Increased ventilation during exercise in polluted areas could trigger airway inflammation. We evaluated blood DNA methylation of the SOX2-promoter region in relation to exercise and PM2.5 in Taiwanese adults. Data of 948 participants aged 30-70 years were retrieved from the Taiwan Biobank Database (2008-2015) and the Air Quality Monitoring Database (2006-2011). PM2.5 was positively associated with SOX2-promoter methylation (beta = 0.000216; p < 0.0001). The interaction between PM2.5 and exercise on SOX2-promoter methylation was significant (p = 0.0146). After stratification by exercise habits, PM2.5 was positively associated with SOX2 methylation in only individuals who did regular exercise (beta = 0.0003490; p < 0.0001). After stratification by exercise habits and residential areas, SOX2-promoter methylation levels in those who lived in the southern area were higher for both the regular exercise (beta = 0.00272; p = 0.0172) and no regular exercise groups (beta = 0.002610 and p = 0.0162). SOX2-promoter methylation levels in those who lived in the northern area and did regular exercise were lower; beta = -0.00314 (p = 0.0036). In conclusion, PM2.5 was positively associated with SOX2-promoter methylation in participants who did regular exercise. Living in the southern area was positively associated with SOX2-promoter methylation regardless of exercise habits.
