Predictors Of White Blood Cell Interleukin-6 Dna Methylation Levels In Healthy Subjects

DNA methylation at gene regulatory sequences has been associated with risk of human diseases. Interleukin-6 (IL-6) methylation is a candidate biomarker for predicting disease risk, but factors that influence IL-6 methylation in healthy individuals remain largely unknown. The aim of this study was to identify predictors of IL-6 methylation in white blood cells (WBCs) from 673 healthy individuals. DNA methylation of IL-6 regulatory sequences in peripheral WBCs was quantified by PCR-pyrosequencing. Individuals with higher body mass index (BMI) (>= 23.6 kg/m(2)) had higher IL-6 methylation levels (beta = 2.08%, 95% confidence interval (95% CI): 0.59% to 3.58%), compared with subjects with lower BMI. Serum triglyceride also correlated with IL-6 methylation, and an interquartile increase in triglyceride was associated with a 0.69% (95% CI: 0.02% to 1.36%) increase in IL-6 methylation. No associations were found with age, gender, alcohol consumption, smoking, diabetes, hypertension, total serum cholesterol or plasma homocysteine. The total number of WBCs and interquartile plasma C-reactive protein levels were inversely associated with IL-6 methylation. These findings need to be considered in designing future epidemiological investigations aimed at identifying associations between IL-6 methylation and health outcomes.