Study finds central obesity as effective predictor of colorectal cancer

A new study published in the International Journal of Obesity showed that the majority of the colorectal cancer (CRC) risk associated with obesity may be attributed to central obesity, which is a far better predictor of CRC.

One known risk factor for colorectal cancer is general obesity, which is frequently measured by body mass index (BMI). It is unclear, though, how much of this link may be explained by central adiposity. This study by Fatemeh Safizadeh and colleagues wanted to determine if and to what degree waist circumference (WC), waist-to-hip ratio (WHR), and BMI are independent of one another in relation to CRC risk.

Over 500,000 male and female participants between the ages of 40 and 69 who were enrolled in the UK Biobank project between 2006 and 2010 had their data examined. Hazard ratios (HR) and their 95% confidence intervals (CI) were computed after multivariable Cox proportional hazards models were constructed.

A total of 5,977 of the 460,784 individuals who had a median follow-up of 12.5 years developed colorectal cancer. BMI, WHR, and WC all had multivariable adjusted HRs (95% CIs) of 1.10 (1.07–1.13), 1.18 (1.14–1.22), and 1.14 (1.11–1.18) per standard deviation rise, respectively.

Following reciprocal correction, the correlation with CRC was significantly reduced for BMI (1.04 (1.01–1.07)) and maintained for WHR (1.15 (1.11–1.20)). Also, throughout all BMI categories, WHR showed strong, statistically significant relationships with CRC risk, but within WHR categories, BMI connections with CRC risk were modest and not statistically significant.

Following reciprocal adjustment, BMI was likewise not linked to women's risk of colorectal cancer or rectal cancer. On the other hand, WHR was significantly linked to the risk of colon and rectal cancer in both sexes, both before and after controlling for BMI. Because of their strong association, BMI and WC could not be corrected for one another.

Overall, this study evaluated separately the relationships between central and general obesity and the risk of colon, rectal, and colorectal cancer. The findings discovered that central obesity probably accounts for the majority of the obesity-related CRC risk in a population that is primarily European.

Reference:

Safizadeh, F., Mandic, M., Schöttker, B., Hoffmeister, M., & Brenner, H. (2024). Central obesity may account for most of the colorectal cancer risk linked to obesity: evidence from the UK Biobank prospective cohort. In International Journal of Obesity. Springer Science and Business Media LLC. https://doi.org/10.1038/s41366-024-01680-7