[Comparison of risk factors for serrated polyps and conventional adenoma and the suitable age to start colorectal cancer screening].

OBJECTIVE: To compare the risk factors associated with serrated polyps (SPs) and conventional adenoma (CA).

METHODS: One hundred and three healthy control subjects, 100 patients with pathologically confirmed SPs and 115 with CA were randomly selected from individuals undergoing colonoscopy in Nanfang Hospital from 2012 to 2015. The demographic and clinical data were collected from the subjects, including age, gender, height, weight, hypertension, diabetes, smoking status, alcohol use, family history of colorectal cancer (CRC) and blood lipids.

RESULTS: Among the enrolled subjects, the mean onset age of SPs was 48.87 years (95%CI: 47.22-50.52 years), significantly younger than that of CA (P%0.038). The risk factors both for SPs and CA include an advanced age, a male gender (OR%2.75 [95%CI: 1.50-5.07] for SPs, and OR%2.19 [95%CI: 1.22-3.95] for CA), and a high body mass index (OR%1.18 [95%CI: 1.06-1.30] for SPs and OR%1.20 [95%CI: 1.09-1.32] for CA. Relative to the young individuals (below 45 years of age), the middle-aged individuals (45-60 years of age) had increased risks for SPs and CA by 2.31 [95% CI: 1.46-3.65] folds and 4.10 [95%CI: 2.50-6.72] folds, respectively, and in the elderly (beyond 60 years of age), the risks further increased by 2.77 [95%CI: 1.52-5.04] folds for SPs and by 6.00 [95%CI: 3.26-11.05] folds for CA. Age was more strongly associated with CA than with SPs (OR%2.14 [95%CI: 1.21-3.78], the elderly vs the young, P%0.009).

CONCLUSION: SPs and CA have common risk factors, thus the screening strategy for CA may also be applicable to SPs. As the mean onset age of SPs is earlier than 50 years and SPs may rapidly progress to a carcinogenic state, an earlier screening age needs to be considered.