Children who were prescribed antibiotics had twice the risk of developing juvenile arthritis compared to children the same age who were not prescribed antibiotics, according to a study from Rutgers University, University of Pennsylvania and Nemours A.I. duPont Hospital for Children.

The more antibiotics courses prescribed, the higher the risk associated, they found. Risk was highest within one year of taking antibiotics. Earlier studies have shown that about a quarter of antibiotics prescribed to children, and half of antibiotics prescribed for acute respiratory infections, are probably unnecessary.

The latest Centers for Disease Control and Prevention statistics say that between 4,300 and 9,700 children under the age of 16 are diagnosed with juvenile arthritis a year. The condition is a form of autoimmune disease, and involves chronic inflammation of the joints and eyes that can lead to pain, vision loss, and disability.

Genetics accounts for only about one quarter of children developing arthritis, and that means environmental triggers may also play an important role in the onset of disease.

Lead author Daniel Horton, a postdoctoral research fellow working in the Department of Pediatrics at Rutgers Robert Wood Johnson Medical School, said:

“Our research suggests another possible reason to avoid antibiotic overuse for infections that would otherwise get better on their own.”

The researchers also found that upper respiratory tract infections treated with antibiotics were more strongly associated with juvenile arthritis than untreated upper respiratory tract infections. They also observed that antiviral and antifungal drugs were not linked to juvenile arthritis, suggesting that risk for arthritis was specific to antibacterial medicines.

“This is an extremely important clue about the etiology of this serious and potentially crippling disease. If confirmed, it also provides a means for preventing it,” said Brian Strom, chancellor of Rutgers Biomedical and Health Sciences and a senior author on the study.

Viral infections have been proposed as being triggers for juvenile arthritis, however, multiple studies argue against this hypothesis. What is clear, said Horton, is that children with juvenile arthritis have a raised risk of serious infections, partially due to the immune system not protecting against infections as well as it should.

“So an alternative explanation to our findings is that this abnormal immune system makes children more susceptible to serious infection even before they are diagnosed with arthritis. Under this hypothesis, antibiotics would be a marker for abnormal immunity rather than a direct cause of arthritis,” Horton added. “A majority of children get antibiotics, but only about 1 in 1,000 get arthritis. So even if antibiotics do contribute to the development of arthritis, it’s clearly not the only factor.”

More research is needed to confirm the findings and to clarify the mechanism that could be linking antibiotic use and arthritis in children.

Daniel B. Horton, MD, MSCE, et al. Antibiotic Exposure and Juvenile Idiopathic Arthritis: A Case–Control Study Pediatrics doi: 10.1542/peds.2015-0036

Photo: mario/flickr

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