Association between Waist Circumference and Risk of Colorectal Neoplasia in Normal-weight Adults.

BACKGROUND & AIM: Abdominal obesity, measured using waist circumference (WC), is associated with the colorectal neoplasia (CRN) risk. We examined whether WC is associated with the CRN risk even in normal-weight individuals.

METHODS: A cross-sectional study was performed on asymptomatic normal-weight (body mass index 18.5-23 kg/m2 ) individuals who underwent colonoscopy as health checkups.

RESULTS: Of 63,057 examinees, 30,498 were men (mean age, 41.1 years) and 32,559 were women (mean age, 41.7 years). The prevalence of overall CRN in WC quartiles 1, 2, 3, and 4 was 14.2%, 15.5%, 15.5%, and 18.7%, respectively, in men and 7.4%, 8.9%, 9.4%, and 11.5%, respectively, in women. The prevalence of advanced CRN (ACRN) in WC quartiles 1, 2, 3, and 4 was 1.5%, 1.3%, 1.6%, and 2.1%, respectively, in men and 1.0%, 1.3%, 1.2%, and 1.3%, respectively, in women. Among men, the overall CRN risk in quartile 4 (>82 cm) was higher than that in quartiles 1, 2, and 3 (adjusted odds ratio, OR [95% confidence interval, CI], 1.22 [1.11-1.34], 1.12 [1.05-1.23], and 1.18 [1.07-1.29], respectively); the ACRN risk in quartile 4 was also higher than that in quartiles 1, 2, and 3 (adjusted OR [95% CI], 1.41 [1.09-1.81], 1.56 [1.19-2.03], and 1.50 [1.16-1.94], respectively). Among women, the overall CRN risk in quartile 4 (>77 cm) was higher than that in quartiles 1 and 3; the ACRN risk was not different among all groups.

CONCLUSIONS: Even with a normal weight, a large WC was associated with the CRN risk, especially with the ACRN risk in men.