Infants living in high altitude places have a higher risk of sudden infant death syndrome (SIDS), according to a new study published in Pediatrics.

SIDS typically involves the sudden death of an otherwise healthy infant that’s under 1 year old. The cause of SIDS is still relatively unknown, though some doctors believe it may have to do with undetected brain abnormalities. A new study shines some light on the issue: it turns out that in higher altitudes, where oxygen molecules are distributed more sparsely in every breath you take, infants may be at a higher risk of hypoxia — or low oxygen in their blood — which ultimately may be tied to SIDS.

In the study, researchers examined Colorado birth certificates and death registries from 2007 to 2012, as well as the residential addresses for some 395,000 infants. They controlled for maternal age and education, as well as whether the mother smoked cigarettes, and found that infants who lived in altitudes higher than 8,000 feet had double the risk of SIDS than those who lived below 6,000 feet.

This recent study confirms past findings: a 1998 study completed in Austria found that babies sleeping on their stomachs in higher altitudes had a higher risk of SIDS than babies at lower altitudes. In general, parents are advised to have their infants sleep on their backs instead of their stomachs to lower the risk of SIDS. As a result, even though higher elevation poses higher risk, the authors of the study explain that there’s ways to mitigate that risk without having to move to lower altitudes.

“I think it’s important to point out that parents can still focus on modifiable risk factors for sudden infant death syndrome, including putting infants on their back to sleep, avoiding excessive blankets or stuffed animals, and maintaining a no-smoking environment,” Dr. David Katz, a cardiologist at the University of Colorado and an author of the study, told LiveScience.

Dr. Susan Niermeyer, a professor of pediatrics at the University of Colorado School of Medicine and another of the authors on the study, adds that parents do still have some control in preventing SIDS. “I would like parents to feel that they’re empowered to take some very concrete steps to minimize risk of SIDS wherever they live,” she told LiveScience. “If [the babies] are able to turn over, they’re probably going to have the motor development to get themselves out of a situation where they have an obstructed airway.”

The researchers state that the study isn't meant to worry parents who live in higher altitudes; it is, however, a step in the right direction for further research on SIDS.

“I’m afraid people will interpret this study as saying high altitudes are dangerous, but this association really begs for further research into why it exists,” Katz told the New York Times.

Source: Katz D, Shore S, Bandle B, Niermeyer S, Bol K, Khanna A. Sudden Infant Death Syndrome and Residential Altitude. Pediatrics, 2015.