BACKGROUND: Because of their positive impact on individuals’ performance and alertness, blue enriched white light sources are gaining popularity in households and industries. However, these sources of blue light spectrum may cause oxidative stress. On the other hand, there are no empirical studies investigating the negative effect of blue enriched white light on oxidative stress. Thus, the current study aimed at empirical assessment of the effect of such light sources on oxidative stress among night shift workers. METHODS: The study, which adopted a cross-sectional design, focused on 30 control room operators of a petrochemical complex. The subjects followed a shift-work schedule comprising 7 night shifts, 7 day shifts, and 7 days off. The subjects were exposed to 6500 K, 3000 K, and 17,000 K light sources (which have various degrees of blue light) during three consecutive work cycles, with each cycle lasting for 7 nights. In each light condition, three salivary measurements were conducted (at the beginning, in the middle, and at the end of the shift). The measurements were used to assess catalase (CAT), total thiol molecules (TTG), and total antioxidant capacity (TAC), and melatonin. RESULTS: The results of repeated measures ANOVA showed that there was no significant difference among various light conditions with regard to salivary biomarkers (catalase, total thiol molecules, and total antioxidant capacity). There was however a significant difference between 3000 K and 17,000 K conditions with regard to the concentration of salivary melatonin (p = 0.001). CONCLUSION: Given that there was no significant difference among various light conditions in terms of biomarkers, it is concluded that using sources of light with high color temperature can be recommended. Nonetheless, because of the limitations of the present study (e.g. short period of intervention), it is suggested that care should be exercised in using such light sources.
Appointments and Schedules ; Biomarkers ; Catalase ; Family Characteristics ; Hand ; Melatonin ; Oxidative Stress

BACKGROUND: Work Ability Index (WAI) is a well-known and valid self-report tool that has been widely used in various studies to identify and avoid early retirement and work-related disability. Nevertheless, very few studies have been carried out to evaluate work ability in Iran. We aimed to investigate the WAI and the effect of work-related stress on it among Iranian workers. METHODS: A cross-sectional, descriptive and analytic study was carried out among 449 workers from five working sectors in three big cities of Iran. Work ability and work-related stress were measured using the Persian version of WAI and the Persian version of Health and Safety Executive Stress Indicator Tool. RESULTS: More than a third of the workers surveyed (34.70%) did not have an appropriate level of work ability (WAI < 37). There was a significant correlation between subscales of work-related stress and the mean score of WAI. Furthermore, the variables of body mass index, sleep quality, exercise activity, job tenure, and three subscales of work-related stress including demands, supervisor support, and role were significant predictors of WAI. CONCLUSION: According to the results of this study, the interventional programs must be focused on improving supervisors support, eliminating ambiguity and conflicts in the role of workers in their job and organization, reducing job demands, improving sleep quality, and increasing exercise activity.
Body Mass Index ; Iran ; Retirement

BACKGROUND: Night shift work is associated with many problems such as sleep deprivation, sleepiness, decreased cognitive performance, increased human errors, and fatigue. This study set out to measure cognitive performance, melatonin rhythms, and sleep after different consecutive night shifts (7 vs. 4) among control room operators (CORs). METHODS: The participants included 60 CORs with a mean age of 30.2 years (standard deviation, 2.0) from a petrochemical complex located in Southern Iran. Cognitive performance was assessed using the n-back task and continuous performance test. To evaluate melatonin, saliva was collected and tested by enzyme-linked immunosorbent assay. To assess sleep and sleepiness, the Pittsburgh Sleep Quality Index and Karolinska Sleepiness Scale were used, respectively. RESULTS: Individuals who worked 7 consecutive night shifts had a significantly better cognitive performance and sleep quality than those who worked 4 consecutive night shifts. However, salivary melatonin profile and sleepiness trend were not affected by shift type. CONCLUSION: The main duty of CORs working night shifts at the studied industry included managing safety-critical processes through complex displays; a responsibility that demands good cognitive performance and alertness. It is suggested that an appropriate number of consecutive night shifts in a rotating shift system should be planned with the ultimate aim of improving CROs performance/alertness and enhancing safety.
Enzyme-Linked Immunosorbent Assay ; Fatigue ; Humans ; Iran ; Melatonin* ; Saliva ; Sleep Deprivation

Background: Respiratory masks can provide healthcare workers with protection from biological hazards when they have good performance. There is a direct relationship between the visual specifications of a mask and its efficacy; thus, the aim of this study was to develop tools for qualitative assessment of the performance of masks used by healthcare workers. Methods: A mixed-methods design was used to develop a qualitative assessment tool for medical face masks (MFM) and particle filtering half masks (PFHM). The development of domains and items was undertaken using observation and interviews, the opinions of an expert panel, and a review of texts and international standards. The second phase evaluated the psychometric properties of tools. Finally, the validated Mask Qualitative Assessment Tools (MQAT) were used to assess six samples from 10 brands of the two types of masks. Results: MQAT-MFM and MQAT-PHFM shared 42 items across seven domains: “cleanliness,” “design,” “marking, labeling and packaging,” “mask layers,” “mask strap,” “materials and construction,” and “nose clip.” MQAT-MFM included one additional item. MQAT-PHFM included another nine items associated with an eighth “Practical Performance” domain, and the valve version had another additional “Exhalation Valve” domain and six items. The evaluation indicated 80% compliance for MFM and 71% compliance for PFHM. “Marking, labeling and packaging” and “Layers” were associated with the least compliance in both types of masks and should be checked carefully for defining mask quality. Conclusion MQAT can be used for immediate screening and initial assessment of MFM and PHFM through appearance, simple tools, and visual inspection.

Introduction: The aim of this exploratory sequential mixed methods study was to develop an oral presentations assessment tool for postgraduate students’ oral presentations. Methods: First, a literature review and the ideas of 319 experienced professors were used to identify domains and potential items to develop the desired tool. Then the psychometric properties of the preliminary tool were measured using face and content validity, inter-rater agreement and test-retest reliability. Results: The qualitative phase indicated there should be four domains in the developed Oral Presentations Assessment Tool: subject knowledge, delivery, content and organization, and ergonomics, and that items in the developed tool should be weighted according to importance for the efficacy of a presentation. The final version included 19 items across four domains. Mean content validity index and content validity ratio scores were 0.93 and 0.76, respectively. Spearman’s rank correlation coefficient for the two evaluation periods was 0.92. The intra-class correlation coefficient was 0.78. Conclusion: The Oral Presentations Assessment Tool has appropriate psychometric properties and can be used as a valid and applicable instrument to assess postgraduate students’ oral presentations. Important cognitive factors in oral presentations in the form of an ergonomic domain was included for the first time, as part of this new comprehensive tool.

Introduction: The internship course is a very important part of each university course. The present study aimed at designing and validating a standard instrument for evaluating the internship course in the field of Occupational Health and Safety Engineering (OHSE) from the perspective of trainees. Methods: The dimensions and items of the tool were developed using the panel of experts, syllabus provided by the Iranian Ministry of Health and Medical Education, and literature reviews. Validity of the tool was assessed using face validity, Content Validity Ratio (CVR), Content Validity Index (CVI), and Impact Score (IS). Reliability was evaluated by test–retest reliability analyses and internal consistency (Cronbach’s alpha coefficient). Finally, the internship courses were evaluated during three subsequent years (2016-2018) among 45 students of Shahroud University of Medical Sciences (SHMU) in Iran. Results: The final version of the tool contained five dimensions and 20 items. The CVI and CVR were 0.81 and 0.74, respectively. The ISs of all 20 items were above the minimum acceptable value (1.5). The Cronbach’s alpha coefficient was 0.79 and test-retest Pearson’s correlation coefficient was significant at 0.891 (p<0.001). The overall mean score of evaluation was estimated to be 3.81, which was acceptable. However, poor mean scores were obtained in “access to equipment and laboratory instruments” and “familiarity with job opportunities and internship” dimensions. Conclusions: The results of this study led to a valid tool for evaluating the OHSE internship course. This standard tool can be used to evaluate the perspective of OHSE trainees about the training period and use the results to correct the weaknesses and reinforce the strengths of the training programs.