Drinking four or more cups of coffee a day may reduce risk of developing endometrial cancer by almost 25 per cent, a new study has suggested. Originating in the lining of the uterus, endometrial cancer is one of the most widespread invasive gynaecological cancers. High levels of oestrogen and insulin are associated with an increased risk of the disease but researchers involved in the Nurses' Health Study from the Department of Nutrition at the Harvard School of Public Health have discovered that high-coffee-consuming women have lower levels of these hormones, compared with those who drink little or no coffee, Stuff.co.nz reported. "This is an observational study - coffee intake is self-selected, not randomised - so our study cannot prove causal relationship between coffee and endometrial cancer risk, but we found an inverse association between coffee and endometrial cancer risk," said study author Youjin Je, doctoral student at the Harvard School of Public Health. "Four or more cups of coffee may contribute to lower risk of endometrial cancer by lowering levels of oestrogen and insulin which are related to endometrial carcinogenesis due to increased cell proliferation and reduced cell death," Je noted. The researchers took into consideration 67,470 women aged 34 to 59 from 1980 to 2006 and asked that them to report every four years how frequently, on an average, did they consume coffee over the previous year. They then calculated cumulative average coffee intake to show long-term consumption patterns for the individual subjects and found that those who had four cups per day on an average were 25 per cent less likely to develop the cancer. And it is not just caffeine that helps decrease the risk as participants who drank two or more cups of decaffeinated coffee per day experienced a 22 per cent decrease. But Je also cautioned that a high intake of sugars and fats in coffee might counteract the proposed benefits of consumption.