Latitude, Birth Date, and Allergy

Competing Interests: The authors have declared that no competing interests exist. Author Contributions: All authors participated in the local study management, DJ and PB planned and organised the study centre. MW developed the hypothesis for this paper, conducted the analysis, and wrote the first draft of the paper following two working group meetings in Malaga 2003 and in Bergen 2004, chaired by CS. All authors participated in the local study management, commented on the analysis, and revised the paper