Preventive Medicine: Preventive Medicine 4

Physical Hazards

• Acute traumatic injuries can occur in various workplaces, such as industrial accidents, motor vehicle crashes, falls, and trauma involving farming or mining equipment.
• Establishing a causal link between workplace exposure and health outcome can be challenging for gradual traumas, such as repetitive strain injuries.
• Examples of health conditions caused by gradual traumas include lumbar disc disease in nurses, carpal tunnel syndrome in clerical workers, and degenerative joint disease in materials handlers.

Radiation

• Radiation exposure is a widespread physical hazard, with occupations accounting for only a small portion of overall population exposures.
• The largest occupational group monitored for radiation is health care workers, although most exposures do not exceed typical background levels.
• Extremely high levels of radiation exposure can cause acute radiation sickness, with symptoms including skin sloughing, bone marrow damage, and gastrointestinal ulcers.
• Survivors of very high acute radiation doses are at elevated risk of blood and solid-organ malignancies.

Noise

• Noise is a prevalent physical hazard in workplaces, with more than 10 million U.S. workers exposed to greater than 80 decibels.
• By age 50, an estimated half of heavily exposed construction workers and 90% of heavily exposed miners will have hearing impairment.
• Substantial noise exposure occurs in various industries, including manufacturing, mining, construction, and transportation.

Heat and Cold

• Thermal stress is a physical hazard in workplaces, with excessive heat exposure occurring in foundries, smelting operations, firefighting, and outdoor settings.
• Health effects of heat exposure include lightheadedness, swelling, muscle cramping, and in severe cases, agitation, delirium, and kidney failure.
• Cold exposure can cause hypothermia, frostbite, Raynaud's phenomenon, and cold-induced hives.

Chemical Hazards

• There are over 80,000 chemicals in common use, with many posing health risks to workers.
• Solvents are widely used in industrial processes and can cause acute encephalopathic effects, skin irritation, and defatting of dermal tissue.
• Certain solvents have uniquely toxic properties, such as n-hexane and methyl-n-butyl ketone, which can cause a mixed motor and sensory neuropathy.

Metals and Mineral Dusts

• Metal exposures can trigger a broad range of health effects, including behavioral and cognitive effects, anemia, peripheral neuropathy, and chronic encephalopathy.
• Lead exposure is a significant risk to workers, particularly in construction, welding, and battery manufacturing.
• Other metals, such as arsenic, mercury, and beryllium, can also cause a range of acute and chronic effects.

Hydrocarbons and Pesticides

• Polycyclic aromatic hydrocarbons (PAH) are a risk factor for lung cancer and have been linked to increased lung cancer risk in various industries.
• Pesticides are a broad category of chemicals used to control insect, plant, and fungal species, and can cause acute and chronic health effects.
• Exposure to pesticides can occur among farm and orchard workers, landscapers, and others.

Inorganic Gases

• Inorganic gases are a concern in industrial settings due to their acute toxicity and potential for long-term sequelae.
• Simple asphyxiants, such as methane and nitrogen, can dilute oxygen in enclosed spaces, while cyanide and carbon monoxide interfere with cellular respiration and oxygen transport.

Biologic Hazards

• Occupational biologic hazards are encountered in health care workplaces, areas of contact with animals or arthropod vectors, and locations with exposure to altered ranges of diseases.

• Blood-borne pathogens, such as HIV, HBV, and HCV, are a significant risk to health care workers, particularly through needlestick injuries.

• Aerosol and droplet-spread infections, such as tuberculosis, measles, and influenza, can also be transmitted in health care settings.### CDC Recommendations for Health Care Workers

• In the event of a rapidly spreading virus with a high risk to younger people, the CDC recommends the use of fit-tested N95 respirators for health care workers caring for affected patients.

• This recommendation is based on the precautionary principle, which states that if the level of harm may be high, action should be taken to prevent or minimize that harm even when there is uncertainty about the likelihood of harm occurring.

Occupational Infectious Diseases

• Major groups at increased risk of occupational infectious diseases include:
  • Those with frequent animal contact (e.g., farmers, veterinarians, animal handlers)
  • Those likely to have contact with arthropod vectors (e.g., outdoor workers)
  • Those working in other than their native microbiologic milieu (e.g., workers in developing countries)
• Examples of zoonotic diseases include:
  • Brucellosis
  • Cat-scratch disease
  • Leptospirosis
  • Plague
  • Psittacosis
  • Tularemia
  • Cryptococcosis
  • Histoplasmosis
  • Ringworm
  • Giardiasis
  • Cryptosporidiosis
  • Hantavirus
  • Monkeypox
  • Rabies
• Diseases requiring an arthropod vector include:
  • West Nile virus
  • Rocky Mountain spotted fever
  • Lyme disease
  • Babesiosis
  • Ehrlichiosis
  • Several viral encephalitides

Psychosocial Stress

• Long hours, rotating work shifts, demanding jobs, limited decision latitude, competing time demands, repetitive tasks, threat of violence, job insecurity, and poor management contribute to stress in the workplace.
• Chronic exposure to such work circumstances may have adverse physiologic effects, including:
  • Increased cardiovascular disease
  • Increased injury risk
  • Perception of poor health
• The physiologic connection between stress and adverse health outcomes is not completely understood, but possible etiologic links include:
  • Elevated catecholamine levels
  • Abnormalities of the pituitary-adrenocortical axis
  • Effects on the immune system

Environmental Hazards

• Environmental hazards differ from workplace hazards in that they:
  • Affect all age groups at all times
  • Usually have lower exposure levels
• Examples of environmental hazards include:
  • Water contamination from industrial effluents or toxic waste disposal
  • Soil contamination from fallout of fumes or particulates released into the air
  • Food contamination from compromised soils, water, or processing methods
  • Air pollution from industrial or natural sources

Radon Exposure

• Radon is a product of the radioactive breakdown of uranium and can become concentrated in indoor spaces.
• Epidemiologic studies have shown that exposure to radon in the home may elevate lung cancer risk.
• The U.S. Environmental Protection Agency (EPA) recommends retesting and mitigation of homes where basement radon levels exceed 4 pCi/L.
• Radon mitigation systems work by establishing a pressure gradient to reduce travel of radon into basements from surrounding soil and rock.

Ambient Air Pollution

• Ambient air pollution is derived largely from human activity, particularly industrial and vehicular combustion.
• Pollutants of major concern include:
  • Sulfur dioxide
  • Nitrogen oxides
  • Acid aerosols
  • Particulates
  • Volatile organic compounds
  • Lead
  • Ozone
• Health outcomes linked to air pollution include:
  • Increased cardiopulmonary mortality
  • Increased numbers of visits to emergency departments and physician offices
  • Increased rates of hospitalization
  • Exacerbations of asthma
  • Higher frequency of respiratory infection
• Laboratory studies have revealed that air pollution can increase airway inflammation, decrease lung function, and increase upper respiratory irritation.