Cutting down on smoking and drinking seems to have little overall impact on a woman’s risk of developing ovarian cancer, suggests a study in the journal Cancer.
But drinking more tea and coffee may be protective, especially in the absence of oral contraceptive or hormone replacement therapy (HRT).
The findings follow on from the publication this week of research showing that high caffeine consumption can double the risk of miscarriage.
The researchers tracked the health and dietary habits of more than 110,000 women who were part of the long-term US Nurses Health Study.
From 1976 onwards, participants filled in questionnaires every two years on potential risk factors for ovarian cancer, including smoking.
And every two to four years, starting in 1980, they also completed food frequency questionnaires on their dietary habits, including caffeine and alcohol intake.
In all, 737 women developed ovarian cancer between 1976 and 2004, of whom 507 had completed questionnaires going back to 1980.
Disease was invasive in 443 cases and borderline in 64.
The results showed that there did not seem to be any association, overall, with smoking―either current or past.
But smokers were twice as likely as non-smokers to have the mucinous type of surface epithelial tumour. And the longer a woman had smoked, the greater was her chance of developing this particular type of tumour.
There was no difference in risk between women drinking 15g or more of alcohol a day and those who drank none, or in the type of alcohol consumed.
But caffeine intake seemed to be protective. Those drinking the most caffeine, including tea, every day were 20% less likely to develop the disease than those drinking the least.
And women drinking three or more cups of coffee a day were 25% less likely to develop the disease than those who drank none.
The association was even stronger among those who drank coffee and who had never used oral contraceptives or HRT.
This might be explained by the potential for artificial hormones to interfere with caffeine metabolism, suggest the authors.
No protective effects were seen for decaffeinated beverages.
“The results of the current study suggest that reducing alcohol intake and the cessation of smoking is not likely to have a substantial impact on risk of ovarian cancer,” conclude the authors from the Universities of Harvard and Melbourne.
“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 biologic mechanisms,” they continue.
Caffeine, Alchohol, Smoking, and the Risk of Incident Epithelial Ovarian Cancer.
Cancer 2008;112; doi 10.1002/cncr.23275
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