1. From the Nursing, Midwifery and Allied Health Professions Research Unit (M.C.B., D.L.C.F.), Glasgow Caledonian University, Glasgow, UK; the Unit of Restorative Dental Care and Clinical Dental Sciences (R.V.H.), Dental School, University of Dundee, Dundee, UK; Public Health Sciences (S.C.L.), University of Edinburgh, Edinburgh, UK; and the Health Analytic Services Division (V.M.), The Scottish Government, Edinburgh, UK.