[1] Umea Univ, OLIN Unit, Dept Publ Hlth & Clin Med Occupat & Environm Med, Umea, Sweden
[2] Malmo Univ, Fac Hlth & Soc, Dept Care Sci, Malmo, Sweden
[3] Uppsala Univ, Dept Med Sci Resp Med & Allergol, Uppsala, Sweden
[4] Lulea Univ Technol, Div Nursing, Dept Hlth Sci, Lulea, Sweden