Traditional cardiovascular risk factors but not homocysteine are associated with obstructive sleep apnea

The objective of this study was to determine if obstructive sleep apnea (OSA) subjects had elevated plasma homocysteine levels and a greater incidence of traditional cardiovascular risk factors. Case subjects (OSA group, n = 24) without cardiovascular disease had an apnea-hypopnea index of 5 or higher; control subjects without cardiovascular disease served as a non-OSA group (n = 65). Demographic and anthropometric (ie, weight, height, body mass index [BMI], neck, waist, and hip circumferences) data were collected. Systolic and diastolic blood pressure (DBP) were measured. Fasting venous blood samples were collected to determine total cholesterol, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, triglycerides, creatinine, homocysteine, vitamin B6, vitamin B12, and folate status. In univariate analysis, BMI; neck, waist, and hip circumferences; serum total cholesterol, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, and DBP were all positively associated with OSA. Plasma homocysteine concentration, however, had no effect on OSA. The age-adjusted odds ratio (OR) for all OSA and control subjects was significantly increased in the third tertile of homocysteine concentration (OR, 9.29; 95% CI, 1.25-69.12). However, the third tertile of plasma homocysteine showed no effect (OR, 3.24; 95% CI, 0.02-497.80) on OSA after additional adjustment for all cardiovascular risk factors. Homocysteine had no association with OSA; however, obesity, DBP, and serum total cholesterol are associated with OSA. Indices of central obesity (BMI and waist and neck circumferences) and a combination with DBP and serum total cholesterol level should be screened in patients with OSA.