Siblings’ Risk of Adenoid Hypertrophy: A Cohort Study in Children

Background: The aim of this study was to compare adenoid size in preschool-age siblings using flexible nasopharyngoscopy examination (FNE) when they reach the same age. The occurrence of adenoid symptoms in these patients was also analyzed. This study was conducted to analyze the adenoid size in siblings when they reach the same age and substantiate a correlation between adenoid hypertrophy (AH) and adenoid symptoms. Methods: We analyzed and reported on the symptoms, ENT examination results, and FNE of 49 pairs of siblings who were examined at the same age. Results: There was a strong association in adenoid size between siblings when they are at a similar age (r = 0.673, p < 0.001). Second-born children whose older sibling had III(o) AH (A/C ratio > 65%) had a risk of III(o) AH 26 times greater than patients whose older sibling did not have III(o) AH (OR = 26.30, 95% CI = 2.82–245.54). Over 90% of snoring children whose siblings had confirmed III(o) AH would develop III(o) AH by the time they reach the same age. Second-born children in whom snoring occurs and whose older siblings have a III(o) AH have about a 46 times higher risk of III(o) AH compared to patients who did not meet these two conditions (p < 0.001, OR = 46.67, 95% CI = 8.37–260.30). Conclusions: A significant familial correlation between adenoid size in siblings when they reach the same age was shown. If the older sibling has a confirmed overgrown adenoid (III(o) AH) and their younger sibling presents adenoid symptoms, particularly snoring, it is highly probable that they will also have an overgrown adenoid.