Evidence from laboratory studies indicates that green and black tea preparations may protect against various cancers. But few epidemiological studies have examined the relationship specifically between tea consumption and the risk of ovarian cancer, according to background information in the article.
Susanna C. Larsson, M.Sc., and Alicja Wolk, D.M.Sc., of the National Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden, prospectively examined the association between tea consumption and the risk of ovarian cancer in 61,057 women, aged 40 to 76, who were participants in the population-based Swedish Mammography Cohort. Participants completed a validated 67-item food frequency questionnaire at enrollment between 1987 and 1990, and were followed for cancer incidence through December 2004. At baseline, 68 percent of the participants reported drinking tea (mainly black tea) at least once per month. During an average follow-up of 15.1 years, 301 women were diagnosed as having invasive epithelial ovarian cancer.
"We observed a 46 percent lower risk of ovarian cancer in women who drank two or more cups of tea per day compared with non-drinkers," the authors report. "Each additional cup of tea per day was associated with an 18 percent lower risk of ovarian cancer."
Women who drank less than one cup of tea per day had an 18 percent lower risk of ovarian cancer than non-drinkers. The risk was 24 percent lower for women who drank one cup of tea per day.
"This association does not depend on lower coffee consumption among women with high tea consumption; coffee is not associated with ovarian cancer risk in this cohort," the authors write.
"In summary, our results from a large population-based cohort of Swedish women suggest that tea consumption may lower the risk of ovarian cancer," the authors conclude. "Because prospective data on this relationship are scarce, our findings need confirmation by future studies."
(Arch Intern Med. 2005;165:2683-2686. Available pre-embargo to the media at www.jamamedia.org.)
Editor's Note: This work was supported by research grants from the Swedish Cancer Foundation and the Swedish Research Council/Longitudinal Studies, Stockholm, Sweden.
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