The study examined over 5,100 men and women who had been diagnosed with colorectal cancer within the past six months, along with an additional 4,000 men and women with no history of colorectal cancer to serve as a control group. Participants reported their daily consumption of boiled (espresso), instant, decaffeinated and filtered coffee, as well as their total consumption of other liquids. A questionnaire also gathered information about many other factors that influence the risk of colorectal cancer, including family history of cancer, diet, physical activity and smoking.
"We found that drinking coffee is associated with lower risk of colorectal cancer, and the more coffee consumed, the lower the risk," said Stephen Gruber, MD, PhD, MPH, director of the USC Norris Comprehensive Cancer Center and senior author of the study.
The data showed that even moderate coffee consumption, between one to two servings a day, was associated with a 26 percent reduction in the odds of developing colorectal cancer after adjusting for known risk factors. Moreover, the risk of developing colorectal cancer continued to decrease to up to 50 percent when participants drank more than 2.5 servings of coffee each day. The indication of decreased risk was seen across all types of coffee, both caffeinated and decaffeinated.