[1] Univ New South Wales, George Inst Global Hlth, Sydney, NSW 2042, Australia
[2] Fiji Natl Univ, Fiji Inst Pacific Hlth Res, C POND, Suva, Fiji
[3] Imperial Coll London, George Inst Global Hlth, London, England
[4] Univ Otago, Dept Prevent & Social Med, Dunedin, New Zealand