Body mass index and the prevalence of high-risk colorectal adenomas in a population undergoing screening colonoscopy in Alberta, Canada

There is limited evidence regarding body mass index (BMI) as an early marker of high-risk adenoma (HRA) at the time of screening colonoscopy. Because high-risk adenomas (HRA) can develop into colorectal cancer (CRC), BMI could serve as an important clinical predictor of future risk of CRC.

We examined data from 1831 adults undergoing screening colonoscopy at the Forzani & MacPhail Colon Cancer Screening Center in Alberta, Canada. We fit multivariable logistic regression models to examine the association between BMI and HRA. Non-linear relationships for BMI on HRA were also evaluated using restricted cubic splines.

The mean BMI in patients with HRA was 28.2 kg/m² compared to 27.4 kg/m² in patients without adenomas (t test: p = 0.003). In the adjusted models, those with a BMI over 30 kg/m² had 1.45 (95% CI 1.05–2.00) times the odds of HRA detected during colonoscopy compared to those with a BMI below 25 kg/m². Examining BMI as continuous, the odds of HRA were 1.20 (95% CI 1.04–1.37) times higher for every 5 kg/m² increase in BMI.

The findings of this study suggest that excess body mass is associated with higher risk of HRA among a screening population and may be useful an early marker of future disease.