Young women who drink alcohol may put themselves at higher risk of developing breast disease that is a known risk factor for cancer, a new study suggests.

In a group of nearly 6,900 women aged 16 to 23, researchers found that those who drank six or seven days a week had more than five times the odds of developing so-called benign breast disease years later.

Women with benign breast disease have hard lumps in their breasts, which may in some instances turn cancerous. The broad group of conditions includes irregular cysts, breast discomfort, sensitive nipples, and itching, according to the National Cancer Institute.

Earlier reports have linked adolescent drinking to benign breast disease based on women’s recollections many years later, but the new study is the first to survey alcohol drinking directly during adolescence and follow the girls into adulthood.

It’s not clear why alcohol would have an effect on the condition, but researchers speculate that alcohol’s effect on estrogen could promote breast tissue growth.

“Our study results give older girls and adolescents another reason to avoid alcohol,” Catherine Berkey of Harvard Medical School, who led the research, told Reuters Health in an e-mail.

When the women were interviewed later at age 18 to 27, 67 - or about 1 percent - said they had been diagnosed with benign breast disease and had the diagnosis confirmed with a biopsy. Those who drank more were also more likely to suffer from the condition, with each average daily drink adding to the risk.

“We saw health effects with alcohol amounts that are not intoxicating, so teen girls would be wise to totally avoid alcohol at least until they are of legal drinking age,” Berkey said.

SOURCE: Pediatrics, online April 12, 2010.