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?