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Title: The Four Stages Theory of Prevention


1
The Four Stages Theory of Prevention
  • A Public Health Framework for the prevention and
    management of Diabetes Mellitus and other chronic
    diseases
  • By
  • Prof Winston Mendes Davidson
  • CD JP MBBS DTM H
  • 27th March 2015

2
HR Leavell and Gurney Clarke The Pioneers of
Preventive Medicine
  • Pioneers in Preventive Medicine
  • 1953 to 2015
  • Period- 62 years

3
Historic milestones- 1953
  • 1953
  • In1953 published
  • Textbook of preventive Medicine which
    described five levels of the application of
    Preventive Medicine
  • Health promotion
  • Specific Protection
  • Early recognition and prompt treatment
  • Disability limitation
  • Rehabilitation

4
Historic milestones- 1957
  • In 1957
  • The terms Primary and Secondary Prevention was
    introduced by Chronic Disease Report sponsored by
    the Commonwealth Fund (reported in Harvard
    University Press 1957, Volume 1 pp1-68)
  • Health promotion was defined as maintenance of
    health rather than Prevention of diseases.

5
Historic milestones -1958
  • In 1958-
  • A 2nd edition of Leavell and Clarkes book
    retitled
  • Preventive Medicine for the Doctor and his
    Community
  • Published incorporating the paradigm of the
    Commonwealth report of primary and secondary
    prevention but included a tertiary prevention
    component.

6
Historic Milestones
  • 1958 revised retitled edition
  • Preventive Medicine for the Doctor and his
    Community ( Leavell and Clarke)
  • Primary Prevention
  • Health promotion
  • Specific Protection
  • Secondary Prevention
  • Early recognition and prompt treatment
  • Tertiary Prevention
  • Disability limitation
  • Rehabilitation

7
Historic milestones
  • In 1965 the 3rd edition
  • Preventive Medicine by Leavell and Clarke was
    published and referred to as Phases of
    Prevention.
  • Adopted by Medicine and the Social Sciences
  • Cardiovascular diseases (Joseph et al 2005)
  • Obstetrics ((Decker and Sibai, Lancet Vol 357,
    2001)
  • The only difference between 1958 and 1965 was the
    change of disability limitation from tertiary
    prevention to secondary prevention

8
PRIMARY PREVENTION  (1965- present)Seeks to
prevent a disease or condition at a
pre-pathogenic state to stop something from ever
happening
  • Health Promotion 
  • Health education
  • Marriage counselling
  • Genetic screening
  • Good standard of nutrition adjusted to
    developmental phase of life

9
PRIMARY PREVENTION 1965- present
  • Specific Protection 
  • Use of specific immunization
  • Attention to personal hygiene
  • Use of environmental sanitation
  • Protection against occupational hazards
  • Protection from accidents
  • Use of specific nutrients
  • Protections from carcinogens
  • Avoidance to allergens

10
SECONDARY PREVENTION-1965-present
  •  Also known as Health Maintenance. Seeks to
    identify specific illnesses or conditions at an
    early stage with prompt intervention to prevent
    or limit disability to prevent catastrophic
    effects that could occur if proper attention and
    treatment are not provided
  • Early Diagnosis and Prompt Treatment 
  • case finding measures
  • individual and mass screening survey
  • prevent spread of communicable disease
  • prevent complication and sequelae
  • shorten period of disability
  • Disability Limitations 
  • Adequate treatment to arrest disease process and
    prevent further complication and sequelae.
  • Provision of facilities to limit disability and
    prevent death.

11
TERTIARY PREVENTION- 1965-present
  •  Occurs after a disease or disability has
    occurred and the recovery process has begun
    Intent is to halt the disease or injury process
    and assist the person in obtaining an optimal
    health status. To establish a high-level
    wellness. To maximize use of remaining
    capacities
  • Restoration and Rehabilitation 
  • Work therapy in hospital
  • Use of shelter colony

12
Limitations of the Leavell Clarke Model
  • It is a disease prevention model rather than a
    health and disease prevention model.
  • It has not taken the following into account
  • Fundamental advances in epidemiology since 1953
    and its application to contemporary Public Health
    Practice
  • The role of the environment, as reflected in the
    Epidemiologic Triad Host, Agent and Environment,
    in the analysis of health disease causation and
    development
  • Understanding the health and disease continuum
    as a naturally occurring continuum of the history
    of health and disease in man.
  • This is necessary to enable the development of
    best practices in prevention intervention
    measures

13
Limitations of the Leavell Clarke Model
  • Health is linked to wellbeing and wellbeing is
    linked to clinical interventions related only to
    a diseased state rather than the inclusion of a
    process of health development related to the
    interactions of human and natural ecosystems
  • The impact of disharmonious adaptation of man in
    the environment and climate change is not
    possible with the present WHO definition of
    health, or the three levels of prevention
    paradigm of Leavell and Clarke
  • The re-emergence of communicable diseases,
  • the globally competing interests in human values
    are shaping human behaviours challenging deeply
    embedded core values of every culture in the
    world
  • The process of epigenetics, a feature of the
    process of adaptation, creates new lifestyles and
    nascent cultures leading to clashes of cultures
    and psychological problems on a global scale even
    leading to violence on a mass scale in some
    instances
  • There is an urgent need to find solutions to the
    preventive paradigm
  • The Four Stages Theory of Prevention seeks to
    overcome these limitations,
  • while at the same time building on the
    fundamental work of Leavell and Clarke

14
The Four Stages Theory of Prevention
  • What is the four stages theory of prevention?
  • How does it advance our knowledge and management
    of the prevention of diseases and conditions in
    general and chronic diseases in particular
    Diabetes Mellitus
  • How does it advance contemporary knowledge in
    Public Health practice?
  • Why is this not possible with the Leavell
    Clarke Three levels of Prevention Model?

15
The Four Stages Theory of PreventionFramework
of prevention based on universal Public Health
and Epidemiological principles
Rising Costs
Prof W. Davidson. 1999. (copyright)
Prevention
COMMUNITY
COMMUNITY
Rehab Response
Non-Institutional Response
State of Wellness
Institutional Response
HARMONIOUS ADAPTATION / relationship with any
environment (Healthy Lifestyle / Wellness)
Risk reduction / early diagnosis Incidence
intervention measures
Treatment and Repair (Prevalence
intervention Measures)
Rehab intervention measures
SECONDARY PREVENTION (Decrease Prevalence)
TERTIARY PREVENTION (Avert Chronicity)
PRE-PRIMARY PREVENTION (Maintain Health
Wellness)
PRIMARY P REVENTION (Decrease Incidence)
16
Essence of the difference between the two Models
  • The New Pre-Primary Prevention Paradigm
  • Represents the essence
  • The fundamental point of departure between the
    Three Levels Model of Prevention
  • by Leavell and Clarke
  • and
  • The Four Stages Theory of Prevention Model
  • by W.G. Mendes Davidson

17
What is the meaning of Adaptation?
  • Adaptation is defined as a an unrelenting process
    of interactive change between man and the
    environment.
  • Adaptation is both an event and a process
  • When the process of adaptation is harmonious, a
    state of health and wellness is the outcome.
  • When the process of adaptation is disharmonious,
    a state of harm, illness or disease is the
    outcome.

18
Two Theories of Prevention
  • Leavel Clarke Three levels of Prevention
  • The Four Stages Theory of Prevention
  • (Ref Academia.edu approx 30,000 hits gt100
    countries)

19
What are the differences between the four stages
the three levels prevention paradigms?
  • These differences are
  • Definition of Health
  • Concept of health and disease continuum
  • Concept of prevention being both event and
    process
  • Categories of fundamental health determinants
  • Application of Public health as a science in the
    use of both quantitative and qualitative methods
    of analysis
  • Integration of environmental health and climate
    change in the health and disease continuum

20
World Health Organisation Definition of Health
  • The Definition has not been amended since 1948.
  • Health is a state of complete physical, mental
    and social well-being and not merely the absence
    of disease or infirmity
  • Ref Preamble to the Constitution of the World
    Health Organization as adopted by the
    International Health Conference, New York, 19-22
    June, 1946 signed on 22 July 1946 by the
    representatives of 61 States (Official Records of
    the World Health Organization, no. 2, p. 100) and
    entered into force on 7 April 1948.

21
Four Stages Theory of PreventionDefinition of
Health
  • Health is defined in this instance as
  • The harmonious adaptation of man within his
    environment
  • Definition by
  • Prof W. G. Mendes Davidson 1992

22
The Natural History of Health and Disease in man
THE FOUR STAGES THEORY CONTINUUM A-gtB-gtC-gtD
(Preprimary/ Adaptation)-gt(Primary /Decreasing
Incidence)-gt (Secondary/ Decreasing Prevalence)-gt
(Tertiary / Rehabilitation) Adaptation----------
-gt risk exposure------gt risk contact-------gt
early non-discernible disease /injury-----gt lt-----
---A---------------gt lt----------------------------
---B----------------------------------------------
--------------------------gt early discernible
disease / injury---------gt late discernible
injury------gt advanced disease injury-----gt lt-----
--------------------------------------------------
-------------- C ---------------------------------
-----------------------------gt
----------------?Chronicity / Rehabilitation /
Recovery ---------gt Death lt-----------------------
------------ D------------------------------------
------------gt
23
Four stages theorys definition of Prevention?
  • Prevention is any activity or process (or series
    of activities or processes) which avoids, deters,
    averts or reverses the development of an event or
    process which leads to an undesirable outcome
  • (W. G. Mendes Davidson 1992)
  •  

24
HARMONIOUS ADAPTATIONPRE-PRIMARY PREVENTION
STATE OF HEALTH
  • Pre-primary prevention or harmonious adaptation
    is the desired outcome of mans relationship
    within the environment.
  • This outcome is always referred to as wellbeing
    and is achieved through the practice of a healthy
    lifestyle.
  • The process of adaptation is a continuous
    unrelenting process of interactivity / struggle
    between man and the environment to which he is
    organically linked

25
Pre-Primary PreventionUnderstanding the
Adaptation process
  • Deeply embedded core values form the basis, the
    essence of adaptation and are the antecedents of
    the way we behave in society and in the
    environment
  • A rational and sustainable preventive strategy
    cannot be developed without our understanding or
    clarification of what we mean by core values and
    its variants which determine our behaviours in
    the environment

26
Pre-Primary PreventionWhat are values?
  • Values are the things people strive for, or
    attach meaning or significance to
  • Nascent values are the new things people
    strive for, or attach meaning or significance to
    e.g. popular cultural forms and expressions,
    fashion, contemporary lifestyles and fetishes,
    etc.
  • They may be evanescent or over time develop into
    core values or deeply embedded core values
  • (Prof Davidson NCDA conference Jamaica 1992)

27
Pre-primary preventionHow do we objectively
identify the values which underpin Adaptation?
  • Values clarification together with the
    identification of norms and standards of human
    behavior within the existing culture at a
    particular point or period of time, gives one an
    insight into the identity of a particular value
    or system of values
  • This process of values clarification is necessary
    if one is to engage in meaningful planning of
    preventive intervention measures and strategies
    to achieve desired outcomes

28
Pre-Primary PreventionFramework for analysing
Values
  • The late Professor Carl Stone, a political
    sociologist at the University of the West Indies
    developed this framework for analyzing values
    etc. in his paper Values, Norms and personality
    development in Jamaica (1992).

29
Pre-primary PreventionRelationship between
values and human behaviour
30
Pre-primary Prevention Relationship between
social forces and human behaviours
31
Pre-primary prevention RELATIONSHIP BETWEEN
DOMAINS OF SOCIAL SPACE AND CORE VALUES
32
Pre-Primary PreventionHarmonious Adaptation
State of Health
33
Primary prevention Preventing the Incidence of
diseases New cases
34
SECONDARY PREVENTIONPreventing the Prevalence of
Diseases Old and New Cases
35
TERTIARY PREVENTION Enable timely recovery,
Re-stabilize, Re-train, Re-motivate,
Re-socialize, Re-integrate
36
Pre-Primary prevention Air Pollution and
Diabetes Mellitus
  • Air pollution Sources
  • Traffic-related air pollution
  • from cars,
  • trucks, and
  • diesel exhaust, is the most studied type of air
    pollution in relation to diabetes
  • Some types of traffic-related air pollution
    include
  •  sulfur dioxide (SO2), 
  • sulfate (SO4), 
  • nitrogen oxides(NOx) including nitrogen
    monoxide (NO) and nitrogen dioxide (NO2), 
  • carbon monoxide(CO),
  • ground-level ozone (O3), 
  • polycyclic aromatic hydrocarbonsgt (PAHs),
  • diesel exhaust particles (DEP), and particulate
    matter (PM10 and PM2.5)

37
What do these markers mean?
  • PM2.5 refers to fine air particles less than 2.5
    micrometers in diameter,
  • PM10 refers to particles less than 10 micrometers
    in diameter.
  • Ground-level ozone is a major component of smog.
  • Ozone forms from the interaction of various air
    pollutants with sunlight.
  • Ozone levels therefore peak in the summer.

38
Pre-Primary Prevention and Diabetes Mellitus The
evidence
  • Evidence not derived from causal relationships
    but derived from recent work correlations and
    associations
  • Evidence represents the outcomes from the long
    process of descriptive studies derived from
    multiple sources and reinforcing the principles
    of significance and validation

39
Longitudinal studies in humansType 1 diabetes
  • A 2002 pilot study on five different air
    pollutants and type 1 diabetes in southern
    California found that children with type 1
    diabetes were exposed to higher levels of
    ground-level ozone (O3) before diagnosis than
    healthy children (Hathout et al. 2002).
  • A larger, follow-up study in 2006 found that
    children with type 1 diabetes had higher exposure
    to ozone as well as sulfate (SO4) air pollution,
    as compared to healthy children.
  • The effect of ozone was strongest, while exposure
    to other air pollutants, including sulfur dioxide
    (SO2), nitrogen dioxide (NO2), and
  • particulate matter (PM10) were not associated
    with type 1 diabetes development (Hathout et al.
    2006

40
Longitudinal studies in humansType 1 diabetes
  • The strength of these studies is that the
    researchers measured exposure to air pollutants
    over time, from birth until diagnosis.
  • These authors suggest that oxidative stress,
    which involves an excess of free radicals, might
    be one mechanism whereby air pollutants could
    influence the development of type 1 diabetes.
  • Ozone and sulfate can have oxidative effects.
  • Particulate matter carries contaminants that can
    trigger the production of free radicals as well
    as immune system cells called cytokines (involved
    in inflammation), and may affect organs that are
    sensitive to oxidative stress (MohanKumar et al.
    2008). Beta cells are highly sensitive to
    oxidative stress, and free radicals are likely to
    be involved in beta cell destruction in type 1
    diabetes (Lenzen 2008).
  • A study from Chile found that fine particulate
    matter (PM2.5) levels (as well as certain
    viruses) were associated with the onset of type 1
    diabetes in children, suggesting that air
    pollution levels could be related to peaks of
    type 1 diagnosis (González et al. 2013).

41
Pre-Primary Prevention, Air Pollution
Autoimmunity and Diabetes Mellitus
  • In Montreal, researchers tracked air pollution
    levels and the symptoms of people with the
    autoimmune disease systemic lupus erythematosis
    (SLE). They found that short term variations in
    the PM2.5 air pollutant levels were correlated
    with disease activity, including autoantibody
    levels. They conclude that air pollution may
    influence disease activity, as well as trigger
    autoimmunity. The authors cite other studies that
    have also found that air pollution may trigger
    autoimmune disease in humans (Bernatsky et al.
    2011).
  • Children exposed to higher levels of air
    pollution in Mexico City show increased markers
    of immune dysregulation and systemic
    inflammation, as compared to children living in a
    less polluted city (Calderón-Garcidueñas et al.
    2009). Air pollutants, then, may be toxic to the
    immune system.
  • Gomez-Mejiba et al. (2009) discuss how inhaled
    air pollutants can trigger autoimmunity in
    genetically susceptible people. Inflammation of
    the lung may be an important connection between
    air pollution and autoimmunity by activating
    inflammatory cells, leading to chronic
    inflammation. When the lung is exposed to air
    pollutants, the body reacts by producing
    inflammation in the lung. Damage to the lung
    promotes oxidative stress, and when inflammatory
    and free radical molecules circulate throughout
    the body, they may have damaging effects in other
    organs. Lung dysfunction has been found in some
    people with type 1 (and type 2) diabetes (Tiengo
    et al. 2008).

42
Pre-Primary Prevention, Air Pollution
Autoimmunity and Diabetes Mellitus
  • Ito et al. (2006) looked at the mechanisms behind
    how diesel exhaust particles (DEP), the main air
    pollutants in urban areas, can affect the immune
    system. Exposure to these particles in utero and
    in early life affects the development of the
    thymus, an organ that plays a key role in the
    development of the immune system. Diesel exhaust
    particles contain a number of chemical
    components, including dioxin (TCDD) and
    polyaromatic hydrocarbons (PAHs).
  • These authors found that DEP affected gene
    expression in the thymus, and affected the
    development of immune system cells in the thymus.
    As such, these particles could directly affect
    immune system development, and are considered to
    be immuno-toxicants (discussed on
    the autoimmunity page). Many of the chemicals
    that make up diesel exhaust particles are
    also endocrine disruptors (Takeda et al. 2004).

43
Longitudinal studies in humansType 2 diabetes
  • A number of long-term studies have found that
    exposure to traffic-related air pollution is
    associated with an increased risk of type 2
    diabetes in adults. For example, a study of
    African-American women from Los Angeles found
    that those who had higher exposure to
    traffic-related air pollutants (PM2.5 and
    nitrogen oxides) were more likely to develop
    diabetes (as well as high blood pressure) (Coogan
    et al. 2012).
  • Adults in Denmark had an increased risk of
    diabetes when exposed to higher levels of the
    traffic-related air pollutant nitrogen dioxide
    (NO2)-- especially those who had a healthy
    lifestyle, were physically active, and did not
    smoke-- factors that should be protective against
    type 2 diabetes (Andersen et al. 2012).
  • A study of adult women in West Germany found that
    women exposed to higher levels of traffic-related
    air pollution (NO2 and PM) developed type 2
    diabetes at a higher rate. This study followed
    the participants over a 16 year period (at the
    beginning, none had diabetes) (Krämer et al.
    2010).

44
Longitudinal studies in humansType 2 diabetes
  • A long-term study from Ontario, Canada, found
    that exposure to PM2.5 was associated with the
    development of diabetes in adults (Chen et al.
    2013).
  • From Switzerland, a 10 year long study found that
    levels of PM10 and NO 2were associated with
    diabetes development in adults, at levels of
    pollution below air quality standards (Eze et al.
    2014).
  • A shorter-term (12 month) study from the
    Northeast and Midwest U.S. did find an
    association between diabetes and residential
    proximity to a road (in women), although it did
    not find an association between diabetes and
    exposure to particulate matter in the year before
    diagnosis. The statistical analysis revealed
    slightly increased risk of diabetes to PM
    exposure, although the differences were not
    significant. This study used models based on
    people's addresses to estimate PM exposure, and
    did not measure exposure directly (Puett et al.
    2011). Another 1 year-long study of elderly
    adults from Taiwan found that fasting blood
    glucose levels and hemoglobin A1c (HbA1c), a
    measure of average blood glucose levels over 3
    months, were associated with exposure to
    particulate matter (both PM2.5 and PM10), ozone,
    and NO2, but most strongly with particulate
    matter (higher blood pressure and total
    cholesterol levels were also associated with
    these pollutants (Chuang et al. 2011).

45
Cross-sectional studies in humans
  • Cross-sectional studies are studies that measure
    exposure and disease at one point in time. These
    provide weaker evidence than longitudinal
    studies, since the disease may potentially affect
    the exposure, and not vice versa.
  • Cross-sectional studies often show associations
    between diabetes and air pollution, although
    somewhat inconsistently. A Canadian study found
    that exposure to nitrogen dioxide (NO2) air
    pollution was associated with higher levels of
    diabetes in women, but not men. This study did
    not include other air pollutants, but instead
    considered nitrogen dioxide to be a marker of
    traffic-related air pollution. These researchers
    used each individual's residence location to
    estimate air pollution exposures (Brook et al.
    2008).
  • In a study from the Netherlands, researchers did
    not find consistent relationships between air
    pollution and diabetes, although there were some
    indications that traffic within a 250 m buffer of
    the home address (Dijkema et al. 2011).
  • A small study found that nitrogen oxides may be
    linked to impaired glucose metabolism (diabetes
    and high fasting glucose levels) in German women,
    although the results were not significant after
    adjusting for multiple other factors (Teichert et
    al. 2013).
  •  A U.S. study has found that diabetes prevalence
    among adults was higher in areas with higher
    PM2.5 concentrations. The researchers used
    nation-wide data that measured air pollution
    levels by county, and diabetes prevalence by a
    survey, based on U.S. government data. The
    association between diabetes and air pollution
    was strong, and the increased risk of diabetes
    was present even in areas below the legal limits
    of PM2.5 (Pearson et al. 2010).
  • Also from the U.S., a study found that markers of
    exposure to polyaromatic hydrocarbons (PAHs) were
    associated with diabetes in adults (Alshaarawy et
    al. 2014), as did a study from China (Yang et al.
    2014).
  • Air pollution may contribute to clusters of type
    2 diabetes. A U.S. study found regions with
    higher levels of PM2.5 had higher levels of
    diabetes, after controlling for factors such as
    socioeconomics. They found areas with vulnerable
    counties across many regions of the U.S.,
    especially in the South, Central, and Southeast
    (Chien et al. 2014).
  •  Another study hypothesizes and presents evidence
    for a link between these smaller PM2.5 particles
    and diabetes in Portugal, specifically high
    concentrations of airborne chlorine in PM2.5.
    Specifically, there was a surge in chlorine in
    PM2.5 in Lisbon during the summers of 2004 and
    2005, coincidentally with a spike in diabetes
    diagnoses (Reis et al. 2009). 
  • While not all of the human studies of air
    pollution and type 2 diabetes show positive
    associations, the clear majority do. The
    differences in associations may relate to a
    variety of differences, such as air pollution
    exposure levels, individual and genetic
    differences, population differences, other risk
    factors, sex, how the air pollution was measured,
    length of exposure, socio-economic status,
    stress, and more (Rajagopalan and Brook 2012).

46
Cross-sectional studies in humans
  • Also from the U.S., a study found that markers of
    exposure to polyaromatic hydrocarbons (PAHs) were
    associated with diabetes in adults (Alshaarawy et
    al. 2014), as did a study from China (Yang et al.
    2014).
  • Air pollution may contribute to clusters of type
    2 diabetes. A U.S. study found regions with
    higher levels of PM2.5 had higher levels of
    diabetes, after controlling for factors such as
    socioeconomics. They found areas with vulnerable
    counties across many regions of the U.S.,
    especially in the South, Central, and Southeast
    (Chien et al. 2014).
  •  Another study hypothesizes and presents evidence
    for a link between these smaller PM2.5 particles
    and diabetes in Portugal, specifically high
    concentrations of airborne chlorine in PM2.5.
    Specifically, there was a surge in chlorine in
    PM2.5 in Lisbon during the summers of 2004 and
    2005, coincidentally with a spike in diabetes
    diagnoses (Reis et al. 2009). 
  • While not all of the human studies of air
    pollution and type 2 diabetes show positive
    associations, the clear majority do. The
    differences in associations may relate to a
    variety of differences, such as air pollution
    exposure levels, individual and genetic
    differences, population differences, other risk
    factors, sex, how the air pollution was measured,
    length of exposure, socio-economic status,
    stress, and more (Rajagopalan and Brook 2012).

47
Cross-sectional studies in humans
  • A U.S. study has found that diabetes prevalence
    among adults was higher in areas with higher
    PM2.5 concentrations. The researchers used
    nation-wide data that measured air pollution
    levels by county, and diabetes prevalence by a
    survey, based on U.S. government data. The
    association between diabetes and air pollution
    was strong, and the increased risk of diabetes
    was present even in areas below the legal limits
    of PM2.5 (Pearson et al. 2010).
  • Also from the U.S., a study found that markers of
    exposure to polyaromatic hydrocarbons (PAHs) were
    associated with diabetes in adults (Alshaarawy et
    al. 2014), as did a study from China (Yang et al.
    2014).
  • Air pollution may contribute to clusters of type
    2 diabetes. A U.S. study found regions with
    higher levels of PM2.5 had higher levels of
    diabetes, after controlling for factors such as
    socioeconomics. They found areas with vulnerable
    counties across many regions of the U.S.,
    especially in the South, Central, and Southeast
    (Chien et al. 2014).
  •  Another study hypothesizes and presents evidence
    for a link between these smaller PM2.5 particles
    and diabetes in Portugal, specifically high
    concentrations of airborne chlorine in PM2.5.
    Specifically, there was a surge in chlorine in
    PM2.5 in Lisbon during the summers of 2004 and
    2005, coincidentally with a spike in diabetes
    diagnoses (Reis et al. 2009). 
  • While not all of the human studies of air
    pollution and type 2 diabetes show positive
    associations, the clear majority do. The
    differences in associations may relate to a
    variety of differences, such as air pollution
    exposure levels, individual and genetic
    differences, population differences, other risk
    factors, sex, how the air pollution was measured,
    length of exposure, socio-economic status,
    stress, and more (Rajagopalan and Brook 2012).

48
Longitudinal studies in humansInsulin
resistance and body weight
  • A long-term study of German children found that
    the traffic-related air pollutants NO2 and PM
    were associated with insulin resistance, as was
    proximity to the nearest major road (Thiering et
    al. 2013).
  • In adults, a longitudinal study of elderly
    Koreans found that PM10, O3, and NO2 were
    associated with insulin resistance, especially in
    people with a history of diabetes and who had
    certain genes (Kim and Hong 2012).

49
Exposure during development
  • Exposure to air pollutants in the womb is
    associated with reduced birth weight, as well as
    faster growth during infancy, as shown in a study
    from Massachusetts (Fleisch et al. 2015).
  • A study of New York City children found that
    those whose mothers were exposed to higher levels
    of polycyclic aromatic hydrocarbons (PAHs) during
    pregnancy had a greater risk of obesity at 5 and
    7 years of age (Rundle et al. 2012).
  • In Southern California, traffic pollution was
    associated with growth in BMI in children 5-11
    years of age (Jerrett et al. 2014).
  • These authors also found that both traffic
    pollution and smoking were associated with higher
    BMI in children, and that both exposures together
    increased the risk synergistically (McConnell et
    al. 2014).

50
Gestational diabetes
  • Malmqvist et al. (2013) found that exposure to
    nitrogen oxides (NOx) and high traffic density
    was associated with the development of
    gestational diabetes in a study from Sweden. The
    area studied experiences air pollution levels
    generally well below current World Health
    Organization (WHO) air quality guidelines.
  • The authors compare the risk of gestational
    diabetes due to air pollution to other risk
    factors among women born in Nordic countries,
    the association between the highest versus lowest
    exposure levels of NOx and gestational diabetes
    was comparable to the estimated effect of being
    overweight, but weaker than the estimated effect
    of being obese.
  • The authors also found an association between
    nitrogen oxide exposure and preeclampsia, a
    common complication in women with gestational
    diabetes.

51
Experimental studies in humans
  • Twenty five (25) healthy adults living in rural
    Michigan were brought to an urban location for
    4-5 hours over a few 5 day periods. They found
    that higher PM2.5 exposures were associated with
    increased insulin resistance, even at relatively
    low levels of exposure (Brook et al. 2013). This
    study supports the possibility that air pollution
    could cause diabetes

52
Cross-sectional studies in humansThere is
evidence that air pollution can increase insulin
resistance.
  • A study of Iranian children aged 10-18 found that
    children exposed to higher levels of air
    pollution had increased insulin resistance.
    Again, this study used geographic tools to
    measure air pollution exposures, using an overall
    index to show the combined effect of various air
    pollutants. Individually, particulate matter
    (PM10) and carbon monoxide (CO) were associated
    with increased insulin resistance. Markers of
    oxidative stress and inflammation were also
    higher in children exposed to higher levels of
    air pollution (Kelishadi et al. 2009).
  • A cross-sectional study of US children found that
    higher levels of urinary polycyclic aromatic
    hydrocarbon (PAH) metabolites were associated
    with higher body mass index (BMI), waist
    circumference, and obesity. In children aged
    6-11, the associations increased consistently as
    exposures increased, while in adolescents, the
    associations were still significant but less
    consistent (Scinicariello and Buser 2014). This
    association between PAHs and obesity in U.S.
    children holds true whether or not they were
    exposed to environmental tobacco smoke, but if
    they were, the risk of obesity is much higher
    (Kim et al. 2014). 
  • Indoor air particulate concentrations (associated
    with burning candles) have been linked to higher
    blood glucose levels (HbA1c) in Denmark (Karottki
    et al. 2014).

53
Diabetes management, complications, and
mortality
  • What if you have diabetes and you are exposed to
    air pollution?
  • Higher blood sugar
  • German adults newly diagnosed with type 2
    diabetes had higher HbA1c levels (a measurement
    of long term blood glucose control) if they lived
    in areas with higher levels of particulate matter
    (PM10) (Tamayo et al. 2014).
  • Higher cholesterol levels
  • An Iranian study found that adolescents exposed
    to higher levels of air pollution had higher
    fasting glucose levels, higher "bad" and total
    cholesterol, triglycerides, blood pressure, and
    lower "good" cholesterol than those exposed to
    lower levels of air pollution (Poursafa et al.
    2014).

54
Diabetes management, complications, and mortality
  • Higher mortality from diabetes
  • Three longitudinal studies have found that
    long-term exposure to traffic-related air
    pollution is associated with an increased risk of
    mortality from diabetes among U.S. Medicare
    participants (to PM2.5) (Zanobetti et al. 2014)
    in Denmark (to NO2) (Raaschou-Neilsen et al.
    2013) and in Canada (to PM2.5) (Brook et al.
    2013). The Canadian authors found that people
    with diabetes were more susceptible to the
    mortality-related effects of all air pollutants
    except ozone (Goldberg et al. 2013).
  • A North American study found deaths due to
    diabetes were associated with PM2.5 levels (as
    were deaths from hypertension and cardiovascular
    disease) (Pope et al. 2014).
  • A study from 10 European metropolitan areas also
    found that higher rates of mortality from
    diabetes were associated with PM exposure levels,
    especially during the warmer seasons (Samoli et
    al. 2014).
  • In China, higher NO2 and SO2 levels were
    associated with higher diabetes morbidity,
    especially in the cooler seasons and among
    females and the elderly (Tong et al. 2014).
  • A review and meta-analysis found that exposure to
    high levels of air pollutants is associated with
    an increased risk of diabetes-related mortality
    (Li et al. 2014).

55
Cardiovascular complications higher blood
pressure and heart complications
  • Numerous human studies show that people who have
    diabetes (type 1 or 2) are more susceptible to
    air-pollution induced cardiovascular
    complications and mortality (especially those
    with type 2) (Rajagopalan and Brook 2012).
  • For example, a long-term study of black women
    living in Los Angeles found that air pollution
    increased their risk of hypertension (high blood
    pressure) (in addition to their risk of diabetes)
    (Basile and Bloch, 2012).
  • In India, adults with diabetes exposed to high
    levels of air pollution have high levels of
    systemic inflammation, which could contribute to
    cardiovascular complications (Khafaie et al.
    2013).

56
Type 2 Diabetics and air pollution
  • An experimental study on humans exposed people
    with type 2 diabetes to very fine particulate
    matter, and found that their heart rate and heart
    rate variability increased (compared to people
    with type 2 who inhaled clean air), and that
    these changes persisted for many hours after the
    exposure ended (Vora et al. 2014). Endothelial
    dysfunction is also linked to air pollution in
    people with diabetes, and may help to explain the
    cardiovascular risks of exposure (Lanzinger et
    al. 2014).
  • Among people without diabetes, high blood
    pressure is also associated with air pollution,
    for example in a large-scale study from
    throughout Europe (Fuks et al. 2014). This study
    also found an increased risk for stroke with
    higher levels of air pollution (but still under
    legal limits) (Stafoggia et al. 2014), as well as
    an increased risk of coronary events (Cesaroni et
    al. 2014). Adults exposed to coarse particulate
    matter (PM2.5-10) air pollutants in an
    experimental study experienced higher blood
    pressure and heart rate (Morishita et al. 2014).
    Animal studies also show that air pollution
    (PM2.5) increases blood pressure (Ying et al.
    2014).
  • Obesity appears to worsen the cardiovascular
    health effects of air pollution (Weichenthal et
    al. 2014). When air quality improves, lung
    function also improves. Yet a study from
    Switzerland finds that this only holds true if
    those people are not overweight or obese
    (Schikowski et al. 2013). For an article
    describing this study, see Respiratory disparity?
    Obese people may not benefit from improved air
    quality, published in Environmental Health
    Perspectives (Potera 2013).

57
Other, complications
  • In addition to cardiovascular complications,
    other diabetes complications may also be linked
    to air pollution.
  • Air pollution, along with obesity, is a risk
    factor for non-alcoholic fatty liver disease
    (NAFLD), which is rapidly becoming a health
    problem even in children (Kelishadi and Poursafa,
    2011).
  • A study from Korea, meanwhile, found that people
    with diabetes who are exposed to air pollution
    were more likely to visit the hospital emergency
    room for depression (Cho et al. 2014

58
Diabetes medications and treatment
  • The type of medication someone with diabetes
    takes may also influence the effects of air
    pollution. Adults with type 2 diabetes who take
    insulin are more susceptible to the inflammatory
    effects of traffic-related air pollution than
    those who take only oral diabetes medications.
    The reason for this finding is not clear (Rioux
    et al. 2011).
  • Another study found that people with diabetes and
    those who do not use statins were more
    susceptible to the inflammatory effects of air
    pollution than others, while obesity did not make
    any difference (Alexeeff et al. 2011).
  • When exposed to higher levels of air pollutants,
    people undergoing kidney dialysis have more
    infections (Huang et al. 2014a), and more
    inflammation (Huang et al. 2014b).
  • Omega 3 fatty acids appear to reduce the cardiac
    and metabolic effects of air pollution (Tong et
    al. 2012).

59
The Four Stages Theory of PreventionWhat
conclusions may be drawn?
  • Pre-Primary Prevention is a scientifically valid
    category in the development of the theory and
    practice of the principles of prevention
  • It advances our knowledge and presents a valid
    framework for the prevention, management and
    maintenance of health and diseases as an
    integrated continuum.
  • It may be universally applied to all diseases and
    conditions in general and chronic diseases in
    particular including Diabetes Mellitus and renal
    disease
  • It advances contemporary knowledge in Public
    Health Theory and Practice?
  • This paradigm shift is of greater significance
    in contemporary Public Health Practice than the
    Leavell Clarke Three levels of Prevention
    Model or the 1948 definition of Health by the
    World Health Organisation?
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