Elevated BMI in adulthood may increase GI cancer risk, regardless of aspirin use
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Key takeaways:
- People with overweight or obese BMI had a higher risk for colorectal and noncolorectal gastrointestinal cancers.
- Aspirin may not be effective for prevention among people with overweight or obesity.
Overweight and obese BMI during adulthood appeared associated with increased risk for colorectal cancer and noncolorectal gastrointestinal cancers, according to study results published in JAMA Network Open.
Frequent aspirin use failed to modify the association.
The findings of the secondary analysis of the NCI Prostate, Lung, Colorectal and Ovarian (PLCO) Cancer Screening Trial prompt further exploration into the mechanistic role of obese BMI in carcinogenesis, researchers wrote.
Rationale and methodology
“Obesity is associated with an increased risk for several different cancer types, including gastrointestinal cancers,” Holli A. Loomans-Kropp, PhD, MPH, assistant professor in the division of cancer prevention and control in the department of internal medicine at The Ohio State University, and cancer control program member at The Ohio State University Comprehensive Cancer Center-James Cancer Hospital and Solove Research Institute, told Healio. “With the increasing prevalence of obesity in the United States and globally and growing research indicating that BMI trajectory may influence cancer risk, we wanted to evaluate the association between BMI and gastrointestinal cancer risk using a large population-based study.”
In the retrospective cohort secondary analysis of the PLCO Cancer Screening Trial, researchers examined the association between BMI and aspirin use with the risk for colorectal cancer and noncolorectal GI cancer among 135,161 trial participants (median age, 62 years; 50% women).
They used Cox proportional hazards regression modeling to assess the association between BMI and cancer. Researchers additionally examined the association between cancer risk and change in BMI at different ages and performed an exploratory analysis to assess GI cancer risk among aspirin users.
Diagnoses of colorectal cancer and noncolorectal GI cancer served as primary outcomes.
Findings
Results showed an association between increased colorectal cancer risk and overweight BMI in early adulthood (HR = 1.23; 95% CI, 1.1-1.37), middle adulthood (HR = 1.23; 95% CI, 1.13-1.34) and later adulthood (HR = 1.21; 95% CI, 1.1-1.32).
Results also showed an association between increased colorectal cancer risk and obese BMI in middle adulthood (HR = 1.55; 95% CI, 1.38-1.75) and later adulthood (HR = 1.39; 95% CI, 1.25-1.54).
Researchers observed similar associations between overall GI cancer and noncolorectal cancer GI risk and BMI during middle and later adulthood.
In addition, maintaining overweight or obese BMI or increasing BMI to overweight or obese during later adulthood appeared associated with increased colorectal cancer risk.
Overweight and obese BMI appeared associated with an increased risk for colorectal cancer and noncolorectal GI cancer among those who used aspirin three or more times per week, researchers noted.
“[This suggests] that aspirin may not be efficacious for prevention in overweight or obese states,” they wrote. “The ability of aspirin to protect against GI cancers may be blunted in people with obesity because of inadequate dosing. A suggestion may be that individuals with obesity need to increase aspirin frequency or dosage; however, increased aspirin use comes with its own risks, such as GI bleeding. In our analysis, we did not account for participant dosing, a noted limitation to the study.”
Implications
Although the study is a secondary analysis of a randomized control trial and therefore limited, the results indicate that the presence of overweight and obesity during several phases of life may increase risk for gastrointestinal cancers, Loomans-Kropp said.
“Furthermore, the results suggest that chemoprevention agents, such as aspirin, may exhibit differential efficacy that is dependent upon other factors. We believe that the results of this study could 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 a very exciting avenue for cancer prevention research, Loomans-Kropp added. She and authors of an accompanying editorial noted a need for further study in this area.
“To delineate the effect of age of weight gain and/or loss and cumulative exposures to adiposity on GI cancer and obesity-related cancers, we need transformative epidemiologic and mechanistic studies, involving comprehensive, longitudinal characterization of obesity throughout the lifespan complemented with deeper molecular profiling of malignant tumors, precursors, as well as normal tissues and biospecimens,” Yin Cao, ScD, MPH, associate professor of surgery and medicine, and Mengyao Shi, MBBS, MPH, research data assistant, both at Washington University School of Medicine in St. Louis, wrote in the editorial.
“It is also worth noting that the predictive value of obesity of a particular type of cancer is low. Therefore, precision-based risk stratification strategies that incorporate additional risk factors and/or biomarkers are essential before implementing targeted cancer prevention strategies among individuals with overweight or obesity,” they added.
References :
- Loomans-Kropp HA, et al. JAMA Netw Open. 2023;doi:10.1001/jamanetworkopen.2023.10002.
- Shi M, et al. JAMA Netw Open. 2023;doi:10.1001/jamanetworkopen.2023.9921.
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