The SAPALDIA Youth Study aims at investigating the impact of early life and cumulative life-time ETS exposure on vascular health in the childhood, measured by intima media thickness. The study is based on the hypothesis that ETS exposure in pregnancy and childhood is associated with an increased intima media thickness, and further that the effect is amplified by recurrent childhood infectious diseases and chronic subclinical inflammation. These hypotheses are to be tested in a sample of 200 SAPALDIA off-spring, aged 10-20 years, to equal parts ETS exposed in pregnancy and childhood and non-exposed controls. The study is set withinthe third survey of the Swiss Air Pollution And Chronic Disease In Adults (SAPALDIA) cohort in 2010.