MONDAY, April 12, 2010 (HealthDay News) -- Frequent alcohol consumption by teenage girls may increase the chances that they will develop non-cancerous breast disease in their 20s and possibly breast cancer later in life.
Research published online April 12 in the journal Pediatrics found that girls who drank the most alcohol during their teen years -- daily or nearly every day -- were five times more likely to develop benign breast disease as young adults than were their peers who never drank or drank less than once a week.
Benign breast disease (BBD) includes a number of nonmalignant conditions. Fibroadenoma, a noncancerous tumor, is the most common in those aged 30 and younger. Study co-author Catherine Berkey, a biostatistician at Harvard Medical School in Boston, said that benign breast disease is known to boost the risk for breast cancer.
So does that mean that teens who drink alcohol are increasing their breast cancer risk early in life?
"Our study may suggest that teen drinking increases the risk for breast cancer, whether in all females or in those who go on to develop BBD, but longer-term follow-up is certainly required" to confirm it, she said.
A unique aspect of Berkey's study was that the girls assessed their drinking habits while they were teenagers. Other studies have based their conclusions on adult women's recalling their teenage drinking many years later.
"Our new study is the first in which alcohol data were collected during adolescence, with continued follow-up in the females as they develop disease," she said.
The study involved 6,899 women who had become participants in the "Growing Up Today Study" when they were 9 to 15 years old. Information on alcoholic beverage consumption was collected in a follow-up survey when the participants were 16 to 23 years old, and a survey done when they were 18 to 27 years old included questions on breast disease.
In all, 147 participants reported having benign breast disease, with 67 cases having been confirmed by biopsy.
When Berkey and her colleagues looked at the diagnoses of benign breast disease and drinking, they found that risk for benign breast disease rose along with the frequency of alcohol consumption: from a 1.5 increased risk for drinking one or two days per week, to a three times greater risk for those drinking three to five days per week, and to a 5.5 times greater risk for drinking six or seven days per week, when compared with those who never drank or who drank less than once per week.
Even once-a-week drinkers may not be absolutely safe, Berkey noted. "I suspect there may be some small additional BBD risk for even small amounts of alcohol consumed during adolescence," she said.
Teen years are a critical time for potential cancer-producing exposures, she said, because the mammary glands are undergoing rapid growth during that period.
Berkey said she suspects the link is due to alcohol increasing total estrogen levels, raising the likelihood of benign breast disease.
"For me, this is not a surprise," said Dr. Patricia Ganz, director of cancer prevention and control research at the Jonsson Comprehensive Cancer Center at the University of California, Los Angeles. Regular alcohol consumption is known to increase a woman's risk for both breast cancer and benign breast disease, she said, and "certain forms of BBD increase the risk of breast cancer."
And though she described the new study as excellent, she cautioned that the sample size was relatively small.
"I wouldn't scare [teens] and say, 'You are going to get breast cancer if you drink,'" Ganz said. But, on the other hand, she added: "The public health message is, these young girls shouldn't be drinking anyway."
The American Cancer Society has more on alcohol's effect on the breast.