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Title: Adverse effects of shift work at a biscuits manufacturer
Authors: Mhlongo, Philisiwe Kenlly 
Keywords: Shift work;Continuous;Physiological;Psychological;Convergent
Issue Date: 2017
Shift work is a necessity for many organizations. Reasons for shift work are mainly to ensure continuous and optimized operations. Many studies on shift workers have concluded that it can lead to adverse physiological, social and psychological health effects. This study examines challenges associated with working shifts at a biscuits manufacturing factory. Results should be able to assist the employer in implementing effective interventions directed at limiting the negative effects of shift work on employees.
This is a convergent parallel design multi method stud among 152 shift workers in a biscuits manufacturer located in Durban, KwaZulu Natal. An abbreviated and modified form of the validated SSI questionnaire was used (Barton et al. 1995). The questionnaire contained a battery of items designed to examine the relationship of health and personal adjustment to shift work. Owing to the exploratory nature of the study, a focus group methodology was also used and this allowed for in-depth qualitative research which catered for a more comprehensive understanding of the current shift work issues. A retrospective review of injury records of employees who sustained occupational injuries between 2012 and 2013 was also conducted.

The sample comprised of 85 (56%) males and 63 (42%) females. Logistic regression was used to estimate the association between shift work and the likelihood of sleep disturbance, poor health outcomes and limited time for social and domestic activities, adjusting for age, sex, partner working, years working night shift, marital status, job class and years employed. Odds ratio (OR) for reported sleep disturbance was slightly higher among women (OR=1.65; 95% CI = 0.25; 10.84; p < 0.05) compared to males, but this was not statistically significant.
Longer shift work experience (i.e.11-20 years) was significantly associated with better health status (OR=0.18; 95%CI = 0.06; 0.46; p < 0.05). Shift work experience (11 to 20 years) was also found to be significantly associated with limited time for both social (OR = 0.10; 95%CI = 0.03; 0.30) and domestic activities (OR= 0.25; 95% CI = 0.11; 0.57; p < 0.05) (Table 4). Age had no effect on social and domestic activities, but those 40 years and above were more likely to have limited time for social and domestic activities (OR = 3.06; 95%CI =0.60; 15.60 and OR= 2.5; 95%CI=0.47; 13.06). Those with more shift work experience seemed to have more time for social and domestic activities compared to those with less than 10 years experience.
Findings from the FGD’s revealed that most participants (91%) did not get sufficient sleep time after night shift; this was mainly because of the chores they had to do after getting home form night shift and disturbances from the household and neighbours. The average time spent sleeping by majority of participants after night shift was 5 hours. Swollen feet, gastric, sleep disorders, indigestion and headaches were some common complaints experienced by shift workers in this study. About 27% of participants reported to have been injured at work before. These incidents were reported to be related to drowsiness and fatigue.

The company’s incident records showed a total of 160 injuires between 2012 and 2013, of which 38 occurred during night shift. In 2012, the company recorded 65 injuries which included 51 first aid (FA) injuries, 6 minor injuries (MI) and 8 lost time (LT) injuries, as categorized by the company. 2013 had the highest number of incidents, with 95 total injuries, averaging to 7.9 injuries annually. There were 84 first aid incidents recorded for year 2013, 9 minor injuries and only 2 lost time injuries. Twenty three percent (15, n=65) incidents occurred during night shift in year 2012, of which 11% (7, n=65) were females. The number of night shift incidents slightly increased to 24% (23, n=95) in 2013 and females accounted for 9.40%. The records showed that majority of injuries happened between 17h00 and 21h00 at night.

Results of this study provides evidence that shift work impacts negatively on the lives of the employees and can lead to adverse health outcomes such as poor dietary intake, headaches and swollen feet to mention but a few.
Submitted in fulfilment of the requirements for the Degree of Masters in Technology: Environmental Health, Durban University of Technology, Durban, South Africa, 2017.
Appears in Collections:Theses and dissertations (Health Sciences)

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