9 years. Child serum cotinine levels (a nicotine metabolite and validated TSE biomarker) were available at 7, 15.5, and 17 years of age. After adjusting for demographic and socioeconomic confounding, there was no significant association between TSE level and the risk of ever having AD using cross-sectional multinomial regression models (RRR: 0.80-1.19; p>0.05 at all time points) and no significant association between TSE and AD severity (RRR: 0.69-1.52; p>0.05 at all time points). At 7 years old, there was no significant association between child serum cotinine level and AD severity. In contrast, at 15.5 years, a 1 ng/mL increase in serum cotinine showed a small but statistically significant association with severe AD compared to no AD (RRR: 1.007; 95% CI: 1.000, 1.013), suggesting that active rather than passive TSE may be most relevant to disease activity and severity.