Strong association was shown by the largest analysis between higher total cholesterol, lower high density lipoprotein cholesterol, higher low density lipoprotein cholesterol, elevated triglycerides, and several measures of obstructive sleep apnea severity in the study subjects which consisted of patients enrolled in the European Sleep Apnea Database.
8,592 participants who had not received physician diagnosis of hyperlipidemia and who were not taking lipid lowering drugs were included in this cross sectional analysis from the database cohort, which included data from 30 sleep centers across 20 countries in Israel and Europe. Subject mean age was 50.1 years old, 69% were male, BMI was 30.8 ± 6.6, and mean apnea hypopnea index was 25.7 ± 25.9 event/hour; abdominal obesity and BMI was controlled for. Independent relationship between measures of obstructive sleep apnea, apnea hypopnea index, oxygen desaturation index, mean and lowest oxygen saturation, lipid profile, total cholesterol, lower high density lipoprotein cholesterol, higher low density lipoprotein cholesterol, and fasting triglycerides was determined using general linear model analysis.
Findings showed dose response relationship between total cholesterol and oxygen desaturation index mean ±SE (mg/dL): 180.33 ± 2.46, 184.59 ± 2.42, 185.44 ± 2.42, and 185.73 ± 2.44; P <0.001 across ODI quartiles I-IV. Fasting triglyceride and LDL concentrations were predicted by apnea hypopnea index than by oxygen desaturation index. High density lipoprotein cholesterol was reduced significantly in the highest apnea hypopnea index quartile vs lowest mean ±SE (mg/dL): 48.8 ± 1.49 vs 46.50 ± 1.48; P=0.002. Morbid obesity was associated with lower total cholesterol and higher high density lipoprotein cholesterol values, geographical location was a lipid status factor with highest total cholesterol concentrations being recorded in Northern Europe. Obstructive sleep apnea was identified as an independent predictor of potentially harmful lipid levels, according to the researchers.
Multicenter, multinational design and large sample size of obstructive sleep apnea patients were noted as study strengths with the cross sectional design sited as main study limitation. According to the researchers clinical implications of their findings should make clinicians more aware of the association between dyslipidemia and obstructive sleep apnea; comorbid dyslipidemia is a cardiovascular risk factor highly likely to affect overall cardiovascular consequences and prognosis in obstructive sleep apnea. More studies are needed to gain better understandings of the impacts of obstructive sleep apnea treatment on lipid status.
