title: What can blood biomarkers tell us about cardiovascular risk in obstructive sleep apnea?
abstract: BACKGROUND
  Despite its high prevalence and frequent association with multiple comorbidities, including hypertension, heart disease, and stroke, obstructive sleep apnea (OSA) still lacks appropriate tools for cardiovascular risk assessment and stratification. Circulating biomarkers represent a safe, convenient, and inexpensive possibility, and several studies have been performed to define an ideal marker in this context. Additionally, biomarkers can provide insight into the pathological mechanisms of the disease and suggest new therapeutic approaches.
  
  
  METHODS
  In the present review, the authors critically analyze the biomarkers of cardiovascular risk currently available and other potential markers, including brain natriuretic peptide, C-reactive protein, tumor necrosis factor alpha (TNF-alpha), interleukin 6 (IL-6), cysteine, homocysteine, free fatty acids, 8-isoprostane, gamma-glutamyl transferase, glycated hemoglobin, adipokines, and adhesion molecules.
  
  
  CONCLUSIONS
  The results clearly demonstrate that the relationship between specific biomarkers and OSA is often influenced by age, gender or ethnicity, which has hindered the identification of a unique marker for the evaluation of all patients with OSA. Moreover, given the frequency of comorbidities in OSA, which, by themselves, increase the cardiovascular risk, all confounding factors must be considered in the evaluation of these biomarkers.
authors.affiliation: Department of Medicine, Universidade Federal do Ceará, Rua Prof. Costa Mendes, 1608/4° andar, 60430-140, Fortaleza, CE, Brazil.
authors.forename: Ivan Guerra
authors.initials: IG
authors.lastname: de Araújo Freitas
authors.forename: Pedro Felipe Carvalhedo
authors.initials: PF
authors.lastname: de Bruin
authors.forename: Lia
authors.initials: L
authors.lastname: Bittencourt
authors.forename: Veralice Meireles Sales
authors.initials: VM
authors.lastname: de Bruin
authors.forename: Sérgio
authors.initials: S
authors.lastname: Tufik
mesh_terms: D015415:Biomarkers / Q000097:blood*; D002318:Cardiovascular Diseases / Q000175:diagnosis* / Q000503:physiopathology*; D006801:Humans; D012307:Risk Factors; D020181:Sleep Apnea, Obstructive / Q000150:complications / Q000175:diagnosis* / Q000503:physiopathology*; D013223:Statistics as Topic
chemical_list: D015415:Biomarkers