EHS C200A Midterm 1

What is the definition of environmental health?

The physical, chemical, and biological factors external to a person.

What is the objective on environmental health?

To ID and evaluate environmental sources and agents, as well as to limit exposure to promote healthier lives (both for disease and disability)

What is considered the “environment” in environmental health?

The congregation of physical, chemical, and biological factors, but EXCLUDING the natural environment that cannot be reasonably modified (ex: cannot drain a lake b/c there are a lot of mosquitos)

What is ‘health’ in environmental health?

The physical, mental, and social well being of a person. This tells us about how people perceive their lives, from their own perspective.

What does the WHO risk assessment aim to do?

Prevent disease through Healthy Environments, through policy change and finding funding.

What aspects does the WHO risk assessment include?

Over 133 diseases/injuries linked to the environment, from categories such as air pollution, UV, noise/electromagnetic, occupational risks, built environments, agriculture, man-made ecosystem changes, and behavior (i.e. washing hands)

How does global deaths due to environment change based on different demographic factors?

Higher burden is seen in low income countries, and chances for different environmental risks changes most apparently by age demographic.

How has the shift in communicable and non-communicable diseases changed over time?

We’ve seen a rise in noncommunicable diseases, primarily in higher-income countries

What is the role of NIOSH?

They are under the CDC, and complete research relevant to occupational exposures. They develop recommendations based on the studies they conduct.

What is the role of OSHA?

OSHA is the federal regulation agency that penalizes employers who fail to comply with standards. They develop/adopt policies based on NIOSH findings.

What is industrial hygiene?

The science of protecting and enhancing health and safety of people at work/in communities. The goal is to anticipate the problem, recognize it, evaluate its impact, and control the hazards.

What is exposure?

The proximity or contact with an environmental agent in a manner that potentially impacts health. Can be harmful or beneficial.

What are the different ways that exposures are assessed? Which ones are the dimensions of exposure (the ones we pay the most attention to for health impacts)?

1. Level of exposure/concentration (DOE)

2. Route of exposure, such as inhalation (DOE)

3. Duration and frequency of exposure (DOE)

4. Life stage at which exposure occured

5. Exposure process (absorption, transport, metabolization, excretion)

6. Target of exposure (where the exposure lands - tissues - and how it impacts the human body

What is the most dangerous method of exposure, and why?

Airborne items - they are harder to see and harder to control

What are the different ‘targets’ for exposures?

Organs, tissues, cells, and molecules

What are the physical health exposures?

1. Air pollution (chemical and microbial)

2. Water pollution (chemical and microbial)

3. Disease vectors (i.e. carried by insects)

4. Radiation (ionizing and non-ionizing)

5. Noise

6. Food safety contaminants and sanitation)

What are the work and built environment health exposures?

1. Ergonomics

2. Built Environment (physical environment)

3. Temperature

4. Microbiome

5. Workplace exposures (air, dermal, etc)

What are the social and behavioral (psycho-social) health exposures?

1. Injury risk (e.g. traffic)

2. Retail food environment

3. Greenspace

4. Physical activity opportunities

5. Information and behavioral cues

6. Social interaction

What are the 4 reasons accurate exposure measurements are so important?

1. To develop accurate dose-response models

2. To facilitate robust epidemiological studies (to conclude relationships between exposure and disease)

3. To Identify levels and distribution of exposures (to choose the proper population to monitor)

4. To guide public policy decisions

what is variance?

a measure of data dispersion

what is measurement error?

the difference between the true (or actual) value and the measured value. May or may not be random or systematic (eg bias)

What is reliability?

consistency of a measurement.

In what type of study is reliability usually used as a measurement statistic?

Usually used in correlational studies, and is related to (but not synonymous with) precision in experimental studies.

What is accuracy?

Agreement between the result of a measurement and a true value

What is validity?

the degree to which a measurement actually reflects the property that it purports to estimate

what is measurement bias?

non-random error in measurement

What is the issue with exposure proxy studies?

1. Subjects may not spend all day at the residence being measured

2. Indoor exposures may differ from outdoor exposures

3. Spatial and temporal variation within an areal unit (e.g. census tract or zip code) (‘if stations are five miles apart, what happens between them?’)

4. For many chronic health conditions and reproductive health outcomes, it’s difficult to determine the relevant period of exposure. (‘what if someone had a preexisting disease?’)

How do -omic technologies seem to improve exposure proxies?

1. They can be used to identify potential markers of individual exposure, potentially even decades after an exposure occured

2. Can examine mixed exposures and interactions between exposures

3. Can measure changes in biological pathways that occur prior to endpoints traditionally studied (e.g. organisms death or cell death)

4. By understanding mode of action, can predict harm early (even prior to exposure) when new chemicals are being developed

How do omic technologies work? Which fields are involved?

Omic technologies look at processing speed and variation at the molecular (DNA) level, and try to compare it for associations to chemical interactions. It involves the work of:

1. Genomics

2. Epigenetics

3. Toxicogenomics

4. Transcriptomics

5. Proteomics

6. Metabolomics

What is the exposome?

A total measure of all the exposures of an individual, over the course of a lifetime (including before birth), and how those exposures relate to ones health.

What are the 4 key elements of the exposome?

1. Exposure of the life course (including before birth - sources from environmental and occupational)

2. Windows of sensitivity

3. Downstream, transformed factors and markers

4. Interactions of harmful and protective factors

What are the three types of exposures to the exposome, and what are some examples of each?

1. General External (social capital, education, financial status)

2. Specific External (radiation, medical interventions, diet)

3. Internal (metabolism, body morphology, physical activity)

What was the first major occupational health event in history?

Before 900BC, silk scarves were used to protect Chinese miners from dust

Who is Bernardino Ramazzini?

The ‘father of occupational health’, he documented occupational disease and released ‘on diseases of tradesmen’ in 1700

what is hygiene?

clean workspace = clean workers. the preservation of health and protection from future diseases

What does NCGIH stand for?

National Conference of Governmental Industrial Hygienists

What year was the NCGIH Established (and what year was it later renamed to the ACGIH)

1938 establishment, 1946 renamed

What are the exposure guidelines that the NCGIH (ACGIH) is responsible for?

1. Threshold Limit Value - Time Weighted 8-hour Average (TLV-TWA)

2. Short Term Exposure Limit (STEL)

3. Personal sampling in breathing zones (Setting up measurements)

What does ACGIH stand for? What was it previously called?

American Conference of Governmental Industrial Hygienists —> Changed from NCGIH (National)

What is OSHA?

Occupational Safety and Health Administration

When was OSHA established? By who?

1970; Nixon

What regulations can OSHA enforce?

PEL (Permissible Exposure Limit)

What is the only agency that can enforce regulations, versus just recommend?

OSHA

What is PEL?

Permissible Exposure Limit - adopted by OSHA from ACGIH in 1969. Limits the maximum exposure that individuals can have.

What is REL?

Recommended exposure limit - adopted by NIOSH from 1969 ACGIH list. Research guideline that recommends the allowance of exposure for various hazards. Not regulated by OSHA

What is IDLH?

Immediately Dangerous to Life or Health - a value adopted by NIOSH in 1969 from ACGIH list. Research guideline that states when 30 minutes of exposure to a hazard is considered dangerous to life. Acute exposure metric. Not regulated by OSHA

What type of exposures can the EPA regulate?

Ambient exposures

When was the EPA established? By whom?

1970; Nixon

What is TLV?

Threshold Limit Value. The value that should not be surpassed at any point for exposure in an 8-hour workday. Set forth by ACGIH. Not regulated by OSHA

What is TLV-TWA

Threshold Limit Value- Time Weighted Average. The average value that should not be surpassed in an exposure for an 8 hour workday. Set forth by ACGIH. Not regulated by OSHA

What are the five types of occupational health and safety agents?

1. Chemical

2. Physical

3. Mechanical (Ergonomics)

4. Biological

5. Psychosocial

What types of agents are included in the ‘Physical’ occupational hazards?

1. Noise (intensity, frequency, duration)

2. Radiation (ionizing, non-ionizing)

3. Heat (temperature, humidity, duration)

4. Cold (temperature)

What types of agents are included in the ‘Chemical’ occupational hazards?

1. Air-borne exposures to gases, vapors, aerosols, and particulates

2. Skin contact (toxins, caustic agents)

3. Oxygen levels (i.e. oxygen deficiency)

4. Explosive hazards

What are the 16 sections of a material safety data sheet? (MSDS)

1. Identification of the substance/mixture and of the company/undertaking

2. Hazards identification

3. Composition/information on ingredients

4. First aid measures

5. Firefighting measures

6. Accidental release measure

7. Handling and storage

8. Exposure controls/personal protection

9. Physical and chemical properties

10. Stability and Reactivity

11. Toxicological information

12. Ecological Information

13. Disposal considerations

14. Transport information

15. Regulatory information

16. Other information

What types of agents are included in the ‘Mechanical/Ergonomic’ occupational hazards?

1. Moving objects

2. Moving particulates

3. moving vehicles

4. Moving people

5. Moving Machines

6. Earthquakes/disasters/terrorism

What types of agents are included in the ‘Psychosocial’ occupational hazards?

1. stress

2. interpersonal conflict

3. violence

What are the four steps of the industrial hygiene paradigm/principle?

1. Recognition/Identification

2. Evaluation

3. Control

4. Anticipation/Prevention

What are the implications of the first step of the industrial hygiene paradigm/principle?

recognition/identification —> recognize hazards prior to construction/operation. It’s easy to recognize safety/physical, but not always chemical (as you may need to understand the symptoms)

What are the implications of the second step of the industrial hygiene paradigm/principle?

evaluation —> taking measurements of the environment (concentration, stress level, etc) and then assessing the health risk (the degree of the hazard); done by comparing to standard/recommended values, scientific literature, and chronic health effects

In the exposure assessment model, what occurs if you a) determine exposure is acceptable b) are uncertain of the exposure acceptability or c) determine the exposure is unacceptable?

a) complete a reassessment and return to basic characterization phase

b) gather further information about the specific exposure

c) control the exposure

What are the implications of the third step of the industrial hygiene paradigm/principle?

control —> using the heirarchy of control to best impact the exposure. PPE, administrative controls, engineering controls, substitution, and elimination

What is the hierarchy of controls, from least effective to most effective? What does each control do?

1. PPE —> protect the worker with personal protective equipment

2. Administrative controls —> change the way people work (put up signs, for ex)

3. Engineering controls —> isolate people from the hazard

4. Substitution —> replace the hazard

5. Elimination —> physically remove the hazard

What items are included as PPE?

gloves, safety glasses, safety shoes, earplugs/muffs, hard hats, respirators, coveralls, vests, full body suits

What is the employer’s responsibility with PPE?

To train each worker required to wear PPE so they know:

1. When it is necessary

2. What kind is necessary

3. How to properly put on, adjust, wear, and take off

4. The limitations of the equipment

5. Proper care, maintenance, useful life, and disposal of the equipment

What are administrative controls?

Changes in work procedures to reduce the duration, frequency, and severity of exposure to hazardous chemicals/situations. Includes work practice controls intended to reduce the likelihood of exposure by CHANGING A WAY A TASK IS PERFORMED

What are some examples of administrative controls?

1. Train on job-related hazards

2. Provide mechanical surveillance, vaccination, fit testing, equipment, appropriate selection and availability of PPE

3. Train and educate about proper use and disposal of PPE

4. Adjust work schedules to avoid fatigue and burnout

5. Display warning signs for potential hazards (ex: hazard signs, color coding)

6. Identify and label dedicated areas for hazards

7. Make written health and safety policies and procedure manuals available and accessible

8. Provide a written inventory of hazardous chemicals, SDSs

What are the implications of the fourth step of the industrial hygiene paradigm/principle?

prevention —> how to avoid the exposure in the future. Examples include: substitution-green chemistry, source control, waste minimization, unit processes simplification, recycling, etc.

Why is total worker health so important?

Workers also bring exposures home, so communities are also involved when it comes to total worker health

What is the definition of epidemiology?

The study of the distribution and determinants of health-related states or events in specified populations, and the application of this study to the control of health problems

What two components of health events is epidemiology concerned with?

a. Frequency —> both the number of health events, but also the relationship of this number to the size of the population

b. Pattern (Distribution) —> the occurrence of health-related events by time, place, and person

what are determinants in epidemiology?

causes and health factors that influence the occurrence of disease and other health-related events.

when do epidemiologists assume illness occurs?

not randomly; when the right accumulation of risk factors or determinants exist in an individual

what is the goal of epidemiology?

to provide sufficient evidence to direct prompt and effective public health control and prevention measures by finding the relationship between risk factors and illness

what are ‘health-related events’?

Anything that effects the well being of a population - ‘disease’ is often used as shorthand for this

What are the specific aspects of the population you must strategically select when determining health-related events?

1. identifying the exposure or source that caused the illness

2. The number of other persons who may have been similarly exposed

3. The potential of further spread in the community

4. The interventions to prevent additional cases or recurrences

what is prevalence?

how many people have (or have had) the disease? The proportion of a population who have a specific characteristic in a given time period, regardless of when they first developed the characteristic. = (# of people in sample with characteristic) / (total # of people in the sample)

what is incidence?

a measure of the number of new cases of a characteristic that develops in a population in a specified time. = ( # of new cases) / (total # of people x time frame); “new cases per person(s) per time

what is the typical unit for incidence?

cases per people-year. if units are not per year (say, per month), you can use stoichiometry to change units. 

what is the typical unit for prevalence?

percent. value comes out as a decimal, but multiple by 100 to convert to a percent.

what equation links prevalence and incidence?

prevalence = (incidence) x (disease duration); here though we must assume that incidence is constant over the time frame. disease duration can also be replaced with # of individuals in the population.

what is occupation epidemiology?

the application of epidemiological methods to populations of workers.

does OSHA regulate occupational epidemiology standards?

currently no, though hazards are addressed in specific OSHA standards for access to employee medical records, record-keeping, etc. If a company has over 10 people, you need to keep OSHA injury and illness records, unless you have exemptions

what additional powers did the OSH act give NIOSH?

right of entry into private workplaces, and ensured time and space for examination and interview of workers. This applies if even 1 employee (even anonymous) reaches out.

what are the different types of epidemiological studies?

in increasing order of weight of evidence:
1. case reports (descriptive)

2. case series (descriptive)

3. ecological studies (descriptive)

4. cross-sectional studies (analytical)

5. case-control studies (analytical)

6. retrospective cohort studies (analytical)

7. prospective cohort studies (analytical)

8. randomized clinical studies (analytical)

9. Meta analysis of randomized clinical trials (analytical)

what is environmental epidemiology?

the study of the role of exposures in the general environment as they relate to health and disease in human populations

what is the difference between descriptive and analytic methods in epidemiological studies?

descriptive studies examine patterns of occurrence, focusing on person, place, and time. They use relatively accessible data, and are used to plan a program, generate a hypothesis, and suggest ideas for future studies. Analytic studies are used to test a hypothesis, and require more resources and specialized knowledge.

what is a cohort study?

a study that follows a defined group over time, and compares the health effects in people who have been exposed with those who have not been exposed, to estimate relative risk. can be prospective or retrospective

what is a case-control study?

case subjects are selected among people who have experienced a specific health effect, and controls are selected from the same population who have not experienced the effect. controls are ideally identical to case subjects. odds of exposure to an agent among the cases are then compared with the odds of exposure among controls to generate an odds ratio. ‘what are the odds of an exposure among people with a disease, compared to the offs of an exposure among people without the disease’?

what is a cross-sectional study?

exposure information and health effects info are collected from a group at one specific point in time. The selection of people is independent of exposure to the agent. The objective is to uncover associations between exposure to a specific agent and development of a health effect. can measure relative risk or odds ratio. ‘is there an association between a health outcome and a putative cause’?

what is an odds ratio?

the probability of exposure given disease, which is used to estimate probability of an outcome, given exposure. OR = (case group (# exposed/# not exposed) / control group (# exposed / # not exposed)). OR = 1 indicates no effect, < 1 indicates decreased risl, > 1 indicates increased risk

what is risk ration (relative risk)

the ratio of the probability of an event occurring in an exposed group to the probability of the event occurring the a non-exposed group. RR = ( % with disease among exposed) / (% without disease among unexposed)x

what is bias? what are the five different types of bias?

bias is ‘any systematic error in the design, conduct, or analysis of a study that results in a mistaken estimate of an exposures effect on disease.

a. selection bias: non-random selection leads to different exposure or outcome distributions in comparison groups

b. information bias: bias in measurement

c. recall bias: a type of information bias from inaccurate recall

d. social desirability bias: a type of information bias due to a respondent reporting what they think is appropriate

e. confounding bias: bias caused by an extraneous variable associated with both the exposure and outcome that may affect the observed association between the exposure and outcome (ex: smoking in the theory that alcohol causes lung cancer)

what are the requirements to consider something a confounding factor?

1. it must be associated with both the exposure/risk factor of interest and the outcome

2. it must be distributed unequally among the groups being compared

3. it must not be an intermediary step in the causal pathway between exposure and outcome

what is the healthy worker effect?

a confounding factor of occupational studies. three aspects of the effect:

1. the selection of healthy people into employment, which can be controlled by making an internal comparison rather than a comparison with national mortality rates

2. the selection of unhealthy people out of the workforce, which can be controlled by controlling for time-related employment status

3. the length of time the population has been followed, which can be addressed by controlling for length follow-up.

what happened in the minimata case?

a Japanese factory begins producing plastics that released mercury into the water, and people complained but nobody listened when the community brought up concerns. “dancing cats” began to be observed, and then children and adults with mercury poisoning started becoming prominent in the area. A case study found that the disease was not contagious, was linked to fishing families, and there was a dose-response relationship between eating fish and developing mercury poisoning. nearly 40 years later, mercury was removed from the factory’s production

what were the main public health lessons we learned from the minimata case?

1. pay attention to wildlife

2. prevention is possible

3. understand the limits, but act on emergent findings when there’s significant harm

4. don’t let demands for more evidence be an excuse for inaction

5. recognize manufactured doubt

6. recognize the extent of more subtle effects (pay attention to the early warning signs)

7. don’t ignore, rather seek out and respond to ‘local knowledge’ from ‘non-experts’

what is a toxic?

anything able to cause injury to living organisms as a result of physiochemical interaction

what is toxicology?

the study of the adverse physiochemical effects of chemical, physical or biological agents on living. organisms and the ecosystem, including the prevention and amelioration of such adverse effects

what is a toxicological agent?

chemical, physical, or biological agents causing adverse physiochemical effects on living organisms or ecosystems

what is a toxic substance?

a material causing injury to living organisms as a result of physiochemical interactions