Weight gain in early adulthood predicted adult-onset colonic neoplasia

2010 Digestive Disease Week

NEW ORLEANS — Adults with normal BMI at age 20 years who grew to become overweight or obese had twice the risk for developing colon adenomas compared with those whose BMI remained normal as they aged.

Researchers evaluated 1,865 consecutive patients referred for screening colonoscopy at New York’s Bellevue Hospital from January 2004 to August 2009. Patients were aged from 50 to 75 years, asymptomatic and determined to be at average risk for colorectal cancer.

Researchers measured patients for height, weight and waist circumference, collected a detailed history from each patient — including clothing size — to assess BMI at age 10 years and 20 years, as well as BMI and waist circumference at age 20 to 29 years. At baseline, 33% of patients had normal BMI, 39% were overweight and 23% were obese.

Patients then underwent colonoscopy and the number, size and location of each polyp was recorded.

Ian Fagan, a medical student at NYU Langone Medical Center, presented the results of the study Monday at 2010 Digestive Disease Week. He and colleagues set out to determine whether there was an association between obesity, change in adiposity at various age intervals and adenomas of any size.

“Among the cancers that involve all genders, colorectal cancer remains the second most common cancer and accounts for 11% of annual cancer deaths,” Fagan said. “We were trying to find some modifiable risk factor that might predispose people to colon cancer. We hypothesized that childhood obesity increases the risk for subsequently developing colonic neoplasms later in life.”

Fagan and colleagues found that at age 20 years, BMI and waist size in men and BMI and dress size in women were significantly correlated. Similarly, BMI at age 20 years was significantly correlated with current waist size.

Thirteen percent of patients whose BMI was normal at 20 years and remained normal at present developed adenomas compared with 19% of patients who had normal BMI at 20 years but were obese at present, and 27% of those who were consistently overweight or obese. After controlling for factors such as sex, current BMI and red meat consumption, researchers concluded that BMI from early adulthood remained a significant predictor for the development of colon adenomas (OR=1.8; 95% CI, 1.02-3.23).

“The group whose BMI was normal at age 20 but abnormal at present was at approximately two times increased risk for developing colon cancer compared with the group whose BMI was normal at age 20 and normal at present,” Fagan said. “The conclusion we can draw from that is, in this diverse, average-risk colon cancer screening cohort, the change in adiposity from early adulthood was a significant independent predictor for colon pathology.”

Hispanics (61%) were most likely to progress from normal BMI at age 20 years to overweight or obese at present vs. 50% for blacks, 46% for whites and 7% for Asians. Because early-onset obesity is a growing problem among minority populations, Fagan said these findings suggest that adiposity as a modifiable risk factor against colon cancer deserves further study. – by Jason Harris

For more information:

Fagan I. #314g. The effect of early-onset obesity on adult-onset colon neoplasia. Presented at: the 2010 Digestive Disease Week; May 1-6, 2010; New Orleans.

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