Differential DNA Methylation Between African Americans And European Americans: the Role of Childhood Socioeconomic Status and Relations to Health Disparity

다국어 초록 (Multilingual Abstract)

Different DNA methylation patterns between ethnic groups may reflect the impact of social and environmental factors and contribute to health disparity. Increasing evidence indicates the importance of low socioeconomic status (SES), particularly in childhood, as a partial explanation for poor health outcomes in African Americans (AAs) compared to European Americans (EAs). This study aims to identify ethnicity‐related methylation patterns and their relationship with health disparities, and further determine to what extent the identified signals could be explained by potential difference in childhood SES between AAs and EAs.
Genome wide DNA methylation data from leukocytes of 224 AAs (58% females) and 244 EAs (46% females), aged 18–37, were obtained from Georgia Stress and Heart study using the Infinium HumanMethylation450 BeadChip. Childhood SES was assessed using parental Hollingshead score.
By comparing AAs and EAs, 1671 differentially methylated CpG sites (DMCs) (p<1×10−7) were identified. Gene ontology analysis using DAVID showed that the genes harboring these DMCs were significantly enriched (FDR<0.05) in disease terms of chem dependency, tobacco use, body weight, cardiovascular, metabolic and developmental disorders, which were complex traits with known racial disparities. Furthermore, the ethnicity‐related DMCs showed significant enrichment in DMCs identified by epigenome‐wide association studies for obesity (p<7×10−28), hypertension (p<0.01), and type 2 diabetes (p<2.4×10−5), supporting the role of ethnicity‐related DMCs in explaining the health disparity in metabolic health between AAs and EAs. In addition, AAs showed significant lower childhood SES compared to EAs (37.8±13.4 vs. 45.2±12.2, p<0.001). Moreover, among the 1671 ethnicity related DMCs, 766 were significantly associated with childhood SES (FDR<0.05). Mediation analysis further revealed that childhood SES could partially explain the ethnicity differences in DNA methylation levels in 193 out of the 766 DMCs (mediation effects: 7%–22%, p<0.05).
We found significant differences in DNA methylation levels between AAs and EAs, and these differences were highly enriched with respect to DMCs related to metabolic traits, suggesting that epigenetics underlying the ethnicity difference may partially explain the health disparity in metabolic health between AAs and EAs. We also found that ethnicity related differential methylation may be partially mediated through disproportionately lower childhood SES in AAs relative to EAs.
Support or Funding Information
HL125577, HL069999
This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.