ABSTRACT Background:

An inverse association between circulating vitamin D and adenoma risk hasbeen reported, but less is known about proximal inflammatory-hyperplastic polyps.

Purpose:

To investigate circulating 25(OH)D3and risk factors of proximal inflammatory-hyperplastic and adenoma colorectal polyps.

Methods:

From January 2017 to June 2019, consecutive asymptomatic average-risk partic-ipants undergoing initial screening colonoscopy. Questionnaires provided information oncolorectal polyp risk factors, and plasma samples were assayed for 25-Hydroxyvitamin-D –25(OH)D3. The colorectal polyps were assessed, and medical history and demographic datawere obtained from each patient.

Results:

Of the 220 asymptomatic subjects, the prevalence of proximal inflammatory-hyperplastic polyps and adenoma polyps were 16.8%; 18.1% and 22.2%, respectively.Multivariate analysis revealed that low vitamin D (25(OH)D3< 18 ng/mL, OR = 3.94; 95%CI: 1.81–9.51) and current/former smoking (OR = 6.85; 95% CI: 2.98–15.70), high bodymass index (BMI > 24, OR = 5.32, 95% CI: 2.62–4.71) were independent predictors forproximal inflammatory-hyperplastic colorectal polyps (non-adenoma). Low vitamin D(25(OH)D3< 18 ng/mL, OR = 7.75; 95% CI: 3.19–18.80) and current/former smoking (OR = 3.75;95% CI: 1.30–10.81), age over 60 years old (OR = 2.38, 95% CI: 1.02–5.57), were independentpredictors for adenoma colorectal polyps.

Conclusion:

Low vitamin D and smoking are common risk factors for both adenomatous andproximal inflammatory hyperplastic polyps. Old age and BMI are additional risk factors forthe development of adenomatous and non-adenomatous colorectal polyps.