Is Self-Reported Insomnia a Risk Factor for Subclinical Carotid Atherosclerosis?

Background: Insomnia is considered an additional cardiovascular (CV) risk factor (RF). However, the data on its association with vascular damage is controversial. We analyzed the relation between self-reported insomnia and carotid atherosclerosis in the population-based sample. Material and Methods: We selected 985 (males - 38%; mean age 45.2±11.6 years) participants of the St Petersburg population-based sample (the ESSE-RF study) who did not have previously known CV events. All subjects underwent a structured interview (lifestyle, medical history). Insomnia was diagnosed when complaints occurred ≥3 times/ week (the questions: “How often did you have difficulties in falling asleep for >30 min after going to bed in the last month?”, “How often did you have difficulties in falling asleep after midnight awakening in the last month?”). Subclinical atherosclerosis was assessed by carotid intima-media thickness (IMT): normal ≤0.9 mm, increased IMT 0.9-13 mm, IMT>13 mm indicated an atherosclerotic plaque. Results: In total, 209 subjects reported at least one insomnia complaint, 79 participants (8%) reported both sleep-onset and sleep-maintenance problems. IMT thickening was found in 142 subjects (14.4%). IMT values were higher in those with frequent nocturnal awakenings vs. non-insomniacs (0.75±0.18 vs. 0.71±0.17 mm, p=0.006). They also showed greater prevalence of thickened IMT (χ2=4.6, p=0.026). Mean IMT weakly correlated with insomnia complaints (ρ=0.10, p=0.002), but the association was no longer significant after adjustment for age, BP and total cholesterol level. Conclusion: We demonstrated an association between insomnia complaints and subclinical carotid atherosclerosis, although we assume it to be weak compared to the common CV RF.