Background: An accumulating amount of evidence has linked humoral mediators of inflammation with sleep measures. Nevertheless, important details of this association, in particular the role of the complement components in the context of chronic sleep attributes, have remained largely uncharacterized. Materials and methods: Fifty university students (age, 23.3 ± 3.8 years; BMI, 23.7 ± 2.9 kg/m2) completed the study. Four dichotomized sleep measures assessed by the Pittsburgh Sleep Quality Index (PSQI) were used in association analysis using binary logistic regression with complement component 3, 4, and complement factor I (CFI). The sleep measures were defined as sleep quality (good sleep/poor sleep; PSQI ≤5/PSQI >5), bedtime (early/late; before 00:00 h/after 0:00 h), sleep duration (short/normal ≤6 h/>6 h), and sleep onset latency (normal/disturbed; 0–1 score/2–3 score on the PSQI component of sleep latency). Results: The complement component 4 was associated with sleep quality (unadjusted, OR = 1.025, p < 0.05; adjusted for age, OR = 1.025, p < 0.05; adjusted for BMI, OR = 1.027, p < 0.05) and sleep duration (unadjusted, OR = 1.041, p < 0.01; adjusted for age, OR = 1.041, p < 0.01; adjusted for BMI, OR = 1.046, p < 0.01). CFI was associated with bedtime (unadjusted, OR = 0.737, p < 0.01; adjusted for age, OR = 0.717, p < 0.01; adjusted for BMI, OR = 0.677, p < 0.01) and with sleep duration (unadjusted, OR = 0.796, p < 0.05; adjusted for age, OR = 0.796, p < 0.05). Conclusion: The findings indicate the importance of the role of complement components in the dynamics of sleep. Therefore, sleep should be assessed in conditions where complement components are affected.
