Investigating daily fatigue scores during two-week offshore day shifts

Funding

This study was supported by the Nederlandse Aardolie Maatschappij B.V. and Royal Dutch Shell, Assen, Drenthe, The Netherlands . This study was supported and funded by the Nederlandse Aardolie Maatschappij B.V. and Royal Dutch Shell . We would like to acknowledge the logistic and technical help of Mireille Folkerts in the set-up and conduction of the study. APPENDIX Table A1 Generalized linear (GLMM) and linear mixed model (LMM) results for pre- and post-shift subjective fatigue (KSS) scores, reaction times, average numbers of psychomotor vigilance tests (PVT-B) errors, false starts and lapses over the course of two-week offshore day shifts adjusted and unadjusted for time in bed (TIB). Table A1 Unadjusted scores Adjusted scores for TIB N Estimate 95% CI p-value N Estimate 95% CI p-value Karolinska Sleepiness Score (KSS) Pre-shift 537 .01 (-.02–.04) .476 467 .01 (-.01–.04) .306 Post-shift 540 .06 (.03–.09) <.001 463 .05 (.02–.08) .004 Reaction time (RT) a Pre-shift 374 1.00 (.99–1.00) .142 330 1.00 (.99–1.00) .045 Post-shift 382 1.00 (1.00–1.00) .635 334 1.00 (.99–1.00) .329 Errors (E) a Pre-shift 375 1.07 (.97–1.18) .199 331 1.08 (.97–1.20) .141 Post-shift 380 1.03 (.95–1.11) .494 332 1.01 (.93–1.10) .766 False Starts (FS) a Pre-shift 375 1.04 (.95–1.15) .357 331 1.08 (.97–1.19) .154 Post-shift 380 1.03 (.95–1.11) .523 332 1.02 (.93–1.11) .687 Lapses (L) a Pre-shift 373 1.04 (.96–1.13) .342 329 1.07 (.98–1.17) .141 Post-shift 377 1.02 (.93–1.11) .692 329 1.05 (.96–1.16) .261 In the columns, 95% confidence intervals and p-values of significance are displayed. All models were adjusted for platform location and time in bed (TIB). Subjective fatigue was measured with the Karolinska Sleepiness Scale (KSS) higher scores indicate higher subjective fatigue. a Log-normally distributed values were back-transformed.