Family history, obesity among risk factors for early-onset CRC
Individuals with obesity and high alcohol consumption, as well as other factors, were at higher risk for developing early-onset colorectal cancer, according to study results.
Darren R. Brenner, PhD, from the University of Calgary, and colleagues wrote that about 10% of newly diagnosed cases of CRC are in patients aged younger than 50 years. However, the reasons for a rise in early-onset CRC (EoCRC) are unclear.
“Despite a decrease in the incidence of CRC among older age groups, an increase in the incidence of EoCRC has been observed in recent decades in Canada, the United States and in several other countries,” they wrote. “Establishing risk factors for EoCRC is an important exercise, given it can inform both primary prevention efforts aimed at behavior modification and secondary prevention strategies such as targeted screening approaches for high-risk individuals.”
Investigators searched the literature for studies that explored non-genetic risk factors for EoCRC. Specifically, they analyzed risk factors that were examined in at least three studies.
In 20 studies that fit their criteria, researchers found that CRC history in a first-degree relative (RR = 4.21; 95% CI, 2.61-6.79), hyperlipidemia (RR = 1.62; 95% CI, 1.22-2.13), obesity (RR = 1.54; 95% CI, 1.01-2.35) and high alcohol consumption (compared with non-drinkers, RR = 1.71; 95% CI, 1.62-1.8) were all risk factors for EoCRC. Data suggested that smoking was a risk factors, but it was not significant.
Brenner and colleagues wrote that they identified other potential risk factors, including hypertension, metabolic syndrome and ulcerative colitis but they were only explored in one or two studies.
“High quality studies conducted on generalizable populations and that comprehensively examine risk factors for EoCRC are required to inform primary and secondary prevention initiatives for EoCRC,” the researchers wrote.