Dr. Kashif Shafique of the Institute of Health & Wellbeing at the University of Glasgow and colleagues found those who drank more than seven cups of tea per day for years had a 50 percent higher risk of developing prostate cancer compared with non-tea drinkers or those drinking less than four cups per day.
"Most previous research has shown either no relationship with prostate cancer for black tea or some preventive effect of green tea," Shafique, the study leader, said in a statement. "We don't 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."
Shafique and colleagues used data from a study began in Scotland in 1970 that gathered data from more than 6,016 male volunteers -- ages 21-75 years -- who were asked to complete a questionnaire about their usual consumption of tea, coffee, alcohol, smoking habits and general health.
About one-quarter of the men were heavy tea drinkers and of these, 6.4 percent developed prostate cancer during a follow-up of up to 37 years.
"We found that heavy tea drinkers were more likely not to be overweight, be non-alcohol-drinkers and have healthy cholesterol levels," Shafique said.
The findings were published in the journal Nutrition and Cancer.