Early-Onset AD May Affect Cognitive Functioning in Children

Incidence of atopic dermatitis (AD) before 2 years of age was associated with an increased risk of neurodevelopmental dysfunction later in childhood, according to study findings published recently in Allergology International.

With a greater prevalence among children than in adults, researchers note that AD has been shown to begin within the first 2 years of life in 90% of cases. Multiple systemic effects have been implicated in the pathophysiology of AD, including autoimmune, infectious, and genetic factors, with psychological disorders also having been reported.

“Although AD is a common chronic disease in children and preschool age is a critical period in the development of neuropsychiatric function, there is a paucity of studies on the association between neurodevelopmental dysfunction and AD,” said the study authors.

“Neurodevelopmental disorders in childhood are complex and multifactorial and are widely known to be affected by various clinical conditions in children, including anemia, asthma, and recurrent infections.”

They conducted an observational population-based cohort study of data derived from the Korean National Health Insurance System databases to assess the association between AD and neurodevelopmental dysfunction in children.

A total of 2,395,966 children born between 2008 and 2012 in Korea who were diagnosed with AD before 2 years of age or healthy controls were eligible for the analysis. From this group, 89,452 and 30,557 children were allocated to the control and AD groups, respectively.

Outcomes assessed were suspected neurodevelopmental dysfunction in the gross motor skill, fine motor skill, cognition, language, sociality, and self-care domains of the Korean Developmental Screening Test (K-DST) for Infants and Children at age 6 years. The positive control outcome was defined as attention deficit hyperactive disorder (ADHD). Ordinal logistic regression was used to assess the associations, adjusting for asthma and allergic rhinitis.

Subgroup analyses additionally examined associations within the AD group, stratifying for pediatric patients with AD with systemic steroid use (n = 8351) and without (n = 22,206) and those with hospitalization (n = 1540) and without.

Compared with the control group, weighted data indicated that the AD group was associated with a greater risk of suspected neurodevelopmental dysfunction in the total score (weighted adjusted OR [aOR], 1.10; 95% CI, 1.05-1.16), gross motor skills (weighted aOR, 1.14; 95% CI, 1.04-1.25), and fine motor skills (weighted aOR, 1.15; 95% CI, 1.06-1.25).

Subgroup analyses found an increased risk of suspected neurodevelopmental dysfunction in total score (weighted aOR, 1.21; 95% CI, 1.12-1.31), gross motor skills (weighted aOR, 1.30; 95% CI, 1.12-1.50), fine motor skills (weighted aOR, 1.37; 95% CI, 1.20-1.56), cognition (weighted aOR, 1.20; 95% CI, 1.07-1.35), and sociality (weighted aOR, 1.22; 95% CI, 1.06-1.41) for the AD with steroids group vs the control group. No significant associations were reported in the nonsteroid vs control group for any of the domains.

The hospitalization group showed a greater risk of suspected neurodevelopmental dysfunction in total score (weighted aOR, 1.28; 95% CI, 1.06-1.55), fine motor skills (weighted aOR, 1.65; 95% CI, 1.24-2.20), and cognition (weighted aOR, 1.33; 95% CI, 1.01-1.74) domains vs the control group, with the nonhospitalization group reporting significantly increased risks in the total score (weighted aOR, 1.09; 95% CI, 1.04-1.15), gross (weighted aOR, 1.13; 95% CI, 1.03-1.25), and fine motor skills (weighted aOR, 1.13; 95% CI, 1.04-1.23) domains.

Regarding risk of neurodevelopmental disorders, the AD group showed a significant association with ADHD, mental retardation, psychological development disorder, and behavioral and emotional disorders.

As the study is an observational analysis of administrative data, researchers noted that results could not prove a causative relationship. Other limitations cited regarding the study findings were the inability to assess information about family or genetic history of allergic diseases or neurodevelopmental dysfunction, with these residual unmeasured confounders potentially biasing the association between AD and neurodevelopment.

They concluded that further research is warranted to evaluate the underlying mechanisms of these associations.

Reference

Kim JH, Yi YY, Ha EK, Cha HR, Han MY, Baek HS. Neurodevelopment at 6 years of age in children with atopic dermatitis. Allergol Int. 2022 Sep 1;S1323-8930(22)00088-0. doi:10.1016/j.alit.2022.08.002