Study: Tonsil and adenoid removal associated with respiratory diseases, allergies and infections
Health data from more than one million Danish children serves as foundation for University of Copenhagen study reporting considerably higher risks for certain respiratory diseases, among other things, as a result of tonsil removal.
In a comprehensive study, evolutionary biologists from the University of Copenhagen’s Department of Biology, the University of Melbourne and Yale have demonstrated that people who had their tonsils and adenoids removed during childhood, were subject to an increased risk of developing respiratory diseases, allergies and infectious diseases later on in life.
The researchers analyzed health data from nearly 1.2 million Danish children born between 1979 and 1999, from the age of 10 and up to 30-years-old.
Of the 1.2 million children, more than 60,000 had their tonsils, adenoids, or both removed before the age of 9. The researchers discovered a significantly increased risk of being afflicted by diseases including asthma, pneumonia, chronic obstructive pulmonary disease and other respiratory infections, compared with the group whose tonsils were not removed.
"In particular, we found a significant link between having had tonsils or adenoids removed and upper respiratory tract disease later on in life," says Professor Jacobus Boomsma of the University of Copenhagen’s Department of Biology.
Tonsils are not there by chance
Tonsils and adenoids serve a role in the human immune system and contribute to white blood cell production. They also monitor what passes through the throat and appear to 'train' the immune system of children.
"Our research always begins with evolutionary assumptions – in this case, that the immune organs surrounding our airways are not coincidental, but there due to some sort of useful biological adaptation. As such, it is reasonable to ask if removing them provokes any long-term consequences," states Boomsma
Furthermore, the study suggests an increased risk of pneumonia and asthma later in life as a result of tonsil and adenoid removal, as well as a far higher incidence of nose and eye allergies.
"The extensive dataset from Denmark provides us with unique opportunities to look at broader contexts, as we are able to consider a range of other health factors and socio-economic differences among families, which results in more accurate results," adds Boomsma.
Operations offer mixed long-term results
Researchers were careful to study whether tonsillectomies and adenoidectomies had any real impact on the ailments that they were intended to remedy. The results were mixed.
"According to our study, adenoid removal reduces the risk of sleep disorders and throat inflammation to a slight degree, but increases the risk of middle ear infections. Therefore, the long-term benefits remain unclear," explains Boomsma.
The article emphasizes that the potential long-term effects of tonsil and adenoid removal have not been documented until now, and that this study ought to catalyze renewed discussion in cases where non-surgical treatments are an option for young people suffering from breathing, sinusitis and otitis media problems.
Researchers point out that while there may be medical grounds for performing tonsillectomies and/or adenoidectomies, the study’s conclusions are clear and should be considered within the context of thorough individual assessments.
"We believe that our results are solid, not least because we have been able to clean our data by accounting for 18 other factors that might come into play. We would have liked to correct for smoking, but the health register lacked this information. Other Nordic countries have collected similar datasets for their populations for over roughly thirty years, so corresponding analyses would be of great interest," suggests Boomsma.
Main study results
- There is a nearly threefold increase in the relative risk for upper respiratory system diseases after tonsils have been removed, corresponding to an almost 19% increase in absolute risk of being subject to one of these diseases before the age of 30. As such, every fifth operation leads to an unintended diagnosis later in life. Figures for adenoid removal indicate that relative risk is doubled, corresponding to an almost 11% increase in the absolute risk and an unintended diagnosis for every ninth operation.
- Diseases with elevated risk levels occur at least once per every 50 operations, including asthma, as well as an increased incidence of general infectious disease, such as pneumonia.
- Significant increases in relative risk were presented for rarer diseases including chronic obstructive pulmonary disease and eye allergies.
- Lower, but statistically significant relative risk increased for approximately ¾ of the 28 diseases encompassed by the study.
- The overall impression was that numerous, varied health consequences may occur later on in life as a result of these pediatric surgical procedures, and that correlations can be discovered only by using extremely large datasets.
The study used the health register data of 1.2 million Danish children from 1979-2009. The study focused on three types of surgical procedures: tonsillectomies, adenoidectomies and the removal of both at once. In all, approximately 60,000 people fell within these categories. The researchers registered 28 different diseases later in on life. The diseases included immune diseases, as well as other disease types that ought to have been unrelated to these childhood interventions.
The statistical calculations produced estimates for both relative and absolute risk. With rare diseases, a large increase in relative risk only lead to a limited increase in absolute risk. Conversely, for more common ailments, a limited increase of relative risk lead to a considerably higher absolute risk. As a result, researchers adopted the most clinically practical scale for each disease, namely, the number of pediatric operations, prior to noting a statistical increase in the number of unintended diagnoses later on in life.