1. University Department of Paediatrics (B.S., K.K.O., A.T., D.B.D.), University of Cambridge, Cambridge CB2 0QQ, United Kingdom
2. Department of General Paediatrics and Neonatology (B.S.), University Children's Hospital Düsseldorf, D-40225 Düsseldorf, Germany
3. Medical Research Council Epidemiology Unit (K.K.O., N.J.W.), Institute of Metabolic Science, CB2 0QQ Cambridge, United Kingdom
4. School of Social and Community Medicine (P.E.), University of Bristol, BS8 2PS Bristol, United Kingdom