[1] Univ Med Ctr Rotterdam, Dept Gen Practice, Erasmus MC, Rotterdam, Netherlands
[2] Univ Groningen, Univ Med Ctr Groningen, Dept Gen Practice & Elderly Care Med, Groningen, Netherlands
[3] Univ Med Ctr Rotterdam, Dept Orthopaed & Sports Med, Erasmus MC, Rotterdam, Netherlands
[4] Univ Med Ctr Rotterdam, Erasmus MC, POB 2040, NL-3000 CA Rotterdam, Netherlands