A new study suggests up to 10 percent of U.S. children may have fetal alcohol spectrum disorders (FASD), much more than previously thought.

Prior research indicated that 1 in 100 children is affected, researchers report in JAMA. The new findings come from a study of more than 6,000 first graders in four U.S. communities, according to a news release from the National Institutes of Health (NIH). The study was funded by the National Institute on Alcohol Abuse and Alcoholism, part of the NIH.

The study found at least 1 percent to 5 percent of first graders had FASD. When the researchers used a less-strict estimate, they found the rate soared to as high as 10 percent in one community.

“The earlier that interventions are initiated, the more effective they are likely to be—especially during the early years when there is still relative plasticity of the brain,” study co-author Christina Chambers of the University of California San Diego School of Medicine told Reuters. “There is no cure for fetal alcohol spectrum disorders, but there are definitely intervention strategies that have been demonstrated to help.”