Fig. 2

Smooth curve fitting demonstrates the relationship between serum 25(OH)D after natural log transformation and risk of all-cause death. The predicted log(relative risk) for all-cause death in the y-axis and the continuous covariate in the x-axis. Smooth curve fit is indicated by the solid red line. The 95% confidence interval is represented by the blue band. The adjustment strategy is the same as the fully-adjusted model