Women who drink four or more cups of coffee a day may have a reduced risk of developing endometrial cancer.

A prospective cohort study of over 67,000 women aged between 34 and 59 years, enrolled in the Nurses’ Health Study, found that women who drank four or more cups of coffee daily had 25% lower risk of endometrial cancer than women who averaged less than a cup a day.

The researchers found that while caffeinated coffee was tied to a lower cancer risk, a narrow range of decaffeinated coffee compared with caffeineated coffee in this cohort limited the possibility to osberve an association with higher decaffeinated coffee intake.

The study, published in the journal Cancer Epidemiology, Biomarkers & Prevention¹, adds to other recent studies that have found coffee drinkers to have a lower risk of endometrial cancer.

The strength of the current study is that it was a large, long-term prospective study, and allowed the researchers to account for a number of other factors that could explain the coffee connection.

The researchers found a stronger protective effect among obese women, which has also been found in other research. Obesity is a risk factor for endometrial cancer. The link between four or more cups of coffee and reduced risk of endometrial cancer was also stronger for past or current smokers; women post menopause and women not on menopausal hormone therapy.

The researchers suggest that coffee may have contributed to a decreased risk of endometrial carcinogenesis due to the potential ability to lower concentrations of insulin and free estradiol in addition to the antioxidant ability of phenolic compounds in coffee.

¹Y Je et al, 2011. A Prospective Study of Coffee Consumption and Risk of Endometrial Cancer over a 26-year Follow-up, Cancer Epidemiology Biomarkers and Prevention, Online.

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