Abstract 3772: Lifestyle factors and global methylation in peripheral leukocyte DNA

Abstract

Abstract Global hypomethylation is associated with genomic instability and may mediate the association between environmental and lifestyle factors and cancer risk. We examined the association between lifestyle factors and levels of genomic DNA methylation in the peripheral blood leukocytes of 160 participants in the North Texas Healthy Heart Study aged 45-75. We used in-person interviews for demographics and lifestyle factors, a self-administrated Block food frequency questionnaire for dietary data, bioelectrical impedance analysis (BIA) and CT-scan for body composition including fat mass % and areas of visceral and truncal subcutaneous adipose tissues at the L4L5 level. We measured genomic DNA methylation using bisulfite conversion of DNA and real time PCR (MethyLight) for SAT2-M1. The median level of global methylation was 61.3% in this cancer-free population. Male gender was positively associated with global hypomethylation (i.e. < median) (OR=3.7, 95%CI: 1.4-9.7). Compared to Hispanics (n=58), non-Hispanic whites (n=33) and non-Hispanics blacks (n=68) had a significantly higher level of global hypomethylation (OR=8.4, 95%CI: 2.4-29.6 and OR=4.1, 95%CI: 1.5-11.2 respectively). Although the area of L4L5 subcutaneous adipose tissue was positively associated with DNA methylation in the univariate model (342 cm2 among subjects with methylation < median vs. 395 cm2 among subjects with methylation ≥ median, p=0.04), none of the body composition measures were associated with DNA methylation in the multivariate model after adjusting for age, gender and ethnicity, nor were cigarette smoking, alcohol drinking, dietary folate intake and perceived stress. Although there was no association of lifestyle factors with genomic methylation in the peripheral leukocyte DNA, the strong association with gender and race/ethnicity indicates that interactions between these variables and lifestyle factors need to be explored in a larger sample before firm conclusions can be reached. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 3772.