A high red meat intake and poor education have been linked to an increase in colorectal cancer cases, a study has found.
A new paper in JNCI Cancer Spectrum, published by Oxford University Press, indicates that several non-genetic factors – including greater red meat intake, lower educational achievement, and heavier alcohol use – are associated with an increase in colorectal cancer cases in people under 50.
Colorectal cancer cases have increased significantly in recent years. According to the World Cancer Research fund, colorectal cancer is the third most common cancer in the world with over 1.8 million new cases recorded in 2018.
Researchers have observed the rise particularly among people born since the 1960s in studies from the United States, Canada, Australia, and Japan. During the same period, there have been major changes in diets among younger generations across the developing world. Such changes include decreases in consumption of fruits, non-ptato vegetables, and calcium-rich dairy sources. This is coupled with an increase in processed foods and soft drinks.
Earlier research has outlined potential risk factors for early-onset colorectal cancer including greater consumption of processed meat, reduced consumption of vegetables and citrus fruit, greater body mass index, sedentary lifestyles, greater alcohol use, smoking, reduced aspirin use, and diabetes. However, researchers have yet to perform a comprehensive, large-scale evaluation that compares the magnitude of these risks with those for late-onset colorectal cancer and assesses whether the risks for early-onset colorectal cancer correlate with specific types of colorectal cancer.
Using data pooled from 13 population-based studies, researchers studied 3,767 colorectal cancer cases and 4,049 controls in people under 50 and 23,437 colorectal cancer cases and 35,311 controls in people 50 or above years.
Early-onset colorectal cancer was associated with not regularly using aspirins, greater red meat intake, lower educational achievement, heavier alcohol use, and alcohol abstinence. Researchers also found that lower total fibre intake was linked more strongly to rectal than colon cancer.
Several other colorectal cancer risk factors trended toward an association with early-onset colorectal cancer, including history of diabetes and lower folate, dietary fibre, and calcium intake. However, neither BMI nor smoking were risk factors in the early-onset group, in contrast to the late-onset group.
Professor Richard Hayes, the senior investigator for this research, said: “This first large-scale study of non-genetic risk factors for early-onset colorectal cancer is providing the initial basis for targeted identification of those most at risk, which is imperative in mitigating the rising burden of this disease.”