Belly Fat as a Better Predictor of Colorectal Cancer Risk
Exploring the stronger link between central obesity and colorectal cancer compared to BMI.
Topline
A recent study reveals that waist-to-hip ratio (WHR) and waist circumference (WC) are stronger predictors of colorectal cancer (CRC) risk than body mass index (BMI), emphasizing the importance of assessing central obesity in clinical practice.
Study Details
This study, led by researchers at the German Cancer Research Center, explored the associations between BMI, WHR, and WC with colorectal cancer risk in a large cohort of 460,784 participants aged 40-69 years. The study used data from the UK Biobank, where standardized anthropometric measurements were performed at baseline, and colorectal cancer cases were identified using linked cancer registry and hospital data.
Central obesity, characterized by excess fat around the abdomen, was found to be a significant risk factor for colorectal cancer, even in individuals with a normal BMI.
Methodology
The study employed a prospective cohort design, examining data from participants recruited between 2006 and 2010. Anthropometric measures included BMI, WHR, and WC, assessed using standardized techniques. CRC cases were tracked over a median follow-up period of 12.5 years. Hazard ratios were calculated to evaluate the relative risk of CRC for each measure, adjusted for potential confounders like age, sex, and BMI.
Key Findings
WHR as a Stronger Predictor: Each standard deviation (SD) increase in WHR was associated with an 18% higher risk of CRC, compared to a 10% increase for BMI.
BMI's Limited Impact: After adjusting for WHR, BMI showed no statistically significant association with CRC risk.
Central Obesity Matters: WHR and WC consistently predicted CRC risk across all BMI categories and for both sexes. BMI, however, failed to show significance in women or for rectal cancer after WHR adjustment.
Cancer Risk in Overweight Individuals: Participants with central obesity, irrespective of BMI, had elevated risks for both colon and rectal cancers.
Implications for Practice
These findings suggest that relying solely on BMI to assess obesity-related cancer risks may lead to underestimation, particularly in patients with central obesity. Clinicians should integrate measures like WHR and WC into routine assessments to better identify individuals at higher risk for colorectal cancer.
For patients, this highlights the importance of managing abdominal fat, not just overall body weight, to reduce cancer risk. Lifestyle changes, including targeted physical activity and dietary interventions, may play a crucial role in mitigating central obesity.