Influence of genetic ancestry on the risk of obstructive sleep apnoea syndrome.

The aim of the present study was to evaluate the influence of ethnicity on the risk of developing obstructive sleep apnoea syndrome (OSAS) using genomic analysis methods to estimate ancestry. DNA samples were obtained from 1,010 individuals participating in the São Paulo Epidemiologic Sleep Study, who underwent full-night polysomnography. A total of 31 genetic ancestry-informative markers were selected in order to estimate individual admixture proportions. Of patients with a diagnosis of OSAS, a higher number self-reporting Caucasian ethnicity (65.3%), as well as an increased percentage of European ancestry (78.2±16.7%) and lower percentage of West African ancestry (16.1±15.3%), than among individuals without OSAS (53.6, 73.5±18.1 and 20.1±16.8%, respectively) (p<0.001) was observed. Moreover, after correcting for sex, age, body mass index and socioeconomic status, logistic regression demonstrated that European ancestry was significantly associated with an increased risk of manifesting OSAS (OR 2.80, 95% CI 1.11-7.09). Conversely, West African ancestry was associated with a reduced risk of the OSAS phenotype (OR 0.26, 95% CI 0.09-0.72). This is the first study to incorporate genomic analysis methods to measure the influence of ethnicity on the risk of OSAS. Since genetically determined ancestry may not capture unmeasured cultural and lifestyle differences, the contribution of environmental factors to the current findings should not be disregarded.