General Health Risk Assessment Report

● Assignment #1 and assignment #2 combine into a health risk assessment report

● Assignment #1 is a description of the background associated with the environmental hazard (Due February 17)

● Assignment #2 is an application and a site specific health risk assessment that determines the impact of a hazard on a population in a Canadian city (Due March 31)

This is a 1000-1500 word report on an environmental hazard. The purpose of the report is to find and then summarize key literature on an environmental hazard of your choice. The literature must be from peer reviewed journal articles and official government reports (from Health Canada, the CDC and other major agencies). In this report you must use your research to describe the 1) origin, source and properties of a hazard 2) the route of exposure, 3) the concentration of exposure thought to be harmful to humans and 4) the suspected relationship between exposure to hazard and a specific health outcome.

General health risk assessment report (20%)

General health risk assessment report (20%)

● Must choose a hazard and specific health outcome

● Hazard must be something present in the environment of a typical Canadian city ○ NO2 (ok) ○ Parasite that causes malaria (not ok)

● Health outcome needs to be specific ○ Hospitalization due to asthma (ok) ○ Type 2 diabetes (ok) ○ Influenza (ok) ○ Mortality (not ok) ○ Infant mortality (not ok)

The impact of student noise pollution on sleep quality

•Hazard: Noise from students •Route of exposure: Auditory contact/sound •Health outcome: disrupted sleep •Concentration of noise likely to cause sleep disturbance: 65 dB

Assignment #2 • Concentration of exposure in Westdale: number of days with level of exposure in neighbourhood above 65 between 11 pm and 6 am = 4 • Vulnerable population: persons 65+ • Key finding: Upper limit of exposure concentration 750 people x 4 days = 3,000 disrupted person-nights of sleep per year

Example topic #1

The benefits of existing recreational play space on the physical health of children

•Determinant (‘hazard’): Access to green space •Route of exposure: Proximity (to child-friendly play space) •Health outcome: Likelihood of independent play •Concentration of exposure that would be beneficial: 1.6 Km considered walkable by school boards in Ontario

Assignment #2 • Number of walkable parks/playgrounds within 1.6 Km of Strathcona: > 20, though most would require crossing major street; only 1 large park that does not require street crossing. This is a multi-use recreational space with a small play area for young children • Vulnerable population < 8 ~ 150 • Key finding: Children in the Strathcona neighbourhood have access to one large park, but as a multi-use space, there is little infrastructure available for young children

Example topic #2

The effect of radon gas on lung cancer risk

•Hazard: Radon gas •Route of exposure: inhalation; most exposure is in the residential setting, with gas coming in through cracks in basement foundation •Health outcome: lung cancer •Concentration of exposure that is thought to cause harm: in Canada, annual average of 200 Bq/m³

Assignment #2 Concentration of exposure : 12.1% of homes above 200 Bq/m³ limit based on health Canada report

•Baseline lung cancer incidence in Canada 52/100000 (0.00052) •16% increase risk in lung cancer for every 100 Bq/m³ of exposure (WHO estimate) •Vulnerable population 120 people in older homes •120/100000 x 16 = 2 extra cases of lung cancer every 100 years

• Key finding: every year, roughly 2 extra cases of lung cancer per 100 years in River Heights neighbourhood in Winnipeg due to radon exposure

Example topic #3

General health risk assessment report (20%) ● Describe the hazard and exposure

○ Where does it come from? How long does it stay in the environment? How is it distributed in the environment? ■ Keep in mind the context is a Canadian city; focus on features

related to this context ○ What is the route of exposure for the hazard?

■ Again, context matters ○ What concentrations of the hazard are thought to be harmful to

humans? In what environments is this exposure likely to occur? ■ Again, context matters

● Describe the connection between hazard and health outcome ○ What does the literature say about their association? How strong is

the evidence of an association at doses of exposure people are likely to experience?

General health risk assessment report (20%)

● Sometimes the distinction between hazard and exposure is unclear or debatable

● E.g., food deserts ○ Is the ‘desert’ the hazard? The absence of healthy food? The

presence of unhealthy food? The extra time it takes to get healthy food?

● You need to decide and explain

● What’s important is that you describe the process that has the potential to cause harm, and the level of expo, even if your topic does not perfectly fit the traditional HEO model

● Present information on the association between the hazard and the health outcome

○ Find good research that is likely to be applicable to a population living in a Canadian city

○ Summarize the research findings

■ What is the association between exposure to hazard and the health outcome?

■ Try to find and represent some quantifiable measures of the association (e.g., relative risk, odds ratio, attributable risk)

General health risk assessment report (20%)

General health risk assessment report (20%)

● You should supplement the material with tables or figures that help convey findings

● Ideally, all tables and figures should be your own, but based on data that others have compiled

● Ensure that the research is properly cited

● Authoritative sources (peer-reviewed literature) are important, and it is also important to use primary research sources when possible — cite the researchers that do the research rather than those who refer to it

Site-specific health risk assessment (30%)

● Based on background work of the General Health Risk Assessment

● Select a neighbourhood in a Canadian city

● Assess the risk of the health outcome associated with exposure to the hazard ○ Estimate the level of exposure to hazard (exposure concentration) ○ Identify a vulnerable population in the neighbourhood (e.g., older

residents, children, low income, people with certain diseases that make them more vulnerable)

○ Assess the risk to this vulnerable population given the exposure that you’ve estimated

Environment & Health 4HH3

Dr. N. Yiannakoulias, Winter 2017 Study Design

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Strengths and weaknesses of different study designs

●Random error

●Bias (omitted variable, selection, response and reporting)

●Generalizability

●Other issues? ○Cost ○Ethics ○Time

Strengths and weaknesses of RCTs

● Control for confounding

● Analytically simple and easy to describe

●Less generalizable

●Not applicable to most EH concerns

●Expensive and time consuming

Strengths and weaknesses of animal models

● Control for confounding

● Analytically simple and easy to describe

● Can use in EH research

●Not very generalizable

●Ethical concerns?

Strengths and weaknesses of case studies

●Detailed information

●Targeted

● Unique setting

●Less generalizable

●Considerable potential for bias

●Not statistically rigorous

● Can be used in EH if health and exposure data are available

● Relatively inexpensive and fast

● More power to generalize (because they can be larger)

Strengths and weaknesses of case-control studies

●Bias

○ Omitted variable ○ Response/recall

Asthma

Income

Age

Sex

Diet

Stress

Allergens Genetics

Earlier Exposures

Parental History

Immune System

Pollution

Strengths and weaknesses of case-control studies

Strengths and weaknesses of cohort studies

●Less bias in measuring exposure

●Confounders may be less of a problem than in case control studies

●Still potential for bias (omitted variable, reporting)

●May be less generalizable depending on the cohort selected

●Time consuming (prospective)

Strengths and weaknesses of meta analyses and systematic reviews

●Combine results from many studies

● Large

● More generalizable

● Relatively inexpensive

● Depends on good primary research

● More subjective, prone to research bias

●Cheap, fast and flexible

●Diverse study subjects

●Generalizable

Strengths and weaknesses of ecological correlation study

●Hard to control for confounders

●Ecological fallacy

Strengths and weaknesses of ecological correlation study

STUDY OBJECTIVE–The aim of the study was to assess the effect of inhaled pollutants on lung cancer risk. DESIGN–The study was a […] of lung cancer deaths over a six year period (1980-1985). Information on occupation, smoking habits, and residency was collected from next of kin. Classification of exposure to community air pollution was based on measured levels of total suspended particulate matter and sulphur dioxide. SETTING—Subjects had been resident in the city of Cracow, Poland. PARTICIPANTS–Cases were male (n = 901, questionnaire response rate 70.7%) and female (n = 198, response rate 65.1%) lung cancer deaths; controls were deaths from other causes, excluding other respiratory diseases, and frequency matched by age and sex (males n = 875, response rate 73.5%; females n = 198, response rate 64.0%).

We investigated the association between total and cause-specific mortality and individual measures of long-term air pollution exposure in […] Norwegian men followed from 1972-1973 through 1998. Data from a follow-up study on cardiovascular risk factors among 16,209 men 40-49 years of age living in Oslo, Norway, in 1972-1973 were linked with data from the Norwegian Death Register and with estimates of average yearly air pollution levels at the participants’ home addresses from 1974 to 1998. Cox proportional-hazards regression was used to estimate associations between exposure and total and cause-specific mortality. During the follow-up time 4,227 men died from a disease corresponding to an ICD-9 (International Classification of Diseases, Revision 9) code < 800. Controlling for a number of potential confounders, the adjusted risk ratio for dying was 1.08 [95% confidence interval (CI), 1.06-1.11] for a 10- microg/m3 increase in average exposure to nitrogen oxides (NOx) at the home address from 1974 through 1978. Corresponding adjusted risk ratios for dying from a respiratory disease other than lung cancer were 1.16 (95% CI, 1.06-1.26); from lung cancer, 1.11 (95% CI, 1.03-1.19); from ischemic heart diseases, 1.08 (95% CI, 1.03-1.12); and from cerebrovascular diseases, 1.04 (95% CI, 0.94-1.15). The findings indicate that urban air pollution may increase the risk of dying. The effect seemed to be strongest for deaths from respiratory diseases other than lung cancer.

OBJECTIVES: Outdoor air pollution has consistently been shown to predict mortality. The finding that this association is stronger in infants than in children or adults raises the question whether air pollution could also be related to pregnancy outcomes–such as birthweight and stillbirth. The association between outdoor air pollution and stillbirths and low birthweight in the Czech Republic, where air pollution was high, was examined. METHODS: An […] study was conducted, with routinely collected data on stillbirths and low birthweight (< 2500 g), air pollution (total suspended particulates, sulphur dioxide (SO2), and nitrogen oxides (NOx)), and socioeconomic factors (mean income, car ownership, divorce rate, etc). The analyses were restricted to 45 districts on which data on air pollution were available for the period 1986-8. The effects of exposure variables on frequency of pregnancy outcomes were estimated by logistic regression with district-years as the units of analysis.