A Swedish study linked the surgical removal of the appendix and tonsils before the age of 20 with an increased risk of premature heart attack in a large population.
Tonsillectomy increased the risk by 44% (hazard ratio 1.44) and appendectomy by 33% (HR 1.33). The risk increases were just statistically significant, and were even higher when the tonsils and appendix were both removed. However, there was no risk association evident when the operations were performed in people over the age of 20.
Both the appendix and tonsils are lymphoid organs and thus components of the body's immune system, albeit of modest importance. The recurrence of tonsillitis and appendicitis - caused by infection - are the usual reasons for removal. Behind the study lay evidence that removal was associated with moderate long-term effects on the immune system and alterations in risk for some autoimmune disorders. Studies suggest that between 10 and 20% of all young people have tonsils or appendix removed.
"Given the strong biological and epidemiological evidence linking inflammation with coronary heart disease," said investigator Dr Imre Janszky from the Department of Public Health Science of the Karolinska Institute in Stockholm, "one might anticipate that surgical removal of the tonsils and appendix, with their consequent effects on immunity, might also have a long-term effect on CHD. However, we were aware of no studies evaluating the potential effects of appendectomy or tonsillectomy on atherosclerosis or CHD risk."