HSS1101E Determinants of Health

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HSS1101E Determinants of Health

• Jan 12, 2009 - Definition of health, illness,
  disease and disability

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From the readings
John Last defines six domains for generic
determinants of health

• Inherent or genetic
• Environmental exposures
• Biological factors
• Social circumstances
• Behavioural patterns
• Medical care

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1. Innate/Genetic Determinants

• Biological predispositions to disease (e.g., Tay
  Sachs disease), usually linked to a gene
• Personal/innate characteristics typically found
  on medical record sheets (age, sex, race)

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2. Environmental Determinants

• Radiation
• Noise
• Heat/Cold
• Pollution
• Chemicals/Fabrics/Fibres
• Humidity/Aridity

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3. Biological Determinants

• Infectious disease pathogens
• Viruses
• Bacteria
• Fungi
• Prions
• Immune responses

How about if youre eaten by a tiger? How about
Walkerton?
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4. Behavioural Determinants

• Dietary factors
• Physical exercise
• Sexual behaviours
• Tobacco drugs
• Self-harm?

What if you decide to eat a peanut youre
allergic to?
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5. Social Determinants

• Poverty
• Education
• Peer groups
• Family/work/social stress

Is culture a social determinant?
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6. Medical Care Determinants

• Is medical care available?
• Prevention
• Treatment

If you live in the USA and cant afford health
insurance, is that a medical care determinant or
a social one?
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Is Anything Missing From This List?

• Inherent or genetic
• Environmental exposures
• Biological factors
• Social circumstances
• Behavioural patterns
• Medical care

7. Healthy child development 8. Work conditions
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Example FTO gene

• Does having the FTO gene imply that obesity is
  determined by genetic (innate) factors or by
  behavioural factors?

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Example Tuberculosis

• Mycobacterium Tuberculosis
• People with the disease cough and release aerosol
  droplets into the air
• Healthy people inhale the droplets and become
  infected
• Bacteria infect the alveolar tissue of the lungs
• Only 10 of infection cases actually lead to TB
  disease (coughing, pain, fever, etc) 90 remain
  latent
• 50 of untreated cases of TB disease lead to death

So what causes TB?
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Some More TB Facts

• Its the biggest killer of people with HIV/AIDS
• 2 billion people have latent TB right now
• In Canada, 65 of all cases are immigrants
• There is medication to prevent latent TB from
  becoming active TB disease
• Active TB disease can be cured through D.O.T.S.

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Who Gets TB?

• Those living near other people with TB
• In poor countries, in poor neighbourhoods
• Those living in very close proximity
• Multi-family dwellings
• Prisons
• The physiologically vulnerable
• HIV/AIDS patients
• malnourished

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Therefore, What Are TBs Determinants?

• SES ?
• Geography ?
• Occupation ?
• Diet ?
• Age ?
• Race ?
• Access to medical care ?

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From one of the readings
Community
Indiv.
Community
Community
Indiv.
Indiv.
Community
Community
Indiv.
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Be Aware of Interactions

• Women have more social support than do men (86
  vs 80)
• Children have less social support than
  adolescents, who have more social support than
  older adults
• Men are more likely to have less healthy work
  environments

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Healthy Childhood

• A healthy childhood is a predictor of many health
  conditions later in life
• Premature and low birthweight babies are more
  likely to have
• Neurological disease
• Congenital abnormalities
• Cognitive issues
• Perinatal health is correlated with mothers SES
  and health status

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Question What Are Determinants of Obesity in
Canada?

• Age
• Activity
• SES
• Diabetes
• Geography
• Occupation
• Peer groups

Disability
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What Is Disability?

• Lack of ability relative to a norm
• What is the problem with this definition?

Normal is a wide spectrum that varies with age,
sex, degree of accommodation and other factors.
Am I disabled if I wear glasses?
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Types of Disability

• Physical impairment
• Sensory impairment
• Cognitive/intellectual impairment
• Mental disorder
• Various types of chronic disease

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Medical Model of Disability

• Focus is on the individual disabled person and
  how his situation could be improved
• Disability is the result of a medical condition
• Accommodation is based on addressing the medical
  condition
• Prosthetic limbs
• Cochlear impants

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Social Model of Disability

• Focuses on the context of the individual in
  society as the defining principle of disability
• Barriers and exclusion are what define who is
  disabled and who is normal
• Address disabilities by making society redefine
  itself to accommodate
• Making buildings accessible
• Making TV shows close-captioned

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Why Is It Important to Distinguish Between The
Two Models?

• Philosophy will determine how we approach
  disabilities
• In the UK, they deliberately define disability
  according to the Medical Model
• In the USA, they deliberately define according to
  the Social Model
• Medical model sees disabled people as an economic
  drain
• Social model sees disabled people as an economic
  opportunity

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Disability Rate by Age and Sex in Canada, 2001
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Prevalence of Disability Types in Canada, 2001
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Some Facts about Disability in Canada

• Men more likely than women to be limited by
  memory problems
• Mobility problems more common among women 65 and
  over
• Disability related to mobility affects the
  greatest number of adults
• Activity limitations related to emotional,
  psychological or psychiatric conditions are
  relatively frequent in persons aged 45 to 64
• A large majority of persons with disabilities
  aged 15 and over have more than one disability

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Disability Affects How We Think About Health
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Life Expectancy
Life expectancy in the USA, stolen from
www.imminst.org
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Life Expectancy
Whats the problem with using life expectancy as
a gauge of population health?

• More ill-health and disabilities, and greater
  suffering?
• Longer period of life in good health?
• Does long life productive life? ?economics
• Some have proposed using healthy life
  expectancy or HLE (meanwhile, TLEtotal life
  expectancy)
• The expected number of years to be spent in good
  health
• Need to weight different disabilities based on
  severity

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Traditional Indicators in Pop Health
QALYs

• Quality Adjusted Life Years
• www.jr2.ox.ac.uk/bandolier/booth/glossary/QALY.htm
  
• Used to measure both the quality and quantity of
  life years lived as a result of a medical
  intervention
• QALY (year lived) x (index)
• Index 0 ? 1
• 0 death, 1 perfect health
• E.g., new heart valve saves your life, but
  hinders your quality of life

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Traditional Indicators in Pop Health
DALE

• Disability Adjusted Life Expectancy
• Measure life expectancy in a population,
  shortened to account for quality years lost due
  to disability
• Eg Japan has one of the worlds highest life
  expectancies 81.3 years, computed at birth
• But DALE in Japan is 74.5 years!

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Traditional Indicators in Pop Health
DALYs

• Disability Adjusted Life Year invented in 1996
• Measure of overall disease burden in a population
• www.who.int/healthinfo/boddaly
• A DALY is considered a bad thing
• The number of years of productive life lost in a
  population due to both death and disability

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The Value of DALYs

• Now that we can include a measure of suffering,
  non-lethal diseases begin to take on prominence
• According to WHO, by 2020 the 2nd most costly
  disease in the world, in terms of DALYs, will be

DEPRESSION
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Announcements

• Next class (Jan 15), no readings required
• Jan 19 Alan Rock will speak at HSS4331,
  followed by an event at HSS offices on Templeton
• Jan 26 class is cancelled. Instead, I will send
  you an online video to watch.