FOS and sleep apnea syndrome: Another limitation of our study is that measures of oxygen saturation (avgO2 and minO2) are not specific to SDB and can be affected by pulmonary and cardiac function; however, the reversal of gene expression changes by CPAP treatment indicates that SDB, rather than other disorders, was the likely cause of the gene expression changes in RAB40 and CD1D observed in MESA and FOS.