Environment, Society, Climate and Health:

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Environment, Society, Climate and
Health Analysis, Understanding and
Prediction Mark L. Wilson Department of
Epidemiology and Global Health Program School of
Public Health The University of
Michigan Colloquium on Climate and
Health NCAR Boulder, Colorado 23 July, 2004
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Outline

1. Introduction Infectious Disease Epidemiology
2. Patterns of Environmental Influences
3. Climate as an Environmental Driver
4. Examples from our research
5. Discussion of examples from your
   research/interests

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Climate Variability vs. Climate Change

• Climate Change
• - persistent change or trend in mean atmospheric
  conditions
• - current changes unprecedented in human history
• Climate Variability
• - day-to-day (weather) or relatively short term
  (seasonal) changes in atmospheric conditions
• - effects on disease patterns most easily
  analyzed, and used in forecasts

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Classical Epidemiological Triad
Environment
Agent
Host
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Environment (biophysical, psycho-social, etc.)
Agent (diverse exposures, including
non-contagious )
Host (animal, plant, ultimately human)
CLIMATE is an Environmental Influence
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Environment
Agent
Host
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Examples Involving Infectious Diseases
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But for ALL diseases, complex interactions
occur...
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Environment
Agent transport to new areas
New antibiotics, pesticides
Labor actions affecting toxin exposure
Agent
Host
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Environment
Agent
Host
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Examples of Environmental and Epidemiological Data

• Climate patterns variability perhaps change
• Land Use / Land Cover patterns
• Human case data (specific or syndromic)
• Vector abundance and pathogen infection
• Reservoir abundance / infection prevalence
• Environmental use and exposures
• Economic development, human demography, migration
  more

Each of these is historically changing in time
and space
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Environmental Determinants of Human Disease
Modified from Kaplan, 2002
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Research Challenge Analyze and understand
interactions!
Climate?
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What is climate change? Climate variability?
High
Unchanging Average, Unchanging Extremes
Average Trend
Environmental Variable
(solid line)
Actual Measure
(dashed line)
Low
Time
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High
Unchanging Average, Increasing Extremes
Average Trend
Environmental Variable
(solid line)
Actual Measure
(dashed line)
Low
Time
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High
Increasing Average, Unchanging Extremes
Environmental Variable
Average Trend (solid line)
Actual Measure (dashed line)
Low
Time
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High
Increasing Average, Greater Extremes
Environmental Variable
Average Trend (solid line)
Actual Measure (dashed line)
Low
Time
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High
Increasing Rate of Increasing Average, Unchanging
Extremes
Environmental Variable
Average Trend (solid line)
Actual Measure (dashed line)
Low
Time
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High
Increasing Rate of Increasing Average, Greater
Extremes
Environmental Variable
Average Trend (solid line)
Actual Measure (dashed line)
Low
Time
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Each of these climate change patterns may have
different impacts on particular disease
risks. Effects will depend on the ecology of
transmission and the etiology and expression of
disease.
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• Each exposure type should be considered in
  context of
• PERSON (age, behavior, gender, SES, etc.)
• TIME (year, season, adjacent periods, etc.)
• PLACE (geographic location, habitat, proximity,
  etc.)

• Most Epidemiological studies only superficially
  consider this for environmental (climatic)
  exposures
• PERSON most often involves standard descriptors
  that do not include "social" characteristics or
  other environmental exposures (e.g. climatic).
• TIME is rarely dynamic, considers only recent
  past, and climate pattern over long periods not
  always available.
• PLACE often ignored or not carefully evaluated
  (e.g. spatial autocorrelation, climate patterns
  in regions may be important ).

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Environment and Exposure
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Environment and Exposure Where might Climate
Impact?
Environmental Exposures
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Environment and Exposure Where might Climate
Impact?
Anthroponotic Infections
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Environment and Exposure Where might Climate
Impact?
Zoonotic Infections
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Elements of Climate and Health
Heat-related mortality Extreme Events Air
Pollution Vector-borne Diseases Water-borne
Diseases Agricultural Production
Maximum Temperature Minimum Temperature Mean
Temperature Rainfall Amount Rainfall
Frequency Rainfall Rate
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What diseases are climate sensitive?
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What diseases are climate sensitive?
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Heat stress
Sexually transmitted Disease
Effects of Storms
Water-borne disease
More Complex
Food-borne disease
Asthma
Atherosclerosis
Vector-borne Disease
Cancer (not skin)
Myocardial Infarction
Violence
More Climate Sensitive
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• Discussion
• From YOUR EXPERIENCES or INTERESTS
• What diseases might have a climate link and what
  climate variables might impact on which diseases?
• WHY? What are the biological or social pathways?
• How would these be investigated/researched?
• What additional information would you seek?
• How would you integrate this into OTHER
  determinants of risk?
• Could you forecast risk based on these analyses
  alone?
• What other factors should be considered and why?

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• Importance of temporally and spatially extensive
  data in analyzing and interpreting role of
  climate
• Climate change occurring over long time period
• Climate variability change not easy to recognize
  without long-term observations
• Time-space changes in disease patterns require
  accurate and consistent surveillance (often
  non-existent, especially in developing countries)
• Inference of climate-disease links limited
  without carefully considering time-space patterns

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Interpreting Spatial Patterns of Risk

• Area of risk
• Size of areas
• Location and pattern
• Inter-area distances
• Connectivity among locations

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How can extensive time-space datasets help?
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How can extensive time-space datasets help?
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How can extensive temporal datasets help?
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How can extensive temporal datasets help?
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How can extensive spatial datasets help?
High
Abundance or Infection
Low
Environmental Index
Low
High
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Some Sources of Data

• Meteorological Stations (climate, weather)
• Satellite climate, vegetation, soil moisture,
  etc
• Census population, age, sex, location, etc
• Passive or active surveillance of human cases
• Surveillance of vector, reservoir abundance
• more...

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Knowing is not enough we must apply.Willing is
not enough we must do.(Goethe)