Tonsillitis May Predispose People to Ankylosing Spondylitis, Study Suggests

People who are diagnosed with ankylosing spondylitis (AS) are more likely to have had tonsillitis than those without this disease, a study found, suggesting that tonsillitis might predispose a person for AS.

“Association between tonsillitis and newly diagnosed ankylosing spondylitis: A nationwide, population-based, case-control study” was published in PLOS ONE.

Exactly what causes AS is not clear, but both genetic and environmental factors likely play a role. Some recent research has suggested that inflammatory conditions like tonsillitis could predispose people to autoimmune conditions like rheumatoid arthritis — but what about AS?

To find out, researchers analyzed data from the National Health Insurance Research Database of Taiwan, which holds information for patients covered by Taiwan’s public insurance program, covering over 99% of people in the country.

They identified 37,002 people who were diagnosed with AS between 2005 to 2012, as well as 222,012 people matched to the AS group by age and sex to serve as controls. Researchers then looked at the frequency of previous tonsillitis and other inflammatory conditions in these two groups.

People with AS were more likely to have had tonsillitis, as well as appendicitis and periodontitis (gum disease). This association held true when the researchers analyzed different subtypes of tonsillitis (i.e., acute and chronic) separately, and it was slightly stronger in female than in male patients.

More tonsillitis-related hospital visits and high tonsillitis-associated costs were also linked with higher odds of developing AS. The researchers proposed that both are indicative of more severe tonsillitis that required more intensive care. But such information is not recorded in the insurance database analyzed, so a direct correlation with disease severity was impossible to draw.

This study shows a link between tonsillitis and AS, but it was not designed to detect a cause-and-effect relationship, just an association. It’s not clear why tonsillitis might predispose people toward AS, though the researchers think it may have to do with immune imbalances following tonsil inflammation, which sets the stage for inflammatory conditions like AS. At present,  this is mostly speculation; more research will be needed to understand the interplay between tonsillitis and AS.

“We … postulate that the alteration of immune tolerance in patients with tonsillitis might lead to dysregulated inflammation in autoimmune arthritis including AS; therefore, tonsillitis might lead to the diagnosis of AS due to the exacerbated spondylitis,” the researchers noted.

“In conclusion, we identified an increased risk for AS in patients with tonsillitis,” they wrote, adding, “[m]ore studies are warranted to explore the underlying mechanisms linking tonsillitis with AS and to investigate the roles of tonsillitis in other autoimmune diseases.”