Risk Factors Such as Male Sex, Smoking, Metabolic Syndrome, Obesity, and Fatty Liver Do Not Justify Screening Colonoscopies Before Age 45

Abstract

Background: Recently, many studies have reported that male sex, smoking, fatty liver, metabolic syndrome (MetS), and obesity are risk factors for colorectal neoplasia (CRN). However, current guidelines recommend that persons at average risk of colorectal cancer begin screening colonoscopy at age 50 years without consideration of those risk factors.

Aim: To investigate an appropriate time to start screening colonoscopies in persons with risk factors for CRN.

Methods: We performed a cross-sectional study on 27,894 Korean aged ≥30 years who underwent a first colonoscopy as part of a health screening program. To compare the efficacy of colonoscopic screening for the detection of advanced CRN among age groups with risk factors, we calculated the number needed to screen (NNS) to identify 1 patient with advanced CRN.

Results: The NNS for those 30-39 years old with all risk factors, male gender, smoking (≥10 pack-years), MetS, obesity, and fatty liver, was higher than that for ≥50-year-old female subjects (55.4 vs. 26.4). The NNS for those 40-44 years old with all risk factors (37.1) was also higher than that for ≥50-year-old female subjects. However, the NNS for those 45-49 years old with risk factors (16.9-22.9) was lower than that for ≥50-year-old women.

Conclusions: The efficacy of colonoscopic screening in people 30-44 years old with multiple risk factors is lower than that in ≥50-year-old women. Risk factors such as male sex, smoking, MetS, obesity, and fatty liver do not justify starting screening colonoscopies before age 45.

Keywords: Colorectal neoplasia; Risk factor; Screening colonoscopy.