People who have their tonsils or adenoids removed before age 9 years are at higher risk for respiratory, infectious, and allergic diseases up to the age of 30 years, a population-based study of almost 1.2 million patients suggests.

“We found that tonsillectomy was associated with a nearly tripled risk of upper respiratory tract diseases, and that adenoidectomy was associated with doubled risk of [chronic obstructive pulmonary disease] and upper respiratory tract diseases and nearly doubled risk of conjunctivitis,” Sean Byars, PhD, from the University of Melbourne in Victoria, Australia, and colleagues write.

“Physicians often remove adenoids and tonsils to treat recurrent tonsillitis or middle ear infections,” they add.

“Understanding the longer-term impact of these surgeries is critical because the adenoids and tonsils are parts of the immune system, have known roles in pathogen detection and defense, and are usually removed at ages when the development of the immune system is sensitive.”