Parents of children insured by Medicaid, the U.S. health program for the poor, are more likely to incorrectly assume antibiotics can treat colds and flu and seek these drugs when kids don’t actually need them, a study suggests.

Parents surveyed in Massachusetts reported using antibiotics for their kids on average less than once a year, the study found. But when asked if antibiotics should be used for colds of flu, only 44 percent of the Medicaid parents correctly said “no,” compared with 78 percent of parents with private coverage.

“Understanding the nuances about what is treatable with an antibiotic (a bacterial infection) versus what requires time and supportive care to let your body take care of it (colds and other viruses) can be challenging for parents,” lead study author Dr. Louise Vaz of Oregon Health & Science University in Portland said by email.

Health officials around the world have worked in recent years to curb unnecessary use of antibiotics because overuse helps breed superbugs that are harder to treat, particularly for common problems such as urinary tract infections, pneumonia and bloodstream infections.

Each year in the U.S. alone, at least 2 million people become infected with bacteria that are resistant to antibiotics, and at least 23,000 people die as a direct result, according to the Centers for Disease Control and Prevention.

Vaz and colleagues surveyed 345 Medicaid-insured parents and 353 commercially insured parents in 2013 to see how well they understood the role of antibiotics in pediatric care. They compared those results to a separate survey done in 2000.

In the 2013 survey, roughly one quarter of parents with private insurance and half of those with Medicaid incorrectly thought their child would be sick with a cold for longer if they didn’t receive antibiotics.

Most parents that year, regardless of insurance type, also incorrectly thought antibiotics should be regularly used for a deep cough or bronchitis, and many also wrongly assumed antibiotics might remedy a runny nose or green nasal discharge.

The 2013 survey did show some improvements compared to the 2000 results, however. The proportion of parents who rightly thought antibiotics didn’t work for nasal discharge increased from 23 percent to 49 percent among the commercially insured, and from 22 percent to 32 percent among Medicaid parents. Those who realize antibiotics rarely work for bronchitis rose from 9 percent to 14 percent among privately insured and from 5 percent to 12 percent for Medicaid families.

Part of the knowledge gap by insurance type may be due to the fact that families with Medicaid may be poorer and less educated, Dr. Sharon Meropol, an investigator at the Center for Child Health and Policy at Rainbow Babies and Children’s Hospital in Cleveland, noted in an editorial published with the study in Pediatrics.

“Often pubic insurance status is used as a proxy for the risk of decreased socioeconomic status and poor educational opportunities,” Meropol said by email. “Parents of disadvantaged children are at risk of decreased health literacy.”

Beyond spawning superbugs that are harder to treat, greater use of antibiotics may also be linked to an increased risk of a common form of juvenile arthritis, another study in Pediatrics suggests.

Researchers in the U.K. compared children ages 1 to 15 who were newly diagnosed with so-called juvenile idiopathic arthritis (JIA) to another group of similar kids without the condition.

Any exposure to antibiotics was associated with a doubled risk of developing JIA, and the risk was tripled for children who had more than five previous courses of antibiotics, the study found.

While the study can’t show that antibiotics cause JIA, it joins a growing body of research exploring the connection between antibiotic use and the development of chronic disease – research that offers an added incentive for overuse to be curbed, Dr. Jennifer Goldman, an infectious disease researcher at Children’s Mercy Hospitals & Clinics in Kansas City, wrote in an editorial.

It’s possible that antibiotics may contribute to changes in healthy bacteria in the gut, known as the microbiome, which could potentially lead to JIA and other diseases, said Dr. Daniel Horton, a researcher at Rutgers Robert Wood Johnson Medical School and lead author of the JIA study.

“We can’t say with certainty that it is the antibiotics that cause arthritis,” Horton said by email. “That said, we need to acknowledge that antibiotics have a long – and growing – list of potential downsides, both short-term side effects including fever and allergic reactions and long-term risks such as drug resistance and the development of chronic diseases.”