Atherogenic Lipid Profile in Non-Obese Adults with Untreated Obstructive Sleep Apnea

Background/Objectives: Obstructive sleep apnea (OSA) is associated with dyslipidemia, but obesity is a major potential confounder. We investigated whether untreated OSA is associated with an adverse atherogenic lipid profile in non-obese adults. Methods: This retrospective single-center study included 104 eligible non-obese adults selected from 703 consecutive patients undergoing respiratory polygraphy; 76 had OSA and 28 did not. Fasting lipid measurements obtained during routine clinical care were retrospectively retrieved from medical records. The Atherogenic Index of Plasma (AIP) was the primary lipid outcome, with additional analyses of conventional lipid components and supportive atherogenic indices. The primary model adjusted for age, sex, body mass index, and statin therapy. Results: AIP was higher in participants with OSA than in those without OSA (−0.104 ± 0.303 vs. −0.266 ± 0.296; p = 0.020). After adjustment, OSA remained associated with higher AIP (β = 0.150; 95% CI, 0.009 to 0.290; p = 0.038). OSA was also associated with lower HDL cholesterol (adjusted β = −7.89 mg/dL; 95% CI, −15.03 to −0.76), whereas LDL cholesterol and total cholesterol showed no clear differences. No clear relationship emerged between AIP and conventional measures of OSA severity. Conclusions: In non-obese adults, untreated OSA was associated with an adverse atherogenic lipid profile characterized by higher AIP and predominantly lower HDL cholesterol. These findings suggest that lipid alterations may accompany OSA even without overt obesity, without a clear relationship with conventional measures of OSA severity.