Jani Ruotsalainen1, Jos Verbeek2, Consol Serra3, Christina Tikka2. 1. Cochrane Work Review Group, Finnish Institute of Occupational Health, Kuopio, Finland. jani.ruotsalainen@ttl.fi. 2. Cochrane Work Review Group, Finnish Institute of Occupational Health, Kuopio, Finland. 3. CiSAL -Centre for Occupational Health, Pompeu Fabra University, Barcelona, Spain.