[1] Univ Guelph, Dept Populat Med, Guelph, ON N1G 2W1, Canada
[2] Univ Guelph, Ctr Publ Hlth & Zoonoses, Guelph, ON N1G 2W1, Canada
[3] Univ Otago, Dept Prevent & Social Med, Dunedin, New Zealand
[4] Univ Auckland, Dept Social & Community Hlth, Auckland 1, New Zealand
[5] New Zealand AIDS Fdn, Res Anal & Informat Unit, Auckland, New Zealand
[6] Univ Guelph, Dept Family Relat & Appl Nutr, Guelph, ON N1G 2W1, Canada
[7] Univ Guelph, Dept Biomed Sci, Guelph, ON N1G 2W1, Canada