INTRODUCTION
Adenotonsillectomy (AT) is one of the most common surgical procedures performed in children. The most frequent indications for AT are obstructive sleep apnea (OSA), refractory or recurrent sinusitis or middle ear infections, and recurrent infection of the tonsils and/or adenoids. Since birth to adolescence, several mucosal immune systems develop in the upper and lower respiratory tract. The nasopharyngeal-associated lymphoid tissues comprise the nasopharyngeal adenoidal tissue nasopharyngeal, tubal, palatine, and lingual tonsils. Hypertrophy or frequent episodes of inflammation can occur within adenotonsillar tissues due to continuous exposure to antigens, such as micro-organisms and allergens [1,2].
Asthma is a common chronic disease in children and its association with sleep-disordered breathing (SDB) has been observed by our group and others [3-5]. Furthermore, SDB may affect asthma control [6]. Although, causality has not been proven [4].
Published evidence regarding the effect of AT on asthma in children is controversial. Some observational studies have demonstrated that AT has a positive effect on childhood asthma by reducing the effect of stressors on the lower airway, leading to decreased inflammation and improved asthma control [7-9]. In most of these studies, adenotonsillar hypertrophy, and symptoms of sleep-disordered breathing, were the commonest indications for AT. In contrast, one cohort study showed that early-life adenoidectomy due to recurrent otitis media or otitis media with effusion, may contribute to the subsequent development of asthma in children [10], and a recent South Korean cohort study showed that the adjusted asthma hazard ratio was 2.25 in the AT vs. non-AT groups [11]. However, the only randomized clinical trial (RCT) that has analyzed the role of adenoidectomy in the development of atopy and respiratory function changes characteristic of asthma in young children, showed that adenoidectomy did not promote the occurrence of asthma or allergy [12]. Since tonsils have an important function in the differentiation of B lymphocytes to antibody-producing plasma cells and were not removed in that RCT; results should be interpreted with caution.
Therefore, our objective was to conduct a post-hoc analysis of CHAT [13], the largest RCT of AT in children with OSA to test the hypothesis that AT would result in fewer wheezing episodes in children randomized to AT vs watchful waiting.