Stenholm S, Koster A, Alley DE, Houston DK, Kanaya A, Lee JS, Newman AB, Satterfield S, Simonsick EM, Visser M, Harris TB, Ferrucci L. Joint association of obesity and metabolic syndrome with incident mobility limitation in older men and women--results from the Health, Aging, and Body Composition Study. J Gerontol A Biol Sci Med Sci. 2010 Jan; 65(1):84-92.