Being overweight or obese during adolescence may increase the risk of colon or rectal cancer later in life, according to research published in Cancer.1

Previous research yielded inconsistent findings about the relationship between weight and colon/rectal cancer risk. Yet these studies used “reported or recalled body mass index (BMI) values,” potentially limiting their predictive value.

For this study, researchers evaluated measured BMI data from 1,087,358 men and 707,212 women in Israel to determine any link between weight in adolescence and colon/rectal cancer incidence. All participants underwent health examinations in late adolescence (at 16 to 19 years).

Continue Reading

Hazard ratios (HRs) were determined for colon and rectal cancer before and after adjusting for age, sex, and BMI group. Overweight and obese were defined as between the 85th and 95th percentile and at least the 95th percentile, respectively.

Median follow-up was 23 years. In the male cohort, 1403 cases of colon cancer and 574 cases of rectal cancer were observed; among women, 764 cases of colon cancer and 226 cases of rectal cancer were observed.

Using normal weight as a reference, overweight and obese men had adjusted HRs for colon cancer of 1.54 and 1.52, respectively. Obese men had an adjusted HR for rectal cancer of 1.73.

Among women, adjusted HRs for colon cancer were 1.55 and 1.52 for overweight and obese participants, respectively. Obese women had an adjusted HR for rectal cancer of 2.07.

Overweight adolescents of either sex were not, however, at an increased risk for rectal cancer.

Notably, underweight adolescent men were at an increased risk for rectal cancer, with an adjusted HR of 1.45.

RELATED: Nivolumab Provides Durable Response in dMMR/MSI-H Colorectal Cancer

The authors concluded that “findings from our study provide evidence that overweight and obesity at adolescence are associated with colon cancer among both men and women and that obesity, but not overweight, is significantly associated with rectal cancer among men and nonsignificantly increased among women.”


  1. Levi Z, Kark JD, Katz LH, et al. Adolescent body mass index and risk of colon and rectal cancer in a cohort of 1.79 million Israeli men and women: A population-based study. Cancer. 2017 Jul 24. doi: 10.1002/cncr.30819 [Epub ahead of print]