Researchers say teenage girls and young women who drink even moderate amounts of alcohol could increase their risk of breast cancer.
The study followed 29,000 women and found those who drank as teenagers were more likely to develop noncancerous breast disease called proliferative benign breast disease that can later lead to cancer.
Just one drink increased the risk by 15%.
The finding is in next month's issue of the journal "Pediatrics".
The American Cancer Society already reported a link between alcohol and breast cancer. Adult women who drank two to five alcoholic drinks a day were found to have 1.5 times the risk of developing breast cancer compared to women who did not drink.
Researchers think this may be because alcohol can limit the body's absorption of folate which can have an abnormal affect on DNA.
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