TUESDAY, Jan. 22, 2008 (HealthDay News) -- Drinking alcohol doesn't seem to boost a woman's risk of ovarian cancer, while caffeine may help protect against the disease, a new study found.
In the same study, smoking cigarettes wasn't linked with an increase in the most common types of ovarian cancer but was associated with an increase in a rare subtype of the disease.
It's too soon to recommend drinking caffeine to lower ovarian cancer risk, said study senior author Shelley S. Tworoger, an assistant professor of medicine and epidemiology at Harvard Medical School and the Harvard School of Public Health.
"The results do need to be confirmed in other studies," Tworoger said. The lack of risk for alcohol and smoking has been found in other research, she added.
For the study, Tworoger and her colleagues looked at data from questionnaires in the Nurses' Health Study, which includes 121,701 U.S. female registered nurses. The study began in 1976, with women then aged 30 to 35 completing questionnaires, then replying every two years to update the data.
Tworoger's team looked at the association between smoking and ovarian cancer risk among 110,454 of the women, and the association between alcohol and caffeine and ovarian cancer risk among 80,253 women, all followed from 1976 to 2004. For the smoking analysis, the researchers found 737 confirmed cases of epithelial ovarian cancer, the most common type of ovarian cancer. For the diet analysis, they found 507 women with epithelial ovarian cancer.
No association was apparent for drinking alcohol and ovarian cancer, or for smoking, with one exception. "It [smoking] does appear to increase the incidence of a rare type, mucinous ovarian tumors," she said, a subtype of epithelial ovarian cancer.
However, the researchers found an "inverse trend" for total caffeine intake and caffeinated coffee consumption and ovarian cancer, but the individual risk reductions didn't reach statistical significance.
The association for caffeine was strongest if the women had never used either birth control pills or hormones after menopause, Tworoger said. Why caffeine may be protective isn't certain, she said, but its consumption may lower estrogen levels, at least in postmenopausal women.
The study findings are published in the March 1 issue of Cancer.
Sherry Salway Black, executive director of the Ovarian Cancer National Alliance and an ovarian cancer survivor, agreed it's too early to recommend caffeine as a risk-lowering strategy.
Tworoger said her team plans to further study the caffeine-ovarian cancer link.
For now, she advised: "Always talk to your doctor before you make any huge lifestyle changes." And keep the risks in perspective, she added. "Because ovarian cancer is relatively rare, women should talk to their doctor first about the risk of getting ovarian cancer."
Black agreed, adding: "Know the symptoms of ovarian cancer. Know your family history and your risk and talk with your health-care provider." Get advice about what to do, she said, especially if you have a higher-than-average risk.
About 22,430 new cases of ovarian cancer were found in the United States in 2007, according to the American Cancer Society, and about 15,280 women died of the disease that year. Ovarian cancer is the eighth most common cancer in women -- not counting skin cancer -- and it's the fifth-leading cause of cancer death in women.
Symptoms include bloating, pelvic or abdominal pain, urinary frequency and difficulty eating or feeling full quickly.
In another study published this week, caffeine was found to increase the risk of miscarriage. Kaiser Permanente researchers in California looked at 1,063 pregnant members of the HMO and found those who drank 200 milligrams or more of caffeine a day -- about two or more cups of coffee or five 12-ounce sodas -- had twice the miscarriage risk of those who avoided caffeine entirely. Even smaller amounts increased risk, with women drinking less than 200 milligrams of caffeine a day showing more than a 40 percent increased risk of miscarriage, compared to those who took in no caffeine.
The study was published online in the January issue of the American Journal of Obstetrics and Gynecology.
More information
To learn more about ovarian cancer symptoms, visit the Ovarian Cancer National Alliance.
