Drinking ≥ 8 cups of coffee per day may lower a woman’s risk of endometrial cancer, say researchers from The Arctic University of Norway in Tromsø.
The researchers analyzed data from 97,926 postmenopausal women in the prospective Norwegian Women and Cancer study, conducted from 1991 to 2010, and included a randomly selected sample of women aged 30 to 70 years. During an average of about 11 years of follow-up, 462 women developed endometrial cancer. After multivariate adjustment, the researchers found significant risk reduction with heavy coffee drinking.
Coffee may produce effects in a number of ways, the researchers say. For one, it can alter hormonal levels. Coffee also has antioxidant properties. Another theory proposes that coffee compounds block the initiation phase of the carcinogenic process, reduce DNA damage, and protect cells against reactive oxygen species by inducing the production of detoxifying enzymes.
The question of which bioactive compounds have the higher antioxidant capacity remains open, the researchers say. It depends, in part, on the beans and brewing method. For example, Norway mostly imports coffee Arabica, which has a lower concentration of caffeine compared with that of other types of beans. Moreover, different brewing methods can change the chemical composition of coffee, although in this study, brewing methods did not seem to have an impact on cancer risk.
The researchers also stratified analyses by body mass index and smoking status. Total coffee consumption was significantly inversely associated with endometrial cancer only among overweight women who were heavy coffee drinkers or heavy consumers of filtered coffee (P = .009 and P = .05). Current smokers who were heavy coffee consumers also had a significantly lower risk (P = .01). The fact that weight and smoking status were potential factors may point to beneficial synergies. For instance, some researchers have suggested that caffeine plus nicotine enhances the clearance of estradiol and thus might confer some protection against hormone-dependent tumors.
Finally, the researchers note that Scandinavians, in general, drink a lot of coffee. During the study period, 90% of Norwegians aged > 40 years drank an average of 4 to 5 cups a day. Although that is no longer true, the researchers say, it is possible that years of heavy consumption changed mechanisms involved between coffee consumption and cancer risk. That hypothesis however, they add, needs further exploration.
Source
Gavrilyuk O, Braaten T, Skeie G, Weiderpass E, Dumeaux V, Lund E. BMC Womens Health. 2014;14:48.
doi: 10.1186/1472-6874-14-48.
