Atopic dermatitis, cognitive function and psychiatric comorbidities across early childhood and adolescence in a population-based UK birth cohort

Within a large population-based birth cohort, we examined the relationship between AD assessed at multiple time points during childhood and adolescence, and four measures of intellectual ability (IQ) between 1.5 and 15.5 years of age. We found no meaningful associations between AD activity or severity and general cognition; the results remained similar in analyses stratified by comorbid psychiatric or learning disorders and in an exploratory longitudinal analysis across all four outcome assessments. Future studies should incorporate objective measures of AD severity and investigate outcomes beyond IQ. Background Atopic dermatitis (AD) may affect cognitive function, but studies are limited and inconsistent. The effect of AD severity on cognition remains underexplored and few previous studies have examined clinically validated or repeated measures of cognition throughout childhood.Objectives To evaluate the relationship of AD activity and severity with validated measures of general cognition in a longitudinal birth cohort.Methods We conducted cross-sectional analyses using data from the Avon Longitudinal Study of Parents and Children (ALSPAC), a UK cohort of 14 975 individuals followed prospectively since their birth in 1991-92. AD was assessed 11 times between the age of 6 and 166 months. Mothers were asked if their child had an 'itchy, dry skin rash in the joints and creases', and AD status was time-updated accordingly as 'never', 'maybe', 'inactive', 'active/mild' or 'active/moderate-severe'. General cognition [i.e. intelligence quotient (IQ)] was measured at 18, 49, 103 and 186 months of age using the Griffiths Mental Development Scales (GMDS), Wechsler Preschool and Primary Scale of Intelligence (WPPSI), Wechsler Intelligence Scale for Children (WISC) and Wechsler Abbreviated Scale of Intelligence (WASI), respectively. Multivariable linear regression was used to compare IQ with respect to nearest time-updated AD status. Secondary analyses were stratified by the presence or absence of psychiatric or learning disorders. An exploratory longitudinal analysis of IQ across all four outcome assessments was conducted using generalized estimating equations.Results No significant associations between AD status and full-scale IQ scores on the GMDS, WPPSI, WISC and WASI were observed after adjustment for sociodemographic factors, atopic comorbidities and sleep characteristics. However, at 8 years of age, WISC Performance IQ was slightly, although statistically significantly, lower among children with active/moderate-severe AD [beta coefficient -2.16, 95% confidence interval (CI) -4.12 to -0.19] and Verbal IQ was slightly, but statistically significantly, higher among those with inactive AD (beta coefficient 1.31, 95% CI 0.28-2.34) compared with those without AD. Analyses stratified by psychiatric or learning disorders, and exploratory longitudinal analyses of cognition revealed similar findings.Conclusions We did not find any clinically meaningful associations between AD activity and severity and general cognitive function during early childhood and adolescence. Future studies should incorporate objective measures of AD severity and investigate outcomes beyond IQ.