1. A cohort study follows groups of individuals over time to examine the effects of exposures on disease outcomes. The Framingham Heart Study is a landmark prospective cohort study that began in 1948 and studied the relationship between cardiovascular risk factors and disease.
2. Cohort studies can be prospective, following exposed and unexposed groups forward in time, or retrospective, identifying exposure status from past records and determining current disease status. Doll and Hill's 1954 study on smoking and lung cancer used a prospective design to establish this causal link.
3. Key elements of cohort studies include selecting and characterizing the study population, establishing exposure status, choosing comparison groups, long-term follow-up, and analysis of disease incidence and relative
Periodontal disease is a widely prevalent disease worldwide which often gets unnoticed or it often ignored due to its slowly progressive nature. It is of concern since it can cause irrepairable damage to tooth supporting structures if not early diagnosed or treated.
Cohort, case control & survival studies-2014Ramnath Takiar
The presentation discusses about Cohort, Case-control and Survival studies. The concept of Cohort and Case-control studies is explained with the help of diagrams as perceived by me. Some discussion is also there about survival and relative survival. Appropriate data is also provided to explain about survival and relative survival.
Periodontal disease is a widely prevalent disease worldwide which often gets unnoticed or it often ignored due to its slowly progressive nature. It is of concern since it can cause irrepairable damage to tooth supporting structures if not early diagnosed or treated.
Cohort, case control & survival studies-2014Ramnath Takiar
The presentation discusses about Cohort, Case-control and Survival studies. The concept of Cohort and Case-control studies is explained with the help of diagrams as perceived by me. Some discussion is also there about survival and relative survival. Appropriate data is also provided to explain about survival and relative survival.
The STUDY of the DISTRIBUTION & DETERMINANTS of HEALTH-RELATED STATES in specified POPULATIONS, and the application of this study to CONTROL of health problems.
Risk factors in Multiple Sclerosis: Detection and Treatment in Daily Life
Caroline Pot and Patrice Lalive
Unit of Neuroimmunology and Multi Sclerosis Geneva University Hospital
The international health regulations (IHR) is an agreement among 194 countries, including all WHO member countries ,to work together for healthy security of the world. Under the IHR, all countries need to report all events of international public health impact
The STUDY of the DISTRIBUTION & DETERMINANTS of HEALTH-RELATED STATES in specified POPULATIONS, and the application of this study to CONTROL of health problems.
Risk factors in Multiple Sclerosis: Detection and Treatment in Daily Life
Caroline Pot and Patrice Lalive
Unit of Neuroimmunology and Multi Sclerosis Geneva University Hospital
The international health regulations (IHR) is an agreement among 194 countries, including all WHO member countries ,to work together for healthy security of the world. Under the IHR, all countries need to report all events of international public health impact
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
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.
ARTIFICIAL INTELLIGENCE IN HEALTHCARE.pdfAnujkumaranit
Artificial intelligence (AI) refers to the simulation of human intelligence processes by machines, especially computer systems. It encompasses tasks such as learning, reasoning, problem-solving, perception, and language understanding. AI technologies are revolutionizing various fields, from healthcare to finance, by enabling machines to perform tasks that typically require human intelligence.
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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!
Ozempic: Preoperative Management of Patients on GLP-1 Receptor Agonists Saeid Safari
Preoperative Management of Patients on GLP-1 Receptor Agonists like Ozempic and Semiglutide
ASA GUIDELINE
NYSORA Guideline
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These simplified slides by Dr. Sidra Arshad present an overview of the non-respiratory functions of the respiratory tract.
Learning objectives:
1. Enlist the non-respiratory functions of the respiratory tract
2. Briefly explain how these functions are carried out
3. Discuss the significance of dead space
4. Differentiate between minute ventilation and alveolar ventilation
5. Describe the cough and sneeze reflexes
Study Resources:
1. Chapter 39, Guyton and Hall Textbook of Medical Physiology, 14th edition
2. Chapter 34, Ganong’s Review of Medical Physiology, 26th edition
3. Chapter 17, Human Physiology by Lauralee Sherwood, 9th edition
4. Non-respiratory functions of the lungs https://academic.oup.com/bjaed/article/13/3/98/278874
micro teaching on communication m.sc nursing.pdfAnurag Sharma
Microteaching is a unique model of practice teaching. It is a viable instrument for the. desired change in the teaching behavior or the behavior potential which, in specified types of real. classroom situations, tends to facilitate the achievement of specified types of objectives.
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.
The prostate is an exocrine gland of the male mammalian reproductive system
It is a walnut-sized gland that forms part of the male reproductive system and is located in front of the rectum and just below the urinary bladder
Function is to store and secrete a clear, slightly alkaline fluid that constitutes 10-30% of the volume of the seminal fluid that along with the spermatozoa, constitutes semen
A healthy human prostate measures (4cm-vertical, by 3cm-horizontal, 2cm ant-post ).
It surrounds the urethra just below the urinary bladder. It has anterior, median, posterior and two lateral lobes
It’s work is regulated by androgens which are responsible for male sex characteristics
Generalised disease of the prostate due to hormonal derangement which leads to non malignant enlargement of the gland (increase in the number of epithelial cells and stromal tissue)to cause compression of the urethra leading to symptoms (LUTS
2. Concept of cohort
• The term “cohort” - a group of people who share a common
characteristic or experience within a defined time period.{age,
occupation, exposure)
E.g.-
o Birth cohort
o Exposure cohort
o Marriage cohort
3. Indication of cohort studies
When there is good evidence of association between exposure and disease or
the alleged exposure is known.
When exposure is rare, but the incidence of disease is high among exposed.
When attrition of study population can be minimized (cooperative, easily
accessible).
When ample funds are available.
When the time between exposure and disease is relatively short.
4. Design of cohort study
Population without
the disease
Exposed
disease
No disease
Not
exposed
disease
No disease
Exposure
(cause)
Outcome
(effect)
Direction of inquiry
5. Framework of cohort study
Cohort Disease total
yes no
Exposed to etiologic
factor
a b a+b
Not Exposed to
etiologic factor
c d c+d
Where
a+b = study cohort
c+d = control cohort
6. Types of cohort study
On the basis of time of occurrence of disease in relation to the time at which
the investigation is initiated and continued:
1. Prospective cohort studies / concurrent cohort/ longitudinal study
2. Retrospective cohort studies / non concurrent cohort / historical cohort study
3. A combination of both retrospective and prospective cohort study
/Ambispective cohort study.
7.
8. • Investigator starts the study with identification of population and the
exposure status.
• Follows them over time for the development of disease.
• Takes relatively long time to complete the study .
• E.g.
1. Framingham heart study
2. Doll and Hill study on smoking and lung cancer.
Prospective cohort study
9. Framingham heart study
A prospective cohort study
By USPHS & NHLBI, initiated on 1948 at the town of Framingham .
To study the relationship of a number of risk factors (e.g. serum cholesterol ,BP,
weight, smoking)to subsequent development of cardiovascular diseases.
Exposures – BP, Smoking , Bodyweight ,Diabetes ,Exercise etc
Outcomes –coronary heart disease, stroke, congestive heart failure, peripheral
arterial disease.
Several hypothesis where tested – different exposures and outcomes.
The lower and upper limits of study population was set at 30 & 59 yrs.
The study population was examined every 2 yrs for a period of 20 yrs.
10. total
Study population (of age group 30-59) 10000
Random sample 6507
Respondents 5209
Respondents with clinically relevant CHD 82
Respondents free of CHD 5127
Total repondents that actually underwent 1st examination 4469
The table depicts the number of study participants in Framingham heart study by USPHS
11. 1948
• Start of FRAMINGHAM HEART STUDY
1960
• Cigarette Smoking found to increase risk of Heart Disease
1961
• Cholestrol , BP, and ECG abnormalities found to increase risk of heart
disease.
1965
• First Framingham heart study report on stroke.
1967
• Physical activity found to reduce risk of heart disease: obesity to increase
the risk
1970 • High BP found to increase the risk of stroke.
https://www.framingham.com/heart/timeline.htm
TIMELINE OF MILESTONES FROM THE FRAMINGHAM STUDY
12. In October 1951 DOLL and HILL sent
questionnaire to 59600 british doctors.
• Enquiring about smoking
habits
40701 replies
• Followed up for a period of
4yrs and 5 months
Obtaining notification pf
phisicians’ death from registrar
general,general medical council
and british medical association.
DOLL and HILL prospective study on relation of smoking to
lung cancer.
13. • Investigator uses existing data collected in the past to identify the
population and their exposure status
• Investigator spends a relatively short time to assemble study population
from past data and determine disease status at present time no future follow
up.
• E.g.:-
1) Boston hospital study on electronic fetal monitoring during labour and
outcome measured was neonatal death.
2) Aniline dyes and urinary bladder cancer .
3) Study of role of arsenic in human carcinogenesis
4) Study of lung cancers in uranium miners.
Retrospective cohort study
14. Employees working in dye
industry (n=4622)
Exposure to
aniline dyes
Death due to bladder
tumors
1920 1930 1940 1950
Start of the study
Expected cases of bladder cancer using
national statistics.
Aniline dyes and urinary bladder cancer
15. Combination of retrospective and prospective cohort
studies
Investigator uses existing data collected in the past to identify the population
and the exposure status− Follow them into the future for the development of
the disease .
Spends a relatively short time to assemble study population (and the
exposed/not exposed groups) from past data − Will spend additional time
following them into the future for the development of disease .
E,g:-court brown and doll study on effects of radiation(1957)
16. Court brown and doll study on effects of
radiation(1957)
Pts of ankylosing spondylitis receiving
high dose dose of radiation
n= 13352 Death from
leukemia or
aplastic
anemia
Start of the
stuidy
1934-1954
In 1955 a prospective component was added
to the study and cohort was followed in
subsequrent years
17. Elements of cohort study
1. Selection of study population.
2. Obtaining data on exposure .
3. Selection of comparison groups.
4. Follow-up
5. Analysis
18. 1.Selection of study population.
General population cohorts or subsets
E,g:- Framingham heart study
Selected groups
e.g.:-Doll And Hill’s study
Special exposure cohorts
e.g.:- occupational exposure groups
19. 2. Obtaining data on exposure
Valid assessment of exposure status of members of cohort
• Identification data
• Exclude individuals having disease at baseline
• Define individuals at risk
• Obtain data on co-variables (other exposure variables)
20. Sources of baseline information
Existing records
• Hospital records, employment records
Interviews
• Personal interviews/mailed questionnaires etc.
Examinations
• Medical and other special examination
Environment Survey
• E.g. air pollution, exposure to radiation
21. 3.Choice of comparison group
Internal comparison group
• Unexposed persons in the population
External comparison group
• When internal comparison group not available.
• Ex: a cohort of radiologists compared with a cohort of
ophthalmologists.
Comparison with general population
• The mortality experience of exposed is compared with mortality
experience of whole population.
22. 4.Follow-up
The procedure involves
a) Periodic medical examination of each member of the cohort
b) Reviewing physician and hospital records .Routine surveillance of
death records
c) Mailed questionnaires, telephone calls, periodic home visits-
preferably all three on an annual basis
d) Uniform surveillance in exposed and unexposed groups
e) Complete ascertainment of exposures and outcome/s
f) Standardized diagnosis of outcome events
23. 5.Analysis
Data can be analyzed in terms of :-
1. Incidence rate
2. Relative risk
cigarette
smoking
Develop lung
cancer
Do not
develop lung
cancer
total
Yes 70(a) 6930(b) 7000(a+b)
No 3 (c) 2997 (d) 3000 (c+d)
An hypothetical example of lung cancer and smoking depicted in a contingency table
24. Incidence rate
Incidence rate of cancer in exposed(i.e. cigarette smoking ) is
=a/a+b =70/7000
Incidence rate among smokers = 10 per 1000 exposed population.
Incidence rate of cancer among non exosed = c/c+d
= 3/3000
Incidence rate among non smokers = 1 per 1000 exposed population.
25. Relative risk / risk ratio
Relative risk (RR) is the ratio of incidence of the disease among
exposed and the incidence among non exposed.
RR= incidence among exposed
incidence among non exposed
= 10/1 =10
A relative risk of 10 indicates that the incidence rate of disease is 10
times higher in exposed group as compared to the non- exposed.
26. Interpreting Relative risk
RR=1
• Incidence in exposed and unexposed is same
• Exposure is not associated with disease
RR > 1
• Incidence in exposed is higher than unexposed
• Exposure is positively associated with disease
RR < 1
• Incidence in exposed is lower than unexposed
• Exposure is negatively associated with disease
27. Attributable risk / risk difference
Expressed in percent.
attributable risk = incidence among exposed – incidence among non exposed
incidence among exposed
= 10-1/10 *100
=90 percent .
It indicates to what extent the disease under study can be attributed to the
exposure.
*100
28. Population attributable risk
Population attributable risk = incidence in total population – incidence
among non-exposed
Incidence in the total population 73
Incidence among exposed 70
Incidence among non - exposed 3
Population AR =73-3/73
= 95.8%
IT PROVIDES AN ESTIMATE OF THE AMOUNT BY WHICH THE DISEASE COULD BE
REDUCED IN THAT POPULATION
29. Cardiovascular risk
100,000 patient years
age (30-39) (40-44)age
Relative risk 2.8 2.8
Attributable risk 3.5 20.0
Table .The relative and attributable risks of cardiovascular complications in women taking oral contraception
Cause of death Death rate/1000 RR AR(%)
smokers Non-
smokers
Lung cancer 0.90 0.07 12.86 92.2
CHD 4.87 4.22 1.15 13.3
Risk assessment ,smokers vs non smokers
30. Advantages and disadvantages of cohort study
Advantages
• Allows calculation of
incidence
• Examine multiple
outcomes for a given
exposure
• Direct estimate of
relative risk
• Dose- response ratio can
also be calculated
Mis- classification of
individuals is minimized.
• Disadvantage
• May have to follow large no. of
subjects for a long time.
• Expensive
• extensive record keeping is
required
• time consuming.
• Not good for rare diseases.
• Study may alter the people’s
behavior .
• Ethical problems.
• Differential loss to follow up
can introduce bias.
31. Case control study Cohort study
1 Proceeds from “effect to cause” Proceeds from “cause to effect”
2 Starts with the disease Starts with people exposed to risk factor or
suspected cause
3 Usually first step in testing of a
hypothesis, but also useful for exploratory
studies.
Reserved for testing of precisely formulated
hypothesis.
4 Yields relatively quick results Long follow up
5 Fewer number of subjects Involves large number of subjects
6 SN Inappropriate when the disease or exposure
under investigation is rare.
7 Relatively inexpensive expensive
8 Cannot yield information about disease
other than that selected for the study
Can yield information about more than one
disease outcome.
32. References
1. Park 25th edition.
2. BCBR by ICMR.
3. https://www.framingham.com/heart/timeline.htm