[1] Department of Public Health,
[2] University of Turku,undefined
[3] Lemminkäisenkatu 1,undefined
[4] 20500 Turku,undefined
[5] Finland,undefined
[6] e-mail: minna.aromaa@tyks.fi,undefined
[7] Tel.: +358-2-3338477,undefined
[8] Fax: +358-2-3338439,undefined
[9] Department of Paediatric Neurology,undefined
[10] University of Turku,undefined
[11] Turku,undefined
[12] Finland,undefined
[13] Department of Mental Health and Alcohol Research,undefined
[14] National Public Health Institute,undefined
[15] Helsinki,undefined
[16] Finland,undefined
[17] Department of Public Health,undefined
[18] University of Tampere,undefined
[19] Tampere,undefined
[20] Finland,undefined