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BMI associated with colorectal cancer diagnosis in patients aged less than 50 years
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SAN DIEGO — Colorectal cancer diagnosed in those aged younger than 50 years is positively associated with BMI but not with other risk factors associated with colorectal cancer diagnosis at older ages, according to data presented at the 2012 Digestive Disease Week Annual Meeting.
While several studies have identified personal characteristics and environmental factors — such as body mass index (BMI) — associated with risk of colorectal cancer, little evidence exists regarding risk factors for early-onset colorectal cancer risk.
To identify risk factors for colorectal cancer diagnosed in patients aged less than 50 years, researchers performed a matched case-control study using participants in the Colon Cancer Family Registry, which comprised 3,007 incident colorectal cancer cases from Australia, the US and Canada from population cancer registries, and 2,964 of their siblings without diagnosis of any cancer.
“For this study, we investigated the role of the environmental risk factors on the risk of colorectal cancer diagnosed before age 50, to see if they are the same or different to the risk factors that we already know for colorectal cancer generally diagnosed in older age” Aung Ko Win, MBBS, MPH, a research fellow from the University of Melbourne in Australia told HemOnc Today. “Most studies to date have been focusing on colorectal cancer typically diagnosed in older age as it accounts for more than 90% of colorectal cancer cases. In contrast, we know almost nothing about the causes of early-onset colorectal cancer except for some rare inherited genetic mutations”
Using multivariable conditional logistic regression, researchers projected ORs and 95% CIs for within sibship associations of colorectal cancer with BMI, Metabolic Equivalent Tasks for physical activities, cigarette smoking, alcohol consumption, use of aspirin and other non-steroidal anti-inflammatory drugs, and diabetes.
“Obesity was associated with an increased risk of colorectal cancer diagnosed before age 50, but there was no evidence for overall associations with other factors including physical activity, alcohol drinking, cigarette smoking, diabetes, aspirin use, meat consumption or vegetable and fruit consumption,” said Win.
According to study results, after adjusting for other potential risk factors, early-onset colrectal cancer was positively associated with BMI at age 20 years (OR 1.14 per 5 kg/m2, 95% CI 1.00-1.29, P=0.05), recent BMI (OR 1.18 per 5 kg/m2, 95% CI 1.06-1.32, P=0.003), and change in BMI from age 20 years to recent age (1.20 per 5 kg/m2, 95% CI 1.05-1.38, P=0.009).
“The main finding from this study is that similarly to colorectal cancer mostly diagnosed in older age, colorectal cancer diagnosed before age 50 is positively associated with body mass index,” said Win. “However, we didn’t observe evidence for associations of colorectal cancer diagnosed before age 50 with other risk factors that have been found to be associated with colorectal cancer diagnosed in older age”. Potentially, this could mean that the causes for colorectal cancer differ by age, and that preventive strategies could be targeted by age.
Disclosure: The researchers reported no relevant financial disclosures.
For more information:
- Win AK. #Mo1607: Role of Environmental Risk Factors on Early-Onset Colorectal Cancer Risk. Presented at: the 2012 Digestive Disease Week Annual Meeting; May 19-22, 2012; San Diego.