Environmentally-Induced Epigenetic Changes Correlate with Race and Childhood Asthma Severity

Rationale: Socioeconomic status, genetic predisposition and environmental factors contribute to asthma incidence and severity. Children with asthma who are economically disadvantaged likely live in substandard housing with potential indoor environmental exposures that may manifest through epigenetic mechanisms. We examined the association of global DNA methylation with socioeconomic status, asthma severity and race/ethnicity.

Methods: Global DNA methylation was measured in peripheral blood of children with asthma between the ages of 2 and 17 yrs enrolled in the Kansas City Safe and Healthy Homes Program. Inclusion criteria included residing in the same home for a minimum of 4 days per week and total family income of less than 80% of the Kansas City median family income (MFI). A three-way mixed factorial ANOVA was used to analyze global DNA methylation. When appropriate, follow-up analyses were performed using independent-samples ttests and ANOVA models with Bonferroni corrections.

Results: Our results indicate that overall, African American children with asthma had significantly higher levels of global DNA methylation than children with asthma of other races/ethnicities (p = 0.029). This difference was more pronounced when socioeconomic status and asthma severity were considered (p = 0.042). In children with persistent asthma from the lowest income families (<50% Kansas City MFI), significantly higher levels of global DNA methylation were observed in African American children compared to children of other races/ethnicities (p = 0.05).

Conclusion: Our study demonstrates a significant interaction effect among global DNA methylation levels with asthma severity, race/ethnicity, and socioeconomic status.