Study design and population
“Influence of L ife-Style Factors on the Development of theI mmune S ystem and A llergies in East and West Germany” (LISA) is an ongoing multicentre population-based German birth cohort. 15,16 Briefly, healthy full-term neonates with a normal birth weight were recruited at selected maternity hospitals in Munich, Leipzig, Wesel and Bad Honnef between 1997 and 1999. Parent-completed questionnaires were administered at birth and at ages 0.5, 1, 1.5, 2, 4, 6, 10 and 15. Blood samples were drawn from a subset of children at the ages of 2, 6, 10 and 15 years. For the purpose of this study, we utilized the data from 631 children from Leipzig (for details, see the flowchart, Figure E1). The LISA Leipzig cohort was approved by the local ethics committee at the University of Leipzig (560/1998; 206/2003; 345/2007) and the State Medical Council of Saxony (EK-BR-02/13-1), and informed consent was obtained from all families.