[1] Univ Stavanger, Dept Hlth Studies, N-4036 Stavanger, Norway
[2] North Zealand Hosp, Dept Pulm & Infect Dis, DK-3400 Hillerod, Denmark
[3] Univ London Imperial Coll Sci Technol & Med, London W2 1PG, England
[4] Inst Super Ciencias Trabalho & Empresa, P-1649026 Lisbon, Portugal
[5] Erasmus Univ, Dept Hlth Policy & Management, NL-3000 DR Rotterdam, Netherlands
[6] Jonkoping Univ, Jonkoping Acad Improvement Hlth & Welf, S-55111 Jonkoping, Sweden
[7] UCL, Dept Appl Hlth Res, London WC1E 7HB, England