Previous studies suggesting that coffee decreases risks of colorectal, colon or rectal cancer have been debunked by recent studies that confirm coffee contributes insignificantly to these cancers, according to the findings of a collaboration of studies published in the International Journal of Cancer, Reuters reported.
“An inverse association between coffee consumption and the risk of colorectal cancer has been found in several case-control studies,” but the association was not consistent in prospective cohort studies, which are devised differently, Dr. Youjin Je, of Harvard School of Public Health in Boston, and colleagues indicate.
When patients with a disease or condition are evaluated with “controls,” healthy individuals teamed up with the study group for factors like age and sex to avoid unfairness, it is termed a case-control study. On the other hand, prospective cohort studies are studies in which participants share a common characteristic, such as a smoking habit or birth order, are distinguished and then observed into the future; the concluding result is not known to the researchers before the trial ends.
An orderly review of prospective cohort studies was directed by the researchers to scrutinize the connection between coffee consumption and colorectal cancer. The researchers identified 12 studies in 3 different countries that included a total of 646,848 participants, and of these, 5,403 were colorectal patients.
In a collective review of each of these studies, judging against high and low coffee consumption categories, no considerable connection between coffee consumption and colorectal cancer risk was found.
Mostly, differences by sex and cancer site were irrelevant. There was, however, a minor inverse relationship between coffee consumption and colon cancer in women, particularly Japanese women who indicated a 38 percent reduced risk, but most had a 21 percent reduced risk.
More significant inverse associations between coffee consumption and colorectal cancer was evident in studies that examine the data accounting for the damages of smoking and alcohol use as well as those with shorter follow-up.
Je’s team of researchers commented, “Since any effect of coffee intake on colorectal cancer risk could vary by regular or decaffeinated coffee and boiled or filtered coffee, further investigation regarding type- and preparation method-specific analyses is warranted.”
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