To do this, researchers assigned a “lifestyle score” to nearly 30,000 people based on blood levels of certain biomarkers and lifestyle data. They found that those with higher scores were more likely to develop colon cancer. The findings were presented March 31 at the annual meeting of the American Association for Cancer Research.
The researchers used data on more than 2,600 people participating in the American Cancer Society’s Cancer Prevention Study-II’s Lifelink Cohort to calculate the lifestyle score. [7 Cancers You Can Ward Off With Exercise]
Specifically, the researchers looked at lifestyle data as well as the levels of three biomarkers in blood samples collected from the participants. Biomarkers are molecules or other substances in the body that serve as a sort of signature for a certain condition. In this case, the researchers were looking for a molecule called hs-CRP, a biomarker for inflammation; C-peptide, a biomarker for an increase in insulin; and HbA1c, a biomarker for glucose.
Using data from 80 percent of the 2,600 participants, the researchers compared the levels of these biomarkers to the survey responses on nine lifestyle factors and developed a weighted score. In other words, they calculated how much each lifestyle factor influenced the biomarker levels. These factors included BMI, hours of exercise per week, hours of screen time per week, weekly fruit and vegetable intake, weekly grain and red or processed meat intake, alcohol consumption, and smoking.
Then, using data from the remaining 20 percent of participants, they confirmed that these scores made sense.
BMI had, by far, the highest weighted score, suggesting that it has the biggest impact on increasing the levels of all three biomarkers. “That’s not too surprising, considering the large effects that obesity has on all levels of a lot of different [aspects of] metabolism,” said lead study author Mark Guinter, a postdoctoral fellow at the American Cancer Society.
This was followed by eating red or processed meat at a much lower but still positive score.
Some lifestyle factors had negative scores, suggesting that these behaviors lowered the levels of the biomarkers. Exercise, drinking alcohol, and eating whole grains, fruits, and vegetables, for example, all had slightly negative scores. Surprisingly, smoking also had a somewhat negative score.
However, this could be because the models they used adjust only for lifestyle factors, so “there could be other factors like age or [other medical conditions] coming into play,” Guinter said. “In light of this, we try to refrain from concluding when looking at the individual [scores], especially if they are not large.”
Indeed, the researchers used these weighted scores to calculate an overall score for nearly 29,000 participants who had submitted lifestyle data. They found that people with higher overall scores had a higher risk of developing colorectal cancer. “The key takeaway is that lifestyle can influence colorectal cancer in a variety of different ways through your metabolic health,” Guinter told Live Science. If you had to home in on one key lifestyle factor, maintaining a healthy weight seems to be the “most important.”
Though the conclusion seems “very obvious … sometimes it’s good to confirm the obvious,” said Sheetal Hardikar, an assistant professor at the Huntsman Cancer Institute of the University of Utah, who was not a part of the study. “I thought it was a good way of combining biomarker and lifestyle data.”
Hardikar told Live Science that the researchers could compare this data to molecular data from tumor samples. Indeed, that’s the plan, Guinter said. He hopes that these follow-up studies will allow them to “see if there’s a tumor subtype that’s particularly susceptible to a high-inflammatory lifestyle. ”
The findings have not yet been published in a peer-reviewed journal.
