[1] Karolinska Inst, Div Global Hlth IHCAR, Dept Publ Hlth Sci, Stockholm, Sweden
[2] Hanoi Med Univ, Dept Dermato Venerol, Hanoi, Vietnam
[3] Nord Sch Publ Hlth & Apoteket AB, Gothenburg, Sweden
[4] Umea Univ, Dept Publ Hlth & Clin Med, Dept Clin Sci Obstet & Gynaecol, Umea, Sweden
[5] Inst Math, Dept Probabil & Math Stat, Hanoi, Vietnam
[6] Hanoi Med Univ, Dept Publ Hlth, Hanoi, Vietnam