Epigenome wide association analysis of daytime sleepiness in the Multi Ethnic Study of Atherosclerosis reveals African American specific associations
Abstract Study Objectives Daytime sleepiness is a consequence of inadequate sleep, sleep wake control disorder, or other medical conditions. Population variability in prevalence of daytime sleepiness is likely due to genetic and biological factors as well as social and environmental influences. DNA methylation (DNAm) potentially influences multiple health outcomes. Here, we explored the association between DNAm and daytime sleepiness quantified by the Epworth Sleepiness Scale (ESS) Methods We performed multi ethnic and ethnic specific epigenome wide association studies for DNAm and ESS in the Multi Ethnic Study of Atherosclerosis (MESA; n 619) and the Cardiovascular Health Study (n 483) with cross study replication and meta analysis. Genetic variants near ESS associated DNAm were analyzed for methylation quantitative trait loci and followed with replication of genotype sleepiness associations in the UK Biobank. Results In MESA only, we detected four DNAm ESS associations: one across all race/ethnic groups; three in African Americans (AA) only. Two of the MESA AA associations, in genes KCTD5 and RXRA, nominally replicated in CHS (p value 0.05) In the AA meta analysis, we detected 14 DNAm ESS associations (FDR q value 0.05, top association p value 4.26 x 10 8) Three DNAm sites mapped to genes (CPLX3, GFAP, and C7orf50) with biological relevance. We also found evidence for associations with DNAm sites in RAI1, a gene associated with sleep and circadian phenotypes. UK Biobank follow up analyses detected SNPs in RAI1, RXRA, and CPLX3 with nominal sleepiness associations. Conclusions We identified methylation sites in multiple genes possibly implicated in daytime sleepiness. Most significant DNAm ESS associations were specific to AA. Future work is needed to identify mechanisms driving ancestry specific methylation effects.
Sleep