WASHINGTON: Researchers have taken a step forward in the fight against ovarian cancer by showing that caffeine consumption may lower a woman's chances of developing the disease, and that smoking and alcohol do not have an effect on the cancer's risk.

The team at the Harvard Medical School and the Harvard School of Public Health found that the chance of getting the disease was 25 percent lower in women who consumed the most caffeine, compared with those who drank little or no caffeine.

The report comes after another study found pregnant women who consume the caffeine equivalent of two or more cups of coffee daily were twice as likely to miscarry as those who avoided the stimulant.

"Pending further research, there's a suggestion that higher caffeine intake may lower your risk of ovarian cancer, especially among women who aren't taking hormones," said lead author Shelley Tworoger.

"For women who are at high risk, it may be one possible way for them to avoid ovarian cancer," she added.

Dr Tworoger and her co-investigators prospectively examined associations between smoking and ovarian cancer risk among 110,454 women and between alcohol or caffeine and ovarian cancer risk among 80,253 women, all followed between June 1, 1976 and June 1, 2004.

For the smoking analyses, they identified 737 confirmed cases of epithelial ovarian cancer, and for the dietary analyses, they identified 507 cases.

They found no association between current or past smoking and ovarian cancer risk, however smoking status, duration, and pack-years were significantly associated with risk of mucinous tumors, a rare form of ovarian cancer.

The authors also found no link between alcohol consumption and ovarian cancer risk. However they observed an inverse trend of risk with total caffeine and caffeinated coffee intake, but no association with decaffeinated coffee.

The potential reduction in risk with higher caffeine intake appeared to be strongest for women who had never used oral contraceptives or postmenopausal hormones.

The authors concluded, "Reducing alcohol intake and cessation of smoking is not likely to have a substantial impact on risk of ovarian cancer."

They further add, "The possibility that caffeine may reduce ovarian cancer risk, particularly for women who have not previously used exogenous hormones, is intriguing and warrants further study, including an evaluation of possible biological mechanisms."

The study is published in the March issue of Cancer , a peer-reviewed journal of the American Cancer Society.