Our previous retrospective study also found that the levels of low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, apolipoprotein A1, apolipoprotein E, and total cholesterol in patients with distal colitis were significantly higher than those in patients with extensive colitis.13 However, no other studies have linked the above pathways to the disease extent of UC. Here, APOA1 is linked to distal colitis.