Shift rotation scheme, sleepiness and sleep quality in night-shift workers.

Background: Shift rotation schemes can influence workers' tolerance of night-shift work and its impact on health.

Aims: This study was aimed to assess the influence of shift work rotation schemes on sleepiness and sleep quality.

Methods: We conducted a cross-sectional study of 145 male workers, 77 from a ceramic tile factory on a fixed, forward-rotating shift work scheme, and 68 from a dockyard company, working on-call night shifts. Participants self-administered the Epworth Sleepiness Scale (ESS) and the Pittsburgh Sleep Quality Index (PSQI) questionnaires and provided data on demographic and lifestyle variables. We set two logistic regression models to predict the risk of daytime sleepiness and poor sleep quality as a function of night-shift work and on-call night shifts, adjusting for personal and lifestyle covariates.

Results: Marital status, body mass index, smoking and alcohol intake did not affect ESS and PSQI scores, nor did they differ between the two cohorts. Night-shift workers from both cohorts were more likely to have a PSQI score ≥6, suggestive of poor sleep quality, with no variation between the two cohorts. ESS scores suggestive of daytime sleepiness were strongly associated with on-call night shifts among dockyard workers for (odds ratio = 13.4; 95% confidence interval 2.9-63.9), in respect the regular, forward-rotating night-shift work among ceramic tile factory workers.

Discussion: Daytime sleepiness occurred more frequently among dockyard workers working on-call night shifts. Poor sleep quality occurred more frequently among night-shift workers, but it did not differ between the two companies.