title: Significant differences in global genomic DNA methylation by gender and race/ethnicity in peripheral blood.
abstract: Reduced levels of global DNA methylation are associated with genomic instability and are independent predictors of cancer risk. Little is known about the environmental determinants of global DNA methylation in peripheral blood. We examined the association between demographic and lifestyle factors and levels of global leukocyte DNA methylation in 161 cancer-free subjects enrolled in the North Texas Healthy Heart Study aged 45-75 years in 2008. We used in-person interviews for demographics and lifestyle factors, a self-administrated Block food frequency questionnaire for diet, and bioelectrical impedance analysis and CT-scan for body composition. We measured genomic DNA methylation using bisulfite conversion of DNA and pyrosequencing for LINE-1. Body composition measures including body mass index, waist circumference, areas of subcutaneous fat and visceral fat, percent of fat mass and fat-free mass were not associated with global genomic DNA methylation after controlling the effect of age, gender and race/ethnicity. Instead, female gender was significantly associated with a reduced level of global methylation (β = -2.77, 95% CI: -4.33, -1.22). Compared to non-Hispanic whites, non-Hispanic blacks (β = -2.02, 95% CI: -3.55, -0.50) had significantly lower levels of global methylation. No association was found with age, cigarette smoking, alcohol drinking and dietary intake of nutrients in one-carbon metabolism. Global leukocyte DNA methylation differs by gender and race/ethnicity, suggesting these variables need to be taken into consideration in studies of global DNA methylation as an epigenetic marker for cancer.
authors: Department of Nutrition Science, Friedman School of Nutrition Science, Tufts University, Boston, MA, USA. fang_fang.zhang@tufts.edu
authors: Fang Fang
authors: FF
authors: Zhang
authors: Roberto
authors: R
authors: Cardarelli
authors: Joan
authors: J
authors: Carroll
authors: Kimberly G
authors: KG
authors: Fulda
authors: Manleen
authors: M
authors: Kaur
authors: Karina
authors: K
authors: Gonzalez
authors: Jamboor K
authors: JK
authors: Vishwanatha
authors: Regina M
authors: RM
authors: Santella
authors: Alfredo
authors: A
authors: Morabia
mesh_terms: D000368:Aged; D000375:Aging / Q000235:genetics; D019175:DNA Methylation; D004032:Diet; D005006:Ethnicity / Q000235:genetics; D005260:Female; D015894:Genome, Human; D006801:Humans; D020071:Interspersed Repetitive Sequences / Q000235:genetics*; D050152:Intra-Abdominal Fat / Q000378:metabolism; D007962:Leukocytes / Q000378:metabolism; D008019:Life Style; D020084:Long Interspersed Nucleotide Elements / Q000235:genetics; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000235:genetics; D012737:Sex Factors; D050151:Subcutaneous Fat / Q000378:metabolism; D013781:Texas