PARIS – A major worldwide survey of the 12-month prevalence of atopic dermatitis (AD) across the course of life provides new insights into global disease trends, Jonathan I. Silverberg, MD, PhD, reported at the annual congress of the European Academy of Dermatology and Venereology.
Dr. Jonathan Silverberg
Among the most important takeaways from this Internet-based survey of more than 273,645 infants, children, and adults in 18 countries across five continents conducted in 2017 was that “global atopic dermatitis prevalence appears to be higher in adults, at 10%, than in younger cohorts, where it’s 4%-8%, which I think is quite provocative and requires further study and confirmation,” said Dr. Silverberg, a dermatologist at Northwestern University in Chicago.
“Let’s keep in mind that there’s this accepted dogma in the literature than atopic dermatitis is somehow only a childhood disorder – it doesn’t affect adults. Well, these data tell a very different story because we’re actually seeing overall highest prevalences throughout the world occurring in adulthood,” based on the U.K. Working Party’s Diagnostic Criteria for Atopic Dermatitis (Br J Dermatol. 1994 Sep;131[3]:383-96).
This is the biggest epidemiologic survey ever to examine the 12-month prevalence and severity of AD around the world for both adults and children. Survey respondents included 172,627 adults aged 18 years and older, 34,212 adolescents aged 12-17 years, 54,806 children aged 2-11 years, and more than 12,000 infants.
Key findings from the study include the following:
- AD prevalence rates varied widely from country to country around the world, as well as by age groups (see graphic).
- The highest rate in adults was observed in China. South Korea had the highest rates in both children and adolescents. The top AD rates in infancy occurred in France and the United Kingdom.
- Rates across the age spectrum were consistently lowest in Israel and Switzerland.
“These kinds of patterns raise fascinating questions about the potential risk factors or protective factors that happen in different countries. There are some startling differences in terms of the different regions,” Dr. Silverberg observed. “Certain regions of the world really stand out as having much higher prevalences, particularly China and South Korea, and then as you get into the adult years, Brazil and Mexico, which I think are areas that, at least in the global atopic dermatitis epidemiology community, are not quite as well recognized as being hot spots for atopic dermatitis.”
Indeed, the 12-month prevalence rate of AD among adults was 14% in Mexico and 12% in Brazil, as compared with 13% in Saudi Arabia, 11% in Australia and Spain, 10% in Canada and the United Kingdom, and 9% in the United States.
The prevalence was generally lowest in infants, then jumped substantially within countries during the childhood years, declined slightly in adolescents, and then peaked in adulthood.
AD severity was assessed using PO-SCORAD, the Patient-Oriented Scoring AD measure. Most affected individuals had moderate AD as defined by a PO-SCORAD score of 25-50. Across the age spectrum, the highest proportion of infants with AD who had moderate disease was in China, with 72%. In Taiwan, 63% of children with AD had moderate disease, as did 68% of adolescents and an equal proportion of adults.
In the United Kingdom, 49% percent of infants with AD had severe disease, making that country the world leader in the youngest age group. Severe AD was most common among Turkish children, where 30% of kids with the skin disease had a PO-SCORAD score greater than 50. In Brazil, 31% of adolescents with AD had severe disease, the world’s highest rate in that age group. Among adults with AD, the world’s highest rate of severe disease was 25%, which was seen in the United States, Brazil, and Saudi Arabia.
Across the age spectrum, Japan had a consistently lower-end, overall, 12-month AD prevalence rate of 5%. Germany, Italy, and France had overall rates of 6%, 7%, and 8%, respectively. The rate was 9% in the United States and Canada, and it was 10% in Australia.
Dr. Silverberg performed validation analyses using the Patient-Oriented Eczema Measure (POEM) and diagnostic criteria similar to the earlier landmark International Study of Asthma and Allergies in Childhood, or ISAAC (Lancet. 1998 Apr 25;351[9111]:1225-32). This was a huge study that excluded the United States, leaving a hole in the epidemiologic picture of the disease that the new survey fills. The validation analyses were supportive of the main findings based on the U.K. Working Party criteria.
Dr. Silverberg reported serving as a consultant to Pfizer, which sponsored the global epidemiologic survey, as well as to roughly a dozen other pharmaceutical companies.
bjancin@mdedge.com
SOURCE: Silverberg JI. EADV Congress, Abstract FC01.01.