(Medical Xpress) -- Men who are heavy tea drinkers may be more likely to develop prostate cancer, according to research from scientists at the University of Glasgow which is published in the journal Nutrition and Cancer.
The study, which was led by Dr Kashif Shafique of the Institute of Health & Wellbeing at the University of Glasgow tracked the health of more than 6,000 male volunteers over a period of 37 years and discovered that those who drank more than seven cups of tea per day had a 50% higher risk of developing prostate cancer compared with non-tea drinkers or those drinking less than 4 cups per day.
The Midspan Collaborative study began in Scotland in 1970 and gathered data from more than 6,000 male volunteers, all between 21 and 75 years of age. Participants were asked to complete a questionnaire about their usual consumption of tea, coffee, alcohol, smoking habits and general health, and attended a screening examination.
Just under a quarter of the 6,016 men included in the study were heavy tea drinkers. Of these, 6.4% developed prostate cancer during a follow-up of up to 37 years. Researchers found that men who drank more than seven cups of tea per day had a significantly increased risk of prostate cancer compared to those who drank no tea or less than 4 cups per day.
Dr. Shafique said, Most previous research has shown either no relationship with prostate cancer for black tea or some preventive effect of green tea. We dont know whether tea itself is a risk factor or if tea drinkers are generally healthier and live to an older age when prostate cancer is more common anyway.
We found that heavy tea drinkers were more likely not to be overweight, be non alcohol-drinkers and have healthy cholesterol levels. However, we did adjust for these differences in our analysis and still found that men who drank the most tea were at greater risk of prostate cancer.
Prostate cancer is the most common cancer amongst men in Scotland and between 2000 and 2010 incidence increased by 7.4%.
More information: dx.doi.org/10.1080/01635581.2012.690063