Impacts of Tonsillectomy on Growth Trajectories in Children

ABSTRACT Objectives To characterize long‐term growth trajectories after tonsillectomy and examine whether they differed according to preoperative body size. Methods This retrospective cohort study included 117 children aged 5–9 years who underwent tonsillectomy between 2008 and 2020. Longitudinal BMI, weight, and height z score were analyzed using linear mixed‐effects models. Baseline BMI z score was modeled continuously, with adjustment for baseline age, sex, and tonsil size. Primary analyses included Years 1 through 5. Results Lower baseline BMI z score was associated with a greater increase in BMI z score from preoperative assessment to Year 1. Little change or a modest decrease was estimated at higher baseline values. For each 1‐unit higher baseline BMI z score, the estimated preoperative‐to‐Year 1 change was 0.206 smaller ( β = −0.206; 95% CI, −0.319 to −0.094; p < 0.001), reaching zero at approximately +1.0. However, the overall baseline BMI z score‐by‐postoperative year interaction was not significant ( p = 0.817), indicating no difference in BMI trajectory shape during Years 1 through 5 by baseline BMI z score. Weight z score showed a similar pattern, whereas height z score showed less variation. Overall interactions were nonsignificant for weight ( p = 0.541) and height ( p = 0.119). Conclusions Lower preoperative BMI z score was associated with greater early postoperative increases in BMI z score, whereas little change or a modest decrease was estimated at higher baseline values during postoperative Year 1. Thereafter, changes during Years 1 through 5 did not differ significantly by baseline BMI z score. Level of Evidence 4 (Retrospective cohort study).