TOPLINE:

In a Danish prospective study, preterm birth was associated with a lower prevalence of atopic dermatitis (AD) through the age of 4-5 years. Among children with AD, those born preterm had a higher prevalence of asthma than those born at term.

METHODOLOGY:

• Researchers conducted a prospective cohort study including 450 Danish children (300 born at term and 150 born preterm) between August 2017 and August 2019, with clinical follow-up began from birth to the age of 2 years.
• Participants included were singleton children born preterm (median gestational age, 33.5 weeks) and at term (median gestational age, 39.6 weeks). Skin was assessed for AD at birth and 2 and 12 months; if skin signs appeared during the first 2 years, additional visits were conducted to confirm diagnosis and severity using the Eczema Area and Severity Index (EASI).
• One parent of each of 391 children (261 born at term and 130 born preterm; median age at follow-up, 4.4 years) completed the follow-up telephone interview after 4 years of initial recruitment between March and September 2023. This interview included 94 questions covering symptoms and potential treatments for AD, asthma, rhinitis, and food allergies.
• Researchers compared the prevalence, age at onset, and persistence of AD and allergic comorbidities between children born preterm and at term.

TAKEAWAY:

• Children born preterm had a lower cumulative prevalence of AD at the age of 4-5 years than those born at term (19.2% vs 39.1%; P < .0001), with a later median age at onset (12.0 vs 7.5 months; P < .01) and a lower severity of disease (median EASI score, 1.4 vs 4.8; P < .01).
• In adjusted Cox regression analysis, preterm birth was associated with a lower risk for AD than term birth (hazard ratio, 0.37; P < .01).
• Among children with AD, those born preterm had a higher prevalence of asthma than those born at term (36.0% vs 17.3%; P = .05); however, none of those born preterm vs 6.7% of those born at term developed food allergies.
• Filaggrin mutations were more prevalent in children born at term than in those born preterm. Among children with AD, the prevalence was similar between those born preterm and at term.

IN PRACTICE:

"Gestational age should be considered in the interpretation of atopic outcomes and when designing early-life preventive and risk-stratification strategies for future studies, including both in utero maternal interventions and early postnatal approaches," the authors wrote.

SOURCE:

This study was led by Iben Frier Ruge, Department of Dermatology and Venereology, Bispebjerg and Frederiksberg Hospital, University of Copenhagen, Copenhagen, Denmark. It was published online on April 28, 2026, in the British Journal of Dermatology.

LIMITATIONS:

The collection of follow-up data by telephone interview rather than clinical visits may have introduced recall and reporting bias. The absence of clinical examination may have led to the misclassification of conditions such as food allergies or mild rhinitis. AD was more common in the study sample than in the general population. The small sample size limited statistical power and CI estimates. As this was an observational study, unmeasured or incorrectly measured factors may have confounded the results.

DISCLOSURES:

This study received financial support from the LEO Foundation, Lundbeck Foundation, Novo Nordisk Foundation, Aage Bangs fond, and Herlev and Gentofte Hospital Research Foundation. Seven authors reported receiving grants from the Kgl Hofbundtmager Aage Bangs Foundation, Herlev and Gentofte Hospital Research Foundation, LEO Foundation, Novo Nordisk Foundation, and Lundbeck Foundation. Additional disclosures are noted in the original article.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.