 This study examined the incidence of asthma in children aged 8-28 years old and evaluated early life risk factors for asthma onset at different ages. The results showed that the incidence of asthma was high during childhood and the teenage period, and decreased substantially during young adulthood. Early life factors such as family history of asthma, allergic sensitization, low birth weight, maternal smoking during pregnancy, severe respiratory infections, rhinoconjunctivitis and eczema were associated with asthma onset at various ages. This article was authored by Linnea Headman, Linnea Anquist, Anders Pjerg and others.