Occupational

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Occupational Environmental Health
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Occupational Health

• The workplace has a significant impact on human
  health
• Occupational health directed to health promotion,
  prevention of illness specific protection in
  the workplace

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• Multi-disciplinary
• Medicine
• Nursing
• Industrial hygienists
• Engineering
• Natural sciences

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• In Canada, 90 of all workers compensation cases
  related to injuries (2000)
• Other types of occupational illnesses important,
  but more difficult to get data
• This lecture will focus on injuries in the
  workplace

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Epidemiology of Work Injuries

• Canadian Data (2000)
• 392,502 lost time injuries
• 822 fatalities
• Fatality rate 5.5/100,000 workers
• Average of 2.4 fatalities/day

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• Manitoba
• 5.9 of all workers covered by Workers
  Compensation Board (WCB) injured at work

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Fatalities
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• Major occupational diseases reported 2000-03
• Pulmonary
• Chronic obstructive lung disease
• Pulmonary fibrosis
• Asbestosis
• Mesothelioma
• Cancer (which could have included mesothelioma)
• Cardiovascular

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Fatalities by Workplace, Including Those Not
Covered by WCB 1983-2002
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Time-loss Injury Rate/100 FTE workers Manitoba
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Nature of Injuries in 2002 of total
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• Two occupational groups are particularly
  vulnerable to injury in the work place
• Farmers
• Health care providers

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• Epidemiology of Farm Injuries
• Young children and older farmers more likely to
  be injured or killed

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Age-Specific Agricultural Fatality Rates
1990-2000
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• Males are more likely to be injured than females
• The majority of fatalities are associated with
  machinery

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• Mechanized injuries deaths
• Rollovers
• Runovers
• Entangled in machinery
• Pinned or struck by machinery
• Collision

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• Non-mechanized injuries deaths
• Animals
• Struck by object
• Drowning
• Falls
• Toxic substances

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• Seasonal variations in injury/death rates
• Response rates are compromised because many
  farmers work alone
• Risk for injury is increased because the family
  farm is one of the few worksites where people
  also live

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• Epidemiology of Health Care Workers Injuries
• Study by OBrien-Pallas et al (2004)
• Highest rate of injury-related absenteeism
  reported by nursing aides orderlies
• Second highest group is RNs
• absenteeism 83 higher than that reported by the
  full Canadian work force

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• Most frequently reported injury is
  musculoskeletal
• Nurses have the highest reported prevalence of
  back injuries
• Probability of injury increases with
• Number of hours of overtime worked
• Higher than average previous sickness episodes
• Poor working relationships with physicians

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• Other data related to the health of the nurses
  included in the study
• Their perception of their health status was
  better than the reported statistics on injury
  absenteeism
• Absenteeism has been on the rise since 1999
• Evidence of moderate high levels of emotional
  exhaustion
• 40 report working with back, neck or buttock
  pain some of the time

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• 25 worked while in pain most to all of the time
• Recent study by Yassi et al. found that injury
  rates amongst Canadian health care workers has
  decreased since 2000
• Still significant challenges
• Musculoskeletal injuries
• Violence is an emerging concern

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• Fear of contracting infections
• Needle-stick injuries likely under-reported

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• Factors Affecting the Health of Workers
• Safety hazards
• Physical hazards
• Noise
• Vibration
• Ionizing radiation
• Excessive heat or cold

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• Chemical hazards
• Enter the body in several ways
• The number of known carcinogens is comparatively
  small,
• Many more chemicals are suspected to be
  carcinogenic
• Biological hazards

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• Ergonomic hazards
• Psychosocial hazards
• Identification of illnesses associated with work
  is difficult

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• Many health-related problems go unreported
• There can be significant time lag between cause
  effect
• Occupational cancers

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• 10 leading long-term health problems in workers
• Lung disease
• Musculoskeletal injuries
• Occupational cancers
• Severe traumatic injuries
• Cardiovascular disease
• Reproductive problems

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• Neurotoxic illnesses
• Noise-induced hearing loss
• Dermatological problems
• Psychological disorders

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• Principles Processes that protect workers
• Right to know that the work is hazardous
• Right to refuse hazardous work
• Right to participate in workplace safety health
  committees
• Incorporation of occupational histories into
  routine health assessments

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• Selective examinations to guide worker placement
  monitor exposure to occupational risks
• Adoption, wherever possible, of passive rather
  than active safety devices

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Environmental Health

• Definition
• The study of conditions in the natural and built
  physical environment that influence human health
  and well-being. (Shah, 1998, p. 216)
• Requires a broad approach to health
• Ecological definitions of health provide broadest
  perspective

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• Environmental health also multidisciplinary
• Much of what is known about the ecosystem comes
  from
• Biological sciences
• Engineering
• Anthropology
• Health sciences can provide insight into the
  interface between humans the ecosystem

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Sources of Environmental Contamination

• Air
• Primarily result of incomplete combustion of
  hydrocarbons
• Consequences
• Ozone layer depletion ? ? radioactive exposure
• Increased risk of
• Cancer
• Cataracts

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• Increased atmospheric C02 ? climate change
• Change in weather patterns
• Change in food production
• Change in habit
• Acid rain
• Deforestation
• Depletion of fish stocks

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• Water
• Most common pollutants
• Sewage
• Pathogenic organisms
• Plant nutrients
• Synthetic chemicals

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• Industrial waste
• Radioactive substances
• Heat
• Heavy metals
• Impact of water pollution on the food chain
• Food poisoning
• Toxicity diseases
• Mercury ? Minamata disease

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• Soil
• Major sources
• Pesticides
• Herbicides
• Persistence in soil/water
• Debates about health impact of their use

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• Food
• Major sources
• Pesticides
• Herbicides
• Preservatives
• Antibiotic and hormonal residues
• Radioactive materials

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• Toxins
• Microbes
• Parasites
• Protozoa
• Viruses
• Bacteria
• Health impacts
• Acute illnesses
• Chronic illnesses

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• Noise
• Industrial exposures
• Ordinary exposures
• Consequences
• Hearing loss
• Stress

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• Waste
• Landfill
• Sewage
• Hospital
• Hazardous
• Chemical
• Biological
• Nuclear

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Environmental Links to Human Illness

• Too much material to cover comprehensively in
  this course
• Some examples previously discussed
• Focus of this lecture will be environmental links
  to cancer

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• Very controversial topic
• Much is not known about it

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• Endocrine Disrupters
• Mimic naturally occurring estrogen testosterone
  
• May lock onto estrogen receptors in reproductive
  organs

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• Known or suspected disrupters include
• Dichlorodiphenyltrichloroethane (DDT)
• Pesticide used to control insects
• Banned in Canada/US in 1972, but still used
  elsewhere
• Residues still measurable in Canada/US

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• Polychlorinated biphenyls (PCBs)
• Used to insulate electrical equipment
• No longer manufactured in US
• Still in old equipment
• Residues still measurable

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• Dioxins
• Family of hundreds of chemicals
• Unintentional by-product of many industrial
  processes involving chlorine
• Formed by burning chlorine-based chemical
  compounds with hydrocarbons
• Primary toxic component of Agent Orange
• Highly persistent in the environment

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• Furans
• Used in the production of agricultural chemicals
  (insecticides), stabilizers, and pharmaceuticals
• Occurs naturally in certain woods and during the
  combustion of coal
• Found in engine exhausts, wood smoke and tobacco
  smoke

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• Other suspected substances
• Other pesticides
• Plasticizers
• Fungicides
• Persist in environment long after initial use

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• Exposure result of
• Direct contact
• Ingestion
• Food
• Water
• Air

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• Sources of exposure
• Work
• Food
• Stored in bodies of animals consumed by humans
• Residue on vegetables, fruit, cereals,
• Air
• Soil
• Water
• Leached from plastics

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• Body burden
• Total sum of these exposures
• Often stored in body fat
• 177 different organo-chlorine residues can be
  detected in the body of an average middle-aged
  American male

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• Carcinogenic effects of these substances focus of
  current debates
• Exposure to these substances creates many other
  health risks
• Cardiovascular
• Gastro-intestinal
• Pulmonary
• Hepatic
• Neurological
• Reproductive

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Why Children Are at Greater Risk

• Children are not miniature adults
• Experience different exposures to environmental
  pollutants
• Also experience different responses

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• Fetal Growth Development
• Fastest rate of growth in human lifespan
• Higher uptake of nutrients
• Vulnerability of specific tissues organs
• Brain neural tissu
• Lungs
• Immune system
• Genitalia

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• Anatomical Differences
• More total body water extracellular water
• 3X greater intake of water/kg of body weight
• Less mature hepatic renal system
• Greater gastric absorption
• Increased absorption from other routes
• Inhalation
• Skin

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• Behavioural Differences
• Inability to control their environments
• Different sources of nutrition
• Different nutritive needs
• Play exploration
• Short stature
• Close to ground

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• Childrens risk of exposure can begin before
  conception
• Contaminants stored in ova sperm
• Childrens ? vulnerability observed in
• ? childhood cancers
• ? asthma rates
• Neuro-behavioural changes

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Challenges of Environmental Health

• Exposure to environmental contamination an
  integral part of life
• Not an excuse for doing nothing
• Exposure occurs through physiological processes
  necessary to sustain life
• Breathing
• Eating
• Drinking

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• Non-specific outcomes of environmental
  contamination make cause-effect relationships
  difficult to establish
• Other equally plausible explanations can be found
• Precautionary principle
• Most industrial agricultural chemicals have
  never been tested for their impact on human health

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• Bio-concentration occurs because of the
  persistence of contaminants in the environment

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• Environmental contamination accelerated by
  developments underpin the way we live
• Industrialization
• Production of synthetic chemicals
• Intensification of agricultural production
• Chemical warfare
• High costs of hazardous waste disposal
• The automobile

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• Difficult for governments to regulate threats to
  the environment
• Unclear jurisdictions
• Lack of coordination
• Limited budgets
• Lobby groups
• Lack of specific information
• Lack of enforcement
• Globalization free trade
• National economic realities

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• Current focus of health care research contributes
  little to current knowledge re environmental
  impact on human health
• Focus on genes heredity
• Focus on lifestyle behavioural interventions

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Primary Prevention

• Healthy public policy
• Health consequences of new existing
  technologies should be evaluated
• Sustainable development
• Economic development that leaves natural
  resources the environment intact

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• Environmental watchdogs
• Canadian Association of Physicians for the
  Environment
• Sierra club
• Informed politically active citizens

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• Changing personal behaviour
• Food choices
• Use of lawn chemicals
• Use of automobile