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Back to Basics, 2012 POPULATION HEALTH: Environmental & Occupational Health

Back to Basics, 2012 POPULATION HEALTH: Environmental & Occupational Health. B. Pinard, MD (PGY5) G. Dunkley, MD Epidemiology & Community Medicine Based on slides prepared by Dr. R. Spasoff and Dr. N. Birkett. MCC Objectives: Population health 78-6 Environment. Rationale:

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Back to Basics, 2012 POPULATION HEALTH: Environmental & Occupational Health

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  1. Back to Basics, 2012POPULATION HEALTH:Environmental & Occupational Health B. Pinard, MD (PGY5) G. Dunkley, MD Epidemiology & Community Medicine Based on slides prepared by Dr. R. Spasoff and Dr. N. Birkett March 2012

  2. MCC Objectives: Population health 78-6 Environment Rationale: • Environmental issues are important in medical practice because exposures may be causally linked to a patient's clinical presentation and the health of the exposed population. A physician is expected to work with regulatory agencies to help implement the necessary interventions to prevent future illness. Physician involvement is important in the promotion of global environmental health. Terminal Objectives: • Recognize the implications of environmental hazards at both the individual and population level. • Respond to the patients concerns through appropriate information gathering and treatment. • Work collaboratively with local, provincial and national agencies/governments as appropriate to address the concerns at a population level. • Make appropriate recommendations for patients and exposed populations so as to minimize their health risks and maximize their overall function. Enabling objectives • Identify common environmental hazards and be able to classify them into the appropriate category of chemical, biological, physical and radiation. • Identify the common hazards that are found in air, water, soil and foods. • Describe the steps in an environmental risk assessment and be able to critically review a simple risk assessment for a community. • Conduct a focussed clinical assessment of exposed persons in order to determine the causal linkage between exposure and the clinical condition. • Be aware of local, regional, provincial and national regulatory agencies that can assist in the investigation of environmental concerns. • Describe simple interventions that will be effective in reducing environmental exposures and risk of disease (e.g. sunscreen for sunburns, bug spray for prevention of West Nile Virus infection). • Communicate simple environmental risk assessment information to both patients and the community. March 2012

  3. 78-6 ENVIRONMENT (1) • Objectives: - Identify common environmental hazards and be able to classify them into the appropriate category of chemical, biological, physical and radiation. - Identify the common hazards that are found in air, water, soil and foods. Mach 2012

  4. 78-6 ENVIRONMENT (2) • Environmental exposure: • Natural and human-made environment • Reservoirs: air, water, soil, food • Route: inhalation, ingestion, absorption • Exposure setting: • Workplace: occupational health (high level exposure, acute or chronic) • Outside workplace : environmental health (low level exposure, chronic) March 2012

  5. 78-6 ENVIRONMENT (3) • AIR • Physical contaminants • Radiation: Radon (lung cancer), UV (skin cancer) • Sound waves (hearing loss) • Chemical contaminants • Ozone at ground level (worsens asthma) • Carbon monoxide (asphyxiation) • Sulphur dioxide; nitrogen oxides (exacerbation of breathing problems) • Organic compounds: Benzene (carcinogen – leukemia) • Second hand tobacco smoke (lung cancer) • Heavy metals; industrial emissions (specific syndromes) March 2012

  6. 78-6 ENVIRONMENT (4) • AIR: • Biological contaminants: • Bacteria: Legionella (pneumonia) • Dust mites (upper and lower-airway sx) • Pollen (upper and lower-airway sx) • Moulds (allergies) • Particulates (pollen, spores, aerosols) (asthma) • Global warming: • Extreme weather (heat waves), change in distribution of vectors of disease, crop failures, etc. March 2012

  7. 78-6 ENVIRONMENT (5) • WATER • Biological agents: • Bacteria : E. coli, Salmonella, Pseudomonas • Protozoa (cysts): Giardia, Cryptosporidium (GI symtoms mainly) • Blue green algae (skin irritation, GI symptoms) • Higher risk: aboriginal Canadians, rural population • Chemical agents: • Volatile organic compounds (VOC), pesticides, heavy metals, other waste from industries (effects depend on contaminant) • Chlorination by-products - trihalomethanes (THM) (cancer) • SOIL • Chemical agents: • Pesticides, petroleum hydrocarbons, solvents, motor oil, lead (effects depend on contaminant) • Higher risk: infants/toddlers • Biological agents: • Bacteria (tetanus) March 2012

  8. 78-6 ENVIRONMENT (6) • FOOD • Biological Contaminants • Salmonella- raw eggs, poultry, meat (GI sx) • Campylobacter - raw poultry and milk (GI sx, joint pain) • E. Coli - hamburger meat (diarrhea, HUS) • Listeriamonocytogenes(listeriosis) • Clostridium botulinum(botulism) • Mould toxin (aflatoxin), BSE, virus, parasites • Chemical Contaminants • PCBs, dioxins/furans, pesticide residues (DDT), mercury • Food additives: nitrites, sulfites (allergy) • Drugs given to livestock: antibiotics, hormones March 2012

  9. 78-6 ENVIRONMENT (7) • Objective: • Describe the steps in an environmental risk assessment and be able to critically review a simple risk assessment for a community. • Risk assessment: • Process of evaluating the likelihood of occurrence and probable severity of health effects due to a hazard • Done by: Occupational health agencies, Environmental protection agencies , Public health authorities, Clinicians March 2012

  10. 78-6 ENVIRONMENT (8) • Steps in risk assessment: 1. Hazard identification: Is an environmental hazard involved? What is it? 2. Risk characterization: Is the hazard likely to cause these types of symptoms in this type of patient? 3. Exposure assessment: Is the patient’s exposure enough to cause these symptoms? 4. Risk estimation: How much has the hazard contributed to the patient’s condition? Source: Primer in Population Health March 2012

  11. 78-6 ENVIRONMENT (9) • Hazard Identification: • Agent (based on clinical history – see later on) • Adverse effect • Target population • Condition of exposure • Risk characterisation: • Describe the potential health effects of hazard • Sources of info: scientific literature, toxicology or poison center, public health department March 2012

  12. 78-6 ENVIRONMENT (10) • Workplace Hazardous Material Information System (WHMIS): • Labeling requirements for hazards • Indicates availability of Materials Safety Data Sheets (MSDS): more details on hazard, how to handle it, what to do if emergency • MSDS are available on the web – should find one site and bookmark it (Health Canada: http://www.hc-sc.gc.ca/ewh-semt/occup-travail/whmis-simdut/index-eng.php) March 2012

  13. 78-6 ENVIRONMENT (11) • Exposure assessment: • Characterize exposure of individual or population • Can be measured directly at times in people (ex: blood lead level) or in environment • Estimated most of the time (from history or inspection of environment) • Consultants: environmental medicine specialists, toxicologists, industrial/occupational hygienists • Risk estimation • Probability of being affected and severity of effect March 2012

  14. 78-6 ENVIRONMENT (12) • Objective: - Conduct a focussed clinical assessment of exposed persons in order to determine the causal linkage between exposure and the clinical condition. • Clues to environmental causes • Detailed environmental history March 2012

  15. 78-6 ENVIRONMENT (13) • Clues that illness is caused by environmental factors: • Patient suspects it • Pattern of illness atypical (absence of usual risk factors, unusual age group, course of illness unusual, no response to tx) • Temporal pattern of illness (weekends/weekdays, holidays/home) • No obvious other cause • Signs/symptoms suggest specific toxins March 2012

  16. 78-6 ENVIRONMENT (14) Environmental history - CH20PD2: • Community: neighborhood sources of hazard; industry, waste storage • Home: year of construction, renovations; materials used in construction and decoration; moulds; garden and house plants; use of cleaning products, pesticides, herbicides • Hobbies and leisure: exposure to chemicals, dusts, or micro-organisms • Occupation: current and previous occupations; work with known hazards; air quality • Personal habits: hygiene products; smoking • Diet: sources of food and water; cooking methods; food fads • Drugs: prescription, non-prescription, and alternative medications; health practices Source: Primer in Population Health March 2012

  17. 78-6 ENVIRONMENT (15) • If a scanning question reveals a possible hazard, ask detailed questions to find out as much as possible about the nature and level of the hazard and then check Time, Place and Person: • Time: When did symptoms begin? When did exposure begin? When do symptoms get worse? When do they improve? • Place: Where is the patient when symptoms get worse? Where is the likely hazard? What is the channel through which the hazard reaches the patient? • Person: Does anyone else have similar symptoms? Who? When? Where? Source: Primer in Population Health March 2012

  18. 78-6 ENVIRONMENT (16) • Objective: • Be aware of local, regional, provincial and national regulatory agencies that can assist in the investigation of environmental concerns • If evidence supports, or a strong suspicion exists for, a causal connection between exposure and the clinical presentation, notify the appropriate authorities to inspect the site and thereafter to decrease and eliminate exposure. March 2012

  19. 78-6 ENVIRONMENT (17) • Environmental Health Jurisdiction • Public Health Unit • Enforcement of water and food safety regulations, sanitation, local hazard assessment, reportable diseases • Municipal • Garbage disposal, recycling • Province/territory • Toxic waste disposal, air/water standards • Federal • Food regulations (Health Canada), designating and regulating toxic substances • International • Multilateral agreement (Kyoto Protocol) March 2012

  20. 78-6 ENVIRONMENT (18) • Objective: • Describe simple interventions that will be effective in reducing environmental exposures and risk of disease. • Examples: • Carbon monoxide: CO home detector • Salmonella: well cooked poultry and eggs, safe food handling • Listeria: avoidance of unpasteurized cheese for pregnant women • West Nile Virus: bug spray • UV light: sunscreen, sunglasses, shade • Radon: ventilation, air exchanger March 2012

  21. 78-6 ENVIRONMENT (20) • Objective: • Communicate simple environmental risk assessment information to both patients and the community. • Important to allow people to understand the risk and take action to avoid it • Elements of communication: message, messenger (meaning), encoding, channel, decoding, recipient (understanding) March 2012

  22. 78-6 ENVIRONMENT (19) WHO, 2002, Global Solar UV Index March 2012

  23. Air Quality Health Index • New public health information tool developed by Health Canada and Environment Canada • Support decision-making about activity levels during increased levels of air pollution. • Calculated based on: • Ozone (O3) at ground level, • Particulate Matter (PM2.5/PM10) • Nitrogen Dioxide (NO2) March 2012

  24. March 2012

  25. 78-6 ENVIRONMENT (21) • Factors increasing perception of danger: • Characteristics of exposure: • Involuntary; not under personal control • Unnatural; unfamiliar • No trust in institution involved; media attention • Characteristics of outcome: • Catastrophic (not chronic); immediate; irreversible • Unknown, uncertain outcome, dreaded outcome • Affect children or identifiable people Source: Primer in Population Health March 2012

  26. 74-4 WORK-RELATED HEALTH ISSUES • Key Objective: • Determine whether the work place or environmental conditions are potentially hazardous, the impact on the health of the workers, and recommend preventive strategies. • Importance in Canada: • 920 work place deaths in 2001 • 373,216 lost-time injuries in 2001 March 2012

  27. Work-related Health Issues (2) • Selected Specific Objectives: • Elicit history of occupation, list of current and longest held jobs, exposure to toxic/hazardous environments and identify potential relationship to patient presentation (temporal relationship to work or home activities) - Counsel patients about safety issues and report findings to affected patients as well as employers (considering medical confidentiality issues) • Consider underlying medical conditions and work risk March 2012

  28. Work-related Health Issues (3) • Categories of occupational hazards: • Chemical: organic solvents (carbon tetrachloride), mineral dusts (silica, asbestos), heavy metals, gases, second-hand smoke • Physical: noise, temperature, air pressure, radiation • Biological: bacteria, blood • Mechanical: repetitive strain, trauma • Psychosocial stress March 2012

  29. Work-related Health Issues (4) • Occupational health history: • Work description and occupational profile • Prior and current exposure to hazards • Review of relevant workplace materials safety data sheets • Look for sx of disease; job-related injuries • Temporal relationship between sx and exposure • Other environments, hobbies, occupation of family members (Toronto Notes, 2011) March 2012

  30. Work-related Health Issues (5) • Under provincial jurisdiction except for 16 federally regulated industries (e.g. banks, airports, highway transport) – Canada Labour Code • 90% of workers are under provincial jurisdiction • Ontario: Occupational Health and Safety Act • Defines rights of workers: • participate, know, refuse and stop • Employers have duties to protect health and safety • Enforced by Ministry of Labour (inspectors) March 2012

  31. Work-related Health Issues (6) • Ontario: Workplace Safety and Insurance Act • Establishes WSIB to oversee work-site injuries/disease • Funded by employers only • Non-fault protection but no right to sue • MD must submit medical report to WSIB; no need for patient waiver. • MD must report exposure to designated substances • Asbestos, arsenic, benzene, lead, mercury, vinyl chloride, etc. March 2012

  32. Work-related Health Issues (7) Occupational Health Program – Essential responsibilities: • Health evaluation of employees • Diagnosis/treatment of occup. injuries/illnesses • Emergency treatment of other injury/illness • Education of employees re: occupational hazards • Evaluation of programs for the use of indicated personal protective devices • Assist management in providing a safe and healthful work environment. Inspect workplace. March 2012

  33. Controlling Occupational Risks Source Path Receiver Potential approaches to risk control Modify Redesign Substitute Relocate Enclose Absorb Block Dilute Ventilate Enclose Protect Relocate March 2012

  34. Work-related Health Issues (9) • Work place safety issues can affect family members as well as the workers. • Asbestos • Causes asbestosis and lung cancer in miners and other workers • Asbestos in the air adheres to work clothing, even if the clothes are brushed • Cleaning of clothes at home liberates asbestos fibers and has been shown to cause cancer in family members. March 2012

  35. Environmental and occupational health Multiple Choice Questionsfor discussion March 2012

  36. 1) Which one of the following is not a typical feature of asbestosis? a) increased risk of cancer b) pleural thickening and calcification c) interstitial fibrosis d) obstructive pattern on pulmonary function tests e) none of the above March 2012

  37. 3) The following statements regarding noise are true EXCEPT: a) temporary threshold shift recovers following cessation of noise exposure b) permanent threshold shift is characterized by a progressive pattern of hearing loss c) most cases of permanent threshold shift are surgically treatable d) higher frequency noise is more damaging than low frequency noise e) none of the above March 2012

  38. 4) The frequencies most necessary for the understanding of speech extend from about: a) 20-20 000 Hz b) 400-4 000 Hz c) 250-8 000 Hz d) 100-5 000 Hz e) none of the above March 2012

  39. 5) Lead exposure typically results in: a) chronic dermatitis b) resting and intention tremor c) extensor muscle weakness d) arrhythmias e) cerebellar ataxia March 2012

  40. 6) Which of the following statements concerning the Worker’s Compensation Act is true? a) the worker reserves the right to sue the employer for negligence b) funding is provided by the provincial government c) the worker is guaranteed payment from the first day of injury/illness if it is deemed to be work-related d) the Worker’s Compensation Board is an independent, private agency e) none of the above March 2012

  41. 7) Which of following statements regarding radiation is false? a) natural background radiation accounts for about half of a typical person’s exposure b) ionizing radiation causes intestinal villi to become denuded c) exposure to non-ionizing radiation may result in cataracts d) ionizing radiation results in an increased incidence of neoplasia such as lung and thyroid e) none of the above March 2012

  42. 36) All of the following statements concerning occupational health are true EXCEPT: a) disorders of reproduction are among the top 10 work-related diseases and injuries b) most workers are covered by both federal and provincial legislation with respect to workplace health and safety c) skin problems and hearing problems together are responsible for half of WCB claims d) a complete occupational medical history includes investigation of the temporal relationship between symptoms and exposure March 2012

  43. 37) Which of the following statements concerning exposure to solvents in the workplace is true? a) each solvent compound has a specific antidote that can be used to treat exposure b) a prominent symptom of solvent exposure is memory loss c) some solvents can cause skin dryness and loss of subcutaneous adipose tissue d) solvents do not affect the bone marrow e) all of the above March 2012

  44. 39) All of the following statements about environmental health are true EXCEPT: a) levels of toxic agents measured in the environment may not reflect internal organ levels b) the federal government monitors the quality and types of industrial emissions and toxic waste disposal c) sick building syndrome is associated with Pontiac fever and Legionnaire’s disease d) all humans have detectable levels of PCBs e) none of the above is true March 2012

  45. More MCQs • Here are some more questions that students can use to test their own knowledge: http://www.medicine.uottawa.ca/sim/data/Self-test_Qs_Environmental_e.htm • (The questions contain comments on the answers, to illustrate why a given response is not correct) March 2012

  46. Self-test (1) • Which one of the following gases is NOT irritating to the respiratory tract? a) ozone b) sulfur dioxide c) hydrogen chloride d) carbon monoxide e) chlorine

  47. Self-test (2) • How much radiation is an "average Canadian adult woman" typically exposed to each year from the following sources: background dose; one screening mammography, and one abdominal CT scan? a) Background 0.1 Sv; mammography 0.5 Sv; CT 1.0 Sv. b) Background 1.0 Sv; mammography 0.5 Sv; CT 0.1 Sv. c) Background 1.0 mSv; mammography 50.0 mSv; CT 5.0 mSv. d) Background 2.0 mSv; mammography 3.0 mSv; CT 10.0 mSv. e) Background 1.0 mSv; mammography 0.1 mSv; CT 0.1 mSv.

  48. Self-test (3) • Toxicokineticsrefers to: a. The speed of distribution of a toxin. b. The biochemical and physiological effects of toxins. c. The diffusion gradient of a toxin. d. The activity or fate of toxins in the body over a period of time. e. The transport of toxins through cell membranes.

  49. March 2012

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