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.