The study, released this week in Cancer Epidemiology, Biomarkers & Prevention Journal reviewed the data from over 67,000 women who participated in the Nurses’ Health Study (NHS) that began in 1976. The researchers determined that women who consumed the caffeine in four or more cups of coffee daily had a 25% lower incidence of endometrial cancer than women who consumed one or no cups of coffee daily. The lower incidence of cancer was effected by caffeine, as proven by the fact that decaffeinated coffee was not associated with a decreased cancer risk.
According to co-author Youjin Je, MS, of Harvard School of Public Health in Boston, “Our findings provide prospective evidence with the potential beneficial role of four or more cups of coffee per day against endometrial cancer risk.”
That’s hefty coffee consumption — but it offers a hefty protection against a serious health risk!
It’s the Caffeine that Counts!
Rearchers found that the Nurses’ Health Study contained a dataset with variables that could overcome the limitations of previous investigations of caffeine consumption and endometrial cancer. Initiated in 1976, the NHS had data on 121,700 female nurses ages 30 to 55 at enrollment.
Researches used a “cup of coffee” as their standardized unit of caffeine consumption. However, they were equally interested in the effects of caffeine that came from sources other than coffee. Je and colleagues examined a subgroup of 67,470 NHS participants who answered an initial food frequency questionnaire in 1980 and continued with six follow-up questionnaires until 2002. Participants were grouped into six categories of coffee consumption on a continuum from never, to less than once a month, to six or more times daily. After researchers examined the data on other sources of caffeine, they translated frequency of caffeine consumption into cups of coffee per day. The source of the caffeine consumption criteria was the U.S. Department of Agriculture food composition and these included not only coffee but tea, cola, chocolate, and other caffeinated carbonated drinks.