The influence of socio-economic status on the severity of obstructive sleep apnea: a cross-sectional observational study.

There is limited evidence about the effect of socio-economic status (SES) on the severity of obstructive sleep apnea (OSA). We aimed to investigate this relationship in a referral population in Greece, with regards to other established risk factors. We used a retrospective cross-sectional design to assess socio-economic status based on occupational activity in a sample of 282 OSA patients diagnosed in a public hospital sleep laboratory during one-year period. Demographic, anthropometric and social characteristics, as well as the Epworth sleepiness scale (ESS) scores and apnea-hypopnea indexes (AHI) of subjects in each socio-economic class were recorded and statistically significant differences were explored in univariate and multiple regression analysis. 99 (35.1%) of the subjects were categorized in the upper, 70 (24.8%) in the intermediate and 113 (40.1%) in the working class. Subjects of the intermediate class had significantly larger neck circumference than those of the upper class (=0.022). Neither class differed significantly in terms of ESS score and intermediate class had a trend for higher AHI than upper class (=0.075 in univariate and =0.082 in multivariate analysis). Age (=0.020) and occasional alcohol consumption (=0.022) were independent negative and neck circumference (<0.001) positive correlates of the variance in ESS score, while body mass index (=0.004), neck circumference (<0.001), being married (=0.014) and current smoker (=0.025) were independent positive correlates of the variance in AHI. SES has a minor effect on OSA severity that is only partially accounted for by other known risk factors. Neck circumference was found to be the most useful predictor of both subjective daytime sleepiness and severity of respiratory events during sleep.