Global pediatric atopic dermatitis increased over 6% from 2000 to 2021
Key takeaways:
- Girls had higher AD prevalences globally.
- Regions with higher sociodemographic index values saw larger decreases in AD cases.
- The changes in prevalence are due to varying underlying factors.
While pediatric atopic dermatitis cases rose globally between 2000 and 2021, the prevalence rate dropped, showing important global patterns, according to a study in Annals of Allergy, Asthma & Immunology.
“Analyzing AD prevalence in the context of geographical diversity reveals variations in environmental factors, health care access and diagnostic practices across different regions,” Ling Jin, MD, of the department of dermatology, Shanghai Children’s Medical Center, School of Medicine, Shanghai Jiao Tong University, and colleagues wrote. “A detailed examination of these geographical patterns is instrumental in identifying high-risk areas and understanding the global burden of AD.”
Jin and colleagues conducted a systemic analysis utilizing data focused on children aged 0 to 14 years with AD from the Global Burden of Disease (GBD) Study 2021, which covered a period the authors said marked “significant socioeconomic and environmental changes globally, potentially influencing the epidemiology of AD.”
Study findings
Global pediatric AD cases amounted to 72.4 million in 2021, a 6.2% increase since the year 2000. However, the annual prevalence rate dropped by 0.15% (3.72% in 2000 vs. 3.6% in 2021; P < .0001).
Countries or regions with a high and middle sociodemographic index (SDI) saw decreases in pediatric AD, whereas high-middle, low-middle or low SDI regions saw increases.
The highest prevalence in 2021 was seen in high SDI regions at 6.54% even though the percentage fell between 2000 and 2021 by 7.5%. High-middle SDI areas saw a 1% increase in prevalence, and middle SDI areas saw a 0.7% decrease in prevalence.
The regions with the highest point prevalences for pediatric AD as of 2021 were Central Asia (10.52%), high-income Asia Pacific (10.06%) and Western Europe (8.02%). The regions with the lowest prevalence were mostly in Sub-Saharan Africa, including Eastern Sub-Saharan Africa (2.11%), Western Sub-Saharan Africa (2.18%) and Central Sub-Saharan Africa (2.2%).
However, the greatest percentage changes in AD case numbers between 2000 and 2021 were also observed in Western Sub-Saharan Africa (87.9%), Central Sub-Saharan Africa (76.5%) and Eastern Sub-Saharan Africa (56.5%). The largest AD case number decreases occurred in high-income Asia Pacific (–25.7%), Central Europe (–20.7%) and Central Latin America (–10.9%).
Eastern Europe had the most significant increase in AD prevalence with an annual average percentage change (AAPC) of 0.96 (95% CI, 0.69-1.23). High-income North America experienced the largest decrease in AD prevalence between 2000 and 2021 with an AAPC of –0.19 (95% CI, –0.26, –0.13).
Study authors noted that at the regional level, between 2000 and 2019, data analysis showed a consistently increasing correlation between SDI and AD prevalence. SDI values for 2020 to 2021 were not available.
They also highlighted that regional trends showed AD prevalence rising among regions with higher SDI levels with an exception of Central Asia, which had intermediate SDI values but also one of the globally highest AD prevalences.
On a national level, countries with the highest numbers of pediatric AD cases in 2021 included India with 12.9 million cases, China with 7.6 million and the U.S. with 3.3 million. The national point prevalence of AD showed a varying range from 1.5% to 10.67% with the highest prevalences seen in Mongolia, Japan and Uzbekistan. The lowest prevalences were seen in Rwanda, Congo and Ghana.
An increase in number of AD cases was seen in almost 50% (n = 98) of countries, the highest being in Qatar (211.9%), Niger (130.2%) and Angola (126.7%). The highest increases in AAPC in AD prevalence occurred in 108 countries with the most significant rises in Russia (AAPC, 0.9%; 95% CI, 0.6%-1.21%), Ghana (AAPC, 0.62%; 95% CI, 0.43%-0.8%) and Latvia (AAPC, 0.59%; 95% CI, 0.39%-0.8%).
A “marked decrease” in AAPC occurred in 48 countries, with the U.S. (AAPC, –0.22%; 95% CI, –0.28% to –0.15%), Syria (AAPC, –0.22%; 95% CI, –0.29% to –0.16%) and Japan (AAPC, –0.21%; 95% CI, –0.25% to –0.16%) being the most significant.
Significant age and sex patterns were also observed. Children aged 5 to 9 years had the highest AD prevalence in 2021 among both sexes (3.88% boys; 4.62% girls). Notably, girls consistently had a higher prevalence across all age groups. A rise in AD case numbers was also seen across all age and sex groups, peaking in 2010.
Prevalence rates dropped and had a downward trend in all groups, with the largest average decrease seen in girls aged 5 to 9 years (AAPC, –0.27%; 95% CI, –0.29% to –0.25%).
Conclusions, global impact
Study authors noted that the rise in pediatric AD rates along with the drop in AD prevalence showed a complicated interplay of different changing factors. The rise in rates could be explained by better diagnostic procedures or a real rise in rates.
Regions where a higher than expected AD prevalence rate was observed, such as in Eastern Europe or high-income Asia Pacific, could mean that environmental and lifestyle variables could be playing a substantial role, according to study authors. Factors such as urbanization, climate change, diet and allergen exposure could also be contributing to higher rates of AD.
“The lack of a significant correlation between national AAPCs and SDI levels emphasizes that AD prevalence is influenced by a complex mix of factors, necessitating multifaceted public health strategies that are sensitive to regional and demographic specifics,” Jin and colleagues wrote.
Perspective
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This study provides a very good overview of the global prevalence of pediatric AD, and how that has changed since 2000, highlighting just how common it is. The wide range in prevalence suggests that further research is needed to tease out how much is due to diagnostic, genetic, environmental or other differences. The overall increase in cases highlights the ongoing need for safe and effective therapeutics that are accessible across the globe.
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