Association of visceral obesity and early colorectal neoplasia

Abstract

Aim: To examine whether visceral adipose tissue (VAT) serves as a risk factor for colorectal adenoma-early colorectal cancer (CRC) sequence.

Methods: A retrospective case-control study was conducted with 153 patients with stage I CRC, age/sex-matched 554 patients with colorectal adenoma and 557 normal controls. All subjects underwent various laboratory tests, abdominal fat computed tomography (CT), and colonoscopy. VAT was defined as an intra-abdominal adipose tissue area measured by CT scan. Adipose tissue area was measured at the level of the umbilicus from CT scan. We used the lowest quartile of VAT and subcutaneous adipose tissue area as a reference group.

Results: The body mass index (BMI), total cholesterol, fasting glucose and VAT areas were significantly different among normal, adenoma and CRC groups. The VAT area was 120.6 ± 49.0 cm(2) in normal controls, 130.6 ± 58.4 cm(2) in adenoma group and 117.6 ± 51.6 cm(2) in CRC group (P = 0.002). In univariate analysis, increased BMI was a risk factor for CRC compared to control (P = 0.025). However, VAT area was not a risk factor for CRC compared to control. In multivariate analysis that adjusted for smoking, alcohol consumption and subcutaneous adipose tissue area, VAT area was inversely related to CRC, compared to the adenoma (OR = 0.53, 95%CI: 0.31-0.92, highest quartile vs lowest quartile).

Conclusion: Our study shows that visceral obesity is not a risk factor for early CRC. Visceral obesity might influence the normal-adenoma sequence but not the adenoma-early carcinoma sequence.

Keywords: Abdominal computed tomography; Adipose tissue; Colorectal adenoma; Colorectal cancer; Obesity; Visceral fat.

Figure 1

Comparison of visceral adipose tissue area (cm²) among patients with colorectal carcinoma, those with colorectal adenoma, and controls. Visceral adipose tissue (VAT) area in colorectal carcinoma patients was significantly lower than in adenoma patients (P = 0.018), but it was not significantly lower than in control group (P = 0.513).