The investigators want to assess differences in lung function and bronchial inflammation of young smokers and non-smokers with (BMI > 30) and without obesity (BMI < 25)(4 patient groups). The aim of the study is to compare differences in lung function (VC, FEV1, VC/FEV1, metacholine challenge) and bronchial inflammation in relation with smoking history and levels of exhaled CO. For the latter the investigators will analyze the levels of IL-8, IL-6, TNF alpha and INF gamma and mRNA of LBP, TLR2 and TLR4 in sputum. Further, inflammatory markers e.g. low CRP and inflammatory cytokines levels in the blood will be investigated. The aim is to describe a early stage of chronic obstructive pulmonary disease caused by cigarette smoke in juvenile smokers, and the relationship between bronchial inflammation and obesity in adolescents.