Health impact assessment and health risk assessment: Common methods and future challenges
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Transcript of Health impact assessment and health risk assessment: Common methods and future challenges
Jonathan I. Levy, Sc.D.Professor and Associate Chair, Department of
Environmental HealthBoston University School of Public Health
SRA-New England seminar seriesApril 3, 2013
Statement of taskAn NRC/IOM committee will develop a framework,
terminology, and guidance for conducting health impact assessment (HIA) of proposed policies, programs, and projects (for example, transportation, land use, housing, agriculture) at federal, state, tribal, and local levels, including the private sector. The committee will assess the value and potential value of such assessments; the impediments and countervailing factors that have limited the practice of HIA to date; the circumstances and criteria for conducting them; the concepts, tools, and information required; and the types, structure, and content of HIAs. Based on these considerations, the committee will develop a systematic, conceptual framework and approach for improving the assessment of health impacts in the United States.
What is HIA? “HIA is a systematic process that uses an
array of data sources and analytic methods and considers input from stakeholders to determine the potential effects of a proposed policy, plan, program, or project on the health of a population and the distribution of those effects within the population. HIA provides recommendations on monitoring and managing those effects.” (NRC, 2011)
NRC, 2011
Key differences from risk assessment (NRC, 2011)
Risk assessment focuses on:Individual chemicals, not numerous factors
influencing health across various policies, programs, projects, and plans
Adverse health effects rather than beneficial and adverse effects
Quantitative outputsCharacterizing impacts more than informing
specific interventions or decisionsRisk assessment omits stakeholder and
community engagement
But…EPA 2003: Cumulative risk assessment: An
analysis, characterization, and possible quantification of the combined risks to health or the environment from multiple agents or stressors
EPA 1999: Cumulative impact assessment: The cumulative impacts of an action can be viewed as the total effects on a resource, ecosystem, or human community of that action and all other activities affecting that resource no matter what entity (federal, non-federal, or private) is taking the actions
But…Sexton and Linder (2010): Cumulative risk
assessment: involves evaluation of collective health effects of
multiple stressors [as opposed to individual effects of a single stressor];
broadens the spectrum of environmental agents being appraised to include psychological (e.g., residential crowding) and sociological (e.g., racial discrimination) stressors [not just chemicals];
focuses on population-based or location-based assessments of real-world cumulative exposures experienced by actual people
provides for the possibility of a semi-quantitative or qualitative analysis/result
• What are the relative health or environmental benefits of the proposed options?
• How are other decision-making factors (technologies, costs) affected by the proposed options?
• What is the decision, and its justification, in light of benefits, costs, and uncertainties in each?
• How should the decision be communicated?
• Is it necessary to evaluate the effectiveness of the decision?
• If so, how should this be done?
Stage 1: Planning
• For the given decision-context, what are the attributes of assessments necessary to characterize risks of existing conditions and the effects on risk of proposed options? What level of uncertainty and variability analysis is appropriate?
Stage 3: Confirmation of Utility
• Does the assessment have the attributes called for in planning?
• Does the assessment provide sufficient information to discriminate among risk management options?
• Has the assessment been satisfactorily peer reviewed?
FORMAL PROVISIONS FOR INTERNAL AND EXTERNAL STAKEHOLDER INVOLVEMENT AT ALL STAGES
• The involvement of decision-makers, technical specialists, and other stakeholders in all phases of the processes leading to decisions should in no way compromise the technical assessment of risk, which is carried out under its own standards and guidelines.
• What problem(s) are associated with existing environmental conditions?
• If existing conditions appear to pose a threat to human or environmental health, what options exist for altering those conditions?
• Under the given decision context, what risk and other technical assessments are necessary to evaluate the possible risk management options?
• Hazard Identification
What adverse health or environmental effects are associated with the agents of concern?
• Dose-Response Assessment
For each determining adverse effect, what is the relationship between dose and the probability of the occurrence of the adverse effects in the range of doses identified in the exposure assessment?
• Risk Characterization
What is the nature andmagnitude of risk associated with existing conditions?
What risk decreases (benefits) are associated with each of the options?
Are any risks increased? What are the significant uncertainties?
• Exposure Assessment
What exposures/doses are incurred by each population of interest under existing conditions?
How does each option affect existing conditions and resulting exposures/doses?
Stage 2: Risk Assessment
NO YES
PHASE I: PROBLEM FORMULATION
AND SCOPING
PHASE II: PLANNING AND CONDUCT
OF RISK ASSESSMENT
PHASE III: RISK MANAGEMENT
But…
NRC, 2009
Key differences from risk assessment (NRC, 2011)
What truly differs?A matter of degree
Amount of quantitative vs. qualitativeExtent of stakeholder participationFocus on impacts vs. intervention/mitigationBreadth vs. depth
Current practice vs. proposed approachesRisk assessment strives to be more holistic and
cumulative but often is still narrowly focusedHIA strives to be more quantitative and decision-
driven but is often still descriptive and informational
Can a blended approach give greater insight?
Case example (MAPC/BUSPH/HSPH) January 2012: MBTA announces proposed rate increases
and service cuts to meet projected $161M budget deficitScenario 1: Fares increase by 43%, service reductions
affect between 34–48 million trips each year. Scenario 2: Fares increase by 35%, service reductions
would affect between 53-64 million trips each year Analysis requested by March 2012 to be timely for fare
decision: What are the health implications of these proposed
policies?How does the economic impact compare with the cost
savings?
Wasted time/wasted fuelStraight economic analysis without direct
health component (other than broad-based health-wealth argument)
Determined mode shift from transit to driving, resulting changes in average vehicle speeds and time commutingAdditional time driving x value of time
(individual and commercial)Fuel economy as function of speed
Air pollutionTraffic volume inputs linked to MOBILE6.2 to
estimate emissions of primary PM2.5, SO2, NOx
Source-receptor matrix used to link emissions estimates to county-resolution PM2.5 concentration outputs
Epidemiological evidence and population data used to calculate mortality and morbidity impacts
Value of statistical life used to monetize
Physical activityLiterature values:
8.3 minutes additional walking for those using public transit vs. driving
Relative risk of obesity vs. time spent walking (analysis of National Household Travel Survey data)
WHO HEAT model to estimate mortality and economic impact associated with decreased walking
AccidentsNational statistics show rate of fatal injury per
person-trip 23 times lower for bus vs. car, rate of non-fatal injury per person-trip 5 times lower
Baseline traffic fatality rate per VMT taken from NHTSA estimates for MA
Crash costs derived from AAA study (property damage, lost earnings, lost production, medical costs, emergency services, travel delay, rehab, workplace costs, administrative, legal, pain, quality of life): $0.26 per VMT
Other dimensionsGreenhouse gas emissions: Increased CO2
emissions from motor vehicle use linked to social cost of carbon value
Access to healthcare: Number of individuals estimated to lack cars who currently have MBTA access to healthcare facilities but would no longer, based on combination of ArcGIS buffer mapping and census data on car availability (Not monetized)
Noise: Look-up tables from Transportation Noise Model, estimation of additional people exposed to 60 dB (Not monetized)
Lessons learnedMBTA HIA had 2 key dimensions that attracted
public and policymaker attentionRaising awareness of links between policy and
health that were previously not considered (HIA) Providing quantitative insight (even if simplified)
to compare the impact of a policy in relation to its cost (risk assessment/benefit-cost analysis) http://www.wcvb.com/Study-MBTA-Rail-Cuts-Could-
Be-Harmful-To-Health/-/9849586/12198090/-/14aqsmm/-/index.html
Promising press (Dec 2012)Most effective, efficient quantitative
analysis. The folks at the Boston Metropolitan Area Planning Council, in their work with the Harvard and Boston University Schools of Public Health, broke the record for the shortest full HIA report with their HIA of the MBTA’s proposed service cuts and fare increases for the T. Twenty pages including references! It is remarkable how they do this while still including a solid, compelling quantitative analysis of the health and economic effects of the public transit proposal. - Human Impact Partners
ConclusionsBroad scope of HIA coupled with analytical
methods typical to risk assessment can lead to valuable insights for public policyScreening-level risk assessment highly
informative for many HIAsPractitioners in both fields need to recognize
increasing commonalities and find ways to combine effortsHIA session at SRA?Risk assessment session at HIA meetings?