Effects of tobacco exposure on lung health and pulmonary biomarkers in young, healthy smokers aged 12-25 years: a systematic review.

Chronic obstructive pulmonary disease (COPD) is associated with high personal and societal burden and mortality. COPD is usually diagnosed during middle or late adult life, but the starting point for a 'COPD career' may be found earlier in life, during adolescence: first, because of smoking initiation and subsequent accumulation of risk, and second, because of the adverse effects of cigarette smoking on lung-function development. The objective of this paper is to systematically review the literature on the effects of active smoking on lung health in 12-25-year-old healthy boys and girls, measured with simple and noninvasive methods: lung function by spirometry, exhaled gases (including nitric oxide, carbon monoxide and hydrocarbons) and exhaled breath condensate. The identification of biomarkers may be useful for early detection of tobacco-related respiratory disease in this population, for targeted smoking prevention or smoking-cessation programs and, in the long term, for a reduction of personal and societal impact of COPD and other smoking-related diseases.