[1] Univ Amsterdam, Acad Med Ctr, Dept Gen Practice, Div Clin Methods & Publ Hlth, NL-1105 AZ Amsterdam, Netherlands
[2] Univ Med Ctr Rotterdam, Erasmus MC, Dept Gen Practice, Rotterdam, Netherlands
[3] Univ Amsterdam, Dept Social Med, Div Clin Methods & Publ Hlth, Acad Med Ctr, NL-1105 AZ Amsterdam, Netherlands