Variance components and ICCs estimating the concordance between Day 1 and Day 4 DNA methylation measures.

Annotation: σID represents the between-subject variance in DNA methylation; σID, Day represents the variance due to within-subject changes in DNA methylation between Day 1 and Day 4; σRun represents the variance between duplicate pyrosequencing runs on the same sample (i.e., analytical measurement error from pyrosequencing). Two types of Intraclass Correlation Coefficients (ICCs) were computed using the quantities above: ICC1, subtracted of the measurement error (σRun), was calculated as follows ICC1 = (σID/(σID+σID, Day)); and ICC2, which included the measurement error (σRun) at the denominator, was calculated as follows ICC2 = (σID/(σID+σID, Day+σRun)).