Frailty and sarcopenia: definitions and outcome parameters by Cooper, C, Dere, W, Evans, W, Kanis, J, Rizzoli, R, Sayer, A, Sieber, C, Kaufman, J, Abellan van Kan, G, Boonen, S, Adachi, J, Mitlak, B, Tsouderos, Y, Rolland, Y, Reginster, J