Simultaneous publication: This article is being simultaneously published in 2008 in Diabetes Care and Diabetologia by the
American Diabetes Association and the European Association for the Study of Diabetes. Copyright 2008 by the American Diabetes
Association, Inc. and Springer. Copying with attribution allowed for any non-commercial use of the work.
An erratum to this article can be found at
http://dx.doi.org/10.1007/s00125-007-0917-4