Social factors and leukocyte DNA methylation of repetitive sequences: the multi-ethnic study of atherosclerosis

PLoS One. 2013;8(1):e54018. doi: 10.1371/journal.pone.0054018. Epub 2013 Jan 8.

Abstract

Epigenetic changes are a potential mechanism contributing to race/ethnic and socioeconomic disparities in health. However, there is scant evidence of the race/ethnic and socioeconomic patterning of epigenetic marks. We used data from the Multi-Ethnic Study of Atherosclerosis Stress Study (N = 988) to describe age- and gender-independent associations of race/ethnicity and socioeconomic status (SES) with methylation of Alu and LINE-1 repetitive elements in leukocyte DNA. Mean Alu and Line 1 methylation in the full sample were 24% and 81% respectively. In multivariable linear regression models, African-Americans had 0.27% (p<0.01) and Hispanics 0.20% (p<0.05) lower Alu methylation than whites. In contrast, African-Americans had 0.41% (p<0.01) and Hispanics 0.39% (p<0.01) higher LINE-1 methylation than whites. These associations remained after adjustment for SES. In addition, a one standard deviation higher wealth was associated with 0.09% (p<0.01) higher Alu and 0.15% (p<0.01) lower LINE-1 methylation in age- and gender-adjusted models. Additional adjustment for race/ethnicity did not alter this pattern. No associations were observed with income, education or childhood SES. Our findings, from a large community-based sample, suggest that DNA methylation is socially patterned. Future research, including studies of gene-specific methylation, is needed to understand better the opposing associations of Alu and LINE-1 methylation with race/ethnicity and wealth as well as the extent to which small methylation changes in these sequences may influence disparities in health.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Aged
  • Aged, 80 and over
  • Alu Elements* / genetics
  • Atherosclerosis / ethnology
  • Atherosclerosis / etiology
  • Atherosclerosis / genetics*
  • Black or African American / genetics
  • DNA Methylation* / genetics
  • Ethnicity / genetics*
  • Female
  • Hispanic or Latino / genetics
  • Humans
  • Leukocytes / metabolism*
  • Long Interspersed Nucleotide Elements*
  • Male
  • Middle Aged
  • Risk Factors
  • White People / genetics