Occupational Health at Work 2011; 8(x): xxâxx ... acute psychological problems â in other words, the risk ... Professor Andy Smith is director of the Centre for.
Occupational Health at Work 2011; 8(x): xx–xx
1 FEATURE
A holistic approach to stress and wellbeing Part 3: combined effects of job characteristics on stress and other outcomes THERE has been much previous research on a large number of workplace hazards, and for the most part the nature and effects of such factors have been considered in isolation. Such an approach is not likely to be representative of the real-life workplace where employees are often exposed to multiple hazards. For example, individuals are very unlikely to work in a noisy environment that does not also expose them to other stressors that have considerable potential to harm. There is limited information on the combined effects of these hazards on health and safety. Indeed, there have been no systematic literature reviews, no attempt to produce a coherent framework for studying these factors, and a dearth of studies using a variety of methods to investigate the topic. This article reviews the information currently available, and describes a variety of methods that have been used to investigate the combined effects of occupational health hazards1.
COMBINED OCCUPATIONAL STRESSORS Data from a number of sources were analysed to investigate the health and safety impact of exposure to multiple workplace stressors. The starting point was a reanalysis of two large-scale community samples (each with more than 4,000 participants): the Bristol Stress and Health at Work study2 and the South Wales Health, Work and Safety study3. The main approach to assessing multiple stressors was through a questionnaire that asked the individual about many different facets of their work, including: ➤ hours worked and whether they worked shifts or at night ➤ any exposure to hazards such as noise and fumes ➤ the demands of their work ➤ the support they received from senior staff and coworkers and the control they felt they had over how they did their work ➤ the effort that their work involved and the reward for their endeavour. Scores for all these items were summed to create a composite measure that reflected both physical and
psychosocial job characteristics – the Negative Occupational Factors (NOF) score. A higher NOF score reflects exposure to a greater level of multiple stressors. The score was split into four quartiles and the pattern of associations between these and the various outcome measures were assessed. There were linear associations with stress, anxiety and acute psychological problems – in other words, the risk increased proportionally with each successive quartile of the NOF score. Depression, acute health problems, accidents and minor injuries at work were more likely in the fourth (highest) quartile of NOF only. In summary, the NOF score acts as a global risk factor that can then be dissected to determine which components underlie observed effects.
NOF SCORE COMPONENTS
Stress at work and related mental health problems have become major occupational health issues. Prof Andy Smith, Rachel McNamara and Ben Wellens describe how it is important to consider the combined effects of occupational health hazards on these outcomes.
The NOF score had three broadly different components: ➤ job demand–control–support4 ➤ effort–reward imbalance5 ➤ exposure to physical hazards/working hours. Only one outcome measure, work-stress, was found to be significantly influenced by all three components of the NOF score. Work stress was most likely to be reported by workers whose jobs were highly demanding, required high levels of effort and exposed them to high levels of physical hazards and/or deleterious working hours. Higheffort jobs alone exerted the most negative influence on work stress. Anxiety levels were influenced by job demand–control–support and effort–reward imbalance; workers who reported high levels of intrinsic effort (‘overcommitment’) were found to be most likely to be anxious. Looking at the Job–Demand–Control–Support Model, likelihood of being anxious was only significantly increased where workers reported that their work was highly demanding, where they had low control over their work and where they had low levels of support from their peers and superiors. Workers with the combination of low support from colleagues/superiors and low control over how they worked were most likely to be also depressed.
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OCCUPATIONAL HEALTH [at Work]
STRESS AND WELLBEING
2
ANDY SMITH, RACHEL MCNAMARA, BEN WELLENS
FEATURE
CONCLUSIONS ■ Workplace hazards often combine cumulatively to produce negative outcomes ■ The level of exposure that predicts negative effects may be dependent on outcomes ■ Particular combinations of stressors often produce selective effects on outcomes ■ A negative occupational factors (NOF) score, the sum of negative job characteristics, is a good predictor of outcomes such as stress, mental health problems and accidents ■ This approach is able to predict longer-term changes in health status ■ Effects observed from subjective data generalise to more objective measurement ■ The approach can be used to assess industry-specific issues (eg seafarers’ fatigue) ■ It has implications for policy issues, such as the development of stress management standards
Another area of interest concerned work-related accidents minor injuries and cognitive failures, but few effects were observed. This may have been due to the relatively low incidence of these outcomes within the dataset. The aim of the next study, therefore, was to repeat these analyses for accidents, minor injuries and cognitive failures using data specifically sampled and selected to contain a higher proportion of individuals who had experienced an accident at work.
A&E SURVEY The study presented here represented an investigation designed to increase the number of work-accident cases available for analysis. Instead of random sampling from the population, the sampling frame covered individuals who had attended hospital accident and emergency (A&E) departments. Analysis of the A&E data demonstrated a strong association between the NOF score and the likelihood of having had at least one work-accident, which required hospital treatment. Further analysis showed that exposure to physical hazards (fumes exposure, handling hazardous substances, noise that causes a ringing in the ears, background noise that disturbs the concentration) and/or the deleterious organisation of working hours (nightwork or shiftwork, long, unsociable hours, unpredictable hours of work) were crucial. Research from other samples, such as seafarers5 and installation workers6, has demonstrated that outcomes such as stress and fatigue are best predicted by the NOF score. Indeed, general exposure to combined negative occupational factors was associated with an increased susceptibility to fatigue over the course of a work session, working day and working week7. Other research has included organisational factors and show that workplace culture is a good predictor of stress. For example, a poor safety culture not only predicts accidents but also is
OCCUPATIONAL HEALTH [AT WORK]
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associated with higher stress levels8. Culture is often considered to represent the combined effects of many specific factors. The HSE Management Standards Indicator Tool, which was described in detail in the previous article in this series, initially had a total score that represented the sum of the different risk factors. This can still be calculated and may provide a good initial indicator of the extent of problems. Examination of the individual scales then allows one to identify specific issues that need to be addressed.
A USEFUL TOOL Taken together, these findings offer a significant contribution to the study of combined effects of workplace stressors. Although not an exhaustive list of all possible hazards that occur in the working environment, the NOF score appears to be a valuable tool in the prediction of poor health, wellbeing and accident and injury outcomes. Our current research suggests that it is possible to use a small number of questions to derive such a score. This measure appears to have the same predictive validity as the longer version and can now be used in audits to quickly obtain a profile of potential problems. There is also a need to develop a combinedeffects approach to positive aspects of work (wellbeing) and this will be described in a subsequent article in this series. ■ Professor Andy Smith is director of the Centre for Occupational and Health Psychology at Cardiff University. Rachel McNamara and Ben Wellens are former members of his research group. Notes 1 Smith A, McNamara R, Wellens B. Combined effects of occupational health hazards. HSE Contract Research Report 287. Sudbury: HSE Books, 2004. 2 Smith A, Johal SS et al. The scale of occupational stress: the Bristol Stress and Health at Work Study. HSE Contract Research Report 265/2000. Sudbury: HSE Books, 2000. 3 Smith A, Wadsworth E et al. The scale and impact of drug use by workers. HSE Research Report 193. Sudbury: HSE Books, 2004. 4 Karasek R. Job demands, job decision latitude and mental strain: Implications for job redesign. Administrative Science Quarterly 1979; 24: 285–306. 5 Siegrist J. Adverse health effects of high-effort/low-reward conditions. Journal of Occupational Health Psychology 1996; 1: 27–41. 6 Smith, A, Allen P, Wadsworth E. (). Seafarer fatigue: the Cardiff Research Programme. Southampton: Maritime and Coastguard Agency, 2006, http://goo.gl/sJxZy 7 McNamara RL, Smith AP. The combined effects of fatigue indicators on health and well-being in the offshore oil industry. Archives of Complex Environmental Studies 2002; 14, 3–4. 8 Smith AP, Wadsworth EJK. Safety culture, advice and performance. Leicester: Institution of Occupational Safety and Health, 2008, http://goo.gl
