About the Authors

Marie Ekbäck

Affiliation Division of Pediatrics, Department of Clinical and Experimental Medicine, Faculty of Health Sciences, Linköping University and Department of Pediatrics, County Council of Östergötland, Linköping, Sweden

Michaela Tedner

Affiliation Pediatric Clinic, Täby, Stockholm, Sweden

Irene Devenney

irene.devenney@lio.se

Affiliation Division of Pediatrics, Department of Clinical and Experimental Medicine, Faculty of Health Sciences, Linköping University and Department of Pediatrics, County Council of Östergötland, Linköping, Sweden

Göran Oldaeus

Affiliation Pediatric Clinic, County Hospital Ryhov, Jönköping, Sweden

Gunilla Norrman

Affiliation Pediatric Clinic, Hudiksvall, Sweden

Leif Strömberg

Affiliation Department of Pediatrics in Norrköping, County Council of Östergötland, Norrköping, Sweden

Karin Fälth-Magnusson

Affiliation Division of Pediatrics, Department of Clinical and Experimental Medicine, Faculty of Health Sciences, Linköping University and Department of Pediatrics, County Council of Östergötland, Linköping, Sweden

Competing Interests

GlaxoSmithKline supported the study with a minor grant in 2004 given as a scholarship to one of the junior researchers in the group. This does not alter the authors' adherence to PLOS ONE policies on sharing data and materials. There are no competing interests, and the funder has no role in the study design, data collection and analysis, decision to publish, or preparation of the manuscript. No products in development or marketed products from GlaxoSmithKline were part of the study.

Author Contributions

Conceived and designed the experiments: MT ID GO GN LS KFM. Performed the experiments: ME MT ID GO GN LS KFM. Analyzed the data: ME ID. Wrote the paper: ME ID KFM.