Overweight teenagers are twice as likely at risk of having colorectal cancer (CRC) in middle age, a scientific study published in Gut revealed.

For those in their late-adolescent stage, obesity poses a 2.4 fold of developing the disease. The study concluded that "late-adolescent BMI and inflammation" could be "independently associated with future CRC risk."

Various experts on their field -- Elizabeth D. Kantor, Ruzan Udumyan, Lisa B. Signorello, Edward L. Giovannucci, Scott Montgomery and Katja Fall -- collaborated on the research. The lead correspondent of the study is Dr. Kantor from Department of Epidemiology of Harvard School of Public Health in Boston, Massachusetts.

To determine how adolescent body mass index (BMI) and inflammation is linked to colorectal cancer (CRC) risk, 239,658 Swedish men conscripted in the army with ages between 16 to 20 years old were evaluated since 1969 to 1976. The men were followed up over an average of 35 years and results showed that 885 cases of CRC -- 501 cases colon cancers and 384 cases of rectal cancer.

The study revealed that overweight conscripts (BMI values between 27.5 and 30) in late adolescent were linked to a 2.08 times greater risk of developing bowel cancer compared to those with normal weight (BMI value between 18.5 and 25). Obese individuals (BMI greater than 30) were associated with a 2.38-fold of getting CRC compared to normal weight people.

Bowel cancer is a great issue people should focus on especially during these recent years that the number of people considered obese is increasing. In America alone, the reported percentage of American adults who are obese last year is 27.7 percent, informs Gallup and Healthways. It was higher than the 27.1 percent reported in 2013. The data suggests that previous U.S. adults who were classified as overweight are now categorized as obese.

What's more bothering about these data is an NIH study that appeared in July 8, 2014, in PLOS Medicine reveals that extreme obesity -- people with BMI greater than 40 -- could reduce life expectancy up to 14 years, as noted on the NIH site.

This is because people with extreme obesity are more prone to dying due to cancer, heart disease, stroke, diabetes, and kidney and liver diseases, at a young age, the site notes, citing analysis of data from 20 studies from U.S., Sweden and Australia.

Patricia Hartge, Sc.D., Division of Cancer Epidemiology and Genetics, and lead author of the research said, "Given our findings, it appears that class III obesity is increasing and may soon emerge as a major cause of early death in this and other countries worldwide."

A lifestyle change is important for those who are at high risk. Proper diet and exercise must be part of one's routine at an early age. One should also avoid eating too much red meat and processed meat products as they are also linked to higher bowel cancer risk, informs Cancer.org.