1. UCD School of Public Health, Physiotherapy and Sports Science, Woodview House University College Dublin Belfield, Dublin 4, D04 V1W8, Ireland
2. Department of Public Health, Health Service Executive, Dr. Steevens' Hospital, Dublin 8, D08 W2AB, Ireland
3. The Irish Longitudinal Study on Ageing (TILDA), Lincoln Gate, Trinity College, Dublin 2, D02 PN40, Ireland
4. Department of Medical Gerontology, Trinity College, Dublin 2, D02 PN40, Ireland
5. Mercer's Institute for Successful Ageing, St James's Hospital, James's St, Dublin 8, D08 RT2X, Ireland