The Lifestyle-Related factors on the Immune System and the Development of Allergies in Childhood plus the influence of traffic emissions and genetics (LISAplus) population-based study aimed to assess the influence of lifestyle-related factors on the immune system, as well as the effects of air pollution and genetics on the development of allergies in childhood. In total, 3097 healthy full-term neonates were recruited from 14 obstetrical clinics in Munich, Leipzig, Wesel and Bad Honnef between November 1997 and January 1999. Follow-up for this study occurred at the age of six, twelve and eighteen months, and two, four, six and ten years. After the six-year follow-up, two children removed their consent to participate in the LISAplus study, and are thus not included in this analysis. A detailed description of the screening and recruitment of these studies has been described elsewhere