Depression is one of the most common mental illnesses in the U.S., impacting more than 15 million American adults each year.

Some of the risk factors for depression are well-known, like having a family history of the disease and going through a traumatic event. But there are lesser-known elements that can increase the odds you’ll suffer from depression, and new research has uncovered a new one: Your childhood weight.

According to the study, which was presented at the European Congress on Obesity, being overweight—especially from a young age—puts people at an increased risk of depression. For the study, researchers analyzed longitudinal data from 889 people, including their height and weight at age eight, 13, and around 50. Researchers discovered that being overweight or obese at age eight or 13 and continuing to be overweight through your life carried a four-times greater risk of lifetime major depressive disorder compared to kids who were a normal weight but went on to become overweight as adults.

But even children who were obese or overweight and lost the weight as they aged had an increased risk of depression: Researchers found they were three times as likely as others for developing major depression at some point in their life.

The findings are especially disturbing given that one in three children in the U.S. are classified as “overweight” by BMI standards and one in five are considered “obese,” per CDC data.

However, being overweight as a kid doesn’t mean you’re destined to be depressed as an adult. This was an observational study, so researchers can’t definitively say that excess weight in childhood makes people depressed—just that there’s a link. But additional research has also found a link between childhood obesity and depression, so there may be something there.