1. Celiac Disease Center (B.L., P.H.R.G.), Department of Medicine, Columbia University College of Physicians and Surgeons, New York, New York 10027
2. Clinical Epidemiology Unit (B.L., J.F.L.), Department of Medicine, Karolinska University Hospital and Karolinska Institutet, SE-171 77 Stockholm, Sweden
3. Department of Surgical Sciences (K.M.), Section of Orthopaedics, Uppsala University, SE-751 05 Uppsala, Sweden
4. Department of Pediatrics (J.F.L.), Örebro University Hospital, SE-70185; Örebro, Sweden