Recognizing Occupational Disease --
Taking an Effective Occupational History

MICHAEL B. LAX, M.D., M.P.H., and WILLIAM D. GRANT, ED.D.,

Central New York Occupational Health Clinical Center,

State University of New York Health Science Center at Syracuse, Syracuse, New York

FEDERICA A. MANETTI, M.D., M.S.,

Syracuse, New York

ROSEMARY KLEIN, M.S., C-ANP, COHN-S,

Central New York Occupational Health Clinical Center,

State University of New York Health Science Center at Syracuse, Syracuse, New York

Occupational exposures contribute to the morbidity and mortality of many diseases. However, occupational diseases continue to be underrecognized even though they are responsible for an estimated 860,000 illnesses and 60,300 deaths each year. Family physicians can play an important role in improving the recognition of occupational disease, preventing progressive illness and disability in their own patients, and contributing to the protection of other workers similarly exposed. This role can be maximized if physicians raise their level of suspicion for workplace disease, develop skills in taking occupational histories and establish routine access to occupational health resources.

The patient with a possibly work-related illness frequently seeks care initially from a family physician. The physician's recognition of a possible link between work and disease often determines the diagnostic tests that are performed and the treatment that is recommended. Early diagnosis of an occupational illness may prevent progressive morbidity and disability from conditions such as occupational asthma and may facilitate the reversal of adverse effects from exposures to substances such as lead.¹ The identification of an occupational illness in one patient also provides the physician with an opportunity to protect other patients with similar exposures.² Since much remains to be learned about the effects of toxins on health, the family physician is in a crucial position to contribute new information about occupational disease.

A variety of factors are responsible for the present underrecognition of occupational illnesses. Some of these factors include the difficulties physicians can encounter in dealing with the Workers' Compensation system, the reluctance of patients to connect a health problem with their work (primarily because they fear they will lose their jobs) and the present managed care environment, which reduces the time available to take a complete occupational history.^3-5

This article describes ways in which family physicians can improve the detection of occupational disease in their patients. In particular, physicians need to raise their level of suspicion for occupational disease, build skills for efficiently obtaining an occupational history and develop routine access to occupational medicine resources.

Raising the Level of Suspicion

Occupational disease is surprisingly common. An estimated 860,000 illnesses and 60,300 deaths from workplace exposures occur annually in the United States.⁶ Studies^7,8 have found that 75 percent of hospitalized and ambulatory primary care patients report hazardous exposures, and 17 percent suspect that their illness is linked to their job. Work-related illness is diagnosed in approximately 10 percent of these patients.

Since the spectrum of occupational diseases is extremely broad (Table 1),^2,4,8-11 many conditions commonly encountered in primary care practice may be work related.^12,13 The following illustrative case is but one example of an illness with an occupational source.

Illustrative Case

A 38-year-old man reported several weeks of generalized headaches. A diagnosis of stress-tension headache was made, and he was given an analgesic. Because he continued to have pain, computed tomographic (CT) scanning was performed. The CT scan was normal.

The patient was referred to a neurologist and then to a specialty headache clinic. Various treatments were applied without effect.

An occupational history revealed that he had been a spray painter for 11 months. While at work, he was routinely exposed to mixed organic solvents. When he was taken out of work for four weeks, his headaches cleared.

Musculoskeletal Disorders
Patients with musculoskeletal disorders involving the arm and neck frequently seek medical care. Work tasks contribute to symptoms in a significant proportion of these patients. More than 60 percent of reported occupational illnesses are work-related musculoskeletal disorders of various types.¹⁴ Specific diagnoses, such as localized nerve entrapment (e.g., carpal tunnel syndrome), tendinitis (e.g., lateral epicondylitis, de Quervain's tendinitis), muscle strain and less well-defined regional pain syndromes, have been associated with jobs in all sectors of the economy. Repetition, force, awkward or static postures, vibration, work speed and restricted tasks are job factors that may contribute to the development of these ailments.⁹

Respiratory Diseases
A variety of respiratory diseases are also commonly occupational in origin. Pneumoconiosis due to inhalation of asbestos, silica or other nonorganic dust should be considered in patients who report progressive dyspnea and dry cough. Airway diseases, including rhinosinusitis, bronchitis and asthma, have been increasingly recognized as work related.

A widening array of exposures has been linked to occupational asthma related to possible exposure to allergens (e.g., grain dust), respiratory irritants (e.g., sulfur dioxide) or substances acting through other mechanisms (e.g., isocyanates).^10,15 Less frequently, recurrent "flu" or "pneumonia" may actually be symptoms of hypersensitivity pneumonitis from exposure to mold, other organic materials or certain chemicals.

Neurologic Disorders
The nervous system is a frequent target of toxins, including organic solvents (e.g., toluene and chlorinated hydrocarbons), metals (e.g., lead and manganese) and pesticides (e.g., organophosphates). Peripheral polyneuropathy may be caused by agents such as lead, methyl butyl ketone and organophosphate pesticides. More commonly, chronic organic solvent exposure is responsible for a syndrome that includes headaches, fatigue, light-headedness, cognitive difficulties and depression.¹⁶

Cancer and Heart Disease
Work exposures also contribute to a notable percentage of cancers and have been increasingly recognized as factors in the development of coronary artery disease.^11,17

Stress-Related Illnesses
Stress has also emerged as an important hazard in the contemporary workplace. It has been associated with a range of emotional and physical ailments, including coronary artery disease and myocardial infarction. The risk of stress-related illness is increased in jobs with high emotional/psychologic demands and low potential for control by the worker.¹¹

Work Conditions and Illness
As the focus of business has shifted from manufacturing to service in most industrialized countries, traditional notions of hazardous work have, by necessity, been expanded. Occupational illnesses continue to occur in manufacturing, construction and agricultural sectors, but they are also increasingly being recognized in the burgeoning service sector. For example, rapidly expanding computer use has been associated with musculoskeletal and eye problems in a growing number of office workers.

Today a significant proportion of occupational illnesses are related to building conditions, such as inadequate fresh-air ventilation, low humidity and the presence of cigarette smoke, volatile organic compounds and fibers, molds or other microbiologic materials.

Typically, workers with symptoms related to indoor air quality report upper airway and eye irritation, frequently accompanied by fatigue and difficulty concentrating. These symptoms generally occur in a group of workers in the same environment. Furthermore, the workers report rapid clearing of the symptoms when they leave the workplace. Other illnesses, including asthma, hypersensitivity pneumonitis and respiratory infections, have also been linked to specific building-related exposures.¹⁸

Index of Suspicion
An occupational etiology should be considered if an illness fails to respond to standard treatment, does not fit the typical demographic profile (i.e., lung cancer in a 40-year-old nonsmoker) or is of unknown origin. Much is still unknown about the health effects of most workplace exposures. The introduction of new chemicals and other materials has far outpaced general knowledge of their potential toxicity. Consequently, family physicians continue to play a crucial role in recognizing unsuspected links between exposures and specific illnesses.

Taking the Occupational History

A standardized set of questions asked of every patient is the single most important method of recognizing the link between illness and occupation.^1,8,19 In a busy practice, a set of screening questions and a self-administered questionnaire can be helpful in obtaining an efficient occupational history.

Screening Questions
Key screening questions include the following^8,19:

1.      What type of work do you do?

2.      Do you think your health problems might be related to your work?

3.      Are your symptoms different at work and at home?

4.      Are you currently exposed to chemicals, dusts, metals, radiation, noise or repetitive work? Have you been exposed to chemicals, dusts, metals, radiation, noise or repetitive work in the past?

5.      Are any of your co-workers experiencing similar symptoms?

If the answers to one or more of these questions suggest that a patient's symptoms are job related or that the patient has been exposed to hazardous material, a comprehensive occupational history should be obtained.

Self-Administered Occupational History
Every patient's chart should include a self-administered occupational history form that the patient fills out before a visit. The completed form is then available for subsequent review and periodic updating by the family physician or office staff.²⁰ A sample form for a self-administered occupational history is provided in Figure 1.

Comprehensive Occupational History
The elements of the comprehensive occupational history are listed in Table 2.

Job History. A job history, including employer names, dates of employment, job titles and major job duties, serves as the framework for assessing occupational exposures and the risk of illness. The job history should include a list of all positions held, because some occupational diseases, particularly work-related cancers, have long latent periods.

Job duties are distinguished from job titles because titles alone often provide little or misleading information about occupational exposures. Furthermore, workers with the same job title, even within the same company, may have vastly different exposures based on their job duties.

Military service should also be included in the job history. Hazardous exposures are common in military settings (e.g., asbestos exposure in naval shipyards and dioxin exposure in Vietnam).

Exposures. The second element of the history is an assessment of specific exposures. Major exposures should be listed for each job in the job history. The physician should ask for additional details about job tasks that appear relevant to the patient's current symptoms.

Exposures are recorded for each of the patient's various job duties. These exposures may include metals, chemicals, dusts, physical factors (i.e., repetitive motion, noise, radiation), microorganisms and stress. Both indirect and secondary exposures should be recorded because the patient's health can be affected by exposures originating in other parts of the workplace. For example, asthma in a woman assembling spark plugs may be exacerbated by exposure to volatilized products from a molding operation 20 feet away from her workstation.

Exposure dosage should also be assessed. Although a patient may present a list of numerous chemicals used in a workplace, some substances may be used infrequently or in very small amounts, whereas others may be used daily, gallons at a time.

The presence of exposure controls may significantly affect the extent of exposure. Ventilation is a crucial control and includes both general and local systems. The patient should be asked specific questions about general ventilation, including the presence of operable doors and windows, the location of walls and partitions that may affect air flow, and the configuration of the mechanical ventilation system. Workers are usually aware of a local exhaust ventilation system, such as a hood, a vacuum apparatus attached to a machine or exhaust slots on a tank. The patient should be asked whether the exhaust mechanisms are functioning.

Personal protective equipment such as respirators, gloves and earplugs are other commonly used exposure controls. To assess exposure dosage, the physician needs to know whether the patient uses the protective equipment consistently, whether the equipment fits correctly (especially a respirator), whether the equipment is appropriate for the exposure and whether the equipment is stored and maintained properly.

Temporal Relationship of Symptoms to Work. The timing of symptoms in relation to work is often crucial in the assessment of a potential occupational illness. A patient with asthma may state that symptoms appear soon after he or she arrives at work and then abate after the shift and on weekends. The timing of symptoms may be more specifically linked to the use of a certain substance, the activation of a specific process or a change of materials or other work conditions. However, it is important to recognize that as many job-related illnesses progress, the clear relationship of symptoms to work may be obscured by a lack of marked improvement away from work.

Symptoms Among Co-workers. The probability that work is contributing to a common illness is strengthened if the patient's co-workers are experiencing similar symptoms. When queried, patients with occupational illness commonly report others who are similarly affected.

Nonoccupational Exposures. Nonwork activities may also contribute to illness and therefore should be assessed as part of the comprehensive history. Tobacco smoking and excessive alcohol use contribute to a variety of diseases and may interact with occupational exposures to increase the risk of adverse health effects. Recreational activities, hobbies, unpaid work (e.g., home renovations) and drug use are other potential sources of hazardous exposure. For example, a miner may be exposed to noise both at work (drilling and blasting) and at home (snowmobiling and hunting) or a construction painter may be exposed to lead during bridgework and while scraping and repainting the house. The history should allow the physician to evaluate the relative contribution of exposures, both on and off the job, to an illness.

Additional Exposure Information
It is often desirable to supplement the occupational history with additional exposure data. Patients may have only partial knowledge of the specific substances to which they have been exposed.

With the patient's permission, the physician can request exposure information from the employer. The Occupational Safety and Health Administration's (OSHA) Hazard Communication and Access to Medical Record Standards mandate access to this information for both clinicians and workers.²¹

Alternative strategies may be employed if the patient is reluctant to have the physician contact the employer. The patient may make the request for exposure information, or the physician may contact the manufacturer or distributor of the suspect materials. Labels from workplace containers provide the names of appropriate contacts. The patient can also ask representatives of a trade union, if present, to obtain exposure data. Employers are sometimes amenable to a site visit by the physician. This visit can provide valuable exposure information.

In response to a request for exposure data, the physician usually receives a material safety data sheet (MSDS) for each substance used in the workplace. The MSDS identifies the hazardous ingredients and notes potential health effects of the substance. The MSDS is often limited, however. Since many substances remain unstudied and their toxic effects are unknown, they have not been deemed harmful by OSHA. As a result, they are not covered in MSDS materials. The lack of toxicity data is also reflected in the emphasis the MSDS places on acute health effects. The potential effects of chronic lower level exposure often are not included in the MSDS. Therefore, the physician should view the MSDS as an informational starting point that frequently requires supplementation.

In addition to the MSDS, quantitative exposure data are often available. These data typically include levels of air contaminants that are compared to OSHA permissible exposure limits (PELs). However, if the air level of a substance is below the recommended PEL, it should not automatically be assumed that the substance carries no risk of adverse health effects. The limitations of monitoring techniques and OSHA's standard setting process frequently call this assumption into question.²² Consequently, even if air levels of various substances are below the PELs, a patient whose history is consistent with a work-related illness is likely to be experiencing the adverse effects of exposure.

Occupational Health Resources

The need for consultation or referral depends on the physician's skill, confidence and time, as well as the specifics of a given case. A telephone consultation or referral to an occupational medicine specialist can provide information on the extent of a patient's exposure, the likely health effects of the exposure, appropriate diagnostic tests, possible workplace interventions to reduce exposure and recommendations on the patient's return to work. Corroboration by an occupational medicine specialist may also increase the family physician's confidence in his or her professional assessment of the situation.

Many occupational health centers employ multidisciplinary teams that include industrial hygienists, nurses and social workers. This structure allows occupational illness to be addressed comprehensively. In addition, resources are available to conduct workplace evaluations, to provide educational programs and to help patients access appropriate benefits systems and cope with the emotional ramifications of an occupational disease.

The Association of Occupational and Environmental Clinics and the American College of Occupational and Environmental Medicine can provide lists of occupational medicine specialists for any part of the country (Table 3). Other resources accessible to physicians who need information on a specific hazard include the National Institute for Occupational Health and regionally based poison control centers. Similar information can be obtained from a variety of computerized databases available by subscription or through a medical library. The Internet contains a growing number of sites with useful toxicity information.

Further investigation of the workplace is indicated when the physician perceives that a serious hazard is not being addressed. Local OSHA offices can be asked to intervene in these situations. Most states offer analogous programs to regulate public sector workplaces.

Figure 1 adapted with permission from Central New York Occupational Health Clinical Center, State University of New York Health Science Center at Syracuse, Syracuse, New York.

The Authors

MICHAEL B. LAX, M.D., M.P.H.,
is medical director of the Central New York Occupational Health Clinical Center, Syracuse, and assistant professor in the Department of Family Medicine at the State University of New York Health Science Center at Syracuse.

WILLIAM D. GRANT, ED.D.,
is research professor and executive vice chairperson of the Department of Family Medicine at the State University of New York Health Science Center at Syracuse.

FEDERICA MANETTI, M.D., M.S.,
is a family physician in Syracuse.

ROSEMARY KLEIN, M.S., C-ANP, COHN-S,
is a certified adult nurse practitioner and certified occupational health nurse. She is the clinic coordinator at the Central New York Occupational Health Clinical Center and a faculty member in the Department of Family Medicine at the State University of New York Health Science Center at Syracuse.

Address correspondence to Michael B. Lax, M.D., M.P.H., Central New York Occupational Health Clinic Center, Department of Family Medicine, State University of New York Health Science Center at Syracuse, 6712 Brooklawn Parkway, Suite 204, Syracuse, NY 13211-2195. Reprints are not available from the authors.

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