Figure 2.

Longitudinal associations of vitamin C plasma concentrations with age, vitamin C intake, absolute fat-free mass and physical activity index separated by sex if appropriate. This figure illustrates the changes in vitamin C plasma concentrations with increasing age (A), vitamin C intake (B), fat-free mass (C) and physical activity index (D) after controlling for the cofactors included in the linear mixed-effects model 3 (n = 399). The thick lines represent the estimated means and the respective colored areas reflect the 95% confidence intervals. The associations are illustrated in magenta color for females (n = 278) and blue color for males (n = 121). For physical activity index, no sex-specific associations are displayed because no such interaction term was investigated.