Predictors of Sexual Desire and Sexual Function in Sedentary Middle-Aged Adults: The Role of Lean Mass Index and S-Klotho Plasma Levels. The FIT-AGEING Study - Dote-Montero, Manuel; De-la-O, Alejandro; Castillo, Manuel J.; Amaro-Gahete, Francisco J. (JOURNAL OF SEXUAL MEDICINE, 2020)