The findings of this study appear in the Journal of the National Cancer Institute. The authors explain that not many studies have focused on what impact coffee intake might have on the most lethal form of prostate cancer. This is the largest one so far to determine whether coffee might have an effect on lethal prostate cancer risk.
Sixteen million men around the world have survived prostate cancer - 2 million in the USA. It is the most frequently diagnosed male cancer in America and the nation's second highest cancer killer, the authors informed.
Kathryn Wilson, lead author, said:
"At present we lack an understanding of risk factors that can be changed or controlled to lower the risk of lethal prostate cancer. If our findings are validated, coffee could represent one modifiable factor that may lower the risk of developing the most harmful form of prostate cancer."
Several biologically active compounds exist in coffee, such as caffeine and phenolic acids. These substances are potent antioxidants; they affect glucose metabolism and levels of sex hormones. The researchers wondered whether they might reduce prostate cancer risk.
Previous studies had shown how coffee can lower the risk of developing breast cancer, liver cancer, cirrhosis of the liver, gallstone disease, diabetes type 2, and Parkinson's disease.
In order to find out whether regular coffee consumption might influence prostate cancer risk, particularly the lethal form, the scientists evaluated data from the Health Professional Follow-Up Study involving 47,911 US men. The participants had reported coffee consumption habits every four years from 1986 to 2008. During this 22-year period there were 5,035 cases of prostate cancer, including 642 metastatic (lethal) cases.
The authors discovered that a man who drank six cups of coffee or more each day had a nearly 20% reduced risk of developing prostate cancer (any type), and a 60% lower chance ever getting the lethal type. They were surprised to find that both normal and decaffeinated coffee offered the same levels of protection. Even moderate coffee drinkers - those consuming between one to three cups per day - had a 30% reduced risk of developing metastatic prostate cancer.
The researchers concluded in an abstract in the journal:
"We observed a strong inverse association between coffee consumption and risk of lethal prostate cancer. The association appears to be related to non-caffeine components of coffee."
Related reading: Drinking Coffee: More Good Than Harm? (9 July 2012).