Belly Fat Beats BMI in Predicting Colorectal Cancer Risk

TOPLINE:

Individuals with normal body mass index (BMI) measurements may still face an increased risk for colorectal cancer (CRC) if they have central obesity, characterized by excess fat around the abdomen.

METHODOLOGY:

• General obesity, often measured using BMI, is a recognized risk factor for CRC, but how much of this association is due to central obesity is unclear.
• Researchers assessed the associations between BMI, waist-to-hip ratio (WHR), and waist circumference (WC) with CRC risk and the degree of independence among these associations in patients aged 40-69 years recruited in the UK Biobank cohort study from 2006 to 2010.
• Anthropometric measurements were performed using standardized methods.
• Cancer registry and hospital data linkage identified CRC cases in the UK Biobank.

TAKEAWAY:

• Researchers included 460,784 participants (mean age, 56.3 years; 46.7% men), of whom 67.1% had either overweight or obesity, and 49.4% and 60.5% had high or very high WHR and WC, respectively.
• During the median 12.5-year follow-up period, 5977 participants developed CRC.
• Every SD increase in WHR (hazard ratio [HR], 1.18) showed a stronger association with CRC risk than in BMI (HR, 1.10).
• After adjustment for BMI, the association between WHR and CRC risk became slightly attenuated while still staying robust (HR, 1.15); however, after adjusting for WHR, the association between BMI and CRC risk became substantially weakened (HR, 1.04).
• WHR showed strongly significant associations with CRC risk across all BMI categories, whereas associations of BMI with CRC risk were weak and not statistically significant within all WHR categories.
• Central obesity demonstrated consistent associations with both colon and rectal cancer risks in both sexes before and after adjustment for BMI, whereas BMI showed no significant association with CRC risk in women or with rectal cancer risk after WHR adjustment.

IN PRACTICE:

“[The study] results also underline the importance of integrating additional anthropometric measures such as WHR alongside BMI into routine clinical practice for more effective prevention and management of obesity, whose prevalence is steadily increasing in many countries worldwide, in order to limit the global burden of CRC and many other obesity-related adverse health outcomes,” the authors wrote.

SOURCE:

The study was led by Fatemeh Safizadeh, German Cancer Research Center (DKFZ), Heidelberg, Germany. It was published online in the International Journal of Obesity.

LIMITATIONS:

This study relied on only one-time measurements of anthropometric measures at baseline, without considering previous lifetime history of overweight and obesity or changes during follow-up. Additionally, WHR and WC may not be the most accurate measures of central obesity, as WC includes both visceral and subcutaneous adipose tissue. The study population also showed evidence of healthy volunteer bias, with more health-conscious and socioeconomically advantaged participants being somewhat overrepresented.

DISCLOSURES:

The authors declared no competing interests.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.