Overviews non-parametric and parametric approaches to (bivariate) linear correlation. See also: http://en.wikiversity.org/wiki/Survey_research_and_design_in_psychology/Lectures/Correlation
Part 1 of the Epidemiology Exercises for the Practical Exam in the subject of Social and Preventive Medicine at Shadan Institute of Medical Sciences
Covering Questions 1 to 10 along with their detailed answers
Declining sex ratio is a great concern as it create the imbalance in the society which might be irreversible for many more decades. This PPT Presentation highlighted the issue of declined sex ratio and its impact .
Overviews non-parametric and parametric approaches to (bivariate) linear correlation. See also: http://en.wikiversity.org/wiki/Survey_research_and_design_in_psychology/Lectures/Correlation
Part 1 of the Epidemiology Exercises for the Practical Exam in the subject of Social and Preventive Medicine at Shadan Institute of Medical Sciences
Covering Questions 1 to 10 along with their detailed answers
Declining sex ratio is a great concern as it create the imbalance in the society which might be irreversible for many more decades. This PPT Presentation highlighted the issue of declined sex ratio and its impact .
Epidemiology of chronic non communicable diseases.pptxRomy Markose
Epidemiology of chronic non communicable diseases is the 5th unit in community health nursing subject of 2nd year BSc Nursing students according to their curriculum. this ppt helps to understand regarding the condition, etiological factors, risk factors, signs & symptoms, management at each health care level & prevention.
An overview of a key statistical technique in epidemiology – standardization - is introduced. The process and application of both direct and indirect standardization in improving the validity of comparisons between populations are described.
Application of a test or a procedure to large number of population who have no symptoms of a particular disease for the purpose of determining their likelihood of having the disease.
Incidence (Epidemiology lecture)
short ppt to understand incidence. primary incidence rate, secondary incidence rate, incidence rate, examples of incidence, incidence rate related question are discussed in this lec.
Epidemiology of chronic non communicable diseases.pptxRomy Markose
Epidemiology of chronic non communicable diseases is the 5th unit in community health nursing subject of 2nd year BSc Nursing students according to their curriculum. this ppt helps to understand regarding the condition, etiological factors, risk factors, signs & symptoms, management at each health care level & prevention.
An overview of a key statistical technique in epidemiology – standardization - is introduced. The process and application of both direct and indirect standardization in improving the validity of comparisons between populations are described.
Application of a test or a procedure to large number of population who have no symptoms of a particular disease for the purpose of determining their likelihood of having the disease.
Incidence (Epidemiology lecture)
short ppt to understand incidence. primary incidence rate, secondary incidence rate, incidence rate, examples of incidence, incidence rate related question are discussed in this lec.
Epidemiology is the study and analysis of the patterns, causes, and effects of health, disease & production conditions in defined populations, in terms of space and temporality.
New Drug Discovery and Development .....NEHA GUPTA
The "New Drug Discovery and Development" process involves the identification, design, testing, and manufacturing of novel pharmaceutical compounds with the aim of introducing new and improved treatments for various medical conditions. This comprehensive endeavor encompasses various stages, including target identification, preclinical studies, clinical trials, regulatory approval, and post-market surveillance. It involves multidisciplinary collaboration among scientists, researchers, clinicians, regulatory experts, and pharmaceutical companies to bring innovative therapies to market and address unmet medical needs.
Lung Cancer: Artificial Intelligence, Synergetics, Complex System Analysis, S...Oleg Kshivets
RESULTS: Overall life span (LS) was 2252.1±1742.5 days and cumulative 5-year survival (5YS) reached 73.2%, 10 years – 64.8%, 20 years – 42.5%. 513 LCP lived more than 5 years (LS=3124.6±1525.6 days), 148 LCP – more than 10 years (LS=5054.4±1504.1 days).199 LCP died because of LC (LS=562.7±374.5 days). 5YS of LCP after bi/lobectomies was significantly superior in comparison with LCP after pneumonectomies (78.1% vs.63.7%, P=0.00001 by log-rank test). AT significantly improved 5YS (66.3% vs. 34.8%) (P=0.00000 by log-rank test) only for LCP with N1-2. Cox modeling displayed that 5YS of LCP significantly depended on: phase transition (PT) early-invasive LC in terms of synergetics, PT N0—N12, cell ratio factors (ratio between cancer cells- CC and blood cells subpopulations), G1-3, histology, glucose, AT, blood cell circuit, prothrombin index, heparin tolerance, recalcification time (P=0.000-0.038). Neural networks, genetic algorithm selection and bootstrap simulation revealed relationships between 5YS and PT early-invasive LC (rank=1), PT N0—N12 (rank=2), thrombocytes/CC (3), erythrocytes/CC (4), eosinophils/CC (5), healthy cells/CC (6), lymphocytes/CC (7), segmented neutrophils/CC (8), stick neutrophils/CC (9), monocytes/CC (10); leucocytes/CC (11). Correct prediction of 5YS was 100% by neural networks computing (area under ROC curve=1.0; error=0.0).
CONCLUSIONS: 5YS of LCP after radical procedures significantly depended on: 1) PT early-invasive cancer; 2) PT N0--N12; 3) cell ratio factors; 4) blood cell circuit; 5) biochemical factors; 6) hemostasis system; 7) AT; 8) LC characteristics; 9) LC cell dynamics; 10) surgery type: lobectomy/pneumonectomy; 11) anthropometric data. Optimal diagnosis and treatment strategies for LC are: 1) screening and early detection of LC; 2) availability of experienced thoracic surgeons because of complexity of radical procedures; 3) aggressive en block surgery and adequate lymph node dissection for completeness; 4) precise prediction; 5) adjuvant chemoimmunoradiotherapy for LCP with unfavorable prognosis.
New Directions in Targeted Therapeutic Approaches for Older Adults With Mantl...i3 Health
i3 Health is pleased to make the speaker slides from this activity available for use as a non-accredited self-study or teaching resource.
This slide deck presented by Dr. Kami Maddocks, Professor-Clinical in the Division of Hematology and
Associate Division Director for Ambulatory Operations
The Ohio State University Comprehensive Cancer Center, will provide insight into new directions in targeted therapeutic approaches for older adults with mantle cell lymphoma.
STATEMENT OF NEED
Mantle cell lymphoma (MCL) is a rare, aggressive B-cell non-Hodgkin lymphoma (NHL) accounting for 5% to 7% of all lymphomas. Its prognosis ranges from indolent disease that does not require treatment for years to very aggressive disease, which is associated with poor survival (Silkenstedt et al, 2021). Typically, MCL is diagnosed at advanced stage and in older patients who cannot tolerate intensive therapy (NCCN, 2022). Although recent advances have slightly increased remission rates, recurrence and relapse remain very common, leading to a median overall survival between 3 and 6 years (LLS, 2021). Though there are several effective options, progress is still needed towards establishing an accepted frontline approach for MCL (Castellino et al, 2022). Treatment selection and management of MCL are complicated by the heterogeneity of prognosis, advanced age and comorbidities of patients, and lack of an established standard approach for treatment, making it vital that clinicians be familiar with the latest research and advances in this area. In this activity chaired by Michael Wang, MD, Professor in the Department of Lymphoma & Myeloma at MD Anderson Cancer Center, expert faculty will discuss prognostic factors informing treatment, the promising results of recent trials in new therapeutic approaches, and the implications of treatment resistance in therapeutic selection for MCL.
Target Audience
Hematology/oncology fellows, attending faculty, and other health care professionals involved in the treatment of patients with mantle cell lymphoma (MCL).
Learning Objectives
1.) Identify clinical and biological prognostic factors that can guide treatment decision making for older adults with MCL
2.) Evaluate emerging data on targeted therapeutic approaches for treatment-naive and relapsed/refractory MCL and their applicability to older adults
3.) Assess mechanisms of resistance to targeted therapies for MCL and their implications for treatment selection
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Title: Sense of Smell
Presenter: Dr. Faiza, Assistant Professor of Physiology
Qualifications:
MBBS (Best Graduate, AIMC Lahore)
FCPS Physiology
ICMT, CHPE, DHPE (STMU)
MPH (GC University, Faisalabad)
MBA (Virtual University of Pakistan)
Learning Objectives:
Describe the primary categories of smells and the concept of odor blindness.
Explain the structure and location of the olfactory membrane and mucosa, including the types and roles of cells involved in olfaction.
Describe the pathway and mechanisms of olfactory signal transmission from the olfactory receptors to the brain.
Illustrate the biochemical cascade triggered by odorant binding to olfactory receptors, including the role of G-proteins and second messengers in generating an action potential.
Identify different types of olfactory disorders such as anosmia, hyposmia, hyperosmia, and dysosmia, including their potential causes.
Key Topics:
Olfactory Genes:
3% of the human genome accounts for olfactory genes.
400 genes for odorant receptors.
Olfactory Membrane:
Located in the superior part of the nasal cavity.
Medially: Folds downward along the superior septum.
Laterally: Folds over the superior turbinate and upper surface of the middle turbinate.
Total surface area: 5-10 square centimeters.
Olfactory Mucosa:
Olfactory Cells: Bipolar nerve cells derived from the CNS (100 million), with 4-25 olfactory cilia per cell.
Sustentacular Cells: Produce mucus and maintain ionic and molecular environment.
Basal Cells: Replace worn-out olfactory cells with an average lifespan of 1-2 months.
Bowman’s Gland: Secretes mucus.
Stimulation of Olfactory Cells:
Odorant dissolves in mucus and attaches to receptors on olfactory cilia.
Involves a cascade effect through G-proteins and second messengers, leading to depolarization and action potential generation in the olfactory nerve.
Quality of a Good Odorant:
Small (3-20 Carbon atoms), volatile, water-soluble, and lipid-soluble.
Facilitated by odorant-binding proteins in mucus.
Membrane Potential and Action Potential:
Resting membrane potential: -55mV.
Action potential frequency in the olfactory nerve increases with odorant strength.
Adaptation Towards the Sense of Smell:
Rapid adaptation within the first second, with further slow adaptation.
Psychological adaptation greater than receptor adaptation, involving feedback inhibition from the central nervous system.
Primary Sensations of Smell:
Camphoraceous, Musky, Floral, Pepperminty, Ethereal, Pungent, Putrid.
Odor Detection Threshold:
Examples: Hydrogen sulfide (0.0005 ppm), Methyl-mercaptan (0.002 ppm).
Some toxic substances are odorless at lethal concentrations.
Characteristics of Smell:
Odor blindness for single substances due to lack of appropriate receptor protein.
Behavioral and emotional influences of smell.
Transmission of Olfactory Signals:
From olfactory cells to glomeruli in the olfactory bulb, involving lateral inhibition.
Primitive, less old, and new olfactory systems with different path
TEST BANK for Operations Management, 14th Edition by William J. Stevenson, Ve...kevinkariuki227
TEST BANK for Operations Management, 14th Edition by William J. Stevenson, Verified Chapters 1 - 19, Complete Newest Version.pdf
TEST BANK for Operations Management, 14th Edition by William J. Stevenson, Verified Chapters 1 - 19, Complete Newest Version.pdf
MANAGEMENT OF ATRIOVENTRICULAR CONDUCTION BLOCK.pdfJim Jacob Roy
Cardiac conduction defects can occur due to various causes.
Atrioventricular conduction blocks ( AV blocks ) are classified into 3 types.
This document describes the acute management of AV block.
Basavarajeeyam is an important text for ayurvedic physician belonging to andhra pradehs. It is a popular compendium in various parts of our country as well as in andhra pradesh. The content of the text was presented in sanskrit and telugu language (Bilingual). One of the most famous book in ayurvedic pharmaceutics and therapeutics. This book contains 25 chapters called as prakaranas. Many rasaoushadis were explained, pioneer of dhatu druti, nadi pareeksha, mutra pareeksha etc. Belongs to the period of 15-16 century. New diseases like upadamsha, phiranga rogas are explained.
Explore natural remedies for syphilis treatment in Singapore. Discover alternative therapies, herbal remedies, and lifestyle changes that may complement conventional treatments. Learn about holistic approaches to managing syphilis symptoms and supporting overall health.
Tom Selleck Health: A Comprehensive Look at the Iconic Actor’s Wellness Journeygreendigital
Tom Selleck, an enduring figure in Hollywood. has captivated audiences for decades with his rugged charm, iconic moustache. and memorable roles in television and film. From his breakout role as Thomas Magnum in Magnum P.I. to his current portrayal of Frank Reagan in Blue Bloods. Selleck's career has spanned over 50 years. But beyond his professional achievements. fans have often been curious about Tom Selleck Health. especially as he has aged in the public eye.
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Introduction
Many have been interested in Tom Selleck health. not only because of his enduring presence on screen but also because of the challenges. and lifestyle choices he has faced and made over the years. This article delves into the various aspects of Tom Selleck health. exploring his fitness regimen, diet, mental health. and the challenges he has encountered as he ages. We'll look at how he maintains his well-being. the health issues he has faced, and his approach to ageing .
Early Life and Career
Childhood and Athletic Beginnings
Tom Selleck was born on January 29, 1945, in Detroit, Michigan, and grew up in Sherman Oaks, California. From an early age, he was involved in sports, particularly basketball. which played a significant role in his physical development. His athletic pursuits continued into college. where he attended the University of Southern California (USC) on a basketball scholarship. This early involvement in sports laid a strong foundation for his physical health and disciplined lifestyle.
Transition to Acting
Selleck's transition from an athlete to an actor came with its physical demands. His first significant role in "Magnum P.I." required him to perform various stunts and maintain a fit appearance. This role, which he played from 1980 to 1988. necessitated a rigorous fitness routine to meet the show's demands. setting the stage for his long-term commitment to health and wellness.
Fitness Regimen
Workout Routine
Tom Selleck health and fitness regimen has evolved. adapting to his changing roles and age. During his "Magnum, P.I." days. Selleck's workouts were intense and focused on building and maintaining muscle mass. His routine included weightlifting, cardiovascular exercises. and specific training for the stunts he performed on the show.
Selleck adjusted his fitness routine as he aged to suit his body's needs. Today, his workouts focus on maintaining flexibility, strength, and cardiovascular health. He incorporates low-impact exercises such as swimming, walking, and light weightlifting. This balanced approach helps him stay fit without putting undue strain on his joints and muscles.
Importance of Flexibility and Mobility
In recent years, Selleck has emphasized the importance of flexibility and mobility in his fitness regimen. Understanding the natural decline in muscle mass and joint flexibility with age. he includes stretching and yoga in his routine. These practices help prevent injuries, improve posture, and maintain mobilit
Knee anatomy and clinical tests 2024.pdfvimalpl1234
This includes all relevant anatomy and clinical tests compiled from standard textbooks, Campbell,netter etc..It is comprehensive and best suited for orthopaedicians and orthopaedic residents.
- Video recording of this lecture in English language: https://youtu.be/lK81BzxMqdo
- Video recording of this lecture in Arabic language: https://youtu.be/Ve4P0COk9OI
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3. Introduction
• Epidemiology : ( comes from a Greek epidemic
meaning upon the people)
“Epi” –among, “demio”-population, “logy”-
study.
• The study of distribution and determinants of
health related states or events in specified
populations and the application of this study
to the prevention and control of health
problems.
5. Distribution: Time, Place, Person
Determinants: Causes or risk factors
Frequency: Incidence, Prevalence
6. Distribution of disease:
Time- seasonal(e.g.URTI in winter)
Place- geographical( Kala azar in UP,BIHAR,WB
Person- age(measles in 6month to 3 years, RF
in 5to 15 years, cataract in>55yrs)
-sex (migrain, DM in females, RTA in
males)
7. Epidemiological Purposes in Public
Health Practice
• Discover the agent, host and environmental
factors that affect health.
• Determine the relative importance of causes
(risk factors) of illness, disability and death.
• Evaluate the effectiveness of health programs
and services in improving population health.
9. Epidemiological Studies
1) Observational studies : The investigator
measures but do not intervene.
Descriptive study :
• It is a first step in an Epidemiological Studies.
• Defining the population(Unit of study is entire
population)
• Defining the disease (Inclusion , exclusion and
diagnostic criteria)
• Description of the occurrence of a disease in a
population in terms of time, place ,person.
10. • Measurements of disease.
• Comparing with known indices.
• This study helps to generate the hypothesis.
(Hypothesis: It is a logical supposition, a
reasonable guess. Assumption without proof)
11. Analytical study :
• Second major type
• This study analyses the relationship between
health status and other variables.
• Unit of study is individual.
• This study helps to test the hypothesis.
12. 2) Experimental study : aka Intervention study
• This study confirm the hypothesis.
• It involves an active attempt to change a
disease determinant such as an exposure or a
behaviour or the progress of a disease
through treatment.
• These studies are similar in design to
experiments in other sciences.
13. 1)CROSS SECTIONAL STUDY
• Aka prevalence study.
• It is simplest form of an observational study.
• Unit of study is individual.
• It is based on a single examination of cross
section of population at one point in time so
the results of which can be projected on
whole population.
14. • In this study, measurements of exposure and
effects(outcome) are made at the same time,
so this study is useful for investigating the
casual association.
• Study is similar to a survey in such a way that,
it provides a snapshot of the population at a
point in time. So also called as snap chat
study.
--(Ruspini,2002)
15. • Using this study, the epidemiologist defines
the target population, then collects data from
the population or a subset of the population
at one specific point in time.
• Participants are selected regardless of their
exposure or disease status.
• This study useful in sudden outbreak of
disease and for chronic diseases.
16. Cross sectional study continued……..
• For example ,in a study of prevalence of
hypertension, we collect data during survey
about age, gender, body weight, physical
exercise, salt intake and other variables.
• Study helps in assessing load of disease, needs,
resources, patterns of health utilization,
practices and knowledge attitudes.
• This study tells us about the distribution of a
disease in a population rather than its etiology.
17. Advantages
• Relatively quick and easy to conduct, no follow
up.
• Data related to all variables is collected at
once.
• Study includes multiple outcomes and
exposures.
• It is a best way to understand disease load and
plan health services.
• Generation of hypothesis.
18. Disadvantages
• It is difficult to find out whether the outcome
followed exposure in time or it is resulted due to
outcome.
• Not suitable for rare disease or disease with
shorter duration.
• Study measures prevalent cases( new and old
cases) rather than incident cases so we can’t
measure incidence.
• The associations obtained in this study would be
difficult to interpret.
19. 2)CASE CONTROL STUDY
• Aka case referent or retrospective study.
• This is the first approach to test a casual
hypothesis.
• Study Disease > Risk factor ( Backward looking)
as the Investigator is looking backwards from the
disease to a possible cause.
• In this study, subjects are selected on the basis of
whether they do (cases) or do not (controls) have
the disease.
• The groups are compared with respect to the
proportion having a history of an exposure .
20. Framework of case control study
Suspected or risk
factors(Smoking)
Cases (Lung Cancer) Controls (No lung
Cancer)
Present a b
Absent c d
Total a+c b+d
21. Steps in Case Control Study
1) Selection of Case – A case is someone who has
disease under investigation.
• It should be objective in nature and should be followed
meticulously throughout the study.
• Cases should represent a specified population group on
the basis of disease, not exposure. For this one needs
diagnostic criteria of that particular disease and also
stage of the disease
• The Second criteria is related to eligibility. The old
cases or cases that have advanced stage of the disease
may not be eligible for inclusion in the study.
22. • Sources of cases :
1. Hospitals: From a single hospital or network
of hospitals either case series or a random
sample, admitted during a specified period of
time. ( convenient)
2. General population: selected in a
geographical area through survey, a disease
registry or hospital network.
23. 2) Selection of control
• Control is someone who doesn’t have the
disease under investigation.
• Control should be similar to the cases as
possible except for the disease under study
• So controls should be indentified before the
study.
• Sources: controls from Hospital, relatives ,
neighbors, occupational associates or general
population..
24. 3) Matching
• The controls may differ from the cases in a
number of factors such as age, sex, occupation,
education, social status etc.
• To share the comparability between cases and
controls matching is done.
• It is the process, by which select controls in such
a way that they are similar to cases with regard to
certain pertinent variables, which are known to
influence the outcome of the disease.
• If Matching not done ,this could distort or
confound the results.
25. • Confounding factor – Is defined as one which
is associated with both exposure and disease
and is distributed unequally in cases and
control group.
• Precautions while matching
- matching factor should be associated with
disease not on exposure
26. 4)Measurements of exposure
• In this study, the exposure status of the cases is usually
determined after the development of the disease and
by Questionnaire, physical examination, laboratory
investigations and study of records.
• The exposure may be of various types.(e.g. habit of
alcohol drinking, smoking)
• The measurement of exposure can be done by various
methods. Such as estimation of causative agent in
environment (carbon monoxide in air), estimation of
pathological changes(RBC stripling,Hb level in lead
poisoning).
27. 5) Analysis
• Final step in analysis, done to find out
(a) Exposure rates among cases and controls to
suspected factor : provides direct estimation
of exposure rates(frequency of exposure) to a
suspected factor in disease and non disease.
(b)Elimination of disease risk associated with
exposure.
28. Smoking Lung Cancer Not having Lung
cancer
Total
Exposure present 90(a) 20(b) 110
Exposure absent 10(c) 80(d) 90
Total 100 100 200
29. • Exposure rates:
Cases = a /(a+c) = 90/100
Controls = b /(b+d) = 20/100
This shows that, frequency of lung cancer was
higher among smokers than among non
smokers.
30. Estimation of Risk
• It is obtained by Relative Risk(RR) or risk ratio is
defined as the ratio between the incidence of
disease among exposed persons and incidence
among non exposed.
Incidence among exposed
Relative risk =
Incidence among nonexposed
= a /(a+c) ÷ b /(b+d)
31. • A typical case control study, does not provide
incidence rate from which relative risk can be
calculated.
• Next step Is to estimate the risk of disease
associated with the exposure Odds ratio
(Cross product ratio) : Determine the
association of an exposure and a disease.
• It is similar to risk ratio
32. Derivation of odds ratio is on 3 assumptions:
• The disease under investigation must be
relatively rare.
• The cases must be representative of those
with the disease
• The controls must be free from disease.
33. • Odds ratio = ( a/ b)
( c/ d )
= ad / bc
= 90* 80/ 20* 10
= 7200 / 200
= 36
34. • Interpretation:
Odds ratio is 1 , no association
Odds ratio is >1 , positive association
Odds ratio is <1 , negative association
(protective effect)
In the above example, people who smoke(cases)
were having a risk of developing lung cancer
36 times that of non smokers.
35. Bias
• It is any systematic error in the determination
of the association between exposure and the
disease.
a) Bias due to confounding
b) Memory or recall bias
c) Selection bias
d) Berkesonian bias
e) Interviewers bias
36. Advantages
• Easy to conduct, consume less time,
inexpensive.
• Suitable for rare disease.
• There is no risk to the subjects as disease has
already occurred.
• It is possible to study different causative
factors responsible for a particular disease.
• Minimal ethical problem
37. Disadvantages
• Study depends upon on
history/records/memory.
• It is very difficult to get a perfect control.
Group.
• It is not possible to measure incidence and
relative risk.
• This study can not distinguish between causes
and associated factors
38. 3) COHORT STUDY
• Cohort studies also called as Follow up ,
Incidence study, Prospective study, Forward
looking study or longitudinal study.
• Cohort study is similar to a longitudinal
descriptive study with exception that there is
comparison group in cohort.
• Cohort is defined as a group of people who
share a common characteristics or exposure
within a specified time period (Birth cohort).
39. • Cohort studies are indicated when there is good
evidence of association between exposure and
when exposure is rare and incidence is high.
• They are indicated when follow up is easy, cohort
is stable, cooperative and easily accessible and
ample funds are available.
• Cohorts must be free from the disease under
study and then they are classified into subgroups
according to exposure to a potential cause of
disease or outcome. And followed up for study
under same identical conditions.
40. • Both groups should be comparable in respect
of all the possible variables, which may
influence the frequency of disease.
• Diagnostic and eligibility criteria of disease
must be defined before the study.
42. Steps of a cohort study
1) Selection of study subjects
a) General Population: people residing in well
defined geographical area.
b) Special groups: such as professional group,
governments employees, volunteers, etc.
these groups are usually homogeneous
population.
43. 2) Obtaining data on exposure: data collected
through personal interviews, mailed
questionnaires, previous records, medical
examination or special tests.
• Groups are divided according to whether they
have been exposed to a suspected factor
(case) or not exposed (control) if yes then
divided again as per degree of exposure
44. 3) Selection of comparison group:
Internal comparison: In some study no outside
comparison group required. On the basis of
information obtained single cohort group are
classified into several comparison groups
according to degree or level of exposure to risk
before development of disease.(e.g. smoking,
blood pressure)
External comparison: when degree or level of
exposure is not availble.
45. Comparison with general population: If none
available or the difficulties of selecting the
study and comparison group.
46. 4) Follow up: It is a most important step. To obtain
data for assessing the outcome, the procedures
required,
A. Periodical medical examination of each member
of cohort as it provides more information.
B. Reviewing records from physicians and hospitals.
C. By surveillance of routine death records.
D. Mailed questionnaire, telephone calls and
periodic home visits on annual basis.
47. 5) Analysis: In this study, we analysis data by
calculating incidence rates of disease for both
cohorts, and then estimating relative risk,
attributable risk and population attributable
risk.
48. Disease present Disease absent Total
Cause present a (30) b (70) a+b (100)
Cause absent c (10) d (90) c+d (100)
49. 1. Relative Risk: It is defined as the ratio
between the incidence of disease among
exposed persons and incidence among non
exposed.
• In above example,
Incidence rate among smokers is=30/100
Incidence rate among non smokers is=10/100
50. • Therefore, Relative risk = 30/10 = 3.
• Relative risk has etiological enquiries as it
provides direct measure of the strength of
association between suspected cause or
exposure and effect.
• In this example, relative risk is 3 means people
who smoke cigarettes, have 3 times more risk
of developing lung cancers than non smokers.
51. 2. Attributable risk/Risk difference: It is the
difference in incidence rates of disease
between exposed group and non exposed
group.
• It provides info. about the contribution of
suspected cause for the occurrence of disease.
(or how much of the disease can be attributed
to suspected cause.)
52. AR =
(Incidence of disease in exposed –
Incidence of disease in non exposed × 100
Incidence rate among exposed
53. • In this example,
AR= 0.3-0.1 × 100
0.3
= 0.2/0.1 × 100
= 66%
• So in this example, It shows that, 66% of the lung
cancers among smokers could be attributed to
smoking. And hence there is a causal association.
54. • This information helps in knowing how much
of the disease can be eliminated by
eliminating or controlling the suspected cause
under study.
55. 3. Population attributable risk: It is the
incidence of the disease (or death) in the total
population minus incidence of the disease (or
death) among those who were not exposed to
the suspected causal factor.
• It provides an estimate of the amount by
which the disease could be reduced in that
population if the suspected cause or exposure
was eliminated or controlled.
56. Advantages
• We find out incidence.
• The beginning point is cohort with and
without exposure, so from this we can study
many outcomes related to exposure.
• Relative risk is being calculated.
• Minimal bias
57. Disadvantages
• Unsuitable for rare diseases.
• Time consuming. (migration, death ,behaviour
change or loss of interest, population attrition)
• Administrative problems( lack of experienced
staff, shortage of fund).
• Over a period of time, the diagnostic criteria or
definition of a disease under study may change.
• Expensive.
58. • Selection of comparison groups which are
representative of the exposed and unexposed
segments of the population is a limiting factor.
• Ethical issues.
59. Nested case control study
• It is a case control study “nested” within a
prospective or retrospective cohort study.
• In this study design, Cases and Controls both
are from cohort sample.
• It is useful for predictor variables that are
expensive, useful for costly analysis of
specimens, like biochemical analysis of serum
samples that are taken at the beginning of the
study and then preserved for later analysis.
60. • STEPS :
• Identify a cohort with a pool of specimens
collected at baseline.
• Identify those developing disease during
follow up(Cases).
• Select the sample from cohort who do not
develop the disease(Control)
• Measure the predictor variables.
61. 4)Ecological study
• Aka correlational study
• Useful for generating hypothesis
• Units of analysis are groups of people
• These studies can be done by comparing
populations in different places at same time or
in a time series or comparing same population
at one place at different time.
62. Drawbacks
• As it is easy to conduct, attractive, these study
are often difficult to interpret.
• Ecological studies usually rely on data
collected for other purposes.
• The association between exposure and effect
at the individual level cant be made.
• Ecological fallacy: bias results from if
inappropriate conclusions are drawn on the
basis of ecological data.
Surveillance: The ongoing systemic collection, analysis and interpretation of health data essential to the planning, implementation and evaluation of public health practice,closely integrated with the timely dissemination of these data to those who need to know. [ centers for disease control and prevention proposed by Langmuir 1963]
Hypothesis: . It provides a tentative explanation for a phenomenon under investigation
that are fixed characteristics of individuals such as ethnicity or blood group. (The study involves looking at people who differ on one key characteristic at one specific point in time.)
Case Control studies are longitudinal.
Data : will be collected from hospital ,workplace or general population
Pertinent – getting attached/affiliated
easily accessible which minimizes the problem of attrition of study population.
Term prospective refers to the timing of data collection