[1] Fac Hlth Med & Soc, Dept Publ Hlth & Well Being, Chester CH1 1SL, England
[2] Univ KwaZulu Natal, Sch Nursing & Publ Hlth, Dept Publ Hlth Med, Durban, South Africa
[3] Texas A&M Univ, Sch Publ Hlth, Dept Hlth Behav, College Stn, TX 77843 USA
[4] UNSW Sydney, Ctr Social Res Hlth, Sydney, Australia
[5] Wachemo Univ, Coll Med & Hlth Sci, Sch Publ Hlth, Dept Hlth Informat, Hossana, Ethiopia
[6] Univ Witwatersrand, Sch Publ Hlth & Social Sci, Demog & Populat Studies Programme, Johannesburg, South Africa