title: Intermittent hypoxemia and OSA: implications for comorbidities.
abstract: OSA is a common chronic disorder that is associated with significant morbidity and mortality including cardiovascular, metabolic, and neurocognitive disease and increased cancer-related deaths. OSA is characterized by recurrent episodes of apneas and hypopneas associated with repetitive episodes of intermittent hypoxemia, intrathoracic pressure changes, and arousals. Intermittent hypoxemia (IH) is now being recognized as a potential major factor contributing to the pathogenesis of OSA-related comorbidities. OSA-related high-frequency IH is characterized by cycles of hypoxemia with reoxygenation that is distinctly different than sustained low-frequency hypoxia and contributes to ischemia-reperfusion injury. Data from both animal and human studies support mechanistic links between IH and its adverse impact at the tissue level. IH promotes oxidative stress by increased production of reactive oxygen species and angiogenesis, increased sympathetic activation with BP elevation, and systemic and vascular inflammation with endothelial dysfunction that contributes to diverse multiorgan chronic morbidity and mortality affecting cardiovascular disease, metabolic dysfunction, cognitive decline, and progression of cancer. Data from observational studies in large population groups also support the role for hypoxia in the pathogenesis of OSA comorbidity. Treatment with CPAP to reverse OSA-related symptoms and comorbidities has been shown to provide variable benefit in some but not all patient groups. Early treatment with CPAP makes intuitive sense to promote maximal functional recovery and minimize residual injury. More studies are needed to determine the interacting effects of IH and obesity, differential effects of both short-term and long-term hypoxemia, and the effect of CPAP treatment.
authors.affiliation: Division of Pulmonary, Critical Care, and Sleep Medicine, Mayo Clinic, Mayo Foundation for Medical Education and Research, Rochester, MN.. Electronic address: ndewan@creighton.edu.
authors.forename: Naresh A
authors.initials: NA
authors.lastname: Dewan
authors.affiliation: Department of Medicine, Creighton University and Pulmonary Section, Omaha VA Medical Center, US Department of Veterans Affairs, Omaha, NE; Population Health Sciences, School of Medicine and Public Health, Mayo Clinic, Mayo Foundation for Medical Education and Research, Rochester, MN; Population Health Sciences, School of Medicine and Public Health, Mayo Clinic, Mayo Foundation for Medical Education and Research, Rochester, MN.
authors.forename: F Javier
authors.initials: FJ
authors.lastname: Nieto
authors.affiliation: Division of Pulmonary, Critical Care, and Sleep Medicine, Mayo Clinic, Mayo Foundation for Medical Education and Research, Rochester, MN.; University of Wisconsin-Madison, Board of Regents of the University of Wisconsin System, Madison, WI; and Sleep and Cardiovascular Clinical Research Unit, College of Medicine, Mayo Clinic, Mayo Foundation for Medical Education and Research, Rochester, MN; Sleep and Cardiovascular Clinical Research Unit, College of Medicine, Mayo Clinic, Mayo Foundation for Medical Education and Research, Rochester, MN.
authors.forename: Virend K
authors.initials: VK
authors.lastname: Somers
mesh_terms: D002318:Cardiovascular Diseases / Q000453:epidemiology*; D002908:Chronic Disease; D015897:Comorbidity; D014943:Global Health; D006801:Humans; D000860:Hypoxia / Q000453:epidemiology*; D012307:Risk Factors; D020181:Sleep Apnea, Obstructive / Q000453:epidemiology*