1. Canterbury Geriatric Medical Research Trust (N.L.G., R.L.M., P.M., A.H., P.R.), The Princess Margaret Hospital, Christchurch 8022, New Zealand
2. Department of Medicine (C.M.F., M.G.N.), Christchurch School of Medicine and Health Sciences, Christchurch 8011, New Zealand
3. Spinal Unit (R.H.A., K.M.), Burwood Hospital, Christchurch 8083, New Zealand