[1] Tampere Univ, Fac Med & Hlth Technol, Arvo Ylpon Katu 34, Tampere 33520, Finland
[2] Univ Helsinki, Dept Anesthesiol Intens Care & Pain Med, Haartmaninkatu 8, FIN-00290 Helsinki, Finland
[3] Helsinki Univ Hosp, Haartmaninkatu 8, FIN-00290 Helsinki, Finland
[4] Folkhalsan Res Ctr, Helsinki, Finland
[5] Kuopio Univ Hosp, Primary Hlth Care Unit, Kuopio, Finland
[6] Ilmarinen Mutual Pens Insurance Co, Helsinki, Finland
[7] Helsinki Univ Hosp, Dept Neurosurg, Helsinki, Finland
[8] Paijat Hame Cent Hosp, Dept Pediat, Lahti, Finland
[9] Paijat Hame Cent Hosp, Dept Rheumatol, Lahti, Finland