WASHINGTON, DC — Jonathan I. Silverberg, MD, PhD, MPH, said at the ElderDerm Conference on dermatology in the older patient hosted by the George Washington University School of Medicine and Health Sciences, Washington, DC.
“I walked out of residency under the impression that if it didn’t start in the first year or two of life, it’s not AD,” said Dr. Silverberg, professor of dermatology and director of clinical research at George Washington University. “The numbers tell us a very different story.”
Dr. Silverberg
Dr. Jonathan I. Silverberg
The prevalence of AD in the United States fluctuates between 6% and 8% through adulthood, including age categories up to 81-85 years, according to 2012 National Health Interview Survey data. And while persistence of childhood-onset AD is common, a systematic review and meta-analysis published in 2018 concluded that one in four adults with AD report adult-onset disease.
The investigators, including Dr. Silverberg, identified 25 observational studies — studies conducted across 16 countries and published during 1956-2017 — that included an analysis of age of onset beyond 10 years of age, and other inclusion criteria. Of the 25 studies, 17 reported age of onset after 16 years of age and had sufficient data for the meta-analysis. Using random-effects weighting, the investigators found a pooled proportion of adult-onset AD of 26.1% (95% CI, 16.5%-37.2%).
The research demonstrates that “the age of onset is distributed well throughout the lifespan,” Dr. Silverberg said, with the data “indicating there are many elderly-onset cases of true AD as well.” (Thirteen of the studies analyzed an age of onset from age ≥ 65, and several looked beyond age 80).
A 2021 study of a primary care database in the United Kingdom of 3.85 million children and adults found a “fascinating” bimodal distribution of incidence across the lifespan, with peaks in both infancy and older adulthood, he said. Incidence in adulthood was relatively stable from ages 18-49 years, after which, “into the 50s, 60s and beyond, you started to see a steady climb again.”
Also intriguing, Dr. Silverberg continued, are findings from a study of outpatient healthcare utilization for AD in which he and his coinvestigator analyzed data from the National Ambulatory Medical Care Survey (NAMCS). In the article, published in 2023 covering data from the 1993-2015 NAMCS, they reported that AD visits were more common among children aged 0-4 years (32.0%) and 5-9 years of age (10.6%), then decreased in adolescents aged 10-19 years (11.6%), remained fairly steady in patients aged 20-89 years (1.0%-4.7%), and increased in patients aged > 90 years (20.7%).
“The peak usage for dermatologists, primary care physicians, etc., is happening in the first few years of life, partially because that’s when the disease is more common and more severe but also partially because that’s when parents and caregivers are first learning [about] the disease and trying to understand how to gain control,” Dr. Silverberg said at the meeting, presenting data from an expanded, unpublished analysis of NAMCS data showing these same outpatient utilization patterns.
“It’s fascinating — there’s a much greater utilization in the elderly population. Why? The short answer is, we don’t know,” he said.