My work in munitions plants was interrupted toward the end of 1917 by a summons to Washington The complaint which led to my being sent on this new job came from the limestone cutters of Bedford Indiana. The condition of which the men complained – and doubtless still do – is a spastic anaemia of certain fingers, the ones most tightly cramped around the tool (...). There is a clear line of demarcation between the dead part and the normal part. I had provided myself with outlines on paper of right and left hands and when I examined a man I would make his record with a blue pencil on one of the sheets.

Alice Hamilton

Thomas C Erren calls for identification of research challenges in occupational and environmental medicine during the two coming decades, and suggests useful criteria for it (see page 5).1 We will also focus on the occupational aspects, as a recent commentary suggested coming issues in the environmental area.2 But we advocate a broader approach: occupational medicine must take in an international perspective to “understand what is happening to work itself”.3

We propose that the following global trends should be considered:

• Diverse demographic change over the continents with an extremely young population in many industrialising countries (like Central America), an ageing population in many industrialised countries, and lack of the middle-aged generation in sub-Saharan Africa. There is an increased proportion of women in salaried work and the economically active population in developing countries constitutes an increasing proportion of the global workforce.

• • Implication for occupational and environmental medicine: a shift of interest towards women’s work and work in industrialising countries seems reasonable. Child labour remains a concern in developing countries, as do the large differences in expected survival of work ability in the best and worst trades in developed countries (11 years in Sweden among women, 8 years among men4). Determinants in working life that increase the possibility to remain in the active workforce until higher ages, as well as determinants of diseases occurring at high age causing long-lasting disability (such as neurodegenerative diseases) will be increasingly in focus.

• An increase in migration of labour, goods and capital across national boundaries, with a global increase of the informal sector, an increase of the industrial sector in developing countries, and an increase of the service sector in developed countries.5 This means that an increasing proportion of workers in dangerous trades will not be covered by minimal occupational safety measures.

• • Implication for occupational and environmental medicine: we need to reconsider the present occupational safety structures in, for example, Western Europe, which were developed mainly for work at big industrial plants. Can they be efficiently applied also to the service sector? What strategies should be tried in the informal sector?6 Which strategies should be followed in the rapidly developing economies?

• An increasing proportion of the world population will be exposed to extreme temperatures, flooding and tropical storms. Secondary changes in allergen exposure, patterns of infectious diseases, and exposure to toxic materials released through flooding and other natural catastrophes will occur.

• • Implication for occupational and environmental medicine: epidemiology, allergology, and microbiology will be challenged (and funded) to work with consequences from climate change. Occupational and environmental medicine has many years of experience of transdisciplinary work, which is strongly needed for the climate change challenges. However, it is likely that attention will be insufficient to toxic substances. Moreover, changes in technology to reduce climate change (ethanol as a substitute for gasoline) may not sufficiently consider local environmental effects.7

• International institutions concerned with consumers’ safety will remain stronger than those dealing with workers’ safety.

• • Implication for occupational and environmental medicine: gaps in the assessment of safety of new products are likely to occur, especially in the occupational setting. Nanotechnology is an example of this, with an estimated exposure to 2 million workers worldwide in the next 15 years.8

Overall, these trends suggest a focus on implementation research, directed towards:

• Preventing outbreaks of well-known diseases from well-known causes, such as, for example, silicosis and neurotoxic effects.

• Occupational safety in the service sector and informal sector.

• Establishing validated systems for surveillance of the work environment over time. New tools are currently developed to reduce the necessity for case-by-case exposure measurements,9 but need to be accessible and validated.

• Use of evidence-based health-promoting actions in the work place.

Occupational medicine needs to consider why the existing knowledge has so little impact, and how we can assist in changing this. Moderate sums funding well-focused networking and basic well-standardised fieldwork should be able to achieve a lot. The internet is under-used by occupational medicine: many of our teenagers know how to put a video on the internet. So, why don’t we do it with educational and documentary films?

Basic, but carefully performed, cross-sectional studies were crucial to change dangerous industrial processes and initiate regulations in the pioneering days of industrial medicine in the USA10 and UK.11 We suggest that they still have this potential especially in poorly controlled exposure conditions, be it in the service sector,12 among migrant labourers,13 or the remarkably persistent repetitive work in modern industry.14 The available information about effect levels for many common exposures is surprisingly scant (eg, chronic neurotoxicity levels for common solvents). Community-based studies (including house-to-house surveys) may be useful for investigations of work-related problems in prevalent occupations in the service sector, as well as in the informal sector. This was successfully used to assess asthma risk in domestic cleaning in Spain, and musculoskeletal15 and behavioural16 disorders among child workers in Brazil.

A wealth of knowledge can be acquired from these studies about effect modification from genetics, diet, climate, age and sex. However, the major factor that would tremendously increase the usability of most such studies is improved exposure assessment.17 The development over the last decades has greatly improved and increased the methods at hand.18 Twinning of experienced and new centres in each field could be a way to increase this quality. Also, there is a need for development and validation of specific biomarkers of effect. For example, for many markers of oxidative stress, confounders such as smoking and diet blur the association with exposure.19

However, occupational medicine must also consider research challenges coming from recent development within and outside our discipline. Most diseases of major concern for public health are multifactorial in their aetiology, often with occupational and/or occupational factors as one part of the “causal pie”. We would like to point out some such challenges, which we think will be priorities on the research agenda during the next 10 years.

Mental ill-health is a growing problem, especially among young women, but poorly understood. Recent studies indicate that both work and social conditions are important, and that their relative importance may differ from that of men.20 21 Knowledge correctly identifying the complex interaction and indicating adequate preventive strategies would be of paramount importance for public health.

Environmental medicine is producing results of possibly major importance also for occupational exposure, thus challenging mutual interchange. As an example, exposure to particulate air pollution in the general environment induces significant increase in mortality and morbidity. However, we need to understand how the risk varies with the physical and chemical characteristics of particles, and with subject characteristics (such as age), in order to transfer environmental risk assessment to work environment risk assessment, and vice versa.22

New suggested disease mechanisms, for which the relevance to public health needs to be assessed by occupational and environmental medicine are:

• Oxidative stress, which has been implicated as the action of toxicity of many compounds (eg, cadmium, mercury and paraquat).23 24

• Epigenetic (non-mutational) changes which may be trans-generational, with increased susceptibility to a multitude of disorders.25 26 Compounds, for example, arsenic that is carcinogenic in humans, but only a weak mutagen, has turned out to exert its effect by epigenetic changes (DNA and histone methylation).27

• miRNA alterations: miRNAs are small non-coding RNA species that are important in directing most cellular processes, and disturbances of miRNA patterns represent a new epigenetic mechanism for toxicity of toxins.28 29

• Intrauterine priming of sensitivity to postnatal exposure (cancer, attention disorders).30 31 Hitherto the experience is mainly based on experimental studies, but is increasingly focused on in environmental studies. Carefully conducted occupational studies may be able to contribute in this field. Probably, this priming mechanism involves epigenetic alterations, including miRNA changes.

In conclusion, we need to take global changes of work life into account when assessing coming priorities. Uncontrolled and underprivileged work in economically developed and developing countries will reclaim the need for basic, but well-performed field studies, and new implementation strategies. At the same time, development within our own discipline, and those of others, will challenge our curiosity and abilities to elucidate disease mechanisms, susceptibility, and more importantly vulnerability, using the progress in study design and tools for assessment of exposure and effects acquired during the last decades.