The study, which is published online in the European Heart Journal, examined the national health records of every Swedish resident born between 1955 and 1970 and identified each one who had had tonsils and/or appendix removed. Each of these patients was then matched with five randomly chosen controls which had not had the operations. These subjects were then followed up through the health records for an average of 23.5 years to cross-check for the occurrence of fatal or non-fatal heart attack. Because the appendix and tonsils appear to have reduced function after adolescence, the primary analyses were restricted to individuals below the age of 20 at the time of surgery, which amounted to 54,449 appendectomies and 27,284 tonsillectomies.
The results showed that surgical removal of the appendix and tonsils before the age of 20 was associated with an increased risk of premature heart attack. Tonsillectomy increased the risk by 44 percent and appendectomy by 33 percent. The risk increases were statistically significant, and were even higher when the tonsils and appendix were both removed. However, there was no risk association evident when operations were performed in people over the age of 20.
– One must also remember that the absolute risk differences between subjects and control groups in the study were small, because of the young age of the participants, says Staffan Ahnve, Professor of Cardiovascular Medicine and Prevention, who led the study.
Tonsillitis and appendicitis caused by infection are the usual reasons for removal. Behind the study lay the knowledge that both the appendix and tonsils are lymphoid organs and thus components of the body’s immune system, although of modest importance, and that removal was associated with moderate long-term effects on the immune system and alterations in risk for some autoimmune disorders.
It is estimated that between 10 and 20 percent of all young people have tonsils or appendix removed. Staffan Ahnve is also a cardiologist and chief physician at the Karolinska University Hospital.
Childhood appendectomy, tonsillectomy, and risk for premature acute myocardial infarction – a nationwide population-based cohort study
Eur Heart J 2011; doi:10.1093/eurheartj/ehr137