Plasma homocysteine levels in obstructive sleep apnea: association with cardiovascular morbidity.
OBJECTIVE
Obstructive sleep apnea (OSA) is associated with cardiovascular morbidity and mortality. Plasma levels of homocysteine are also associated with cardiovascular morbidity and mortality. We therefore investigated homocysteine and conventional cardiovascular risk factors in OSA patients with and without cardiovascular morbidity in comparison with normal control subjects and ischemic heart disease (IHD) patients without OSA.


METHODS
Technion Sleep Medicine Center, Haifa, Israel.


METHODS
Levels of homocysteine, cholesterol, low-density lipoprotein, high-density lipoprotein, triglycerides, creatinine, vitamins B(12) and B(6), and folic acid were determined in 345 participants after overnight fasting. These included OSA patients with IHD (n = 49), with hypertension (n = 61), or without any cardiovascular disease (n = 127). Two control groups were employed: IHD patients without or with low likelihood for sleep apnea (n = 35), and healthy control subjects (n = 73).


RESULTS
After adjustment for age, body mass index, creatinine, and existence of diabetes mellitus, OSA patients with IHD had significantly higher homocysteine levels (14.6 +/- 6.77 micromol/L) than all other groups including the IHD-only patients. Hypertensive OSA patients had comparable homocysteine levels to IHD patients (11.80 +/- 5.28 micromol/L and 11.92 +/- 5.7 micromol/L, respectively), while patients with OSA only had comparable levels to normal control subjects (9.85 +/- 2.99 micromol/L and 9.78 +/- 3.49 micromol/L, respectively). No differences in conventional cardiovascular risk factors or in vitamin levels were found between groups.


CONCLUSIONS
Patients with the combination of IHD and OSA have elevated homocysteine levels. We hypothesize that these results may be explained by endothelial dysfunction combined with excess free-radical formation in OSA patients.
Lavie
L
L
Unit of Anatomy and Cell Biology, Bruce Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, Haifa, Israel. lenal@tx.technion.ac.il
Perelman
A
A
Lavie
P
P
D000328:Adult; D004730:Endothelium, Vascular / Q000503:physiopathology; D005492:Folic Acid / Q000097:blood; D006710:Homocysteine / Q000097:blood*; D006801:Humans; D008297:Male; D008875:Middle Aged; D017202:Myocardial Ischemia / Q000097:blood* / Q000503:physiopathology; D011736:Pyridoxine / Q000097:blood; D012307:Risk Factors; D012891:Sleep Apnea Syndromes / Q000097:blood* / Q000503:physiopathology
D006710:Homocysteine; D005492:Folic Acid; D011736:Pyridoxine