[1] Queens Univ Belfast, Med Biol Ctr, Sch Nursing & Midwifery, Belfast BT9 7BL, North Ireland
[2] Dublin City Univ, Fac Sci & Hlth, Sch Nursing Psychotherapy & Community Hlth, Glasnevin Campus, Dublin D09 V209, Ireland
[3] Kingston Univ, Sch Nursing Allied & Publ Hlth, London, England