Occupational Health PDF

Occupational Health Occupational health, as defined by a joint committee of World Health Organization (WHO) and the International Labor Organization in 1950, involves the “promotion and maintenance of the highest degree of physical, mental and social well being of workers in all occupations...

Occupational Health Occupational health, as defined by a joint committee of World Health Organization (WHO) and the International Labor Organization in 1950, involves the “promotion and maintenance of the highest degree of physical, mental and social well being of workers in all occupations” (Forsmann 1983). This definition emphasizes the term “health” rather than “disease”, and further implies a multidisciplinary responsibility as well as a mechanism for the provision of health services for the working population. Historically, the existence of diseases related to work has been documented since antiquity. Imhotep (2780 BC) was the chief vizier to the Pharaoh Zoser, the first king of the Third Dynasty of the Old Kingdom. He was also an engineer and architect of the step pyramid at Sakkara, as well as a physician and priest. He described cases of occupational injuries and “sprain of the vertebrae” among the pyramid builders. Hippocrates (460-377 BC) emphasizes the importance of environmental factors in disease causation in his treatise on Air, Waters, Places. Both Hippocrates and Galen described the diseases of certain occupations, including metallurgists, fullers, tailors, horsemen, farmhands, fishermen, miners, tanners, chemists, and other craftsmen. However, Hippocratic medicine in general did not concern itself with health hazards of occupations. One reason was because of the low social status of worker. The most hazardous and laborious jobs, for example, mining, were done by the lowest strata of society, such as slaves, prisoners of war, and convicted criminals. The Athenian philosopher Socrates (469-399 BC) offers this description of workers: “What are called the mechanical arts, carry a social stigma and are rightly dishonored in our cities… Furthermore, the workers at these trades simply have not got the time to perform the offices of friendship or citizenship. Consequently, they are looked upon as bad friends and bad patriots. And in some cities… it is not legal for a citizen to ply a mechanical trade”. After stagnation for several centuries, occupational health developed further in the Middle Ages. Georgius Agricola (1494 – 1555), a physician-scholar in the mountains of Silesia and Bohemia wrote extensively on the diseases of miners and smelters of gold and silver. In a 12-volume work, De re Metallica, he described a consumptive lung disease of miners. Paracelsus (1493-1541), a Tyrolean physician, produced a three-volume work On Miners' Sickness and Other Miners' Diseases, in which he wrote about pulmonary diseases of miners, diseases of smelters and metallurgists, and diseases caused by mercury. One of the great pioneers in occupational medicine was the Italian physician Bernardino Ramazzini (1633-1714). He is often described as the “Father of Occupational Medicine”. Ramazzini graduated from the University of Parma in 1659, and held the Chairs at Modena (1670) and Padua (1700). His publication De Morbis Artificum Diatriba, which appeared in 1700 with a second edition in 1713, was the seminal text in occupational medicine. He wrote: “I for one have done all that lay in my power, and have not thought it beneath me to step into workshops of the meaner sort now and again and study the obscure operations of the mechanical arts; all the more that nowadays medicine has been 1 almost entirely converted into a mechanical art, and in the schools they chatter continually about automatism”. One of Ramazzini's most significant aphorisms is the important addition to the teachings of Hippocrates to physicians. Hippocrates taught physicians that “When you come to patient's house, you should ask him what sort of pains he has, what caused them how many days he has been ill, whether the bowels are working and what sort of food he eats”. Following this citation, Ramazzini wrote: “I may venture to add one more question: What occupation does he follow?” In his writings, Ramazzini described many occupational illnesses that are still seen today, and, furthermore, described the principles for the control. He condemned the lack of ventilation and unsuitable temperatures, he urged laborers in dusty trades to work in spacious, ventilated rooms, he recommended rest intervals in prolonged work and advocated exercise and correct working postures. The first occupational cancer was described by Percival Pott over 200 years ago. This cancer (skin cancer of the scrotum), occurred in chimney sweeps, and was caused by exposure to polycyclic aromatic hydrocarbon compounds in the soot generated by combustion of organic material. This particular cancer could be prevented by improved personal hygiene. An early piece of legislation in England was the Act for Better Regulation of Chimney Sweeps and their Apprentices in 1788. This act stipulated a minimum age of 8 years for chimney sweeps; provided for inspections and hearing of complaints, and provided for prosecution and penalties for violation. The Health and Morals of Apprentices Act, 1802 applied to apprentices in the cotton and woolen industry. It limited work to a maximum of 12 h a day, and specified that factory walls were to be washed twice a year, and for rooms to be ventilated. This legislation also allowed voluntary factory inspections by visitors. Other work environments were covered by other legislation, such as the Mines Act 1842, which prohibited women and girls from work in mines, and allowed for government inspection and state interference. Subsequent legislation extended occupational health coverage to all occupations, and many countries today have such comprehensive legislation. However, some countries still retain the Factories Act. Occupational health legislation has also developed to list requirements for the provision of occupational health services to certain occupations. This has been spelt out in the legislation of some of the more developed countries. Occupational health has kept pace with developments in society. It remains relevant today. For example, in spite of much improved working conditions compared with two centuries ago, modern day chimney sweeps still experience increased morbidity and mortality. Studies among Scandinavian 2 chimney sweeps show that they have more chest symptoms, and have increased mortality from cancers, notably of the lung, bladder, and oesophagus. As practised today, the cornerstones of occupational health practice are health protection and health promotion of those who work. In many countries, such activities extend beyond the worker to include his or her family members. The protection of the health of the working population is the primary concern of occupational health practitioner. Occupational injuries and diseases are largely preventable. They unnecessarily affect the health of the working population and have effects on work productivity and on the economic and social well being of workers, their families, and society. According to recent estimates, the cost of work-related health loss and associated productivity loss may amount to several per cent of the total gross national product of a country. For example, the Health and Safety Executive (HSE) in the United Kingdom has estimated that the real costs of personal injury, work accidents, and work-related ill health amount to between 5 and 10 per cent of Britain's gross trading profit. In the United States, the total corporate health and safety costs in 1997 were estimated to be $418 billion in direct costs, and over $837 billion in indirect costs. Health protection begins with an assessment of risk. Risk assessment is a structured and systematic procedure that is dependent upon the correct identification of hazards and an appropriate estimation of the risks arising from them. It can be either a qualitative or quantitative process. The expertise, effort, and detail required for risk assessment depends on the nature and degree of risk, and the complexity of the work process. Adequate controls are determined based on several factors: such as the toxicity of substance, numbers exposed, acceptability of risk, the legal requirements, costs, and availability of control measures. There is distinction between the terms “hazard” and “risk”. A hazard is a substance, agent, or physical situation with a potential for harm in terms of injury or ill health, damage to property, damage to the environment, or a combination of these. Hazards can be physical, chemical, biological, ergonomic, or psychosocial in nature (Table 1). Hazard identification is the process of recognizing that a hazard exists and defining its characteristics. Risk relates to the likelihood of the harm or undesired event occurring, and the consequences of its occurrence. It is the probability that the substance or agent will cause adverse effects under the conditions of use and/or exposure, and the possible extent of harm. Risk assessment is the process of estimating the magnitude of risk, and deciding if the risk is tolerable or acceptable. A tolerable risk may not always be acceptable. The levels of tolerability of risk are different for different countries, and in different working populations and the general public. 3  The health risk from the hazards should be determined and assessed, and a decision made if the risk is acceptable or tolerable. Unacceptable risk should be eliminated or reduced with new or improved control measures, and their effectiveness monitored. If needed, further corrective actions should be implemented. At the same time, workers should be informed of the hazards, risks, and appropriate measures that can be taken to protect themselves. An example of an initial assessment for a chemical exposure is given in Table 2. Table 1. Types of hazards at the workplace and their health effects Type of hazard Examples Health effect Physical Noise Noise-induced hearing loss Local vibration Traumatic vasospastic desease/ Hand arm vibration syndrome Chemical Various Chemicals Intoxications (e.g. solvents, heavy fibroses metals) Cancers Allergies Nervous system damage Biological Bacteria Infections Fungi Allergies Viruses Ergonomic Repetitive work Musculoskeletal injuries Work-rest schedules Mental stress Lowered productivity and work quality Psychosocial Organizational stress work dissatisfaction Conflicts Burnout Depression Once the degree of risk is assessed, and a decision made that the risk of exposure is unacceptable, some form of control is necessary. There are a wide variety of methods of prevention. The basic aim of occupational medicine is to prevent the occurrence of disease in an individual or specific population sector, such as the working population. This is usually achieved by attempts to reduce the risk or contracting a disease. If this is not always possible, another way is by undertaking activities targeted at early detection of disease, namely screening procedures. Customarily several levels of prevention are recognized. Table 2. An example of an initial assessment for chemical exposure 4 1 List substances in the area to be assessed 2 Determine which are actually used 3 Obtain suppliers' data sheets 4 Evaluate data sheets 5 Inspect places where the substances are handled 6 Evaluate method of control 7 Perform environmental monitoring for the chemical if needed Primary prevention aims to reduce the occurrence of disease by eliminating the cause of disease or reducing exposure to safe levels that prevent it from causing damage, for example banning the use of blue asbestos and reducing noise at its source to levels that do not cause noise-induced deafness. Secondary prevention aims to detect situations of early effects of disease before they manifest at clinical symptoms and signs in order to take corrective action, for example regular monitoring of blood lead levels among lead exposed workers, regular audigrams among workers exposed to high levels of noise in the work environment. Tertiary prevention aims to minimize the consequences in persons who already have disease. This activity is largely a curative and rehabilitative procedure and depends on proper and appropriate treatment. Thus, it is evident that primary and secondary prevention are the major domains of occupational medicine. Prevention of occupational disease can take place at various levels, such as at the national level, or at the level of the workplace itself. The main aim is to reduce the occurrence of occupational disease by eliminating the cause or by controlling exposure to safe levels in order to prevent it from causing damage to the health of workers. Successful prevention of occupational disease could be achieved by controlling exposure to harmful agents to what are considered as safe and permissible levels. This is a form of primary prevention as it is directed at efforts to prevent damage by controlling exposure to safe levels. There are several mechanisms for the control of exposure at the workplace: - Total elimination of the hazard - Substitution of the hazard - Engineering controls - Redesign of the workstation or process - Administrative controls - Education of workers - Use of personal protective devices Pre - employment or pre - placement examinations 5  Pre-placement/employment medical examinations are undertaken to achieve proper job placement according to the mental and physical capabilities of the worker. By such examination and job placement it is hoped to prevent damage to susceptible workers. It must be recognized that such tests are also undertaken with different objectives, for example: to protect other workers and the general public, for insurance purposes, and to obtain baseline information on fitness. Education of workers should be given during these assessments. Those who work have a right to know the potential hazards and risks in their work and workplaces. They should be educated on these matters and be given information on how to safeguard their health. Immunization against diseases that may possibly be contracted on the job, and for which an effective vaccine is available, should also be given. An example is the immunization of health-care personnel exposed to the hepatitis B virus. Biological monitoring of the worker ideally begins at the pre employment examination stage and can be continued periodically. Biological monitoring complements environmental monitoring in the assessment of health risk in the exposed worker. It is useful tool in the prevention and management of ill health among workers. Figure 1 illustrates and summarizes the terminology and levels of prevention that are used in occupational health practice. Primary prevention Secondary prevention Pre-employment Medical examination Periodic medical Measurement of Early detection of Screening intoxicant or examination asymptomatic metabolite disease Biological Measurement of Measurement of health effects health effects monitoring Molecular ? Not proven ? Not proven biomarkers Fig.1 Summary of terminology and levels of prevention in occupational disease Periodic medical examinations. Periodic medical examinations may be required for some occupational groups in order to effect primary or, failing that, secondary prevention of disease. In many countries, certain categories of employees must undergo statutory periodic medical examination. These examinations are usually for workers exposed to known hazards such as noise, radiation, asbestos, silica, heavy metals, and specific toxic chemicals. In some countries, only properly qualified health personnel, with additional postgraduate training in occupational health, are empowered to perform the 6 examinations, and issue fitness to work certificates. The results of the examinations have to be kept for a specified period of time, and copies sent to the relevant government body. The objectives of such statutory medical examination would be to prevent special groups of “at risk” workers from developing serious occupational diseases. Regular health examinations, which are specific for the type of hazard the worker is exposed to, are conducted. Workers who are found to show sings of overexposure to any hazard or have early sings of disease can be removed from further exposure. They can be given alternative work until they are fit to return to their former jobs. Furthermore, if signs of overexposure are detected, further control measures can be taken to reduce the exposure and prevent other workers from being similarly affected. Sometimes, special groups of workers are required to undergo periodic medical examinations for other reasons, such as to certify ongoing fitness to work. Examples of these workers include professional drivers and food handlers. Most countries require the statutory notification of occupational diseases to the government. Notification should be done on the suspicion of occupational disease. The notified case is subsequently investigated and confirmed by the relevant government specialists. Either the employer or health practitioner who sees the worker can notify. In many countries, a list of notifiable occupational diseases is available. Notification serves as an additional means of control of occupational diseases, undertaken by occupational health and safety professionals in the public sector. It initiates a chain of events, which often includes investigation and confirmation of the index case, and active case finding of other affected persons. An example of a notification form is given in fig. 2 (Ministry of manpower, Singapore 1999). Figure 3 summarizes the continuum of various means of prevention in occupational health practice. Tertiary prevention. Tertiary prevention activities are largely curative and rehabilitative procedures. Workers should be removed from further exposure, and the appropriate medical treatment given if indicated. Examples of appropriate treatment include the reducing of first aid promptly after an injury, chelation for severe cases of overexposure to heavy metals, and hyperbaric treatment for cases of compressed air illness. An evaluation of the health status of the employee returning to work after a prolonged absence from work due to illness or injury is important. The aim is to insure that the worker has sufficiently recovered from the illness or injury, and that he/she is fit to return to work. The following two issues should be considered.  Can the worker perform his/her duty without adverse health and safety risks to himself/herself or fellow workers? 7   Should he/she return to full-time unrestricted duty, or should some modified, restricted, or alternative duty be given? The rehabilitation of workers is another important aspect of occupational health care. Management, fellow worker, occupational health professionals, and the injured worker have to work together to ensure that suitable alternative duties are provided, and that any work restrictions or physical limitations are understood. There should be clear short- and long-term goals in rehabilitation, and alternative duties should be meaningful and contribute to production. Sometimes, the use of external rehabilitation resources may be needed. Worker's compensation. In many countries, workers who are injured at work, or fall ill from hazardous work exposures are eligible for compensation. Employers who carry out economic activities through labour and machines create an environment that may be likely to cause ill in the employees. Thus employers should be liable for payment of compensation to workers if they are injured or fall sick because of their work. Legistlation concerning employment injury benefits is often called a Workmen's Compensation Act, as in the United States. Employers may be required to insure against their liability under the Act. The workmen's compensation system is designed to minimize litigation and facilitate payment of compensation to injured workers. It is based on a “no fault principle”. In different countries, certain categories of workers (e.g. domestic helpers) may be excluded. Other countries may have social insurance to give protection to employment injury victims. The principle of social insurance is that of sharing of risks and pooling financial resources. A social insurance scheme establishes a public channel through a government department or government supervised body, which oversees procedures of screening, determination of award, and payment of benefits. In the early development of such schemes, only injuries from industrial accidents were covered. This was subsequently enlarged to include occupational diseases. In countries where this practiced, the national legistlation would contain a list of those diseases that could be compensated for. The nature of occupation in relation to each disease may also be prescribed. The worker who suffers from the disease has the advantage of not having to prove that the disease was of occupational origin. Some countries have a more flexible system- any disease could be shown to be due to an occupation could be considered as compensatable. Tenth Schedule The Factories Act Chapter 104 Section 67(1) 8  Notice Of Patient Suffering From Industrial Diseases (This notice shall be completed by a registered medical practitioner attending on or called in to visit a patient whom he believes to be suffering from an industrial diseases and forwarded to the Chief Inspector of Factories. c/o Department of Industrial Health. Ministry of Manpower, 18 Havelock Road # 05-01, Singapore 059764) Name of Patient Age Sex Race NRIC/FIN No. Present Occupation Residential Address Case Summary Name and Address of If patient is deceased state Employer date of last attendence LIST OF NOTIFIABLE INDUSTRIAL DISEASES Please tick relevant box  ANILINE POISONING  HYDROGEN SULPHIDE  ANTHRAX POISONING Name of doctor  ARSENICAL POISONING  INDUSTRIAL DERMATITIS Name and Address of  ASBESTOSIS  LEAD POISONING  BAROTRAUMA  LIVER ANGIOSARCOMA Hospital/Clinic  BERYLLIUM POISONING  MANGANESE POISONING Tel. No. Doctor's Ref.  BYSSINOSIS  MERCURIAL POISONING No.  CADMIUM POISONING  MESOTHELIOMA  CARBAMATE POISONING  NOISE INDUCED DEAFNESS Diagnosis  CARBON BISULPHIDE  OCCUPATIONAL ASTHMA POISONING  ORGANOPHOSPHATE  CHROME ULCERATION POISONING  CHRONIC BENZENE  PHOSPHORUS POISONING POISONING  POISONING FROM HALOGEN  COMPRESSED AIR ILLNESS DERIVATIVES OF  CYANIDE POISONING HYDROCARBONS  EPITHELIOMATOUS  REPETITIVE STRAIN  ULCERATION DISORDER OF THE UPPER (due to tar, pitch, bitumen, mineral oil or LIMB paraffin or any compound, product or  SILICOSIS residue of any such substance)  TOXIC ANAEMIA  TOXIC HEPATITIS Date Signature of Doctor Labour 73-2061-77 NOTE FOR THE REGISTERED MEDICAL PRACTITIONER All items in this Notification Form must be completed and accompanied by the relevant documents, viz AUDIOGRAMM for a Noise Induced Deafness notification and INDUSTRIAL DERMATITIS INVESTIGATION FORM for Industrial Dermatitis notification Fig. 2 An example of a notification form for occupational disease. 9  PRIMARY PREVENTION SECONDARY PREVENTION Elimination Substitution Environmental monitoring Biological Health effects Engineering controls monitoring screening Personal protective devices │ Exposure → Identification of → Biological → Biological → Asymptomatic → Disease vulnerable worker exposure index effects disease ↓ Pre-employment Periodic medical medical examinations examinations Notification to authorities ↓ Enforcement of prevention ← Active case finding ← Confirmation of diagnosis Fig. 3 Continuum of preventive actions in occupational health practice 10 Benefits are payable for temporary incapacity or permanent incapacity for workers, and survivors' “benefits for those killed at work. Guidelines for the assessment of disability are available in most countries. The final assessments for disability are made when the workers” medical condition has stabilized, and not likely to improve or deteriorate further. Besides Workmen's Compensation and social insurance schemes, injured workers can sue their employer through common law and claim benefits. This was the only avenue for action in the days before the introduction of Workmen's Compensation schemes. This can be a long process, and the worker has to prove negligence on the part of the employer. In general, workers who have claimed benefits from Workmen's Compensation are not allowed further recourse through this action. Work-related diseases. The term “work-related diseases” has been used to describe not only recognized occupational diseases, but also other disorders in which the work environment and performance of work contribute significantly as one of several causative factors. These are diseases in which workplace factors may be associated in their occurrence but need not be the only risk factor in each case. Common work-related diseases include: hypertension, ischaemic heart disease, psychosomatic illnesses, musculoskeletal disorders, and chronic nonspecific respiratory disease/chronic bronchitis. In these diseases, work may be associated with their causation or may aggravate a pre-existing condition. In terms of frequency of occurrence, work-related diseases are often more common than pure “occupational diseases”. While prevention of occupational diseases is possible by the elimination of the workplace hazard, work-related diseases cannot be entirely prevented by only addressing occupational hazards. Thus, at the workplace, three categories of diseases may be noted in workers. 1. Occupational diseases – these are caused by exposure to specific hazards at the workplace. However, in some situations these occupational diseases may also occur among the general community as a consequence of contamination of the environment from the workplace, for example, lead and pesticides. Occupational diseases are cause specific, for example, asbestos causes asbestosis. 2. Work-related diseases – these are “multifactorial” in origin, where factors in the work environment may play a part, together with other risk factors in the development or aggravation of such diseases. These diseases have a complex aetiology. 3. General diseases affecting the working population – these are medical conditions prevalent in the community, such as malaria, hereditary haemolitic anaemia, or diabetes mellitus, without a causal relationship with work. The unhealthy worker may not be able to be as productive as his healthy counterpart. Furthermore, work may be have a deleterious or aggravating effect on the medical condition. Table 3 shows the differences between occupational and work-related diseases. 11  Table 3 Differences between occupational and work-related diseases Work-related diseases Occupational diseases Occur largely in the community Occur mainly among working population Multifactorial in origin Cause is specific Exposure to workplace may be a factor Exposure to workplace is essential May be notifiable and compensatable Notifiable and compensatable Occupational health practitioners have long recognized health promotion to be an integral part of a comprehensive occupational health-care system (ACOM 1983). However, the definition of what really constitutes health promotion is sometimes unclear, as definitions of health promotion differ consequent to the continual evolution of the basic concept of health. The WHO defines health promotion in its broadest sense as “the process of enabling people to increase control over, end to improve their health”. Health promotion is seen as a continuum ranging from the treatment of disease, to the prevention of disease, including protection against specific risks, to the promotion of optimal health (WHO 1988). Health promotion at the workplace is still developing, and much has still to be learnt. Over time, research and development will unravel much concerning the true capabilities and limitations of health promotion in the workplace. It is still worth remembering, however, that the pursuit of health in itself is a worthy goal. Even if nothing else, the incorporation of health promotion into the workplace context will certainly serve to provide a somewhat more balanced perspective of life for worker. 12