Iranian Journal of Ergonomics

Introduction: Sleep disorder is very common among employees and is considered as one of the crucial health problems. Sleep disorders have a negative impact on job performance. The present study was regarding the relationship of sleep quality, sleepiness and sickness absence.

Methods: This cross-sectional study was conducted on 400 employees of a gas company through random sampling. The study data were collected using the Pittsburg Sleep Quality Index (PSQI) and the Karolinska Sleepiness Scale (KSS). Mann-Whitney U test and Spearman’s correlation coefficient were applied for data analysis.

Results: While 43.2% of the participants enjoyed satisfactory sleep quality, 56.8% had unsatisfactory sleep quality. Statistical tests indicated a significant difference in sickness absence of the personnel with good and poor sleep qualities (P = 0.0001). Spearman’s correlation coefficient (ρ = 0.777) indicated a statistically significant correlation between sleepiness index and sickness absence (P = 0.0001).

Conclusions: The results showed a strong positive correlation in sleep quality, sleepiness index of the personnel and sickness absence; i.e. along with decline in sleep quality and incline in sleepiness, the personnel’s sickness absence increased.