Primary outcome variables: tumor necrosis factor alpha (TNFα); plasma norepinephrine, and free fatty acids. Secondary biomarkers: Interleukin 6 (IL-6), urinary norepinephrine; urinary normetanephrine; glucose, Intercellular Adhesion Molecule (ICAM), leptin. Monocytes will be separated from each blood sample (before, during and after sleep) and RNA extracted. Expression of key genes will be assessed by RT-PCR and microarray studies will be performed in a subset of subjects to assess changes in expression of all genes as a result of OSA. We will evaluate: a)whether individuals with comorbidities have more oxidative stress and inflammatory change for equivalent degrees of OSA than individuals without such comorbidities; b) whether individuals with comorbidities have lower levels of protective mechanisms—melatonin, IL-10; c) different gene variants based on a genetic association study using a recently developed CV SNP array.