LOS ANGELES—Researchers at the University of Southern California, Los Angeles, found vitamin D insufficiency is associated with increased fat infiltration in muscle in healthy young women (J Clin Endocrinol Metab. 2010 Feb 17). The cross-sectional study measured anthropometric measures, serum 25-hydroxyvitamin D (25OHD) radioimmunoassay values, and computed tomography (CT) values of fat, muscle mass and percent muscle fat in 90 postpubertal females, aged 16 to 22 years.
Approximately 59 percent of the subjects were 25OHD insufficient, of which 24 percent were deficient, whereas 41 percent were sufficient. A strong negative relationship was present between serum 25OHD and CT measures of percent muscle fat (r = -0.37; P<0.001). In contrast, no relationship was observed between circulating 25OHD concentrations and CT measures of thigh muscle area (r=0.16; P=0.14). Multiple regression analysis indicated that the relation between 25OHD and muscle adiposity was independent of body mass or CT measures of sc and visceral fat. Percent muscle fat was significantly lower in women with normal serum 25OHD concentrations than in women with insufficient levels and deficient levels.