Researchers have found that individuals in early and middle adulthood who have a body mass index (BMI) indicating that they have overweight or obesity may be at an increased risk of developing gastrointestinal cancer, according to a new study published by Loomans-Kropp and Umar in JAMA Network Open. The findings also demonstrated that frequent aspirin use did not modify the increased risk in this patient population.
Background
Colorectal cancer is the third most common cancer type among patients in the United States, with over 150,000 new cases diagnosed annually in spite of improvements in screenings and early detection.
“In a time when obesity rates are rising globally and 70% of the U.S. population alone is considered overweight or obese, understanding the association between obesity and long-term disease risk, such as cancer, is critical for improving public health,” stressed lead study author Holli Loomans-Kropp, PhD, MPH, Assistant Professor of Internal Medicine in the Division of Cancer Prevention and Control at The Ohio State University College of Medicine as well as a cancer control researcher and epidemiologist at The Ohio State University Comprehensive Cancer Center–Arthur G. James Cancer Hospital and Richard J. Solove Research Institute. “Our study suggests that being overweight or obese during several phases of life can increase an [individual’s] risk for gastrointestinal cancers in later adulthood,” she added.
Obesity results from the buildup and storage of white adipose tissue. Adipose cells are capable of triggering an inflammatory response and promoting immune cell dysfunction—leading to negative outcomes such as the development of cardiovascular disease, metabolic conditions, and certain types of cancers.
Physicians have long stressed the importance of maintaining a healthy weight for improving overall health, but the researchers also suggested it could also reduce future gastrointestinal cancer risk.
Study Methods and Results
In the new study, the researchers examined the data of 131,161 patients—previously collected from the Prostate, Lung, Colorectal, and Ovarian (PLCO) Cancer Screening Trial—to better understand how BMI changes that occur during several phases of adulthood can influence the risk of gastrointestinal cancer.
The researchers explained that the PLCO Cancer Screening Trial looked at the effectiveness of cancer screenings at reducing cancer-related mortality from 1993 to 2001.
For the new analysis, the researchers considered age 20 early adulthood, age 50 middle adulthood, and age 55 and older later adulthood.
To calculate patients’ BMIs, the researchers used self-reported questionnaires completed at the original time of enrollment regarding weight and height at these age points. They then categorized the patients according to the BMI ranges established by the World Health Organization—where a BMI of less than 18.5 was classified as underweight, 18.5 to 24.9 was normal, 25 to 29.9 was overweight, and 30 and over was obese. The patients were also asked to report how often they took aspirin or aspirin-containing products and were followed for 13 years or until December 31, 2009.
The researchers discovered that patients whose BMI was classified as overweight and obese in early, middle, and later adulthood were at an increased risk of developing gastrointestinal cancer. They also noted that an increasing BMI over time was associated with an increased risk for colorectal and noncolorectal gastrointestinal cancers. The correlations were not modified by regular aspirin use.
Conclusions
“We believe that the results of this study highlight the need to better understand the underlying mechanisms of cancer prevention agents as well as who may or may not benefit from their use. The field of precision prevention is still relatively new but is an exciting avenue for cancer prevention research,” concluded Dr. Loomans-Kropp.
Disclosure: The research in this study was partially funded by The Ohio State University and the National Institutes of Health. For full disclosures of the study authors, visit jamanetwork.com.
