The term “migrant worker” refers to someone who will be employed or has been employed in a paid activity in a state of which he or she is not a citizen. The migration phenomenon is constantly growing; according to the latest United Nations’ estimates, the number of migrants has almost doubled, passing from 173 million in 2000 to 258 million in 2017. Over 60% of migrants live on the Asian continent (about 80 million) and in Europe (about 78 million). Regarding their origin, more than 100 million emigrate from Asia (in particular from India), followed by Europe (61 million), Latin America (38 million), and Africa (36 million). In 48% of cases they are female and 74% are between the ages of 20 and 64 [1
Currently, the term “migrant” is confused with “expatriate”. However, there are some conceptual differences between the two terms: expatriates are people who leave their country of origin to live in another context but do not intend to live abroad forever, maintaining their original nationality for practical reasons [2
]. The term “expatriate” is also used for workers from industrialized countries who move abroad for relatively short periods (for example, those engaged in “business travel”).
According to research carried out by the Hongkong and Shanghai Banking Corporation (HSBC) in 2008, the expatriate’s reasons to move to a particular country are not only economic ones. In fact, in addition to standards of living and salaries, more subjective criteria are considered such as the possibility of socializing with the local population, learning the language, and becoming a part of groups or communities. The most positive impressions have thus been recorded in Germany, followed by Canada and Spain. In these countries, expatriates are used to socializing with the local population and learning the language, joining groups or communities, and even buying properties. Generally, in these countries it is quite easy to integrate, both for expatriates and for family members. When considering the same criteria, China and the United Arab Emirates are countries in which immigrants encounter many difficulties with integration and adaptation to culture [3
]. Expatriates can become, if properly integrated, an important resource to promote the sustainable development of the country to which they move. The psychology of sustainability and sustainable development is an innovative field of research, which through the promotion of interpersonal and intrapersonal talents, aims to improve the general quality of life of the community [4
With regard to employment, immigrants are mainly employed in heavy and risky jobs (the so-called “3D jobs”, which are dirty, dangerous, and difficult), namely manual, tiring, and dangerous activities which are characterized by monotony and very intense rhythms. These are often low-income activities which are concentrated in sectors traditionally with higher risks (such as the construction sector, heavy industry, transport, services, and agriculture), employ immigrants for a number of hours’ higher work compared to native workers, and often do not correspond to the actual professional profile of the immigrant [5
The international community has adopted many legal instruments to protect expatriate populations; among these, the documents drawn up during the “International Convention on the Protection of the Rights of All Migrant Workers and Members of Their Families” held in New York in 1990 and the “Protocol to prevent, suppress and punish trafficking in persons” in New York in 2000 stand out for their importance. These tools, along with the rights of migrant workers adopted by the International Labor Organization (ILO), form the foundations of migrants’ international legislations [2
Italy has also acted in this sense with the introduction of the Legislative decree no. 81/2008 and subsequent amendments, in which appears a differentiated and functionalized protection system for this worker category. Migrant workers are included in “priority groups” through which specific strategies on health and safety at work are set up. “Special risks” must be assessed individually and in a reciprocal relationship with each other; in this case, being from other countries is frequently associated with precariousness of work, the use of non-standard contractual forms, stressful situations caused by work contexts (such as one’s role in the organization and interpersonal relationships, etc.), work content (including the type of tasks, load, rhythms, and working hours, etc.), and finally age and gender differences, given the high rates of youth and female immigrant employees [6
]. The psychology of sustainability is another great opportunity for the protection and development of expatriates in the workplace. Their experiences in their country of origin, re-elaborated according to a positive narrative, enriches the companies of the host country with sustainable and multicultural development [7
The purpose of this study is to construct a systematic review of the scientific literature regarding the health status of migrant workers in order to identify the main occupational risks and diseases that these workers may encounter compared to non-migrant workers, and to highlight some suitable preventive strategies to apply in this area.
The issue of attention to the protection of health and safety in the workplace of migrant workers is very relevant, especially for the occupational physician. In fact, it is important to underline the importance of ethical, professional, scientific, and legislative motivations that require the occupational physician to protect the most vulnerable workers, because of possible social and health consequences.
Our review has highlighted some specific risk factors present in this area which are deserving of adequate consideration, in particular for the prevention of repercussions on work activity.
Among these, infectious diseases feature strongly in the etiology of the main disorders of migrant workers. Infections are one of the major causes of mortality and morbidity as regards public health, particularly in developing countries [20
]. Most migrant workers such as farmers, drivers, and waiters come from regions endemic to intestinal infections, characterized by modest socioeconomic levels and poor access to care [54
]. The spread of pathogens has been closely linked to educational, environmental, and health conditions, as well as socio-economic status and access to medical care. Some categories of workers are considered to be most at risk, such as cooks, waiters, and agricultural producers; poor hygiene conditions and inadequate knowledge about food storage can be sources of pathogens and may be involved in the transmission of infections to local communities and consequently to business travelers or tourism [55
Infections such as tuberculosis and malaria are still global public health problems [20
]; according to the latest WHO estimates, tuberculosis is the ninth-leading cause of death in all its forms, with 1.3 million TB deaths in 2016 and 10.4 million people infected, of whom 65% were male, and with 56% of cases coming from countries such as China, the Philippines, and Pakistan [57
Despite significant efforts and resources dedicated to the control of these diseases, they remain a difficult challenge to face due to the increase in mobility between countries, and the difficulties of accessing treatment for some populations and for cases resistant to treatment [58
Emerging infections, such as pathologies not present in a territory but of import due to migrations and higher mobility among workers (for example, cases of dengue and Zika from South America or avian influenza from China), must be taken into account for the purposes of proper health surveillance [60
Moreover, migrant workers exhibit demographic characteristics that may put them at high risk for heterosexual HIV transmission, such as unstable family and work situations, ease of access to high-risk (including commercial) sex, and lack of access to HIV treatment and prevention programs [62
]. Rural residence, longer durations of migrant work and independence, physical isolation, alcohol use, and human rights violations are associated with testing positive; being female, higher levels of education, policy reforms, and workplace interventions are negatively associated with testing positive [65
Many studies report a higher prevalence of obesity and cardiovascular diseases associated with migrants due to environmental factors and changes in lifestyles [67
]. One of the possible explanations for the greater prevalence of metabolic syndrome among migrants is the rapid transition from developing countries to Western countries; rapid changes in environmental factors and changes in lifestyles, such as greater sedentary habits and more consumption of energy foods, worsen the cardiovascular profiles of migrants [69
]. Migration from rural areas to urban areas has in fact been associated with incorrect lifestyles and behavior patterns, with an increase in the consumption of polyunsaturated fats and a reduction in the consumption of saturated fats, complex carbohydrates, and fibers, as well as poor physical activity, having ben observed [27
]. Also important is the role of particularly stressful jobs carried out by expatriate workers, including long shifts and night shifts that can alter biological cycles such as glucose and lipid metabolism [72
These studies support the idea of the “Healthy Migrant Effect”, as reported in 2009, which highlights how migrants experience a decay in their health status which is proportional to the length of their stay in Western countries [73
]; longer durations of stay have been associated with an increase in cardiovascular risks, including being overweight, obesity, and hypertension [74
]. This effect is related proportionally to the country of origin, the reasons for the transfer to another country, the lifestyles adopted, and the determinants examined, such as the relationship between ischemic diseases, diabetes, and number of years of stay of migrants in Denmark [73
The work conditions, climate, and the plans and personal expectations of each individual, together with a host of other factors, combine to form a model of alcohol consumption that may reflect the habits of the country of origin, or even involve increased drinking. The relation between substance abuse and migration is complex. There seems to be a multifactorial relation in which biological, psychological, cultural, and social factors intervene. Some authors have associated hazardous alcohol consumption with the type of work [76
]. Construction and agriculture, both open to inclement weather, traditionally offer hard work conditions, and ingestion of alcohol before beginning work is a common habit [44
]. Occupational health services are one of the pillars for conducting early interventions. For prevention, in fact, work is the ideal place, given the homogeneity of the population concerned, the free access to all employees, and the possibility of follow-up activity.
According to the Italian Workers Compensation Authority (INAIL), in 2016 work accidents in Italy involving foreign workers amounted to 61 thousand (15% of the total), of which 45 thousand occurred to non-EU citizens and about 16 thousand to EU citizens; events occurred in the industrial sector in 87% of cases, with another 6% in agriculture, and 29% involving female subjects [78
The data available to us through this review of the literature confirm this trend, as many studies highlight the greater risk of accidents being incurred for migrant workers, as they often work in hazardous environments without safety devices available, especially in the productive sectors and building [79
]. Construction workers belong to one of the occupational categories most exposed to various risks in the workplace, including those which are physical, chemical, biological, and ergonomic [44
]. This category of work is more likely to incur trauma, (even that which is fatal), and to induce the development of respiratory diseases such as chronic obstructive pulmonary disease, asthma, silicosis, and dermatological diseases [80
]. The authors of these studies suggest some preventive strategies that can be applied in order to prevent and reduce (even fatal) accidents: for example, it is necessary to identify areas with higher risk (e.g., construction, manufacturing, and mining) to improve the training of personnel in the field of safety, to strengthen the use of adequate equipment often not used, and to establish or strengthen national surveillance systems.
From our review, it may be concluded that another particularly risky sector is agriculture. Migrant farmers are among the most marginalized of job classes, being often very poor, without legal protection, and having residence in inadequate facilities [81
]. Workers employed in the seasonal migrant agricultural sector are exposed to climatic conditions with high temperatures, to chemicals and pesticides that can lead to dermatological diseases and respiratory diseases, and to incongruous postures and repetitive movements which result in musculoskeletal disorders and sometimes fatal traumatic injuries [82
]. Housing conditions including poorly ventilated housing, poor hygienic conditions, and humidity and mildew favor the onset of respiratory diseases such as pneumonia and asthma, and infectious diseases [81
Furthermore, a lack of knowledge on occupational diseases combined with poor use of safety devices exposes these workers to a greater risk of having accidents and developing occupational diseases (mainly allergic symptoms) [86
Through our review, we have highlighted that the quality of life of migrant workers is lower than that of native populations. Migrant workers are a vulnerable population group in urban areas [87
]. These people have, in most cases, lower education levels, lower income, heavier workloads, and longer working hours, and are more likely to live in more crowded housing compared to local residents [36
]. Health-related quality of life has become an important target in the medical area, with consideration given to treatment outcome assessments, health economics evaluations, and assessing the effects of health education. HRQOL has been widely applied in epidemiological studies. However, this methodological approach has rarely been used among migrant workers without specific illnesses. New-generation migrant workers experience significant impairment in HRQOL compared with urban workers in terms of psychological and environmental domains, and in general health. Lower HRQOL in migrant workers may be explained by their poor social support and living and working conditions [89
]. Foreign workers may undergo difficulty in adapting to their new positions; they may experience more work-related stress such as inadequate rest due to overtime work and inadequate medical and social security coverage provided by their employers [90
]. Social relationships and networks that exist in the countryside are difficult to achieve in urban areas because of the distances and surroundings, leading to ever-decreasing social support [91
]. To reduce work-related stress and foster interpersonal relationships among migrants, the psychology of sustainable development may be drawn upon, as it promotes greater connection with nature and empathy. Expats who settle in new social and work environments become an irreplaceable resource for the entire community [93
Through this work, it has been made clear how the occupational physician has before him or her the commitment to protect the health of the immigrant worker, a person with specific needs but who must be guaranteed levels of protection similar to those belonging to native workers.
The physician will have to identify the worker’s origin and his or her personal history in order to identify socio-cultural differences, difficulties in linguistic comprehension, and compliance with prevention interventions. Health surveillance will therefore be essential through a careful medical history (i.e., a physiological, pathological, and working history) and a precise objective examination, which is correlated by laboratory and diagnostic examinations and targeted on a case-by-case basis. Information-training courses for workers will be fundamental for prevention purposes. In Italian Law their content is understandable and occurs by verifying the comprehension of the language (Article 36 and 37 of Legislative Decree no. 106/09) to avoid security issues, management of emergencies, and understanding of procedures.
Our scientific review and included studies have some limitations as a whole. First, most of the studies are cross-sectional rather than intervention or efficacy evaluations, which would be of particular interest to the physician given that they could aid in understanding the determinants of occupational diseases and the setting up of appropriate interventions. We have included articles published in the last five years, from 2013 to 2018, as studies before this period were not very relevant to our research field. In fact, in recent years we have observed greater interest in and attention on the part of researchers to this issue, which has been directly proportional to the exponential growth of migratory flows worldwide.
Studies are often being conducted outside the European context on small specific communities with difficulties of extrapolation to our context; in most cases, results on migrant workers have been compared with data on native workers, not allowing for the adequate characterization of the risk. Overall, the quality of the cross-sectional studies was of average value due to the frequent use of subjective assessment tools, such as questionnaires administered to the sample which were not always standardized, and to the lack of description of the characteristics of those who decided not to submit the questionnaire (the so-called “non-respondents”). In addition, the quality of the trials was average; the value assigned, in almost all cases, did not reach the maximum score, due to a lack of specificity of randomization or double/single-blind study, or to the failure to describe cases lost to the follow-up.
Finally, it was a very complex process to compare very different studies according to the type of sector of work of those within the samples in question (from the “business travelers” to the domestic workers or farmers), to gender differences that also affect the type of work, and to environmental contexts totally different for each culture, religion, and legislation (for example, the differences between South America, the United Arab Emirates, and South East Asia).