giving reason to observe patients beyond the pediatric stage, according to a cohort study of more than 30,000 patients.
Early-life environmental factors, such as tobacco smoke exposure, were not reliable predictors of increasing AD into mid-adulthood, suggesting that a patient’s contemporaneous environment may impact disease course throughout life, reported lead author Katrina Abuabara, MD, associate professor of dermatology at the University of California, San Francisco, and colleagues.
“There is a lack of studies that prospectively examine the course of atopic eczema beyond adolescence/early adulthood, and a more comprehensive understanding of disease activity across the life span is needed,” the investigators wrote in JAMA Dermatology. “Data on long-term disease course may offer insight into mechanisms for disease onset and persistence, are important when counseling patients, and would establish baseline trajectories for future studies of whether new treatments can modify disease course and development of comorbidities.”
The present study included 30,905 patients from two population-based birth cohorts: the 1958 National Childhood Development Study () and the 1970 British Cohort Study ( ). Follow-up data were collected between 1958 and 2016 via nine waves of standardized questionnaires, and subtypes of atopic eczema patterns were identified “based on parent-reported or self-reported atopic eczema period prevalence.”
This measure “was previously shown to coincide with standardized clinical examinations among children in the NCDS, and a similar questionnaire demonstrated high sensitivity and specificity for physician-diagnosed atopic eczema in U.S. populations,” the investigators noted.
Latent class analysis identified four disease subtypes based on probability of reporting prevalent AD into midlife: low (88%-91%), decreasing (4%), increasing (2%-6%), and persistently high (2%-3%) probability.
Next, the investigators looked for associations between these subtypes and established early-life risk factors, such as history of breastfeeding and childhood smoke exposure. None of the childhood environmental factors differentiated between high versus decreasing disease in adulthood, or increasing versus decreasing disease in adulthood. In contrast, female sex predicted the high versus decreasing adult subtype (odds ratio, 1.99; 95% confidence interval, 1.66-2.38), and the increasing versus decreasing adult subtype (OR, 1.99; 95% CI, 1.69-2.35).
These findings suggest that “disease trajectory is modifiable and may be influenced by environmental factors throughout life,” the investigators wrote.
Further analysis uncovered associations between adult AD subtypes and other health outcomes. For example, compared with adults in the low probability group, those in the high probability group were significantly more likely to report rhinitis (OR, 2.70; 95% CI, 2.24-3.26) and asthma (OR, 3.45; 95% CI, 2.82-4.21). Adults with the increasing subtype also had elevated rates of asthma and rhinitis, along with worse self-reported mental health at age 42 (OR, 1.45; 95% CI, 1.23-1.72) and poor general health at age 46/50 (OR, 1.29; 95% CI, 1.09-1.53).
“When extending the window of observation beyond childhood, clear subtypes of atopic eczema based on patterns of disease activity emerged,” the investigators concluded. “In particular, a newly identified subtype with increasing probability of activity in adulthood warrants additional attention given associations with poor self-reported physical and mental health in midlife.”
Commenting on these results, Robert Sidbury, MD, professor of dermatology at the University of Washington, Seattle, said that this is an “important study” because it adds to our understanding of natural disease course over time.
This knowledge, as a pediatric dermatologist, will help Dr. Sidbury answer one of the most common questions he hears from parents: When is it going to stop?
“Trying to put a little bit more evidence-based heft behind the answer ... is really important,” he said in an interview.
Based on available data, up to 10% of children with AD may have disease activity into adulthood, according to Dr. Sidbury, who is also chief of dermatology at Seattle Children’s Hospital.
“I would hazard to guess that most of those adults who have atopic dermatitis – at least the ones who had it in childhood – were told that they would grow out of it,” he said. “And so I think awareness is important – that [resolution with age] does not always happen.”
The findings also support the possibility that AD is a systemic disease, and that underlying immune dysregulation may be linked with serious health consequences later in life, Dr. Sidbury said, noting that “the stakes get higher and higher when you start speculating in that way.”
According to Dr. Sidbury, the reported link between childhood AD and poor midlife health raises questions about how modifiable the disease course may be, particularly in response to earlier intervention with emerging AD medications, which “seem to be much more effective and potent.”
“Will the advent of these medications and their adoption and use in treatment perhaps have a significant impact, not just on the prevention of atopic dermatitis itself, but maybe other comorbidities?” he asked.
For the time being, this question remains unanswered.
The study was funded by the National Institute of Arthritis and Musculoskeletal and Skin Diseases and the Wellcome Trust. Dr. Abuabara received grants from the National Institutes of Health during the study, as well as personal fees from Target RWE and Pfizer outside of this study. One author reported receiving NIH grants during the study, another reported receiving grants from the Wellcome Trust and the Innovative Medicine Initiative Horizon 2020 (BIOMAP project) during the study; there were no other disclosures. Dr. Sidbury disclosed relationships with Galderma, Regeneron, and Pfizer.