Having tonsils removed in childhood is linked to a greater risk of arthritis in old age, a study suggests.
Those who had the procedure while young were around a third more likely to develop a type of chronic inflammatory arthritis, ankylosing spondylitis.
People were more at risk if they had an older sibling, Swedish researchers found, suggesting early life environmental factors play a role in the disease.
The study involved almost 7,000 people with the disease, diagnosed between January 2001 and December 2022.
People were analysed according to early life risk factors including mother’s age at delivery, weight (BMI) in early pregnancy, length of pregnancy, baby’s birthweight and delivery type.
Swedish experts say tonsil removal was associated with a 30 per cent heightened risk of developing arthritis in old age (stock image)
Other factors considered were number of siblings, serious childhood infections from birth up to the age of 15 and tonsil and appendix removal before the age of 16.
Researchers found those with older siblings were at between 12-15 per cent heightened risk while serious childhood infections were associated increased the chances by 13 per cent.
However, tonsil removal was associated with a 30 per cent heightened risk of the condition, typically characterised by inflammation of the spine, joints, and tendons, resulting in pain, stiffness, and fatigue.
Being part of a multiple birth raised the risk by almost a quarter (23 per cent) while being born in the summer or autumn months carried a significantly lower risk than being born in the winter, according to the findings in the BMJ.
Scientists speculate the increased risk may be due to infants with older siblings being more exposed to infections early in life while tonsillectomies were often carried out following infections.
The researchers then carried out a sibling comparison analysis, which adjusts for potentially influential environmental factors shared within families.
This analysis indicated an 18 per cent heightened risk for one older sibling compared with none, rising to a 34 per cent for two or more older siblings and 36 per cent for those who had tonsils out.
The researchers conclude: ‘Having older siblings and a history of tonsillectomy in childhood were independently associated with development of [ankylosing spondylitis], even after adjustment for family shared factors in a sibling comparison analysis.
‘This strengthens the hypothesis that childhood infections play a role in the aetiology of [the condition].’