After adjusting for age, exposure to second-hand smoke (SHS), exercise, drinking, body fat, BMI, waist-hip ratio (WHR), asthma, and emphysema, SOX2 promoter methylation was significantly hypermethylated in both men and women residing in central and southern areas compared with the northern areas (Tables 3 and 4). The gene discussed is SOX2; the disease is pulmonary emphysema.