Fig. 1

Association between vitamin D levels and frailty. The estimated odds ratios are indicated by the solid line and the 95% confidence intervals by dashed lines. The vertical dashed lines represent the first, second, and third quartiles of 25(OH)D. Reference is the 75th percentile of 25(OH)D. The model was adjusted for age, sex, baseline frailty status (prefrailty vs. nonfrailty), residence, marital status, education level, economic independence, smoking status, drinking status, regular exercise, sleep time, body mass index, dentition status, calf circumference, season of blood draw, albumin, and high-sensitivity C-reactive protein