Figure 1.

Estimated effects of recent and long-term secondhand tobacco smoke (SHS) exposure on cg05575921 methylation in nonsmokers. Forest plots show SHS-related exposure effect sizes on cg05575921 methylation (x-axis, β and 95% confidence interval [CI]) measured in CD14+ monocyte samples, including recent SHS exposure (hours per week of close contact with indoor SHS, urine cotinine concentrations), and long-term SHS exposure (years exposed to SHS at home, and not at home). SHS-related effect sizes on methylation are shown overall and stratified by smoking status (never-smokers and former smokers having quit for at least 15 years). Covariates included age, sex, race/ethnicity, education level, smoking status, pack-years, time since quitting smoking (former smokers only), site of data collection, and estimates of residual sample contamination with non-monocyte cell types. Significance indicated as follows: **p < .01; *.01 ≤ p < .05.