title: Metabolic, hormonal and immunological associations with global DNA methylation among postmenopausal women.
abstract: DNA methylation is an epigenetic modification essential for the regulation of gene expression that has been implicated in many diseases, including cancer. Few studies have investigated the wide range of potential predictors of global DNA methylation, including biomarkers. Here, we investigated associations between DNA methylation and dietary factors, sex-steroid hormones, metabolic, lipid, inflammation, immune and one-carbon biomarkers. Data and baseline biomarker measurements were obtained from 173 overweight/obese postmenopausal women. Global DNA methylation in lymphocyte DNA was measured using the pyrosequencing assay for LINE-1 repeats. We used correlations and linear regression analyses to investigate associations between continuous data and DNA methylation, while t-tests were used for categorical data. Secondary analyses stratified by serum folate levels and multivitamin use were also conducted. There was little variability in LINE-1 methylation (66.3-79.5%). Mean LINE-1 methylation was significantly higher among women with elevated glucose levels. Mean LINE-1 methylation was also higher among women with high CD4+/CD8+ ratio, and lower among women with elevated vitamin B6, but neither reached statistical significance. In analyses stratified by folate status, DNA methylation was negatively associated with sex hormone concentrations (estrone, estradiol, testosterone and sex hormone binding globulin) among women with low serum folate levels (n = 53). Conversely, among women with high serum folate levels (n = 53), DNA methylation was positively associated with several immune markers (CD4/CD8 ratio, NK1656/lymphocytes and IgA). Results from this screening suggest that global DNA methylation is generally stable, with differential associations for sex hormones and immune markers depending on one-carbon status.
authors.affiliation: Division of Preventive Oncology, National Center for Tumor Diseases, German Cancer Research Center, Heidelberg, Germany. neli.ulrich@nct-heidelberg.de
authors.forename: Cornelia M
authors.initials: CM
authors.lastname: Ulrich
authors.forename: Adetunji T
authors.initials: AT
authors.lastname: Toriola
authors.forename: Lisel M
authors.initials: LM
authors.lastname: Koepl
authors.forename: Tracy
authors.initials: T
authors.lastname: Sandifer
authors.forename: Elizabeth M
authors.initials: EM
authors.lastname: Poole
authors.forename: Catherine
authors.initials: C
authors.lastname: Duggan
authors.forename: Anne
authors.initials: A
authors.lastname: McTiernan
authors.forename: Jean-Pierre J
authors.initials: JP
authors.lastname: Issa
mesh_terms: D000368:Aged; D015415:Biomarkers; D001786:Blood Glucose / Q000235:genetics / Q000378:metabolism; D016516:CD4-CD8 Ratio; D019175:DNA Methylation; D004032:Diet; D044127:Epigenesis, Genetic; D005260:Female; D005492:Folic Acid / Q000235:genetics / Q000378:metabolism; D015894:Genome, Human / Q000235:genetics; D012739:Gonadal Steroid Hormones / Q000235:genetics / Q000378:metabolism; D006801:Humans; D020084:Long Interspersed Nucleotide Elements / Q000235:genetics; D008875:Middle Aged; D017698:Postmenopause / Q000235:genetics* / Q000378:metabolism; D025101:Vitamin B 6 / Q000235:genetics / Q000378:metabolism
chemical_list: D015415:Biomarkers; D001786:Blood Glucose; D012739:Gonadal Steroid Hormones; D025101:Vitamin B 6; D005492:Folic Acid