One big difference between the study by Apostolidou et al8 and the other studies is that the Greek population tends to be racially and ethnically homogeneous, whereas most of the other studies were conducted in the United States and included a substantial number of African-American children. All children in the current study were of Greek ethnicity (personal communication; A Kaditis, MD; August 2008). In both pediatric and adult populations, the prevalence of OSAS is increased in African Americans, even when correction is made for confounding factors such as obesity and socioeconomic status1,10–12; OSAS is more likely to persist postoperatively in African-American children.13 Other populations, such as Asians, also have an increased prevalence of OSAS compared to body mass index-matched control subjects.14 The reasons for these racial differences are unknown. Factors such as craniofacial differences, atopy, the home environment, and differences in ventilatory control may all play a role. For example, it is possible that obese African-American children have a different craniofacial structure and differences in regional fat distribution around the airway, thus rendering them less responsive to adenotonsillectomy.