1. Division of Digestive and Liver Diseases, Department of Medicine, Columbia University College of Physicians and Surgeons, New York, New York, USA;
2. Celiac Disease Center, College of Physicians and Surgeons, Columbia University Medical Center, New York, New York, USA;
3. Clinical Epidemiology Division, Department of Medicine, Solna, Karolinska Institutet, Stockholm, Sweden;
4. Division of Obstetrics, Department of Women's Health, Karolinska University Hospital, Stockholm, Sweden;
5. Department of Medical Epidemiology and Biostatistics, Karolinska Institute, Stockholm, Sweden;
6. Department of Pediatrics, Orebro University Hospital, Orebro, Sweden.