Here are the key points to compare the different research methods:
Cross-sectional study:
- Advantages: Quick, easy, low cost, can study multiple factors at once
- Disadvantages: Cannot determine temporal sequence, prone to biases
- Requirements: Representative sample, standardized data collection
Case-control study:
- Advantages: Efficient to study rare diseases, can study multiple exposures
- Disadvantages: Prone to selection and recall biases, uncertain temporal sequence
- Requirements: Clear case definition, appropriate controls matched to cases
Cohort study:
- Advantages: Directly measures risk, establishes temporal sequence
- Disadvantages: Expensive, long follow up needed
A principal aim of epidemiology is to assess the cause of disease. However, since most epidemiological studies are by nature observational rather than experimental, a number of possible explanations for an observed association need to be considered before we can infer a cause-effect relationship exists.
A principal aim of epidemiology is to assess the cause of disease. However, since most epidemiological studies are by nature observational rather than experimental, a number of possible explanations for an observed association need to be considered before we can infer a cause-effect relationship exists.
This PPT discusses
Basics measurements in epidemiology
Basics requirements of measurements
Tools of measurements
Measures of morbidity
Measures of disability
Measures of mortality
Epidemiology is the study and analysis of the patterns, causes, and effects of health and disease conditions in defined populations. It is the cornerstone of public health, and shapes policy decisions and evidence-based practice by identifying risk factors for disease and targets for preventive healthcare. Epidemiologists help with study design, collection, and statistical analysis of data, amend interpretation and dissemination of results (including peer review and occasional systematic review). Epidemiology has helped develop methodology used in clinical research, public health studies, and, to a lesser extent, basic research in the biological sciences
Introduction to Epidemiology
History of Epidemiology.
Definition of Epidemiology and its components.
Epidemiological Basic concepts.
Aims of Epidemiology.
Ten Uses of Epidemiology.
Scope or The Areas of Application .
Types of Epidemiological Studies.
Social and Preventive Medicine Classroom discussion topic on types of Epidemiological study designs available.
sole reference is Park text book 20th edition
Epidemiology is a basic discipline essential to both clinical and community medicines. It also helps to develop the way of thinking about health and disease.
The STUDY of the DISTRIBUTION and DETERMINANTS of HEALTH-RELATED STATES in specified POPULATIONS, and the application of this study to CONTROL of health problems."
This is the handout version of a lecture I give to medical residents and fellows on the basics of clinical research designs and the inherent issues that go along with each one. I give this lecture as part of a multi-module lecture series on research design and statistical analysis.
This PPT discusses
Basics measurements in epidemiology
Basics requirements of measurements
Tools of measurements
Measures of morbidity
Measures of disability
Measures of mortality
Epidemiology is the study and analysis of the patterns, causes, and effects of health and disease conditions in defined populations. It is the cornerstone of public health, and shapes policy decisions and evidence-based practice by identifying risk factors for disease and targets for preventive healthcare. Epidemiologists help with study design, collection, and statistical analysis of data, amend interpretation and dissemination of results (including peer review and occasional systematic review). Epidemiology has helped develop methodology used in clinical research, public health studies, and, to a lesser extent, basic research in the biological sciences
Introduction to Epidemiology
History of Epidemiology.
Definition of Epidemiology and its components.
Epidemiological Basic concepts.
Aims of Epidemiology.
Ten Uses of Epidemiology.
Scope or The Areas of Application .
Types of Epidemiological Studies.
Social and Preventive Medicine Classroom discussion topic on types of Epidemiological study designs available.
sole reference is Park text book 20th edition
Epidemiology is a basic discipline essential to both clinical and community medicines. It also helps to develop the way of thinking about health and disease.
The STUDY of the DISTRIBUTION and DETERMINANTS of HEALTH-RELATED STATES in specified POPULATIONS, and the application of this study to CONTROL of health problems."
This is the handout version of a lecture I give to medical residents and fellows on the basics of clinical research designs and the inherent issues that go along with each one. I give this lecture as part of a multi-module lecture series on research design and statistical analysis.
From a seminar I gave in my first year MD in Shivamogga Institute of Medical Sciences.
Oxford Textbook of Public Health and Textbook of Preventive Medicine and Public Health by Maxcy, Rosenau and Last are my references.
Might help readers learn the evolution of the concept of public health.
Austin Journal of Public Health and Epidemiology is an open access, peer reviewed, scholarly journal committed to publish articles in all areas of Public Health and Epidemiology. The journal is dedicated to publication of innovative research and reviews subjected to applied, methodological and theoretical issues with emphasis on studies using multidisciplinary or integrative approaches.
Austin Journal of Public Health and Epidemiology aims to progress epidemiological awareness and Public health and also serves as a discussion on the epidemiology of infectious and non-infectious diseases and their control. The outcomes of epidemiologic studies are crucial arguments for action in the ground of public health policies and efforts are made to carry the journal to the decision makers' attention. The journal is also a foundation of material for those who are actively teaching epidemiology.
Austin Journal of Public Health and Epidemiology accepts innovative review articles, research articles, case reports and rapid communication on all the aspects of Public Health and Epidemiology.
The Development of the Biostatistics & Clinical Epideimiolgy Skills (BACES) A...Pat Barlow
A poster based on my dissertation work developing a new biostatistics and clinical epidemiology skills self-assessment for medical residents. I used an Item Response Theory (IRT) approach to gather preliminary data on 30 multiple choice items that will eventually turn into an online self-assessment module for residents looking to hone their skills in these critical areas. The article is currently under review in Medical Teach, and I am looking for more sites / collaborators for expanding the instrument. Email if you're interested!
Thank you to everyone for supporting my content! How have *you* made use of this content in your work? Leave a comment or email them to barlow.p1218@gmail.com. Thanks again!
Bad Statistics, Bad Reporting, Bad Impact on Patients: The Story of the PACE ...Julie Rehmeyer
A talk by Julie Rehmeyer at the Joint Statistics Meetings, 2016.
In 2011, headlines worldwide announced that an effective treatment had been found for a debilitating illness that affects 17 million people around the world. The study was published in The Lancet. Great news!
Except that it wasn't. Patients with the illness, known as chronic fatigue syndrome or myalgic encephalomyelitis, quickly decried the study as having severe scientific problems. Furthermore, it didn't fit with their experience: patients reported that the two treatments -- psychotherapy and gradually increasing exercise -- had little impact and could indeed be dangerous. They analyzed the study and spelled out its serious flaws, particularly statistical ones, in scientific journals, but the authors dismissed the concerns as prejudice against psychiatry.
In late 2015, journalist David Tuller wrote a 14,000-word expose of the flaws in the trial, citing the grave concerns of researchers. Dr. Ronald Davis of Stanford University, for example, said, "I'm shocked that the Lancet published it.I don't understand how it got through any kind of peer review."
I'll describe the problems with the science, with the functioning of the scientific institutions, and with the journalism.
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.
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
Prix Galien International 2024 Forum ProgramLevi Shapiro
June 20, 2024, Prix Galien International and Jerusalem Ethics Forum in ROME. Detailed agenda including panels:
- ADVANCES IN CARDIOLOGY: A NEW PARADIGM IS COMING
- WOMEN’S HEALTH: FERTILITY PRESERVATION
- WHAT’S NEW IN THE TREATMENT OF INFECTIOUS,
ONCOLOGICAL AND INFLAMMATORY SKIN DISEASES?
- ARTIFICIAL INTELLIGENCE AND ETHICS
- GENE THERAPY
- BEYOND BORDERS: GLOBAL INITIATIVES FOR DEMOCRATIZING LIFE SCIENCE TECHNOLOGIES AND PROMOTING ACCESS TO HEALTHCARE
- ETHICAL CHALLENGES IN LIFE SCIENCES
- Prix Galien International Awards Ceremony
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
Ethanol (CH3CH2OH), or beverage alcohol, is a two-carbon alcohol
that is rapidly distributed in the body and brain. Ethanol alters many
neurochemical systems and has rewarding and addictive properties. It
is the oldest recreational drug and likely contributes to more morbidity,
mortality, and public health costs than all illicit drugs combined. The
5th edition of the Diagnostic and Statistical Manual of Mental Disorders
(DSM-5) integrates alcohol abuse and alcohol dependence into a single
disorder called alcohol use disorder (AUD), with mild, moderate,
and severe subclassifications (American Psychiatric Association, 2013).
In the DSM-5, all types of substance abuse and dependence have been
combined into a single substance use disorder (SUD) on a continuum
from mild to severe. A diagnosis of AUD requires that at least two of
the 11 DSM-5 behaviors be present within a 12-month period (mild
AUD: 2–3 criteria; moderate AUD: 4–5 criteria; severe AUD: 6–11 criteria).
The four main behavioral effects of AUD are impaired control over
drinking, negative social consequences, risky use, and altered physiological
effects (tolerance, withdrawal). This chapter presents an overview
of the prevalence and harmful consequences of AUD in the U.S.,
the systemic nature of the disease, neurocircuitry and stages of AUD,
comorbidities, fetal alcohol spectrum disorders, genetic risk factors, and
pharmacotherapies for AUD.
These lecture slides, by Dr Sidra Arshad, offer a quick overview of physiological basis of a normal electrocardiogram.
Learning objectives:
1. Define an electrocardiogram (ECG) and electrocardiography
2. Describe how dipoles generated by the heart produce the waveforms of the ECG
3. Describe the components of a normal electrocardiogram of a typical bipolar leads (limb II)
4. Differentiate between intervals and segments
5. Enlist some common indications for obtaining an ECG
Study Resources:
1. Chapter 11, Guyton and Hall Textbook of Medical Physiology, 14th edition
2. Chapter 9, Human Physiology - From Cells to Systems, Lauralee Sherwood, 9th edition
3. Chapter 29, Ganong’s Review of Medical Physiology, 26th edition
4. Electrocardiogram, StatPearls - https://www.ncbi.nlm.nih.gov/books/NBK549803/
5. ECG in Medical Practice by ABM Abdullah, 4th edition
6. ECG Basics, http://www.nataliescasebook.com/tag/e-c-g-basics
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
Pulmonary Thromboembolism - etilogy, types, medical- Surgical and nursing man...VarunMahajani
Disruption of blood supply to lung alveoli due to blockage of one or more pulmonary blood vessels is called as Pulmonary thromboembolism. In this presentation we will discuss its causes, types and its management in depth.
- Video recording of this lecture in English language: https://youtu.be/lK81BzxMqdo
- Video recording of this lecture in Arabic language: https://youtu.be/Ve4P0COk9OI
- Link to download the book free: https://nephrotube.blogspot.com/p/nephrotube-nephrology-books.html
- Link to NephroTube website: www.NephroTube.com
- Link to NephroTube social media accounts: https://nephrotube.blogspot.com/p/join-nephrotube-on-social-media.html
Flu Vaccine Alert in Bangalore Karnatakaaddon Scans
As flu season approaches, health officials in Bangalore, Karnataka, are urging residents to get their flu vaccinations. The seasonal flu, while common, can lead to severe health complications, particularly for vulnerable populations such as young children, the elderly, and those with underlying health conditions.
Dr. Vidisha Kumari, a leading epidemiologist in Bangalore, emphasizes the importance of getting vaccinated. "The flu vaccine is our best defense against the influenza virus. It not only protects individuals but also helps prevent the spread of the virus in our communities," he says.
This year, the flu season is expected to coincide with a potential increase in other respiratory illnesses. The Karnataka Health Department has launched an awareness campaign highlighting the significance of flu vaccinations. They have set up multiple vaccination centers across Bangalore, making it convenient for residents to receive their shots.
To encourage widespread vaccination, the government is also collaborating with local schools, workplaces, and community centers to facilitate vaccination drives. Special attention is being given to ensuring that the vaccine is accessible to all, including marginalized communities who may have limited access to healthcare.
Residents are reminded that the flu vaccine is safe and effective. Common side effects are mild and may include soreness at the injection site, mild fever, or muscle aches. These side effects are generally short-lived and far less severe than the flu itself.
Healthcare providers are also stressing the importance of continuing COVID-19 precautions. Wearing masks, practicing good hand hygiene, and maintaining social distancing are still crucial, especially in crowded places.
Protect yourself and your loved ones by getting vaccinated. Together, we can help keep Bangalore healthy and safe this flu season. For more information on vaccination centers and schedules, residents can visit the Karnataka Health Department’s official website or follow their social media pages.
Stay informed, stay safe, and get your flu shot today!
Recomendações da OMS sobre cuidados maternos e neonatais para uma experiência pós-natal positiva.
Em consonância com os ODS – Objetivos do Desenvolvimento Sustentável e a Estratégia Global para a Saúde das Mulheres, Crianças e Adolescentes, e aplicando uma abordagem baseada nos direitos humanos, os esforços de cuidados pós-natais devem expandir-se para além da cobertura e da simples sobrevivência, de modo a incluir cuidados de qualidade.
Estas diretrizes visam melhorar a qualidade dos cuidados pós-natais essenciais e de rotina prestados às mulheres e aos recém-nascidos, com o objetivo final de melhorar a saúde e o bem-estar materno e neonatal.
Uma “experiência pós-natal positiva” é um resultado importante para todas as mulheres que dão à luz e para os seus recém-nascidos, estabelecendo as bases para a melhoria da saúde e do bem-estar a curto e longo prazo. Uma experiência pós-natal positiva é definida como aquela em que as mulheres, pessoas que gestam, os recém-nascidos, os casais, os pais, os cuidadores e as famílias recebem informação consistente, garantia e apoio de profissionais de saúde motivados; e onde um sistema de saúde flexível e com recursos reconheça as necessidades das mulheres e dos bebês e respeite o seu contexto cultural.
Estas diretrizes consolidadas apresentam algumas recomendações novas e já bem fundamentadas sobre cuidados pós-natais de rotina para mulheres e neonatos que recebem cuidados no pós-parto em unidades de saúde ou na comunidade, independentemente dos recursos disponíveis.
É fornecido um conjunto abrangente de recomendações para cuidados durante o período puerperal, com ênfase nos cuidados essenciais que todas as mulheres e recém-nascidos devem receber, e com a devida atenção à qualidade dos cuidados; isto é, a entrega e a experiência do cuidado recebido. Estas diretrizes atualizam e ampliam as recomendações da OMS de 2014 sobre cuidados pós-natais da mãe e do recém-nascido e complementam as atuais diretrizes da OMS sobre a gestão de complicações pós-natais.
O estabelecimento da amamentação e o manejo das principais intercorrências é contemplada.
Recomendamos muito.
Vamos discutir essas recomendações no nosso curso de pós-graduação em Aleitamento no Instituto Ciclos.
Esta publicação só está disponível em inglês até o momento.
Prof. Marcus Renato de Carvalho
www.agostodourado.com
2. Define: epidemiology, its uses.
Recognize the different types of
epidemiological research methods.
Explain how to design scientific researches by
the different methods
Compare the different research methods
(advantages and disadvantages)
3.
4. 1. Describe the health status of the population in
certain community and subsequently diagnose its
health problems.
2. Discover the causes of diseases and
determinants of ill or good health.
3. Discover the risk factors that predispose to
diseases of unknown etiology.
4. Complete the clinical picture of diseases from
beginning of pathological changes till cure or
occurrence of complications.
5. Evaluate the effectiveness of health services or
test the validity of diagnostic tests or evaluate
the prognosis
5. ◦ Disease does not occur randomly
◦ Disease has identifiable causes which can be altered
and therefore can be prevented from developing
Health is a state of equilibrium between:
Agent Host
Environment
7. Study of epidemics & epidemic disease
(Stedman’s medical dictionary)
• The science making the obvious obscure
(epidemiologist)
• The worst taught in medical school
(medical student)
8. The word epidemiology comes from the Greek words
epi, meaning “on or upon,” demos, meaning “people,”
and logos, meaning “the study of.”
“Epidemiology is the study of the distribution and
determinants of health-related states or events in
specified populations, and the application of this
study to control of health problems.
9. describe the natural history of diseases
explore disease causality
- direct: biological mechanisms of disease
- indirect: social and environmental causes of
disease
provide disease surveillance
- essential for evaluating community health
problems and setting disease control priorities
evaluate diagnostic testing
- evaluate validity, sensitivity, specificity
- to set cutoff points for abnormalities
evaluate prognosis
- by identifying prognostic factors
12. Development of concepts which help us to
understand social phenomena in natural
settings, giving due emphasis to the meanings,
experiences, and views of all the participants
Explaining complex phenomena not amenable
to quantitative research
Method : Focus group, observation, interview
Application (examples)
Doctor-patient relationship, treatment
compliance, clinical decision making process,
issues on health service organization
and policy issues
13. Two main categories:
1. Observational studies (researcher
not intervene) : cross-sectional(descriptive)–
retrospective (case control) – prospective
(cohort)
1. Experimental studies (researcher intervene)
exposure status is assigned
(intervention)
16. Descriptive Epidemiology deals with the
questions: Who, What, When, and Where?
Analytic Epidemiology deals with the
remaining questions: Why and How?
17. Study the prevalence of diabetes in Zagazig
Study the relation between smoking and lung
cancer
Study women satisfaction for antenatal care
Study the effect of obesity on fetal outcome
Study the risk of iodine deficiency on mental
retardation
Study suggestions for improvement of
in zagazig hospital
18. Explain how to design
scientific researches
by the different
methods
22. Descriptive epidemiological study of any disease can provide
these knowledge: e.g.
Food borne epidemic, TB, parasitic infestation
Pattern =Time , person , place
Frequency = prevalence & incidence rates
May be : Determinants = risk factors
Descriptive epidemiology
what
when
who
where
25. Useful for assessing the burden of disease
within a population
Valuable for planning & follow up
Prevalence rate= number of cases (old & new)
Number examined in the same time & place
26. no. of new cases of disease over
a specific period of time
Incidence = -----------------------------
no. of persons at risk of disease
over that specific period of time
31. Case report
unit of study: single person with a disease
limitation: based on experience of a single
person
provides first clues in the identification of a
disease or adverse effects of exposure
(halothane induced hepatitis)
32. Case series
unit of study: group of persons with a
similar disease
Uses:
o formulation of criteria for diagnosis
o formulation of indications for treatment
o identification of prognostic factors
o determination of survival rates
33. a-Cheap, rapid, easy
b-Can use large sample of the population.
c-Assess health status, and health problems
and indicate priorities for health care
planning. Assess customer’s satisfaction for
health care.
d-Provides the base-line data for further
studies if the problem is not studied before.
e- Cross sectional study is the most
convenient first step in the investigation of
the cause of the outbreak or epidemic.
34. Sequence of events cannot be ascertained
Not useful for diseases of short
period of time
Not practical in studying rare
diseases
Case reports are susceptible to bias
Case reports can not be used to make
treatment decisions.
36. Epidemiology and laboratory science converge
to provide the evidence needed to establish
causation. A team of epidemiologists were able
to identify a variety of risk factors during an
outbreak of a pneumonia or cholera epidemic
etc..
Epidemiology Laboratory
Evidence of causation
37. Two groups: one is the case group “diseased’ and
the other is the control group ‘healthy".
- Both diseased group and the control group
must be matched in everything except the
disease i.e matched in age, sex, socioeconomic
class, occupation, residence etc.
-The collection of data is retrospectively i.e we
ask both cases and controls about their past
exposure of the risk factor under study.
-The proportion of those exposed to a certain
factor in each group is compared.
38. Requirements for valid results
Cases must be representative of all those
with disease and clearly defined.
Controls must be representative of all those
without the disease and come from same
community or source as the cases.
There must be a control ( 1 or more) for
each case
39. Had Exposure No Exposure
Study
Population
Cases Controls
No ExposureHad Exposure
40. Used to find a relation between disease and
exposure
Outcome (disease)
Exposure
(risk)
diseased healthy Total
Yes a b a + b
No c d c + d
Total a + c b + d a + b + c + d
41. Odd’s Ratio (OR)
proportion of those with history of exposure to
the factor among the cases (a/a+c) is compared
to those with history of exposure (b/b+d) to the
factor among the controls
OR = ad/bc
43. Disease Risk Odds Ratio 95% CI p-value
Cancer lung Smoking 2.4 1.3 – 4.4 0.004
Cancer breast Trauma 1.9 1.3 – 2.8 0.001
Infarction Obesity 1.3 1.0 – 1.7 0.04
Duodenal ulcer HP 3.7 1.0 – 5.7 0.04
Diabetes m. Viral infection 0.9 0.5 – 1.8 0.80
Cancer cervix Genital warts 0.4 0.2 – 1.0 0.05
44. advantages
Good for unusual or
rare diseases
Quick, easy, cost-
effective
Can use secondary
data on disease
More easily replicated
Suitable for more than
one risk at a time
Can test hypotheses
disadvantages
Uncertainty is
exposure-disease time
relationship
Representativeness of
cases or controls
Memory problems
Rare exposure
Survivor problem
Bias potential
(selection)
45. Which of these research questions can be
answered by case-control study? how?
1- Evaluation of performance in a health unit
2-Relation between vitamin B deficiency
&nerve conduction
3- Relation between X (rare disease) and Y risk
factor
4- Relation between cancer skin and Y rare
exposure risk
46. Design case-control study to find the relation
between contraceptive pills and deep venous
thrombosis.
Calculate odds ratio for this relationship:
Liver cirrhosis No cirrhosis
Bilharziasis 40 20
No bilharziasis 10 80
48. groups of subjects are chosen on the basis
of having been exposed to a factor or not
groups are followed up to identify those
who develop the disease or outcome
49. Uses
to test prognostic factors
to directly measure risk of development of
disease or outcome
provide more definitive information about
disease etiology
preferred for study of rare exposures
51. Analysis: Assess the strength of an association
between an exposure and the outcome of
interest
Relative Risk or Risk Ratio(RR)
proportion of subjects with the disease or
outcome among the exposed (a/a+b) is
compared to proportion of subjects with the
disease or outcome among the unexposed
(c/c+d)
RR = a/a+b ÷ c/c+d
54. Advantages
provides direct estimate of risk
Time sequence can be ascertained
less biases of recall and observation
controls easier to assemble
variations in exposure can be followed-
up
unsuspected effects of the exposure
may be observed
57. Two main categories:
1. Observational studies (researcher not
intervene) : cross-sectional(descriptive)–
retrospective (case control) – prospective
(cohort)
2. Experimental studies (researcher intervene)
exposure status is assigned
(intervention)
58. Three different ways of classifying intervention
studies
I. Based on population studies
◦ Clinical trial: on patients in clinical settings
◦ Field trial: on healthy people in the field
◦ Community trial: on the community as a whole
II. Based on design
◦ Uncontrolled trial: no control (self-control/cross-
over)
◦ Non-randomized controlled: allocation not
random
◦ Randomized control: Allocation random
59. Randomization: random allocation of study
subjects
into treatment & control groups
Outcome/endpoint
Improvement ( desired effect) and side effects
Must be exactly defined
Measured comparably in all study groups
Blinding: Denying information on
treatment/control status.
Single – subjects (placebo effect)
Double - subjects & investigators
Triple blind - subjects & investigators & statisticians
60. New treatment Current treatment/
no treatment
Improved Not
improved
Improved Not
improved
Intervention
Outcome
Selection of subjects
-similar features
-inclusion/exclusion criteria
Allocation of subjects
Data collection
Masking (blinding)
Define population
61. Evaluate new forms of therapy and prevention
Treatment or drugs
Health care technology - device
Methods of primary prevention - screening
Organizing and delivering health services (community
trial)
Impact of new policies in health care and health care
financing (community trial)
62. Advantages:
Strongest design - randomization, minimal
selection bias
Must be ethical - no harmful intervention,
no poor clinical outcome
63. Disadvantages:
Difficult for intervention in rare disease / rare
outcome
Participation of subjects is crucial
Non-compliance (people who complaint are
very different from those who are not)
* Drop-out: not adherence to experimental
regimen, loss to follow-up
* Drop-in: not adherence to control regimen
Compliance -Need monitoring
Most costly
66. 1. Research questions
2. Occurrence of disease / exposure -
rare/ common
3. Ethical issue
4. Resources- money, manpower, machine
Several designs may well be suitable for a
particular study. Choice must then be guided by
considerations of strength of design, cost and
ethics.
67. Study design Treatment Diagnosis Prognosis Agreement Classification
RCT ## - - - -
COHORT # - ## - ##
CASE-CONTROL - - - - -
CROSS SECTIONAL - ## - ## ##
CASE SERIES # # # - #
Design of research depends on research Q
Treatment efficacy/safety = RCT
Diagnostic methods, prevalence = cross- section
Prognosis- outcome = cohort
satisfaction measurement = cross- sectional
relation between risk and disease = case-
control, cohort
68. 1. Randomized controlled trial
2. Cohort study
3. Case control study
4. Cross sectional study
5. Case report or case series
6. Experimental animals
7. Qualitative research
69. Design a research to find out the relation
between obesity and diabetes (use 2 different
methods)
Design a research to find out which is better
drug A or drug B for hypertension
70.
71. Advantages
Disadvantages
Requirements
Validity
Gold standard test
test diseased healthy Total
positive a b a + b
negative c d c + d
Total a + c b + d a + b + c + d