Fig. 1

Age and seasonal differences in 25-OHD metabolite levels in patients with DM. A Box-and-whisker plot of age groups, * vs. the other age groups, Padj < 0.05; B Box-and-whisker plot of seasonal groups, ^▲ vs. the other seasons, Padj < 0.05; ^☺ vs. autumn and winter, Padj < 0.05. Results indicated that in patients with T2DM, C3-epi-D3 levels decreased during the longevous period and increased during spring and summer, while %C3-epi-D3 increased during spring and summer