Transcript HSS4303B - Deonandan

HSS4303B
Introduction
To Epidemiology
Jan 7, 2010
“Epidemiologic Approaches”
Science of the Gods
HSS4303B
• Mondays 8:30AM-10:AM
• Thursdays 10:AM-11:30AM
• DMS1150
• *No* formal tutorials scheduled for this class
• But we may create some informal ones
Who We Be?
• Professor
– Dr Raywat Deonandan
– Templeton 111 x8377
– [email protected]
• Teaching Assistant
– Ms Erin Russell
– [email protected]
Please email
For appointments
Currently, no
regular office
hours
Everything You Need To Know
classes.deonandan.com/hss4303
If you have a question
about the class, please
check the website
before emailing us.
Marks, Marks, Marks
• Written assignment = 10%
• Midterm = 20%
• Poster = 25%
• Final exam = 45%
Written Assignment
• Abstract
– Very brief
– Test of your reading, research, writing abilities
– Test of your ability to follow instructions
– Instructions are already on the website
– Worth 10%
– Due 11:59pm on Jan 28
Midterm
• Currently scheduled for Feb 11 (though I
might move it to after Reading Week… stay
tuned)
– All multiple choice!
– Very similar to the one given to HSS4303A
Poster
• Your chance to play scientist!
– Test your ability to collaborate, research,
summarize and present
– Everyone will present on April 10
• HSS4303A, HSS4303B and even the French section
– Instructions will be uploaded to website real soon
– Worth 25%
Final Exam
• During Exam Period
– Current plan is to combine HSS4303A and
HSS4303B and give both sections the same exam
– This plan may change if the content diverges
– All multiple choice
– Sample questions will be uploaded to website
– Worth 45%
Textbooks?
The following books are recommended but not required.
In syllabus, readings refer to book #1.
1. Medical Epidemiology 4th Edition, by Greenberg et
al and published by McGraw Hills Publications.
($56.95 + tax at Agora Books)
2. Epidemiology, by Gordis L, published by Elsevier
Sauders. ($60.11 + tax at Agora Books)
The Rules of Raywat
1. If you don’t want to be here, don’t come
-you are not marked on attendance
-I’d rather you not come than to come and talk during
lectures
1. Don’t piss me off
-I *will* find a way to make you pay for it
Lecture Slides
• Slides are provided as a courtesy
• Be sure to take your own notes because one
day there might not be any slides (I’m tricky
like that)
Important Dates
•
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Jan 28 – written assignments are due!
Feb 11 – in-class midterm!
Feb 17-20 – Reading Week!
Mar 11 – submit your poster topic!
Apr 10 – poster presentations!
April 15 on – Exam period
Homework
• Previous years have had a mandatory tutorial
for working through computational problems
together
• This year, you’ll be given more take-home
assignments instead (will not be marked)
• We will try to arrange 1-2 optional tutorial
sessions before exams to go over the
problems
What Is Epidemiology?
• “The study of the distribution and
determinants of disease or health status in a
population”
– CDC
• The Science of the Gods!
– R. Deonandan
The Origin of Epidemiology
Dr John Snow
1854
Used non-medical
means to discover
source of cholera
outbreak
Shoe leather epidemiology
Figure 1-12 Photograph of John Snow. (From the
Wellcome Historical Medical Museum and Library,
London.)
Figure 1-13 A drop of Thames water, as depicted by Punch
in 1850. (From Extracts from Appendix (A) to the Report
of the General Board of Health on the Epidemic Cholera
of 1848 and 1849, published by HMSO, London, 1850. Int
J Epidemiol 31:900-907, 2002.)
Epidemiology Allowed “Miasmatic
Theory” to be Displaced
• Miasmatic theory
– Miasma was considered to be a poisonous vapor
or mist filled with particles from decomposed
matter (miasmata) that caused illnesses. It was
identifiable by its foul smell.
• Supplanted by “Germ theory”
– Most diseases caused by an infectious agent
Deaths from cholera and water theory
Water supply
# of
houses
Deaths
from
cholera
Deaths
per
10,000
houses
Southwark and Vauxhall
Co
40,046
1,263
315
Lambeth Co
26,107
98
38
Other districts in London
256,423
1,422
56
HSS4303: Introduction to epidemiology
Types of Epidemiologists
• Clinical Epidemiologist
• Public Health Epidemiologist
• Population Epidemiologist
The Face of Brilliance
Epidemiology In Pop Culture
Village of the Damned (1995)
Outbreak (1995)
Fringe (2009)
ReGenesis (2004)
Dr Deonandan?
I think not!
Some Terminology
• Clinical research or mathematical
relationships:
– Variable that predicts/causes an outcome is
independent variable
• Epidemiological research:
– Variable that may predict/cause an outcome is
exposure
Some Terminology
• Epidemiological research:
– Exposures that increase or decrease the
likelihood of developing certain disorders,
conditions or diseases are called risk factors
Eg, research has shown a strong statistical association between the
exposure of smoking and the outcome of having lung cancer  smoking
is therefore a risk factor for lung cancer.
Descriptive Studies
• A true “descriptive study” is an example of
“descriptive epidemiology”
– Who
– What
– Where
– When
Descriptive Study
• Who
– Students
• What
– Left handedness
• Where
– This class
• When
– Right now
Right now, 23% of students in
this class are left handed
Qualitative vs. Quantitative
Descriptive vs. Analytic
Who gets the disease?
When do they get it?
Where do they get it?
Case-control
Cohort
Cross-sectional
Observational vs. Experimental
Interventions
Clinical trials
What Is An Experiment?
From the internet: “the act of conducting a controlled
test or investigation”
For our purposes, an experiment differs from other
kinds of investigations in that the researcher
manipulates something.
EXPERIMENTAL STUDY
Historical Triumphs of Epidemiology
Smallpox
The global eradication of smallpox was
certified, based on intense verification
activities in countries, by a commission of
eminent scientists on 9 December 1979 and
subsequently endorsed by the World Health
Assembly on 8 May 1980
-“Resolution WHA33.3”
In 1975, two year old
Rahima Banu contracted
last known case of
naturally-occurring variola
major Smallpox. Wikipedia
“You have erased from the calendar
of human afflictions one of its
greatest. Yours is the comfortable
reflection that mankind can never
forget that you have lived. Future
nations will know by history only
that the loathsome smallpox has
existed.”
-Thomas Jefferson to Edward Jenner, 1806
– 400,000 people died each year in the late 18th
century
– 1/3 of the survivors became blind
– Survivors also developed immunity to smallpox
– Efforts to prevent smallpox
• Variolation
– Edward Jenner took interest in cowpox to find
solutions in the prevention of smallpox
– WHO and eradication of smallpox
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In 1967 WHO began the eradication program
15 million people developed smallpox annually
2 million people died
In 1980 smallpox was “eradicated”
Global eradication was possible
because of…
Herd immunity
More Triumphs of Epidemiology
Before HIV was known to cause AIDS
• We knew it involved the “3 H’s”
– Homosexuals
– Haemophiliacs
– Haitians
• Epidemiologists figured out:
– It was bloodborne
– It was probably a virus
Observational epidemiology
• Many a times we do not know the cause of disease but we
can associate it with certain exposures
– Streptococcal infection follows rheumatic fever and rheumatic heart
disease
– Rheumatic fever is more frequent in army recruits than in school
children
• Lung cancer and smoking
• Epidemiology based on observational data leads us to
understand the association between the morbidity and
mortality from a disease and certain exposures, habits,
lifestyle choices
Where Do Epidemiologists Work?
•
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Universities (ahem)
Government
Public health agencies
Drug companies
Hospitals (MDs)
Private companies
What Are Some Of The Things That
Epidemiologists Do?
Breast and lung cancer mortality in
Canada
35
30
25
20
1993
1994
1995
lung cancer
1996
breast cancer
1997
Prevention and therapy
• Prevention is integral to public health and also to clinical
practice
• In clinical practice therapy is used to prevent complications,
disability and death
• Prevention in public health is primary prevention
• Prevention in clinical practice is
– Secondary prevention (minimize disease complications)
– Tertiary prevention (minimize disability)
• Epidemiology is the basis for effective prevention programs
Diagnostic tests: false positive and false negative tests are used
to assess sensitivity and specificity
Disease prognosis and changes in therapeutic regimens
Disease surveillance
• Monitoring the patterns of occurrence of a disease within a
population is referred to as _____________.
• There are many potential benefits from the collection of
surveillance data:
– (1) can help to identify the new outbreak of an illness, such as AIDS,
– (2) can provide clues, by considering the population groups that are
most affected by the illness, to possible causes of the condition,
– (3) can be used to suggest strategies to control or prevent the spread
of disease,
– (4) can be used to measure the impact of disease prevention and
control efforts, and finally,
– (5) can provide information on the burden of illness, data that are
necessary for determining health and medical service needs
Trend
Analysis
Figure 1-14 Breast versus lung cancer mortality: white females versus black
females, United States, 1973-1995, age-adjusted to 1970 standard. (From Ries
LAG, Kosary CL, Hankey BF, Miller BA, Edwards BK [eds]: SEER Cancer Statistics
Review, 1973-1995. Bethesda, MD, National Cancer Institute, 1998.)