The case for a stronger occupational health evidence base

The Health and Safety Executive’s new strategy for the workplace promises to give health the same priority as safety, but makes scant reference to occupational health provision. In response, Dr Paul J Nicholson looks at the current evidence base for OH and calls for a coherent research programme to establish the value of what the specialism does.

The Health and Safety Executive’s “Helping Great Britain Work Well” strategy and associated draft documents aim to “maintain the gains made in safety, while giving health the same priority” (HSE, 2016).

However, occupational health services only feature within the “strategic plans” insofar as acknowledging that is vital to ensure that the evidence is available to inform OH service provision.

Provision has been discussed for almost 20 years (HSC, 1999) at the very least, and strategy is not just about determining service provision – crucially, it is about making explicit choices to do some things and not others, so as to focus energies on creating maximum value (Lafley, 2013). Hence, OH practitioners are unlikely to view the HSE strategy as a strategy for occupational health.

With this apparent omission, how then will the HSE’s strategy connect with and influence the work of OH professionals and the care given to workers? Given recent trends, we must not underestimate the task when seeking to reduce the incidence of work-related ill health.

The relative lack of evidence for some OH interventions is another challenge. With better evidence we might be more effective in delivering occupational healthcare. And by improving value and allocating resources effectively, we might be better placed to market the benefits of providing workers with access to comprehensive occupational healthcare.

With so many players, we should ask who is responsible for coordinating the development of a coherent strategy for UK OH, for identifying and sharing evidence-based practice, and for identifying research priorities.

This article will examine the existing OH evidence base for interventions related to aspects of the HSE’s broader strategy.

A role for occupational health?

As part of its “strategic approach”, the HSE commits to “foster collaborative relationships with colleagues in other parts of government engaged with common health problems, occupational health advice services and the wider wellbeing agenda” (HSE, undated).

There is a proven role for OH professionals in cases of long-term sickness absence and return to work for employees with common health problems, as will be discussed later. However, we should treat the wider wellbeing agenda with caution since, as noted recently in Occupational Health & Wellbeing, much of the evidence is derived from studies with methodological flaws and bias (Nicholson, 2017).

The “Cochrane Collaboration” notes that there is a significant lack of evidence regarding effective workplace health promotion policies and strategies (Wolfenden, 2016). While some employers may provide additional resources for programmes, the reality for many is that they have to do “more with less”. In that scenario, it is important not to dilute provision of core services by diverting scant resources to deliver interventions of unproven benefit.

One report indicated that only 38% of surveyed start had access to OH services (Young, 2011), but just 14% may have access to comprehensive OH support (hazard definition and measurement, risk management, health and safety information and training and monitoring health (Pilkington, 2002)).

With this in mind, strategy should ensure: a) the most effective use of scarce resources, and b) that OH programmes are effective and cost-effective as supported by best evidence.

A focus on common health problems and wellbeing is undoubtedly in response to the societal burdens of the obesity “epidemic” and an ageing population. But, back to strategy – we must not allow what is urgent to crowd out what is important (Lafley, 2013).

HSE strategy and work-related ill health

Instead of developing winning strategies, many leaders approach it in ineffective ways, including: defining strategy either as a vision or as a plan; or as optimisation of the status quo (Lafley, 2013). The HSE points out that “Great Britain’s health and safety record is the envy of much of the world” and that “the challenge is to improve”. This brings with it a sense of seeking only incremental change – optimising the status quo.

Those 1.3 million working Britons – and 800,000 former workers no longer reported in latest HSE statistics (HSE, 2015) – who have an illness they believe was caused or aggravated by their work, might reasonably consider that transformational (rather than incremental) change is required. And the families of the 13,000 people who die each year from occupational lung disease and cancer (HSE, 2016) would likely agree.

Previous strategies have defined specific targets – for example, in 2000, “Securing Health Together” aimed to reduce the incidence of work-related ill health by 20% and the number of days lost by 30% by 2010 (HSC, 2000). Unfortunately, following a decade that featured a general downward trend, the numbers of self-reported occupational ill health have increased by almost 20% – from 1.1 million in 2011-12 to 1.2 million in 2013-14 (HSE, 2012; HSE 2014).

In business, an individual’s work plan supports their department/functional business plan, which is designed to fit and support the corporate objectives, goals, strategy and measures. It would make sense to mirror this approach, and for employers’ organisations, professional bodies and others to develop their own strategies – not only to deliver against the HSE’s strategy, but also to demonstrate leadership in their areas of interest and/or responsibility. An effective strategy should recognise what does and doesn’t work; so let’s look at some of the evidence.

The HSE’s draft “strategy plans” focus on work-related stress, musculoskeletal disorders (MSDs) and occupational lung disease. Several reviews have identified the workplace interventions that are effective and/or cost-effective for preventing and managing work-related MSDs (separate articles in Occupational Health & Wellbeing will describe these interventions and the evidence for effective interventions). This article focuses on common health problems, occupational lung disease and work-related stress.

There is no single definition of strategy or consensus on how to build one; however, the choices to be made include where to play to win and how to win (Lafley, 2013). Clearly, a winning strategy must involve deciding on the appropriate core competencies and choosing to use them effectively and efficiently – focusing on work that is of proven benefit.  Several systematic reviews indicate what works and can help to inform a winning strategy for OH as a branch of healthcare and for improved worker health as an outcome.

One of the challenges in quantifying the economic benefits of OH interventions is that primary studies usually omit assessing intangible benefits, and in most studies, productivity losses are only measured using sickness absence data (Verbeek, 2009). With those limitations in mind, we can establish what is known, mainly from systematic reviews.

Common health problems

UK employers have consistently ranked referral to OH as the most important way of effectively managing long-term sickness absence (CIPD, 2016).

Systematic reviews of studies with economic evaluations have found strong evidence supporting the effectiveness of disability management interventions (Brewer, 2007); and evidence that these interventions were usually worth making from an economic standpoint (Tompa, 2007).

Most of the studies included in the reviews involved cases of MSDs. There is little direct evidence for other health problems, although there is moderate evidence that interventions which include vocational counselling can enhance return to work in patients with cancer (de Boer, 2015: Tikka, 2017).

In general, the effectiveness of case management has been demonstrated in scientific and grey literature (research either unpublished or published in non-commercial form, including government reports).

The most recent UK study reported on a new service that included a biopsychosocial approach to case management for staff who had been absent for more than four weeks. Sickness absence was reduced by 10.7% in two years compared with a control site, which saw an increase, indicating that the intervention was both effective and cost-effective (Smedley, 2013).

Two systematic reviews concluded that there is strong evidence that workplace interventions reduce the duration of sickness absence (Franche, 2005; van Vilsteren, 2015). The effect was attributed in part to early contact between the employee and their workplace and work accommodation offers (Franche, 2005).

The best level of evidence indicates that job demand reductions for either at-work or off-work staff will reduce sickness absence. However, more high-quality research is needed to assess the relationships and to quantify effect sizes for interventions and outcomes (Williams-Whitt, 2015).

Considering that studies have relatively short follow-up and the chronicity of some common health problems, particularly with advancing age, it is unsurprising that there is limited evidence to support sustainability of effect beyond one year (Franche, 2005).

There is only so much evidence for the effectiveness of workplace interventions aimed at common mental health problems such as depression and anxiety, especially with respect to occupational outcomes (Hill, 2007). A more recent systematic review reported that: most studies are of low quality; there are few randomised controlled trials and economic evaluations; evidence on effectiveness is lacking; and that there are mixed results for the effects of workplace interventions on mental health and productivity (Hamberg-van Reenen, 2012).

For depression, one review considered the quality of evidence to be too poor to arrive at any conclusions (Furlan, 2011). A subsequent Cochrane review confirmed that more studies were needed, and said there was moderate evidence that two interventions reduced sick days compared with the usual care – adding a work-directed intervention or enhancing care with cognitive behavioural therapy (CBT) (Nieuwenhuijsen, 2014).

The lack of evidence for cost benefit for return-to-work interventions for common mental health problems may reflect the lack of relevant studies (Hamberg-van Reenen, 2012). However, new studies are emerging.

A Japanese pilot study reported that comprehensive workplace mental health programmes achieved a net benefit in seven of the 11 companies surveyed. The highest return on investment (ROI) was achieved in companies that employed full-time OH nurses, had higher programme participation rates and significantly lower total costs.

This suggests that, even though employment costs are a major part of programme costs, the engagement of OH nurses to manage them increased ROI (Iijima, 2013).

A US modelling study of combined interventions that included work-related problem-solving skills estimated that the intervention broke even when an individual’s absence was reduced by seven days and was cost beneficial in 85% of cases (Dewa, 2014).

Work-related stress

The HSE’s draft “Health and work strategy plan: work-related stress” aims “to bring about a reduction in the number of new cases of ill health caused by work-related stress” to be achieved mainly “through the promotion of the Management Standards approach”. The plan will achieve this by “collaborating with industry stakeholders, the health and safety community and HR professionals”. But where is OH in this plan?

Of course, the primary responsibility to ensure an enlightened and healthy culture and organisation of work rests with management and with HR, as their moral and legal compass. It is also right that the focus ought to be on primary prevention, as interventions directed at employees – which fail to address the organisational causes of stress (such as management style or culture) – will have a limited effect (Sockoll, 2009).

However, OH professionals, with their specialist expertise, do have a key role to play, particularly in ensuring that procedures are in place to detect and manage cases or outbreaks of work-related stress and take appropriate steps within the organisation.

Heterogeneity of study type and the interventions studied makes it difficult to produce exact statements for the effectiveness of individual interventions and techniques (Sockoll, 2009). That said, it does appear that preventive mental health activities can reduce sickness absence (Hill, 2007) and might be cost effective (Hamberg-van Reenen, 2012).

In terms of intervention components, CBT has been shown to be effective for employees absent from work due to mental health problems and for employees more generally. It was found to be more helpful for those with a high degree of control over how they work and for courses of up to eight weeks (Hill, 2007; Sockoll, 2009).

More recently, a cost-benefit evaluation and cluster-randomised trial examined the impact of OH staff support to nurses as an occupational group whose work is stressful. Participants were screened for functional impairment and mental health symptoms.

Absenteeism and presenteeism were reduced significantly in those who received personal feedback and occupational physician referral and advice (ROI was 11:1 in the short term).  The cost of the intervention was recouped within six months (Noben, 2015).

There is growing interest in newer, employee-focused interventions. A recent study cautioned organisations who offer resilience training not to feel the need to place unreasonable demands on staff (Robinson, 2017).  A meta-analysis of resiliency training programmes found low-quality evidence of a small to moderate effect at improving resilience and other mental health outcomes (Leppin, 2014).

Another meta-analysis noted that while studies are of small size, of mixed quality and have a short follow-up (average of 19 weeks), mindfulness-based stress reduction is moderately effective in reducing symptoms in healthy individuals (Khoury, 2015).  The evidence for the use of mindfulness practice appears to be strongest to reduce “job burnout” among healthcare professionals and teachers (Luken, 2016).

Another systematic review reported that meditation programmes can result in small to moderate reductions of psychological stress (Goyal, 2014). The meta-analyses and review noted the need for further research. Of course, one needs to be aware of the risk of publication bias, where studies that produce nil or negative benefits are not reported.

Occupational lung disease

The HSE’s draft “Health and work strategy plan: Occupational lung disease” aims “to reduce the incidence and number of new cases of occupationally related lung disease through improving the control of exposure to causative agents”. OH practitioners will be familiar with the hierarchy of hazard controls and will support this approach. However, once more, the aim contrasts with the approach taken in 2000, when the HSE Asthma Partnership Board set a specific target to reduce the incidence of occupational asthma by 30% by 2010.

The HSE will establish a new leadership body that has “a broadly-based membership drawn from across the whole health and safety system”. It will be important to explore what works for OH and to provide clear guidance.

One outcome of the Asthma Partnership Board was the “BOHRF Evidence-based guidelines for the prevention, identification, and management of occupational asthma”, first published in 2004. These acknowledged the paucity of studies and the fact that it is difficult to dissociate the effects of health surveillance when implemented as part of a broad programme. They concluded that there was limited evidence that health surveillance can detect occupational asthma at an earlier stage and that the outcome is improved in workers who participate in a surveillance programme (Nicholson, 2010).

Spirometry is commonly performed as part of occupational respiratory surveillance and it is advocated particularly for the early recognition of long-term excessive lung function decline and to detect the onset of occupational asthma, chronic obstructive pulmonary disease, or fibrosis (Redlich, 2014).

Among the issues thought to be inadequately addressed in previous spirometry guidelines is evaluation of spirometry over time. The latest guidelines emphasise the importance of evaluating measurements not only relative to normal ranges, but also relative to the workers’ baseline or prior tests, particularly when lung function values are within or exceed predicted values, when progressive lung disease might otherwise be missed (Redlich, 2014).

Few published reports have evaluated the components of surveillance used in occupational asthma, and there is moderate evidence, based on three studies, that spirometry detects few cases that would not otherwise be detected by a respiratory questionnaire (Nicholson, 2010).

A subsequent UK study reported that spirometry did not detect new cases other than those already identified by a questionnaire (Allen, 2010), supporting some of the studies included in the BOHRF report, although all studies involved few cases.

The BOHRF report also noted that there is no generally accepted questionnaire for use in surveillance for occupational asthma and that the existing ones may be insensitive. More than 10 years on from the first report, no one has acted to close these evidence gaps.

Cost effectiveness of surveillance for occupational asthma has only been demonstrated in mathematical simulation models using estimates; mostly in terms of public healthcare costs (Wild, 2005).


As we can see, there are some occupational interventions that are of established benefit and cost benefit.

At the same time there are traditional practices that have unaddressed questions. A research report stated that the HSE could improve how it generates and uses evidence (Cox, 2008), but there is a much bigger challenge. This is the lack of high-quality evaluation evidence, despite a growing trend of conducting systematic reviews to evaluate the cost-effectiveness of OH interventions (Hill, 2007; Tompa, 2007; Uegaki, 2011).

It would appear there is a need for a coherent and congruent research programme for OH to establish the value of what the specialism does, to identify the most effective and efficient programme components from high-quality primary studies, and to cascade synthesised evidence-based practice.

With the demise of BOHRF and a shrinking UK occupational medicine academic base, someone must take responsibility for a strategically focused and practical research agenda that will enrich the practice of evidence-based occupational healthcare and, ultimately, improve outcomes for employees and organisations. This will contribute meaningfully to the aim of reducing the incidence of work-related ill health.

Dr Paul J Nicholson is an occupational physician.


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