GPT and type 1 diabetes mellitus: Following vitamin D supplementation, there was a significant decrease in ALT in T2D (50.7±50.9 U/L to 35.0±31.0, p = 0.012), but not in T1D (18.0±6.0 U/L to 15.7±2.0 (p = 0.46) (Figure 2).