Disclaimer
Mercedes de Onis is a staff member of the World Health Organization. The author alone is responsible for the views expressed in this publication and they do not necessarily represent the decisions, policy or views of the World Health Organization.
Declaration of interest: The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.
IJPO policy statement
This journal regularly publishes surveys, which classify children by obesity status, using a number of different definitions. We recommend that authors submit their data using both of the leading international classification schemes: the IOTF cut-offs to ensure comparability with already-published studies, and the new WHO cut-offs to ensure comparability as these classifications become more widely used.