In the US alone, around 300,000 children each year have their tonsils surgically removed to improve breathing while sleeping or reduce recurrent infection.
A study by an international team of researchers now suggests this relatively common procedure could increase a patient's risk of developing an anxiety-related disorder later in life.
Scientists Guangxi Medical University in China and the Karolinska Institute in Sweden analyzed data on over a million people held in a Swedish health registry, finding that a tonsillectomy was linked to a 43 percent increased risk of developing conditions such as post-traumatic stress disorder (PTSD), depression, or anxiety.
Being an observational study, the research can't determine the cause of this outcome, however the increased risk was present even after accounting for the sex of the participants, the age at which they had their tonsils out, any family history of stress-related disorders, and the education level of the parents (an indicator of socioeconomic status).
"These findings suggest a potential role of adenotonsillar diseases or associated health conditions in the development of stress-related disorders," the researchers write in their published paper.
Of the conditions identified, PTSD presented the greatest risk increase; a rise of some 55 percent was shown for those who had tonsillectomies earlier in life, compared with those who hadn't.
The researchers compared siblings in some families to control for certain genetic and environmental factors. Even among this sample there was a 34 percent greater risk of anxiety disorders for those family members who had their tonsils removed.
"We found that although the risk increase appeared to be greatest during the first years following surgery, an increased risk of stress-related disorders was still noted more than 20 years after the surgery," write the researchers.
Being a nationwide study with a large sample size, the results provide credible evidence for some kind of link between the surgery and declines in mental health. But what's behind the association?
While we can live without our tonsils, they do help to fight infection, so our bodies are more vulnerable without them. It's also possible that in some cases the reason for the tonsillectomy – like persistent inflammation – might also be the reason for the anxieties later in life.
Previous studies have linked the removal of the tonsils to increases in other health problems, including autoimmune diseases and cancer – and we now have another important consideration to weigh up.
Yet limited to data in a medical registry, the researchers could not take into account clinical characteristics associated with the surgery which could provide crucial insights into the connection. The team also acknowledge challenges in validating and generalizing their records of certain stress-disorders, leaving room for future studies to expand upon.
"If our findings here are validated in future studies of independent study populations, mechanistic studies would be needed to disentangle the role of human tonsils and their diseases, via inflammation or other associated health conditions, in the development of psychiatric disorders in general and stress-related disorders specifically," write the researchers.
The research has been published in JAMA Network Open.
