Investigators Reveal Subtypes in Atopic Disease Activity

Katrina Abuabara, MD, MA, MSCE

Data from a cohort study in California suggested that extending the window of observation of atopic eczema beyond childhood could reveal clear subtypes based on patterns of disease activity.

Atopic eczema has affected up to 20% of children in industrialized settings, with disease patterns having been identified in previous studies.

Newer research had also shown the condition to be common among adults, affecting 7%-10% of the adult UK and US populations.

The investigators, led by Katrina Abuabara, MD, MA, MSCE, Department of Dermatology, University of California, noted a lack of studies that prospectively examined the course of atopic eczema beyond adolescence.

Motivated by this, Abuabara and colleagues examined whether early life risk factors and characteristics were associated with subtypes of atopic eczema, and set out to determine whether they are associated with atopic disease and other general midlife health.

The Study

The investigators evaluated members of 2 population-based cohorts, the 1958 National Childhood Development Study (NCDS) and the 1970 British Cohort Study (BCS70).

A total of 30,905 participants were evaluated from birth into midlife over a period between 1958 and 2016.

Latent class analysis (LCA) was used to identify subtypes of atopic eczema activity patterns based on parent-reported or self-reported atopic eczema period prevalence from standardized questions from the NCDS and BCS70.

From there, Abuabara and colleagues examined associations between early life factors and the newly identified atopic eczema subtypes, which were considered categorical outcomes in multinomial logistic regression models, while early-life factors were selected a priori based on previous literature.

Examinations were conducted on whether atopic eczema subtype was associated with binary outcomes of self-reported asthma, hay fever, general health, and mental health in separate multivariable logistic regression models adjusted for sex, ethnicity, social class, and cohort.

Scores were based on 5 questions regarding general health, all of which ranged from 1 to 100. Higher scores indicated a more positive self-assessment of health.

Finally, the investigators performed a sensitivity analysis repeating the cohort-specific LCAs using only 5 time points that were most consistent across the 2 cohorts.

The Findings

Abuabara identified 4 distinct disease trajectories over the course of the study based on probability of reporting atopic eczema with age.

The disease trajectories were as followed: a majority of people who report no atopic eczema or report it rarely, decreasing probability, high probability and increasing probability of reporting atopic eczema with age.

Previous early life risk factors such as sex, residence, parental social class, in utero smoke, abd breastfeeding were associated with differences in disease trajectory subtype.

Some, such as residence in Central England as compared with Southern England, were associated with an increased risk of the high subtype, as well as female sex and lower childhood social class.

Additionally, investigators found a newly identified subtype with increasing probability of activity in adulthood, which they believed warranted additional attention given associations with poor self-reported physical and mental health in midlife.

The investigators suggested extending the window of observation of atopic disease beyond childhood, as clear subtypes of atopic eczema based on patterns of disease activity emerged throughout the study.

Research into environmental factors were also worth examining.

“Early- life factors shown to be associated with childhood atopic eczema overall did not help differentiate between subtypes, which raises the possibility that disease trajectory is modifiable and may be influenced by environmental factors throughout life,” the team wrote

The study, “Patterns of Atopic Eczema Disease Activity From Birth Through Midlife in 2 British Birth Cohorts,” was published in JAMA Dermatology.