Abstract
BACKGROUND: Colorectal cancer has high global incidence and mortality rates. Colorectal polyps are relatively common, with adenomatous polyps having a higher risk of malignant transformation. Non-alcoholic fatty liver disease (NAFLD) has been identified as a risk factor for the development of colorectal adenomas. Here, inpatients with NAFLD from the Second People's Hospital of Xining, in Qinghai Province, and the Second People's Hospital of Tianjin were investigated, comparing the biochemical indicators, colonoscopy findings, and pathological results of polyps between patients from low-altitude (Tianjin) and high-altitude (Qinghai Province) areas. Risk factors associated with the occurrence of adenomatous polyps in NAFLD patients from high-altitude areas were also explored. AIM: To investigate the clinical characteristics of colorectal polyps in NAFLD patients from high-altitude areas. METHODS: A total of 848 patients with NAFLD were enrolled. Of these, 118 underwent colonoscopy between January 2021 and January 2024 at the Second People's Hospital of Tianjin (low-altitude), while the remaining 730 patients were assessed during the same period at the Second People's Hospital of Xining, Qinghai (high-altitude). All enrolled patients met the diagnostic criteria for NAFLD, and the excised colorectal polyps were analyzed pathologically. RESULTS: Colorectal polyps were found in 585 cases (80.1%) in the Qinghai cohort and 91 patients (77.1%) in the Tianjin group, indicating a slightly higher incidence in the Qinghai group, although the difference was non-significant (P = 0.449, P > 0.05). The two groups showed no significant difference in sex (P = 0.153, P > 0.05) but differed significantly in the proportion of younger patients (P < 0.01), although no differences were seen in terms of middle-aged and elderly patients (P > 0.05). No differences in polyp numbers were observed between the two regions (P > 0.05), while significant differences were found between the ≤ 0.5 cm and > 1 cm and ≤ 2 cm proportions in both regions (P < 0.05), with no differences in other size categories (P > 0.05). Polyp locations (proximal colon, distal colon) also differed significantly (P < 0.05). Patients in Qinghai were more prone to adenomatous polyps, accounting for 89.2% of polyps, compared to those from Tianjin (P < 0.05). Patients in Qinghai had a higher incidence of tubular adenomas with low-grade dysplasia, while tubular adenomas with high-grade dysplasia predominated in patients from Tianjin (P < 0.05). Patients in Tianjin had a significantly higher proportion of mixed hyperplastic-adenomatous polyps (P < 0.05), as well as greater proportions of mixed hyperplastic-adenomas with low-grade dysplasia (P < 0.05). The incidence of hyperplastic polyps was markedly higher in Tianjin, accounting for 58.4% (P < 0.05). Multivariate logistic regression indicated that sex [OR = 1.693, 95% confidence interval (CI): 1.131-2.536], smoking (OR = 0.604, 95%CI: 0.406-0.897), hypertension (OR = 0.683, 95%CI: 0.471-0.991), and white blood cell counts (WBC) (OR = 1.091, 95%CI: 1.015-1.173) were risk factors for the occurrence of adenomatous polyps in patients with NAFLD in high-altitude areas (Qinghai Province). CONCLUSION: Patients with NAFLD from high-altitude regions have a higher incidence of colorectal polyps, with a significantly higher incidence of adenomatous polyps compared to other polyp types. Sex, smoking, hypertension, and WBC are risk factors for adenomatous polyps in NAFLD patients in high-altitude regions.