current smoking men and women who started smoking before age of 18 years was 3.0 and 5.9 compared with their nonsmoking counterparts Early initiation of smoking had stronger relationships to the prevalence of COPD in women than in men.
current smoking men and women who started smoking before age of 18 years was 3.0 and 5.9 compared with their nonsmoking counterparts Early initiation of smoking had stronger relationships to the prevalence of COPD in women than in men.