Interaction effects between characteristics of obstructive sleep apnea and obesity on dyslipidemia.

Objectives Obstructive sleep apnea (OSA) and obesity often coexist, and both can increase the risk of dyslipidemia. However, the interaction effects between the characteristics of OSA and obesity on dyslipidemia are not yet known. This study was performed to investigate this issue. Methods Basic characteristics, polysomnography data, and biochemical markers of patients with suspected OSA seen at the First Affiliated Hospital of Nanchang University were collected. Serum lipid levels were compared after adjusting for multiple confounders. We used binary logistic regression models to assess the interaction effects of the oxygen desaturation index (ODI) and obesity, and the apnea-hypopnea index (AHI) and obesity, on dyslipidemia. Results A total of 343 patients were included in the study. After adjusting for multiple confounders, there were no differences in serum lipid levels between non-obese or obese patients with an AHI ≤ 30 and AHI > 30, and no interaction effect between the AHI and obesity on dyslipidemia. Obese patients, but not non-obese ones, with an ODI > 37.5 had significantly higher total cholesterol (TC) levels, and higher TC/high-density lipoprotein cholesterol (HDL-C) ratios, than patients with an ODI ≤ 37.5. In addition, a significant positive multiplicative interaction effect between obesity and the ODI was found on hyper-TC (odds ratio [OR] = 3.459; 95% confidence interval [CI] = 1.104, 10.838; p = 0.03). Conclusion A positive interaction effect was detected between obesity and intermittent hypoxia on dyslipidemia. Therefore, further attention should be paid to dyslipidemia in obese patients with intermittent hypoxia.