Adolescent Obesity May Have Role in Colorectal Cancer Later in Life

Elizabeth Kantor, PhD

A new study has found that obesity and high inflammation during adolescence was associated with an increased risk of developing colorectal cancer later in life, according to data presented at the 13th Annual AACR Conference on Frontiers in Cancer Prevention Research.

“Obesity and inflammation in adulthood have been implicated in colorectal cancer for a number of years,” Elizabeth Kantor, PhD, a postdoctoral research fellow in the Department of Epidemiology at the Harvard School of Public Health, said in a statement. “But little is known about the role of adolescent obesity and inflammation in the development of colorectal cancer.

Kantor and colleagues analyzed data collected from 239,464 Swedish men who were conscribed in the military during late adolescence (ages 16—20) from 1969 to 1976.

At the time of conscription, erythrocyte sedimentation rate was measured as a marker of inflammation and height and weight were recorded. Colorectal cancer diagnosis was determined through January 1, 2010, by linking the conscription registry with the national cancer registry.

During an average of 35 years of follow-up, those who were obese (as measured by body mass index) as adolescents were 2.37 times more likely to develop colorectal cancer compared with those who were normal weight as adolescents. Adolescents who had high levels of inflammation, as measured by erythrocyte sedimentation rate, experienced a 63% higher risk of the disease compared with those who had low levels of inflammation.

During the follow-up period, 885 cases of colorectal cancer were recorded, the analysis showed.

“Our results suggest that early-life body mass index and inflammation may independently play a role in the development of cancer later in life,” Kantor said. “These results are important because understanding how life-course exposure to high body mass index and inflammation relates to colorectal cancer risk may improve our understanding of this disease and may help guide prevention strategies. However, further research is needed to better understand these relationships.”

The registries the researchers used to obtain the data do not contain information on all variables, such as adolescent diet, that may influence the observed associations.

“Obesity was relatively uncommon among adolescents in Sweden at the time the cohort of men enlisted, and it is possible that ‘obesity’ in this study represents something different from what is represented by ‘obesity’ in populations in which this exposure is more ubiquitous,” she said.

“As a result, the association between obesity and colorectal cancer risk needs to be investigated in large cohorts from different populations, and further research is needed to disentangle body mass index and inflammation from associated exposures, and similarly, from exposure at other points in the life course.”