1 National School of Public Health, Institute of Health Carlos III, Ministry of Science and Innovation, Madrid 28029, Spain. Electronic address: royo1967@yahoo.es.
2 Spanish Confederation of Associations of Parents of Students (CEAPA), Madrid, Spain.
3 Directorate of Awareness-raising and Children's Policies, UNICEF Foundation Spanish Committee, Madrid, Spain.
4 Spanish Society of Epidemiology, Barcelona, Spain.
5 Gasol Foundation Europe, Sant Boi de Llobregat, Spain.