Sleep deprivation and cognitive performance of shift workers in Bangladesh

Abstract

Number of studies revealed that shift workers experience disturbed sleep and excessive sleepiness (Akerstedt, 2003). Sleep has been found to be essential for cognitive performance, especially memory consolidation and changes in mood (Stickgold, 2005; Philibert, 2005). Our present study was aimed at investigating the effect of sleep deprivation on cognitive performances of shift workers in Bangladesh. In investigating so, we took 462 healthcare shift workers from five districts of Bangladesh. Among them 152 were male and 310 were female. The participants ranged from 19 to 65 years of age. We took the participants on the basis of convenience sampling technique from 30 hospitals and medical centers. To collect data we administered Bangla version of Pittsburgh Sleep Quality Index (PSQI), Montreal Cognitive Assessment (MoCA), Epworth Sleepiness Scale (ESS), and The Grit Scale. All these psychometric tools have high reliability and validity. Findings of our study revealed that sleep deprivation and shifts are marginally dependent (χ2 = 11.56, p = 0.07). However, sleep quality has been found independent of shifts (χ2 = 4.31, p = 0.12). We didn’t find any significant correlation between sleep deprivation and overall cognitive performances. But we found significant correlation of sleep deprivation with attention (r =-0.106, p < 0.05) and delayed recall (r = 0.149, p < 0.01). In our study we found a significant correlation between sleep quality and overall cognitive performances (r = 0.196, p < 0.01). Subcomponent-wise correlation revealed significant correlation of sleep quality with attention (r =-0.132, p < 0.01) and delayed recall (r = 0.103, p < 0.05). In regression analysis, we found sleep quality as a significant predictor of cognitive performances (β = 0.20, p < 0.01) but not the sleep deprivation. Shift-wise analyses yielded that sleep deprivation is high (µ = 7.56) and sleep quality is worse (µ = 3.78) in rotating shift workers in comparison to fixed and regular shift workers. Results also revealed significant shift-wise differences in cognitive performances (F xiii = 3.511, p<0.05) of shift workers. Shift-wise differences were evident in executive functions (F = 5.443, p<0.01), language (F = 13.816, p<0.01), and abstraction (F = 7.818, p<0.01). Significant gender differences were observed in overall cognitive performances (t = 2.036, p<0.05), naming (t = 2.204, p<0.05), abstraction (t = 2.201, p<0.05), and orientation (t = 2.044, p<0.05), and sleep deprivation (t =-2.380, p<0.05) of the shift workers in Bangladesh. Sleep quality was found better outside of metropolitan city (t =-3.258, p<0.01). Moreover, results showed significant differences in overall cognitive performances (t =-5.227, p<0.01), executive functions (t =-1.990, p<0.05), naming (t = 3.051, p<0.01), abstraction (t = 5.966, p<0.01), delayed recall (t = 2.459, p<0.05), and perseverance (t =-2.005, p<0.05), between inside and outside of metropolitan city shift workers. Designation-wise differences were found in overall cognitive performances (F = 11.173, p<0.01), executive functions (F = 8.082, p<0.01), language (F = 5.510, p<0.01), abstraction (F = 20.849, p<0.01), and sleep quality (F = 16.902, p<0.01) of the healthcare shift workers. Experiences of the shift workers were not found significantly correlated with sleep quality and sleep deprivation. We have discussed the results in terms of previous findings and contemporary theories. Recommendations are proposed in the light of our findings in conclusion.