The Microbiome and JIA
By: Brian Feldman | February 9, 2016 | What Caught Our Eye
In case you missed it, the microbiome is really hot news these days.
There are those who think the microbiome is the answer to everything, or at least really important; but, there are others who think, well… not so much. (For a balanced look, check out Hanage WP. Microbiology: Microbiome science needs a healthy dose of skepticism. Nature 2014;512:247–8.)
So it was with some interest that we read Daniel Horton’s paper in Pediatrics. In it he, and his team at U Penn, Rutgers, and the Alfred I. duPont Hospital for Children, suggest that “Antibiotic exposure may play a role in JIA pathogenesis, perhaps mediated through alterations in the microbiome.”
The team was interested in earlier reports that antibiotic use seems to lead to JIA. They were–rightly, we think–worried that people get antibiotics for infections, and maybe it was the infections, rather that the antibiotics, that led to children developing arthritis, or even, maybe, that children were being treated with antibiotics because they had early symptoms of JIA.
Horton and the team were determined to figure this out by doing a study that wouldn’t mix these things up. They had access to the UK health improvement network, which is a really big EMR database from over 500 UK general practices. The children they looked at were followed, essentially, from birth. They were able to pick out the children that developed arthritis, and when. They were also able to see when the children were given (or at least prescribed) antibiotics in the years just before developing arthritis. They matched each arthritis child with 10 who didn’t develop arthritis to compare antibiotic use. Then they used some fancy epidemiologic mojo to try and get rid of the problems of the earlier study.
What they found was that children who developed arthritis had twice the odds of having had a prescription for antibiotics than children who didn’t develop arthritis. Horton and his team made some pretty convincing arguments about why – i) infections being the cause of the arthritis, and ii) antibiotics being used to treat early symptoms of arthritis – weren’t enough (likely) to explain away all of this relationship.
Is it the microbiome? Is there something else that explains this relationship? Well, antibiotics certainly do change around the bacteria (at least, that we are good at measuring) from our gut (at least, those portions that we can measure from). This will likely take some time to sort out, but certainly Dan Horton’s paper gives us some food for thought.
 Johnson CL, Versalovic J. The human microbiome and its potential importance to pediatrics. Pediatrics 2012;129:950–60
 Horton DB, Scott FI, Haynes K, Putt ME, Rose CD, Lewis JD, et al. Antibiotic Exposure and Juvenile Idiopathic Arthritis: A Case-Control Study. Pediatrics 2015;136:e333–43
 Arvonen M, Virta LJ, Pokka T, Kröger L, Vähäsalo P. Repeated exposure to antibiotics in infancy: a predisposing factor for juvenile idiopathic arthritis or a sign of this group’s greater susceptibility to infections? J Rheumatol. 2015;42(3):521–526