Patterns of circulating fat-soluble vitamins and carotenoids and risk of frailty in four European cohorts of older adults by Pilleron, S, Weber, D, Pérès, K, Colpo, M, Gomez-Cabrero, D, Stuetz, W, Dartigues, J-F, Ferrucci, L, Bandinelli, S, Garcia-Garcia, FJ, Grune, T, Féart, C