1. Department of Health Sciences; University of Milano-Bicocca; Milan Italy
2. Geriatric Unit; S. Gerardo Hospital; Monza Italy
3. Geriatric Research Group; Brescia Italy
4. Department of Rehabilitation and Aged Care; Ancelle Hospital; Cremona Italy
5. Department of Surgery; University of Milano-Bicocca; Milan Italy
6. Orthopaedic Unit; S. Gerardo Hospital; Monza Italy
7. Unit of Biostatistics, Epidemiology and Public Health; Department of Statistics and Quantitative Methods; University of Milano-Bicocca; Milan Italy
8. Department of Nursing; Umeå University; Umeå Sweden
9. Division of Geriatric Medicine; Department of Community Medicine and Rehabilitation; Umeå University; Umeå Sweden