[1] Mid Sweden Univ, Fac Humanities, Dept Hlth Sci, Holmgatan 10, S-85170 Sundsvall, Sweden
[2] Univ Gavle, Fac Occupat & Hlth Sci, Dept Publ Hlth & Sports Sci, Kungsbacksvagen 47, S-80176 Gavle, Sweden
[3] Eduardo Mondlane Univ, Fac Sci, Dept Biol Sci, 3453 Julius Nyerere Ave, Maputo 257, Mozambique
[4] Univ Warwick, Warwick Ctr Global Hlth, Warwick Med Sch, Div Hlth Sci, Coventry CV4 7AL, Warwick, England
[5] Stellenbosch Univ, Fac Hlth Sci, Dept Global Hlth, Div Epidemiol & Biostat, Francie van Zijl Dr, ZA-7505 Cape Town, South Africa
[6] Univ Porto, EPI Unit, Inst Saude Publ, Rua Taipas 135, P-4050600 Porto, Portugal