[1] Innlandet Hosp Trust, Res Dept, Brumunddal, Norway
[2] Inland Norway Univ Appl Sci, Fac Hlth & Social Sci, N-2411 Elverum, Norway
[3] St Olavs Univ Hosp, Dept Occupat Med, Trondheim, Norway
[4] Norwegian Univ Sci & Technol, Dept Publ Hlth & Nursing, Fac Med & Hlth Sci, Trondheim, Norway
[5] Council Nutr & Environm Med, Toften 24, N-8610 Mo I Rana, Norway