1. A case control study compares exposures in people with a disease (cases) to people without the disease (controls) to determine if any exposures are associated with the disease.
2. Key features of case control studies include directionality from exposure to outcome, retrospective assessment of exposure, and sampling based on outcome status.
3. Potential biases include selection bias, recall/information bias, and confounding which must be addressed through careful study design and analysis.
The most ambitious definition of health is that proposed by WHO in 1948: “health is a state of complete physical, mental, and social well-being and not merely the absence of disease or infirmity.” but,
Practical definitions of health and disease are needed in epidemiology, which concentrates on aspects of health that are easily measurable and amenable to improvement.
Definitions of health states used by epidemiologists tend to be simple.
The most ambitious definition of health is that proposed by WHO in 1948: “health is a state of complete physical, mental, and social well-being and not merely the absence of disease or infirmity.” but,
Practical definitions of health and disease are needed in epidemiology, which concentrates on aspects of health that are easily measurable and amenable to improvement.
Definitions of health states used by epidemiologists tend to be simple.
Observational analytical study: Cross-sectional, Case-control and Cohort stu...Prabesh Ghimire
This presentation provides overview of three observational analytical studies: cross-sectional study design, case-control study design and cohort study design
Case-control study is a variety of analytical studies. This is a brief presentation regarding history, design, issues, advantages - disadvantages and examples of Case-control study.
Observational analytical study: Cross-sectional, Case-control and Cohort stu...Prabesh Ghimire
This presentation provides overview of three observational analytical studies: cross-sectional study design, case-control study design and cohort study design
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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.
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.
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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
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.
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
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
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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
Couples presenting to the infertility clinic- Do they really have infertility...Sujoy Dasgupta
Dr Sujoy Dasgupta presented the study on "Couples presenting to the infertility clinic- Do they really have infertility? – The unexplored stories of non-consummation" in the 13th Congress of the Asia Pacific Initiative on Reproduction (ASPIRE 2024) at Manila on 24 May, 2024.
Title: Sense of Taste
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 structure and function of taste buds.
Describe the relationship between the taste threshold and taste index of common substances.
Explain the chemical basis and signal transduction of taste perception for each type of primary taste sensation.
Recognize different abnormalities of taste perception and their causes.
Key Topics:
Significance of Taste Sensation:
Differentiation between pleasant and harmful food
Influence on behavior
Selection of food based on metabolic needs
Receptors of Taste:
Taste buds on the tongue
Influence of sense of smell, texture of food, and pain stimulation (e.g., by pepper)
Primary and Secondary Taste Sensations:
Primary taste sensations: Sweet, Sour, Salty, Bitter, Umami
Chemical basis and signal transduction mechanisms for each taste
Taste Threshold and Index:
Taste threshold values for Sweet (sucrose), Salty (NaCl), Sour (HCl), and Bitter (Quinine)
Taste index relationship: Inversely proportional to taste threshold
Taste Blindness:
Inability to taste certain substances, particularly thiourea compounds
Example: Phenylthiocarbamide
Structure and Function of Taste Buds:
Composition: Epithelial cells, Sustentacular/Supporting cells, Taste cells, Basal cells
Features: Taste pores, Taste hairs/microvilli, and Taste nerve fibers
Location of Taste Buds:
Found in papillae of the tongue (Fungiform, Circumvallate, Foliate)
Also present on the palate, tonsillar pillars, epiglottis, and proximal esophagus
Mechanism of Taste Stimulation:
Interaction of taste substances with receptors on microvilli
Signal transduction pathways for Umami, Sweet, Bitter, Sour, and Salty tastes
Taste Sensitivity and Adaptation:
Decrease in sensitivity with age
Rapid adaptation of taste sensation
Role of Saliva in Taste:
Dissolution of tastants to reach receptors
Washing away the stimulus
Taste Preferences and Aversions:
Mechanisms behind taste preference and aversion
Influence of receptors and neural pathways
Impact of Sensory Nerve Damage:
Degeneration of taste buds if the sensory nerve fiber is cut
Abnormalities of Taste Detection:
Conditions: Ageusia, Hypogeusia, Dysgeusia (parageusia)
Causes: Nerve damage, neurological disorders, infections, poor oral hygiene, adverse drug effects, deficiencies, aging, tobacco use, altered neurotransmitter levels
Neurotransmitters and Taste Threshold:
Effects of serotonin (5-HT) and norepinephrine (NE) on taste sensitivity
Supertasters:
25% of the population with heightened sensitivity to taste, especially bitterness
Increased number of fungiform papillae
5. Definition -
• An observational epidemiological study of persons with the disease
(or another outcome variable) of interest and a suitable control group
of persons without the disease (comparison group, reference group)
• Porta, M., ed. (2008). A Dictionary of Epidemiology (5th ed.). New York: Oxford University Press
6. FEATURES
1. Directionality:
outcome to exposure - clear definition of outcome is needed ….
2. Timing:
retrospective for exposure, but case-ascertainment can be either
retrospective or concurrent.
3. Sampling:
almost always on outcome, with matching of controls to cases
11. Issues in the Study Design
1. Formulation of a clearly defined hypothesis
2. Case definition – clearly defined at the outset of the investigation to
ensure that all cases included in the study are based on the same
diagnostic criteria.
3. Source of cases –The source of cases needs to be clearly defined.
12. Selection of cases
• Cases should be homogenous
• Criteria or definition of cases must be well formulated and documented
• If diagnostic tests are used to identify cases:
- Low-sensitivity tests & high specificity, will result in a lower number
of false positives
• If cases are misclassified (include false positives), the association may be
false.
13. Sources of cases
• Ideally, cases are a random sample of all cases of interest in the source
population (e.g. from vital data, registry data).
• More commonly they are a selection of available cases from a medical
care facility (e.g. from hospitals , clinics )
• Population based case-control studies are generally more expensive and
difficult to conduct
14. Characteristics of controls
• If cases are a random sample of all cases in the population, then controls should be
a random sample of all non-cases in the population sampled at the same time
(i.e. from the same study base)
• If study cases are not a random sample of the university, it is not likely that a
random sample of the population of non-cases will constitute a good control
population
15. • Comparability is more important than representativeness in the
selection of controls
• The control must be at risk of getting the disease.
• The control should resemble the case in all respects except for the
presence of disease
16. COMPARABILITY vs . REPRESENTATIVENESS
• Usually, study cases are not a random sample of all cases in the population, and
therefore controls must be selected so as to mirror the same biases that entered
into the selection of cases
• It follows from the above that a pool of potential controls must be defined.
• This pool must mirror the study base of the cases
17. STUDY BASE
• The study base is composed of a population at risk of exposure over a period of
risk of exposure.
• Cases emerge within a study base. Controls should emerge from the same
study base, except that they are not cases.
• If cases are selected exclusively from hospitalized patients, controls must also be
selected from hospitalized patients
18. • If cases must have gone through a certain ascertainment process (e.g. screening),
controls must have also (e.g. mammogram-detected breast cancer)
• If cases must have reached a certain age before they can become cases, so must
controls.
• If the exposure of interest is cumulative over time, the controls and cases must
each have the same opportunity to be exposed to that exposure.
• Example - if the case has to work in a factory to be exposed to benzene, the
control must also have worked where he/she could be exposed to benzene
23. Six issues in matching controls in case-control studies
1. Identify the pool from which controls may come. This pool is likely to reflect
the way controls were ascertained (hospital, screening test, telephone survey).
2. Control selection is usually through matching.
Matching variables (e.g. age), and matching criteria (e.g. control must be
within the same 5 year age group) must be set up in advance.
24. Controls can be individually matched or frequency matched
INDIVIDUAL MATCHING: search for one (or more) controls who
have the required MATCHING CRITERIA. PAIRED or TRIPLET MATCHING is
when there is one or two controls individually matched to each case.
FREQUENCY MATCHING: select a population of controls such that
the overall characteristics of the group match the overall characteristics of the
cases. e.g. if 15% of cases are under age 20, 15% of the controls are also.
25. Avoid over-matching. Match only on factors known to be causes of the disease
Obtain POWER by matching more than one control per case. In general, N of
controls should be < 4, because there is no further gain of power above four
controls per case.
Obtain GENERALIZABILITY by matching more than ONE TYPE OF
CONTROL
26. Measuring exposure
• Measurement of exposure is established after the development of
disease and as a result is prone to both recall and observer bias.
• The procedures used for the collection of exposure data should be the
same for cases and controls.
27. Various methods can be used to ascertain exposure status. These
include:
• –Standardized questionnaires
• –Biological samples
• –Interviews with the subject
• –Interviews with spouse or other family members
• –Medical records
• –Employment records
• –Pharmacy records
31. ODDS Ratio
• Measure of association between an exposure and an outcome.
• Odds that an outcome will occur given a particular exposure, compared to the
odds of the outcome occurring in the absence of that exposure.
• Most commonly used in case-control studies
• Can also be used in cross-sectional and cohort study designs as well (with
some modifications and/or assumptions).
32.
33. Confidence interval
• The 95% confidence interval (CI) is used to estimate the precision of the OR.
• A large CI indicates a low level of precision of the OR, whereas a small CI indicates
a higher precision of the OR.
• 95% CI is often used as a proxy for the presence of statistical significance if it
does not overlap the null value (e.g. OR=1)
• Presence of a positive OR for an outcome given a particular exposure does not
necessarily indicate that this association is statistically significant.
• The factors affecting the width of the CI include the desired confidence level, the
sample size and the variability in the sample.
34. ODD ratio≠ RR
• If the disease condition (event) is rare, then the odds ratio and
relative risk may be comparable .
• But the odds ratio will overestimate the risk if the disease is more
common.
• In such cases, the odds ratio should be avoided, and the relative risk
will be a more accurate estimation of risk.
35. Clinical vs statistical significance
1. Clinical importance is best inferred by looking at the effect size, that is how
much is the actual change or difference.
2. However, statistical significance in terms of P only suggests whether there is
any difference in probability terms
3. One way to combine statistical significance and effect sizes is to report CIs.
4. If a corresponding hypothesis test is performed, the confidence level is the
complement of the level of significance, that is a 95% CI reflects a significance
level of 0.05, while at the same time providing an estimate of the ‘true’ value.
36. Advantages:
1. Only realistic study design for uncovering etiology in rare diseases
2. Important in understanding new diseases
3. Commonly used in outbreak investigation
4. Useful if induction period is long
5. Relatively inexpensive
37. Disadvantages:
1. Susceptible to bias if not carefully designed
2. Especially susceptible to exposure misclassification
3. Especially susceptible to recall bias
4. Restricted to single outcome
5. Incidence rates not usually calculable
6. Cannot assess effects of matching variables
38. What is bias and confounding ?
Any systemic error in the design, conduct or analysis of a study
that results in a mistaken estimate of an exposure’s effect on the risk of
disease is called BIAS
A third variable or a mediator variable, can adversely affect the
relation between exposure and outcome is called Confounding
39. 3 important biases in case control study
• Selection bias
• Recall /information bias
• Confounding bias
40.
41.
42.
43. Prevention of confounding
• Before study -
• Randomization (Intervention study )
• Restriction ( Cohort, Case-control)
• Matching (Case-control)
After study –
• Adjustment
• Stratification
• Multivariate analysis
44. Restriction
• A method that limits participation in the study to individuals who are
similar in relation to the confounder
• Problem – 1. Reduces eligible population , 2. Limits generalizability (
external validity )
45. Matching
• Controls and cases are similar in variables, which may be related to the topic of
studying BUT are not of interest in themselves.
48. Table 4: Adjusted and unadjusted odds ratio of variables for the presence of diabetic
nephropathy.
49. SOME IMPORTANT DISCOVERIES MADE IN CASE CONTROL STUDIES
1950’s
• Cigarette smoking and lung cancer
1970’s
• Diethyl stilbestrol and vaginal adenocarcinoma
• Post-menopausal estrogens and endometrial cancer
50. 1980's
1. Aspirin and Reyes syndrome
2. Tampon use and toxic shock syndrome
3. L-tryptophan and eosinophilia-myalgia syndrome
4. AIDS and sexual practices
1990's
1. Vaccine effectiveness
2. Diet and cancer
52. Section A : Are the results of the trial valid ?
53. An issue / hypothesis can be ‘focused’ In terms of
• The population studied
• Whether the study tried to detect a beneficial
or harmful effect
• Risk factors studied
1 . Did the study address a clearly focused issue?
54. 2. Did the authors use an appropriate method to answer their
question?
• Is a case control study an appropriate way of answering the
question under the circumstances
• Did it address the study question
55. 3. Were the cases recruited in an acceptable way?
1. looking for selection bias which might compromise validity of the findings
2. Are the cases defined precisely ?
3. were the cases representative of a defined population (geographically
and/or temporally)
4. Established reliable system for selecting all the cases
5. Incident or prevalent
6. Something special about the cases
7. Time frame of the study relevant to disease/exposure
8. Sufficient number of cases selected
9. Power calculation
56. 4. Were the controls selected in an acceptable way?
• Looking for selection bias which might compromise the generalizability of
the findings
• Were the controls representative of the defined population
(geographically and/or temporally)
• Something special about the controls
• Matched, population based or randomly selected
• Was there a sufficient number of controls selected
57. 5. Was the exposure accurately measured to minimise bias?
1. Looking for measurement, recall or classification bias
2. Was the exposure clearly defined and accurately measured
3. Did the authors use subjective or objective measurements
4. Do the measures truly reflect what they are supposed to measure (have they been
validated)
5. Were the measurement methods similar in the cases and controls
6. Did the study incorporate blinding where feasible
7. Is the temporal relation correct (does the exposure of interest precede the outcome)
58. • 6.(a) Aside from the experimental intervention, were the groups
treated equally?
= author may have missed • genetic • environmental • socio-economic
• (b) Have the authors taken account of the potential confounding
factors in the design and/or in their analysis?
= Look for • restriction in design, and techniques e.g. modelling,
stratified-, regression-, or sensitivity analysis to correct, control or
adjust for confounding factors
60. Consider
1. what are the bottom line results
2. Is the analysis appropriate to the design
3. How strong is the association between exposure and outcome (look
at the odds ratio)
4. Are the results adjusted for confounding, and might confounding
still explain the association
5. Has adjustment made a big difference to the OR
7 . How large was the treatment effect?
61. 8. How PRECISE was the estimate of the treatment effect?
• size of the p-value
• size of the confidence intervals
• have the authors considered all the important variables
• how was the effect of subjects refusing to participate evaluated
62. 9. Do you believe the results?
1. big effect is hard to ignore!
2. Can it be due to chance, bias, or confounding
3. are the design and methods of this study sufficiently flawed to make the results
unreliable
4. consider Bradford Hills criteria (e.g. time sequence, does-response gradient,
strength, biological plausibility)
64. 10. Can the results be applied to the local population?
• The subjects covered in the study could be sufficiently different from
our population to cause concern
• Local setting is likely to differ much from that of the study
• Can the local benefits and harms be quantified
65. 11. Do the results of this study fit with other available evidence?
• All the available evidence from RCT’s Systematic Reviews, Cohort
Studies, and Case Control Studies as well, for consistency
66. Precision
• In observational study, precision determined by sample size and the
efficiency of the study.
• larger study and one with more balanced groups - more precise
estimates
• A large standard deviation relative to the estimate indicates low
precision.
• wide confidence intervals for estimates of association (e.g., odds
ratios or relative risks) indicate low precision.
67. Validity
• Whereas precision is a lack of random error, validity refers to a lack of
systematic error
• Internal validity refers to the strength of the inferences from the study
• For internal validity , conclusions can be logically drawn from the results
produced by an appropriate methodology.
• External validity is the ability to generalize study results to a more universal
population
68. Other check lists
• Joanne Briggs Checklist for Case Control Studies
• SIGN Case-Control Studies Checklist
• STROBE Checklist
69.
70.
71. Take home message
• One observational study like case control study rarely provides
sufficiently robust evidence to recommend changes to clinical
practice or within health policy decision making.
• However, for certain questions observational studies provide the only
evidence.
• Recommendations from observational studies are always stronger
when supported by other evidence
72. References
• Explaining odds ratios., Szumilas M,, Journal of the Canadian Academy of Child and Adolescent Psychiatry, 2010 Aug
• Understanding relative risk, odds ratio, and related terms: as simple as it can get., Andrade C,, The Journal of clinical psychiatry, 2015 Jul]
• Cummings P, The relative merits of risk ratios and odds ratios. Archives of pediatrics Grant RL, Converting an odds ratio to a range of
plausible relative risks for better communication of research findings. BMJ (Clinical research ed.). 2014 Jan 24;
• THE LANCET • Vol 359 • February 2, 2002
• Lancet2005; 365: 1429–33
• Critical Appraisal Skills Programme (2018). CASP (insert name of checklist i.e. Case Control Study) Checklist. [online] Available at: URL.
Accessed: Date Accessed