Changes in Adult BMI and Waist Circumference Are Associated with Increased Risk of Advanced Colorectal Neoplasia

Waist circumference (WC) is a stronger predictor of colon cancer (CRC) risk than body mass index (BMI). However, how well change in either WC or BMI predicts risk of advanced colorectal neoplasia (AN) is unclear. To determine the relationship between change in BMI and WC from early adulthood to later age and the risk of AN and which change measure is a stronger predictor. In 4500 adults, ages 50-80, with no previous neoplasia and undergoing screening colonoscopy, BMI and WC at age 21 and at time of screening were reported. Changes in BMI and WC were defined using universal risk cutoffs. Known CRC risk factors were controlled in the logistic models. Overall, model statistics showed WC change (omnibus test chi (2) = 10.15, 2 DF, p value = 0.006) was a statistically stronger predictor of AN than BMI change (omnibus test chi (2) = 5.66, 5 DF, p value = 0.34). Independent of BMI change, participants who increased WC (OR 1.44; 95% CI 1.05-1.96) or maintained a high-risk WC (OR 2.50; 95% CI 1.38-4.53) at age 21 and at screening had an increased risk of AN compared to those with a low-risk WC. Study participants who were obese at age 21 and at screening had an increased risk of AN (OR 1.87; 95% CI 1.08-3.23) compared to those who maintained a healthy BMI. Maintaining an overweight BMI or increasing BMI was not associated with AN. Maintaining an unhealthy BMI and WC throughout adult life may increase risk of AN. WC change may be a better predictor of AN than BMI change.