WEDNESDAY, June 1 (HealthDay News) -- Although the tonsils and appendix are not considered vital to the body, Swedish researchers have found that people who had them taken out before the age of 20 may be at a slightly greater risk of an early heart attack.

The new study linked the role of the appendix and the tonsils in the body's immune system with the increased risk for heart disease.

"Given the strong biological and epidemiological evidence linking inflammation with coronary heart disease [CHD], 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," investigator Dr. Imre Janszky, from the department of public health science of the Karolinska Institute in Stockholm, said in a news release from the European Society of Cardiology.

"However, we were aware of no studies evaluating the potential effects of appendectomy or tonsillectomy on atherosclerosis or CHD risk," Janszky added.

Persistent infections force roughly 10 percent to 20 percent of young people to have their tonsils or appendix removed, the researchers noted.

In conducting the study, published online June 1 in the European Heart Journal, the researchers identified 54,449 appendectomies and 27,284 tonsillectomies performed on Swedish residents under the age of 20 years. The patients were followed for an average of 23.5 years to determine how many would suffer fatal or non-fatal heart attacks.

Within the follow-up period, a total of 89 of the participants who had had appendectomies and 47 of those who had had tonsillectomies experienced a heart attack, the investigators found.

The study authors concluded that tonsillectomy increased the relative risk of a heart attack by 44 percent, and appendectomy increased the relative risk by 33 percent. The risk was slightly higher for those who had both their tonsils and appendix removed, the results showed.

Janszky noted, however, that the absolute numbers of heart attack cases in the study were small, with slightly more than 400 and 200 total cases of heart attack in more than 7.5 million and nearly 4 million person-years of follow-up, respectively.

"As expected from the young age of the population," he said, "the observed moderate increases in relative risk actually corresponded to very small risk increases in absolute terms."

And because the study was limited to childhood procedures and participants were still relatively young during the follow-up period, the findings may not apply to older people at greater risk for heart disease, the researchers added.

The researchers also pointed out that appendectomies or tonsillectomies could have other "complex" and long-term side effects on the immune system, including decreased production of immunoglobulins.

More information

The American Heart Association has more about risk factors for heart attack.