To the Editors: Sleep apnoea in Asians and Caucasians: comparing apples and oranges

To the Editors: We read with great interest the recent study in the European Respiratory Journal by Yamagishi et al. [1]. The study sheds new light on our understanding of ethnic differences in susceptibility to obstructive sleep apnoea (OSA). Previous studies have shown consistently that among patients referred to sleep laboratories, Asians present a higher apnoea/hypopnoea index (AHI) than Caucasians matched for age and body mass index (BMI). Conversely, when matched for AHI, Asians have a lower BMI than Caucasians. These observations have lead to the concept that Asians are at increased risk of OSA [2]. One attractive explanation is that Asians have decreased cranial base dimensions that would render the upper airways more …