Figure 3.

Scatterplots of the crude correlations between particulate matter exposures and tandem-repeat methylation for the four significant findings from adjusted multivariable analyses. Circles and crosses represent observations from the first and second examination days, respectively. Unadjusted and adjusted regression estimates obtained from mixed-effect regression models are shown. Mixed-effect regression was used to account for the lack of independence of the repeated measures and to compute β coefficients, standard errors (SEs), and P values. Adjusted estimates were computed from models fitting the following independent variables: age, sex, BMI, smoking status, number of cigarettes smoked during the 8 hours of the study, work hours/day, and outdoor humidity and temperature on the examination days. Estimates are scaled to an interquartile range (IQR) increase in exposure.