Naomi G. Swanson

A field study of supplementary rest breaks for data-entry operators.

This study examined the effects of supplementary rest breaks on musculoskeletal discomfort, eyestrain, mood, and performance in data-entry workers. Two rest break schedules were compared in a within-subjects design. Workers alternated between a ‘conventional’ and a ‘supplementary’ schedule in 4-week intervals. The conventional schedule contained a 15-min break during the first half of the work shift and a 15-min break during the second half of the shift. The supplementary schedule contained the same two 15-min breaks, and a 5-min break during each hour which otherwise did not contain a break, for a total of 20 extra minutes of break time. Results are based on data from 42 workers. They indicated that discomfort in several areas of the body, and eyestrain, were significantly lower under the supplementary than under the conventional schedule. While symptoms increased from pre- to post-work periods under both schedules, the magnitude of the increases was significantly less under the supplementary schedule. In addition, increases in discomfort of the right forearm, wrist and hand over the course of the work week under the conventional schedule were eliminated under the supplementary schedule. These beneficial effects were obtained without reductions in data-entry performance.

Modelling relationships between job stressors and injury and near-miss outcomes for construction labourers

Construction work is an inherently dangerous occupation and exposure to additional job stressors is likely to exacerbate the level of danger, increasing workers’ risk for injury. Thus, it is important to identify and then reduce worker exposure to extraneous job stressors. This study examines the relationships between a variety of job stressors and injury or near-miss outcomes among construction workers. Self-reported questionnaire data collected from 408 construction labourers (male and female) via telephone interview were analysed using structural equation modelling. A theoretical model was tested whereby work stressors, classified into three groups, could be related, either directly or indirectly through the mediating effects of physical or psychological symptoms/strain, to self-reported injuries and near misses. Ten of the 12 work-related stressors were found to be directly related to either injury or near misses, including: job demands, job control, job certainty, training, safety climate, skill under-utilization, responsibility for the safety of others, safety compliance, exposure hours, and job tenure. Other stressors (i.e. harassment/discrimination, job certainty, social support, skill under-utilization, safety responsibility, safety compliance, tenure in construction) were indirectly related to injuries through physical symptoms or indirectly related to near misses through psychological strain. There was no support for the modelled gender differences. Implications for health and safety on construction sites are discussed.

Impact of added rest breaks on the productivity and well being of workers

The impact of frequent short rest breaks on the productivity and well being of a group of 30 workers in a meat-processing plant was studied. Two rest break schedules were tested, both of which provided 36 min of extra break time over the regular break schedule (30-min lunch and two 15-min breaks). In the first experimental rest break schedule, workers were given 12 3-min breaks evenly distributed over the workday (3-min break for every 27 min of work). In the second schedule, workers were given four 9-min breaks evenly distributed over the workday (9-min break every 51 min of work). Outcome measures included production rate and discomfort and stress ratings. Results showed that neither of the two experimental rest break schedules had a negative effect on production, and the 9-min break schedule improved discomfort ratings for the lower extremities. The workers in the study mostly preferred the 9-min rest break schedule, indicating that workers in general might not as readily accept fragmentation of break time into short, frequent breaks.

The impact of keyboard design on comfort and productivity in a text-entry task

Concerns have arisen that the keyboard is a causal factor in the development of work-related musculoskeletal disorders (WRMDs) among video display terminal (VDT) operators. A number of alternative keyboard designs have been developed with altered geometry in an effort to improve comfort in keyboard operation. However, few data are available to substantiate whether these new keyboard designs are actually effective in reducing discomfort and musculoskeletal problems in users. The purpose of this study was to provide data on the efficacy of certain alternative keyboard design features (e.g. splitting the keyboard in half, and laterally inclining the keyboard halves) in reducing fatigue and musculoskeletal discomfort among keyboard operators. The study also explored the effects of these design features on performance. Fifty subjects performed a text-entry task for one day on a standard keyboard, then were assigned to one of five keyboard conditions for an evaluation period of two days (i.e. 10 subjects/condition). Outcome measures included performance (i.e. keystrokes/h, errors/h) and self-report measures of discomfort and fatigue. The results indicated an initial decline in productivity when subjects began typing on two of the alternative keyboards, but these productivity losses were recovered within the two-day evaluation period. The results also indicated no significant differences between keyboard conditions in discomfort and fatigue. These results suggest a minimal impact of the keyboard design features examined in this study on productivity, comfort and fatigue, at least after two days of exposure.

Active and passive smoking and depression among Japanese workers

OBJECTIVE To assess the relation of passive and active smoking to depressive symptoms in 1839 men and 931 women working in a suburb of Tokyo in 2002. METHOD Self-reported smoking history and exposure to passive smoking (no, occasional, or regular) at work and at home. Depressive symptoms according to the Center for Epidemiologic Studies Depression Scale, with a cut-off point of 16. RESULTS Compared to never smokers unexposed to passive smoking, never smokers reporting regular and occasional exposure to passive smoking at work had increased depressive symptoms. The adjusted odds ratios (aORs) were 1.92 (95% confidence interval (CI) 1.14, 3.23) for regular exposure and 1.63 (95% CI 1.08, 2.47) for occasional exposure. Current smokers had significantly increased depressive symptoms (aOR ranging from 2.25 to 2.38) but former smokers had only marginal increases of depressive symptoms (aOR ranging from 1.43 to 1.55). Gender did not modify the effects of active/passive smoking on depressive symptoms. CONCLUSION Passive smoking at work and current smoking appear associated with higher levels of depressive symptoms.

Discrimination and occupational mental health

Background: Racial and ethnic discrimination has been shown to occur in work organizations, yet little is known about the relationship of this stressor to occupational mental health. Aims: This paper explores the degree to which racial and ethnic groups may be subjected to discrimination at work and examines associations between discrimination and mental health indicators. Methods: In a national study, 1728 American workers were interviewed about aspects of their jobs, their exposure to racial and ethnic discrimination at work, and dimensions of their mental health. Results: American minorities reported perceptions of discrimination at work at greater frequencies than White Americans, and findings suggested some indication of institutional discrimination against minorities. Further, White, Black, and Hispanic-Americans, who reported that they had been discriminated against, were found to have poorer mental health outcomes than their same-race counterparts, who did not acknowledge being discriminated against. Conclusions: These findings may be used to inform the development of occupational stress and health models that are more cross-culturally applicable. Declaration of interest: None

A review of physical exercises recommended for VDT operators

This paper presents an evaluation of exercises that have been recommended for the prevention of musculoskeletal discomfort among VDT/office workers. 127 individual exercises were analysed for their suitability for performance in VDT workplaces. Additionally, each exercise was judged in terms of its safety and its compliance with principles of physiotherapy. Results showed that, in the majority of cases, the prepared instructions for the exercises were satisfactory and the exercises could be readily performed at the workstation. However, over a third of the exercises were conspicuous and potentially embarrassing to perform, and half would significantly disrupt the work routine. Additionally, a number of the exercises posed potential safety hazards, exacerbated biomechanical stresses common to VDT work, or were contraindicated for persons with certain health problems. These findings suggest a need for greater attention to both the practical and the therapeutic aspects of exercises promoted for VDT users.

The prevalence and correlates of occupational injuries in small-scale manufacturing enterprises.

The Prevalence and Correlates of Occupational Injuries in Small‐Scale Manufacturing Enterprises: Akinori Nakata, et al. National Institute of Occupational Safety and Health—Workers involved in small‐scale manufacturing businesses are known to comprise a high‐risk population for occupational injury. The present study investigated the prevalence and correlates of occupational injury in this population. A self‐administered questionnaire that solicited answers about occupational information including injury, demographic characteristics, health conditions and lifestyle factors was collected from a sample of 1,298 workers in 228 small‐scale manufacturing enterprises (defined as fewer than 50 workers) aged 16–78 (mean 46) yr in Yashio city, Saitama, Japan (response rate 65.5%). The enterprises were randomly selected from the 2000 edition of the city commercial directory corresponding to the distribution of types of businesses in the city. Occupational injury was assessed by asking subjects, ‘Have you ever been injured during your work, including minor scratches and cuts in the previous 1‐yr period?’ The possible response was either ‘yes’ or ‘no.’ The prevalence of study‐defined occupational injury among the workers was 35.6% (male 43.0%, female 17.9%). Among job types, manufacturing (44.2%) and driving (43.5%) had high rates of occupational injuries. Similarly, occupational injuries were high in the papermaking (54.5%) and machinery (47.7%) industries. For males, younger age, current or former smoking, insomnia symptoms, and disease(s) currently under treatment were correlated with injury, whereas for females, being unmarried, higher educational status, and insomnia symptoms were the correlating factors. Occupational injury is common among small‐scale manufacturing businesses, and is associated with multiple controllable factors. Countermeasures such as prohibiting smoking during work, sleep health education, job safety training for young/inexperienced workers are appropriate methods for eliminating or reducing injuries.

Active cigarette smoking, secondhand smoke exposure at work and home, and self-rated health

OBJECTIVES Although active smoking has been reported to be associated with poor self-rated health (SRH), its association with secondhand smoke (SHS) is not well understood. STUDY DESIGN A cross-sectional study was conducted to examine the association of active smoking and SHS exposure with SRH. METHODS A total of 2558 workers (1899 men and 689 women), aged 16-83 (mean 45) years, in 296 small and medium-sized enterprises were surveyed by means of a self-administered questionnaire. Smoking status and exposure levels to SHS (no, occasional or regular) among lifetime non-smokers were assessed separately at work and at home. SRH was assessed with the question: How would you describe your health during the past 1-year period (very poor, poor, good, very good)? SRH was dichotomized into suboptimal (poor, very poor) and optimal (good, very good). Odds ratios (ORs) with 95% confidence intervals (CIs) for reporting suboptimal vs optimal SRH according to smoking status and smoke exposure were calculated. RESULTS Current heavy smokers (20+ cigarettes/day) had a significantly increased suboptimal SRH than lifetime non-smokers after adjusting for sociodemographic, lifestyle, physical and occupational factors (OR 1.34, 95% CI 1.06-1.69). Similarly, lifetime non-smokers occasionally exposed to SHS at work alone had worse SRH than their unexposed counterparts (OR 1.50, 95% CI 1.02-2.11). In contrast, lifetime non-smokers exposed at home alone had no significant increase in suboptimal SRH. CONCLUSIONS The present study indicates an increase in suboptimal SRH among current heavy smokers, and suggests that SHS exposure at work is a possible risk factor for non-smokers. Whether or not the association is causal, control of smoking at work may protect workers from developing future health conditions.

Is self-rated health associated with blood immune markers in healthy individuals?

BackgroundAlthough self-rated health (SRH) has been established as a robust predictor of morbidity and mortality, the immunological mechanisms underpinning this relationship are poorly understood.PurposeThis study examined the association of SRH with humoral and cellular immune markers in healthy individuals who reported no physical illnesses.MethodA total of 116 healthy Japanese white-collar employees (79 women and 37 men) at a pharmaceutical company, aged 23–62 (mean 32) years, underwent a blood draw for the measurement of circulating immune (T, B, and natural killer) cells, inflammatory cytokines (interleukin-6 and tumor necrosis factor-α), and plasma immunoglobulin G (IgG) and completed a health survey including SRH. The question regarding SRH ranged from “very good” (coded 1) to “very poor” (coded 5). Hierarchical multiple regression analysis was carried out to calculate the relationship between SRH and immune markers.ResultsIn this sample, poor SRH was positively correlated with B (CD19+) cell numbers (β = 0.260, p < 0.05) and IgG levels (β = 0.335, p < 0.01) even after adjusting for depressive symptoms, age, education, marital status, smoking, alcohol consumption, physical activity, body mass index, sex, and sex × SRH interaction. The interaction between SRH and sex on the immune markers was not significant.ConclusionAlthough the connection between SRH and immune markers was not strong in this context, the results suggest that poor SRH may be associated with reduced humoral immune system capacity to respond to new/latent challenges. The results provide some support for the immunological basis of SRH in healthier individuals.