Dyslipidemia in obstructive sleep apnea (OSA) has been attributed to confounding obesity and/or diabetes. This study aimed to examine lipid profiles in non-diabetic, non-obese patients with OSA and identify the possible effects of age and sex.

We retrospectively evaluated the lipid parameters of 3050 adults who underwent polysomnography. A total of 2168 patients were excluded due to obesity (BMI ≥ 30 kg/m2), diabetes, alcoholism, untreated hypothyroidism, lipid-lowering drug use, missing sleep data, or treatment for suspected OSA.

Of 882 patients (75% males, aged 46.8 ± 12.2 years) included in the study, 88.4% had OSA. Levels of total cholesterol (p = 0.003), LDL-cholesterol (p = 0.005), non-HDL-cholesterol (p = 0.001), and triglycerides (p = 0.007) were significantly higher in patients with OSA than those without, whereas HDL-cholesterol levels did not differ. The proportion of patients with hypercholesterolemia and/or elevated non-HDL-cholesterol (> 160 mg/dL) was significantly higher in OSA than non-OSA. Correlation analyses by sex revealed stronger and more significant relationships between lipid parameters and AHI in women than men (r = 0.135, p < 0.001 vs. r = 0.080, p = 0.043 for total cholesterol; r = 0.111, p < 0.001 vs. r = 0.080, p = 0.046 for non-HDL-cholesterol; r = 0.122, p < 0.001 vs. r = 0.061, p = 0.107 for LDL-cholesterol, respectively). In regression analysis, the rate of hypercholesterolemia increased with age (p < 0.001 for women and p = 0.031 for men); non-HDL and LDL-cholesterol levels significantly increased with OSA severity (p = 0.035 and p=0.023) and age (p = 0.004 and p=0.001) in women.

After excluding confounding obesity and diabetes, patients with OSA have impaired lipid profile including total cholesterol, LDL-cholesterol, non-HDL-cholesterol, and triglycerides. A significant association between dyslipidemia and OSA severity was observed in women but not men.