Elevated C-Reactive Protein in Patients With Obstructive Sleep Apnea

Abstract

Background-Obstructive sleep apnea (OSA) has been increasingly linked to cardiovascular and cerebrovascular disease.Inflammatory processes associated with OSA may contribute to cardiovascular morbidity in these patients. We tested the hypothesis that OSA patients have increased plasma C-reactive protein (CRP). Methods and Results-We studied 22 patients (18 males and 4 females) with newly diagnosed OSA, who were free of other diseases, had never been treated for OSA, and were taking no medications. We compared CRP measurements in these patients to measurements obtained in 20 control subjects (15 males and 5 females) who were matched for age and body mass index, and in whom occult OSA was excluded. Plasma CRP levels were significantly higher in patients with OSA than in controls (median Epidemiological studies show that an elevated CRP level in the high-normal (0.2 to 1.5 mg/dL) range in apparently healthy men and women is a strong predictor of cardiovascular risk. 7,8 In patients with acute coronary artery disease, stable angina pectoris, and a history of myocardial infarction, higher CRP is also associated with future cardiovascular events. 9 10 OSA results in repetitive and severe nocturnal hypoxemia and sleep disturbances. 11 The hypoxemia of high altitude results in increases in interleukin-6 (IL-6) 12 and CRP 12,13 in normal humans. Sleep deprivation also induces an increase in cytokines. 4,14 We tested the hypothesis that OSA patients have increased plasma CRP. MethodsWe compared subjects with moderate to severe OSA (apnea hypopnea index [AHI] Ն20) to those without OSA (AHI Յ5). We studied 22 patients (18 males and 4 females) with newly diagnosed OSA, who were free of other diseases, had never been treated for OSA, and were taking no medications. We compared CRP measurements in these patients to measurements obtained from 20 control subjects (15 males and 5 females) who were matched for age and body mass index (BMI), and in whom occult OSA was excluded. The control group was free of any acute or chronic cardiovascular, inflammatory, or sleep disorders, and no control subjects were taking medications at the time of the sleep study. The presence and severity of sleep apnea were determined by standard overnight polysomnography, including electroencephalography, electrooculography, electromyography, oximetry, thermistor measurements of airflow, and measurements of rib cage and abdominal movements when breathing. The sleep studies followed a split-night protocol. The first half of the study intended to diagnose OSA, with a therapeutic trial of continuous positive airway pressure during the second half of the night. An apnea was defined as complete cessation of airflow for at least 10 seconds. Hypopnea was defined as a reduction of respiratory signals for at least 10 seconds associated with oxygen desaturation of Ն4%. The AHI was calculated as the total number of respiratory events per hour of sleep.Baseline demographic data, heart rate, blood pressure (SpaceLabs blood pressure monitor 90207), and venous blood ...

Membrane Level of Omega-3 Docosahexaenoic Acid Is Associated with Severity of Obstructive Sleep Apnea

“…43 The underlying mechanisms are unclear at this time, but OSA is associated with hypertension, 44,45 a prothrombotic state, [46][47][48] and chronic inflammation. 2 There is also an association of OSA with susceptibilities to cardiac arrhythmias. [49][50][51][52] In conclusion, our study is the first to examine the relations between sleep disordered breathing and omega-3 FA levels.…”

Leukotriene Modifier Therapy for Mild Sleep-disordered Breathing in Children

“…Notwithstanding such considerations, the overarching concept emanating from this study supports the existence of a chronic inflammatory process in children with SDB. Indeed, C-reactive protein serum levels, an important systemic marker for inflammation, may be elevated in both children and adults with SA (20,44,45), even though this finding may not be consistently observed (46). Such elevations of C-reactive protein suggest that systemic processes may either initiate or maintain the localized inflammatory process and associated proliferative signaling within upper airway lymphoid tissues.…”

Increased arterial stiffness in obstructive sleep apnea: a systematic review

“…8 Although OSA patients commonly demonstrate one or more established cardiovascular risk factors, there is now a considerable body of evidence indicating that OSA itself is an independent cardiovascular risk factor. 3,[9][10][11][12][13][14][15][16] Arterial stiffness determines how quickly the pulse wave generated by the contracting heart travels to the periphery and is reflected back. The larger arteries of the cardiovascular system are critical in the conduction of blood flow to the periphery.…”