Transcript 1-Epidemiology

‫بسم هللا الرحمن الرحیم‬
‫اپیدمیولوژی و کاربردهای آن‬
‫دکتر حسین صافی زاده‬
‫بهمن ‪1389‬‬
‫منبع ‪ :‬درسنامه پزشکی پیشگیری و اجتماعی‪ ،‬پارک‪ ،‬جلد اول‪ ،‬فصل دوم‬
‫اهداف درس‬
‫‪ ‬انتظار می رود شما با مطالعه این درس‪:‬‬
‫‪ ‬تاریخچه اپیدمیولوژی را توضیح دهید‪.‬‬
‫‪ ‬اپیدمیولوژی را تعریف نمایید‪.‬‬
‫‪ ‬اجزاء تعریف اپیدمیولوژی (فراوانی بیماری‪ ،‬توزیع بیماری‬
‫و عوامل تعیین کننده بیماری) را توضیح دهید‪.‬‬
‫‪ ‬اهداف علم اپیدمیولوژی را بیان نمایید‪.‬‬
‫‪ ‬کاربردهای علم اپیدمیولوژی را توضیح دهید‪.‬‬
‫سئوال ؟‬
‫‪ ‬امروزه همواره در جوامع انسانی مسائلی رخ می دهند که با سالمت‬
‫انسان سر و کار دارد و سئواالتی در زمینه های مختلف برای ما ایجاد‬
‫می شود‪:‬‬
‫‪ ‬چه هنگام اپیدمی بعدی آنفلوانزا مورد انتظار است؟‬
‫‪ ‬چرا امروزه بیماری های عروق قلب زیاد شده اند؟‬
‫‪ ‬چگونه به بهترین شکل می توان از سرطانه گردن رحم پیشگیری کرد؟‬
‫‪ ‬آیا واکسن های طراحی شده برای پیشگیری از سالک کارایی دارند؟‬
‫‪ ‬بعد از گذشت ‪ 30‬سال از پیدایش ایدز در دنیا وضعیت فعلی آن چگونه‬
‫است؟ راه انتقال عمده آن در جوامع مختلف کدام است؟‬
‫‪ ‬چگونه می توان از اثربخشی یک داروی جدید در درمان دیابت مطمئن‬
‫شد؟‬
‫‪ ‬افراد سالم چند بار باید چکاپ طبی شوند و این چکاپ ها باید شامل چه‬
‫آزمایش ها و معایناتی باشند؟‬
Epidemiology
Epi
Demos
Logus
Historical Perspective
 Before 1850- Informal epidemiologic methods existed, but
there was no separate discipline of epidemiology
 Hippocrates (about 400 B.C.E.)
Association between external environment and
personal characteristics and health
Historical Perspective
 John Graunt (1662)
Analyzed birth and deaths in london
 Excess of males born
 Infant mortality is very high
 Seasonal variation for mortality
 William Farr (1839)
Examined mortality and occupation and marital
status
 John Snow (1853)
Cholera epidemic in london
Cholera Epidemic: London 1840s
 Incidence of cholera was 86 per 10,000 households
 1849 – Outbreak of cholera in London
 Snow investigates this outbreak and proposes link
between the ‘cholera poison’ and exposure to
contaminated water
 Unable to support his theory with evidence
 Prevailing belief that cholera was caused by bad vapors
Cholera Epidemic : London 1854
 Large epidemic of cholera
 SoHo and Golden Square district, on Broad Street,
especially hard hit
 500 deaths due to cholera during 10 day period in one
summer.
 Many people left London
 John Snow investigated the outbreak
John Snow (1813-1858)
Snow’s Investigation
 Cholera was a well defined clinical entity characterized
by voluminous diarrhea
 Recovery depended on the severity of
disease
 Developed detailed maps and tables of the occurrence of
cases
John Snow Maps of Cholera in London, 1854
The Thames River and Sources of
Water for London
Lambeth
Company
Southwark
And Vauxhall
Company
Snow’s hypothesis: water source determined risk for cholera
Cholera in London by Water Company
Water Supply
No.
Cholera
Houses Deaths
Southwark
and Vauxhall
40,046
1,263
315
Lambeth
26,107
98
38
1,422
56
Other London 256,423
districts
Deaths
/10,000 Houses
Snow’s Investigation
 Public Health Implications
 Pump handle removed from the
Broad Street pump
 Number of cholera cases dropped
dramatically
Epidemiology
 Study of patterns of disease occurrence in
human Populations.
 Observation of disease under natural
conditions in Population as a whole rather
than of individuals.
Epidemiology
Purpose : 
To study the characteristics of those people within a
community (Population) who have a particular
illness / condition / problem as compared to those
without to try to understand :
 Probable cause
 Find a cure
 Prevent reoccurrence
 Prevention
Epidemiology (Definition)
Narrow :
Study of distribution , frequency &
determinants of diseases in human population
Broad :
 Study of distribution , frequency &
determinants of health-related states or events in
specified populations and
 Application of this study to control of health
problems
Epidemiology (Definition)
Narrow :
Study of distribution , frequency &
determinants of diseases in human population
Broad :
 Study of distribution , frequency &
determinants of health-related states or events in
specified populations and
 Application of this study to control of health
problems
Epidemiology Components
Frequency :
 Quantification of existence (prevalence) or
occurrence (incidence) of Diseases; Disability & Death
 Measurements of health states & events in community
Distribution :
 Who is getting the disease? Where? When?
Determinants :
 Factors associated with health state; causal factors
Epidemiology (Objectives)
1.
2.
3.
4.
Identify etiology and risk factors
Determine extent of disease
Study natural history & prognosis
Evaluate existing or new prevention or
intervention strategies
5. Provide foundation for public policy decision
Basic questions in Epidemiology
1.
2.
3.
4.
5.
6.
7.
How much disease is out there?
Who is getting the disease?
Where is the disease occurring?
When is the disease occurring?
Why is the disease occurring?
What is the course of disease?
How can we prevent / treat the disease?
‫خسته نباشید‪.‬‬
‫گلهای آفتابگردان‬
‫اثر‪ :‬وینسنت ون گوک‬
‫محل نگهداری‪ :‬لندن‪ ،‬گالری ملی‪1888 ،‬‬