[1] Auckland Univ Technol, Fac Hlth & Environm Sci, Dept Biostat & Epidemiol, Res Off, Auckland, New Zealand
[2] Auckland Univ Technol, Fac Culture & Soc, Sch Social Sci & Publ Policy, Auckland, New Zealand
[3] Auckland Univ Technol, Fac Hlth & Environm Sci, Sch Nursing, Auckland, New Zealand
[4] Edith Cowan Univ, Sch Midwifery & Nursing, Perth, WA, Australia
[5] Auckland Univ Technol, Fac Hlth & Environm Sci, Sch Oral Hlth, Auckland, New Zealand
[6] Univ Otago, Ctr Postgrad Nursing Studies, Christchurch, New Zealand