Insomnia Symptoms Are Associated With Abnormal Endothelial Function.

This was a cross-sectional analysis of baseline data, so it cannot show whether insomnia symptoms came before the blood vessel difference or whether both were related to another factor. Insomnia symptoms were classified from self-reported questionnaire items, not from a clinical sleep diagnosis or objective sleep testing. The outcome was flow-mediated dilation, a surrogate marker of endothelial function, not heart attack, stroke or cardiovascular death. The sample was mostly female, white and well-educated working adults, so the result may not apply to other populations. Participants with sleep apnea diagnosis or symptoms were excluded, so the finding applies to adults without those sleep problems. The adjusted model accounted for age, baseline artery diameter and dyslipidemia, but the insomnia group also differed in BMI, blood pressure and mood symptoms; some confounding may remain.

Do not conclude that insomnia symptoms caused the lower blood vessel dilation, or that treating insomnia will improve blood vessel function or prevent cardiovascular events. The study measured a surrogate marker at one time point and did not test an insomnia treatment.