| [ Summary ] |
Metabolic syndrome-related diseases, such as diabetes and atherosclerosis, are strongly linked to excessive accumulation of visceral fat tissue (abdominal obesity), but not to subcutaneous fat. It has been elucidated that colorectal tumors are also strongly associated with abdominal obesity. CT scanning images can precisely measure the amount of visceral fat. However, the identification of anthropometric parameters (i. e. waist circumference or waist/hip circumference ratio) as surrogate markers for abdominal obesity would be helpful for predicting risk in a minimally-invasive manner. In Europe and the USA, several large-scale cohort studies have been conducted to estimate the risk of colorectal cancer by considering waist circumferences. The relative risk of colorectal cancer was 1.5 (95 % CI 1.35-1.67) when comparing the highest to the lowest circumferences in a meta-analysis, including 10 cohort studies. The relationship was stronger for colon cancer than for rectal cancer. Recently, case-control studies on the prevalence of colorectal adenomas, which precisely evaluated visceral fat tissue (area or volume) with CT scans, have been reported. Epidemiological studies verifying the relationship between colorectal adenomas and abdominal obesity are in progress. In brief, present findings suggest that we must regard colorectal tumors as a metabolic syndrome-related disease, which is especially important for colorectal cancer prevention. |