Association of Mitochondrial DNA Copy Number With Atopic Dermatitis in Children

Mitochondrial DNA copy number (mtDNA-CN), a marker associated with mitochondrial function and cellular health, has been implicated in several chronic inflammatory diseases. Atopic dermatitis is a common chronic inflammatory skin disorder, yet the relationship between mtDNA-CN and childhood atopic dermatitis remains unclear. This study aimed to investigate the association between mtDNA-CN and atopic dermatitis in a population-based cohort of school-aged children.

We included 1329 singleton children (56.4% boys; mean age ± standard deviation: 6.5 ± 0.5 years) from the Longitudinal Investigation of Global Health in Taiwanese Schoolchildren (LIGHTS) cohort. Genomic DNA was extracted from peripheral blood, and mtDNA-CN was quantified by real-time quantitative polymerase chain reaction. Multivariable logistic regression models were applied.

Among the 1329 children, 328 (24.7%) children had physician-diagnosed atopic dermatitis. Mean mtDNA-CN was lower in children with atopic dermatitis than in those without (289.62 ± 102.06 vs. 299.47 ± 91.90; p = 0.03). Each one-unit increase in log-transformed mtDNA-CN was associated with 28% lower odds of atopic dermatitis after adjustment for potential confounders (adjusted odds ratio: 0.72; 95% confidence interval: 0.54-0.96). Subgroup analyses showed that this inverse association was more pronounced among children breastfed for ≥ 3 months and those with a birth weight ≥ 2500 g.

This study provides novel evidence of an inverse association between mtDNA-CN and atopic dermatitis in children. Further longitudinal and mechanistic studies are warranted to confirm these findings and to evaluate the potential utility of mtDNA-CN as a biomarker for atopic dermatitis.