[1] Univ Porto, Inst Publ Hlth, EPIUnit, Rua Taipas 135-139, P-4050600 Porto, Portugal
[2] Brazilian Inst Consumers Def Idec, Sao Paulo, Brazil
[3] Harvard Med Sch, Boston, MA 02115 USA
[4] Johns Hopkins Univ, Sch Med, Dept Psychiat & Behav Sci, Div Child & Adolescent Psychiat, Baltimore, MD 21205 USA