[1] TNO Qual Life, NL-2301 CE Leiden, Netherlands
[2] Vrije Univ Brussel, Med Ctr, Inst Res Extramural Med, Dept Occupat Hlth, Amsterdam, Netherlands
[3] Municipal Hlth Serv, The Hague, Netherlands
[4] Vrije Univ Amsterdam, Dept Clin Epidemiol & Biostat, Amsterdam, Netherlands
[5] TNO VUmc, Body Work Res Ctr Acitiv Work Hlth, Amsterdam, Netherlands