Midterm Flashcards
(103 cards)
1
Q
Epidemiology comes from the Greek:
A
Epi=among/upon
Demos=people
logy=study
2
Q
How did John Last define Epidemiology
A
The study of the distribution of health related states or events in specific population and the application of this study to the control of health problems
3
Q
What are the objectives of Epidemiology
A
- investigate the etiology (cause) of disease and modes of transmission
- determine the extent of disease problems i the community
- study the natural history and prognosis of disease
- evaluate both existing and new preventive and therapeutic measures and modes of health care delivery
- provide a foundation for developing public policy and regulatory decisions
4
Q
What is the link with public health?
Public health use quantitative methods which combine which 2 disciplines
A
Epidemiology and biostatistics
5
Q
Epidemiology is about the understanding of _________________ and the methods used to uncover the the ______, ________, and ____________ of the disease
A
Epidemiology is about the understanding of disease development and the methods used to uncover the the etiology, progression, and treatment of the disease
6
Q
information and data is collected to investigate a question and then..
A
the methods and tools of biostatistics are used to analyze the data to aid decision making
7
Q
what are the 6 roles of epidemiology in public health
A
- Address a public health question
- Conduct a study
- Collect Data
- Describe the observations/data
- Assess the strength of evidence for/against a hypothesis; evaluate the data
- Recommend interventions or preventive programs
8
Q
How do you address a public health question
A
- generate a hypothesis based on scientific rationale
- based on observations or anecdotal evidence (not scientifically tested)
- based on results of prior studies
9
Q
What are the 4 main types of studies
A
- survey study
- surveillance study
- observational study
- experimental study
10
Q
What is a survey study used for
A
used to estimate the extent of the disease in the population
11
Q
what is a surveillance study designed to monitor
A
designed to monitor or detect specific diseases
12
Q
what do observational studies investigate
A
investigate the association between an exposure and a disease outcome. they rely on natural allocation of individuals to exposed or non-exposed groups
13
Q
what do experimental studies investigate
A
the association between an exposure, often therapeutic treatment, and disease outcome. individuals are intentionally placed into the treatment groups by the investigators
14
Q
what kind of data is collected
A
numerical facts, measurements or observation obtained from an investigation to answer a question
influenced of temporal and seasonal trends on the reliability and accuracy of data
15
Q
how can the observations/data be described
A
descriptive statistical methods provide and exploratory assessment of the data from a study exploratory data techniques organization and summarization of data tables graphs summary measures
16
Q
How to assess the strength of evidence for/against a hypothesis
A
inferential statistical methods provide confirmatory data analysis:
- generalize conclusions from data from part of a group to the whole group
- assess the strength of the evidence
- make comparisons
- make predictions
- ask more questions; suggest future research
17
Q
how to recommend interventions or preventive programs
A
results can appear in a peer-review publication or are disseminated to the public by other means
the policy/action can range from developing specific regulatory programs to general personal behavioural changes
18
Q
Define physical activity
A
body movement produced by skeletal muscles contraction that requires energy expenditure
19
Q
define exercise
A
a type of PA that is planned, structures and repetitive done to improve or maintain components of physical fitness
20
Q
define disease
A
reduced, abnormal or lost structure or function of ells, organs or systems of the body
21
Q
define health
A
state of complete physical, mental and social well-being and not merely the absence of disease or infirmity
22
Q
define morbidity
A
the quality or state of being morbid; morbidness
of or related to disease, having a gloomy state of mind
23
Q
define prevalence
A
how many people have this disease right now
24
Q
define incidence
A
how many people per year newly acquire this disease
25
define mortality
death rate
26
define aetiology/etiology
the cause/origin of a disease or disorder
27
what is physical activity epidemiology
Studies factors associated with participation in physical activity and how this behaviour related to the probability of disease or injury
28
What is cholera
Was the start of epidemiology
still exists but it is less prevalent
used to be an epidemic back in the day
29
Cholera in the 1800's
Epidemics across Europe since the 16th Century
Notable in London in 1840s
Major outbreak in 1853-1854
30
What was the original theory of Cholera
- It was attributed to miasma
- Fecal contamination and exposed to a bad smell
- People who lived in poor conditions (stigma)
31
Who is John Snow
- London based physician
- looked at deaths and water pump locations
- Believed the cause was the drinking water
- Then notices mortality has nothing to do with the water pumps, only the center water pump which was probably contaminated
32
What did John convince local authority to do? And then what happened
Remove handle on the pump, the outbreak subsided
| This small change really helped. Disease and potential causal factors = start of epidemiology
33
What happened next in 1855?
Mortality data on 300,00 people living in London
Went door to door to ask who supplied water
Linked certain companies to high rates of cholera deaths
Companies found to supply unfiltered water
1883 Vibrio Cholerae found by Robert Koch
34
John Snow was the 1st?
Epidemiologist, person to use stats, anesthesiologist
| in 1853 established that cholera was spread through water
35
What are the 3 goals of epidemiology
1. Describe the distribution of disease (who, where, when)
2. Analyze the info to identify risk factors
3. Prevent disease by modifying the identified risk factors
36
When was exercise first used as a therapy
```
-2500 B.C:
china used structured exercise for health promotion
-480 B.C:
Herodicus,
therapeutic gymnastics
therapy based on vigorous exercise
```
37
Who is the father of medicine
Hippocrates 460-377 B.C
| Initially criticized Herodicus and then later agreed on the benefit of exercise
38
Who is Galen
```
130-201 AD
Roman Physician
2 Uses of exercise:
1. Evacuation of excrements
2. Production of the good condition of the firms parts of the body
```
39
Who is Geronimo Mercuriali
- 1530-1606
- Italian philologist and physician
- De Arte Gymnastica: 1569 was the first book on sports medicine and was the foundation of modern rehabilitation medicine
40
Who is William Heberden
- 1710-1801
- British Physician
- 1802: Exercise as a cure for heart disease
- "I know one who set himself a task of sawing wood half an hour every day, and was nearly cured"
41
When was the first article to link CHD with PA published
1953 Morris et al
42
Describe the outcome of the morris et al research
Bus drivers had a higher incidence of acute myocardial infarction and 3 month mortality rate than the conductors
Post men also compared to telephonists and clerks
43
What is the Harvard Alumni Health Study
-17,000 male Harvard graduates were disease free at baseline reported their activity, clinical history and parental history and were followed from 1960-1986
44
What were the results (Paffenbarger et al)
- As weekly energy expenditure increased, all cause mortality and CVD death rates decreased
- Active men gained 1.25 years of life up to age 80
- For each hour spent exercising each week they gained 2 hours of life
45
What is the relationship between relative risk and physical activity volume
The relative risk of all cause mortality decrease and physical activity volume increases expect when kcal exceeds 3500 (prob because its too much and can cause injury and problems)
46
Define a risk factor
- a clearly defined occurrence or characteristic that has been associated with the increased rate of a subsequently occurring disease
- activity or factor that may increase the chance of developing disease
47
Define association
- A connection of persons, things or ideas by some common factor
- a relationship resulting from interaction or dependance
- a functional connection of two ideas, events or psychological phenomena
48
Define causation
The act or process of causing or the act/agency that produces and effect
49
What are the different types of questions/domains
- Etiology (cohort, case control)
- Therapy (RCT)
- Prognosis (cohort)
- Harm (cohort, case control)
- Diagnosis (cross-sectional, case control)
- Economic (cost-effectiveness analysis)
50
What is a cohort study
cohort study design identifies a people exposed to a particular factor and a comparison group that was not exposed to that factor and measures and compares the incidence of disease in the two groups.
51
What is a case control study
identify a group of individuals who had developed the disease (the cases) and a comparison of individuals who did not have the disease of interest. The cases and controls are then compared with respect to the frequency of one or more past exposures
52
What is a cross sectional study
is a type of observational study that analyzes data from a population, or a representative subset, at a specific point in time
53
What does PICO stand for
P: who is the patient or what problem is being addressed
I/E: what is the intervention or exposure
C: what is the comparison group
O: what is the outcome or endpoint
54
What is an independent variable
(Exposure or manipulated)
| A variable used to define treatment groups
55
what is a dependent variable
(measured)
| A variable whose values in different treatment conditions are compared.
56
Define multicausality
every causal mechanism involves the joint action of (multiple) component causes
57
Define Sufficient cause
- The whole pie
- A minimum set of conditions without any one of which the disease would not have occurred
- Not usually a single factor, often several (each factor (slice) is a component cause)
58
Define component cause
- An event or condition that plays a necessary role in the occurrence of some cases of a given disease
- “Interact” to produce disease
- A disease may have several sufficient causes (several pies can produce the same disease)
59
Three Different models: in order of importance
| for CAD
1- Age
2- High cholesterol
3- Smoking
4- Obesity
1- genetic predisposition
2- sex
3- menopause
4- hormone replacement therapy
1- Hypertension
2- Unknown factor
3- Maternal under-nutrition
4- Diabetes
60
What is a necessary cause
A component that appears as a member of each sufficient cause
61
What is a strong cause
A strong cause is a component cause that plays a causal role in a large proportion of the cases, whereas a weak cause would be a casual component in a small proportion of cases
62
Induction period
period of time beginning at the action of a component cause & ending when the final component cause acts & the disease occurs
63
Latency period
Latency period: refers to time delay between disease occurrence & its detection (i.e. diagnosis)
64
What are the criteria for causation
Temporal Sequence
Strength of association
Consistency
Dose response
Biological Plausibility
65
Temporal Sequence
Exposure of the risk factor must precede development of the disease with sufficient time to account for disease progression
66
Strength of Association
There is a large and clinically meaningful difference in disease risk between those exposed and those not exposed to the risk
67
Consistency
The observed association is always observed if the risk factor is present (e.g., regardless of sex, race, age, or methods of measurement)
68
Dose Response
The risk of disease associated with the risk factor is greater with stronger exposure to the risk factor
>exposure to risk factor, > risk of disease
69
Biological Plausibility
The observed association is explainable by existing knowledge about possible biological mechanisms of the disease, which may be alterable (e.g., by physical activity)
70
Describe the Whitehall 1 study
(1967)
18,000 men in the British Civil Service
Socio-economic inequalities in health did not appear to be fully accounted for by differences in well-known risk factors, such as smoking
71
Describe the whitehall II study
Whitehall II study (1985, Professor Sir Michael Marmot, UCL)
To determine other factors that might contribute to this social gradient in death and disease, and to include women
72
?
social class differences in health on the map and investigate
contribution of unhealthy behaviours and traditional risk factors (such as high blood pressure) in heart disease and diabetes, as well as the importance of psychosocial factors such as:
over 500 research papers have been published based on data collected
73
Why are accurate assessments/measures of PA needed
- Understand the specific amounts of physical activity that are needed for health benefits
- Moderate of at least an hours
But what about QOL benefits?
-Determine if a particular behavioral intervention was successful in changing activity behavior
74
What are the consideration when determining the accuracy of an assessment tool
Validity: measure what you’re supposed to measure
Reliability: make sure its reliable among diff people measures
Sensitivity: precision is it able to detect small enough changes
75
Give examples of subjective measures
Questionnaires, Surveys, Interviews, Logs
76
How can subjective measures vary
Complexity
- Self-administered to interviewer administered
- Single question to multiple components
Time Frame of Recall
-Past day, past week, past month, past year, historical/lifetime
77
What are the types of activities assessed using subjective measures
Leisure, occupational, household/self care activities, transportation
78
What are the PROs of a Recall Survey
-Non-Reactive
-Practicality+ Applicability
Quick(-ish)
Easy(-ish)
Cheap(-ish)
-Accuracy
When comparing groups
-FITT?
Frequency intensity time and type
79
What are the CONs of a Recall Survey
- Does not reflect total energy expenditure
- Reliability and validity
-Misinterpretation
across different populations
Ex. Give the same questionnaire to athletes and children with CP obvi not good
-Social Desirability Bias
When you answer to make yourself look good
-Proxy
How close in time did you actually asses the physical activity
80
What are the pros of a LOG/Diary
-Practicality + Applicability
Easy(-ish)
Cheap(-ish)
-FITT?
-Good for small groups
Get a lot of data so you don’t want a diary from 10,000 ppl
81
What are the CONs of LOG/Diary
- Responsiveness
- Social desirability
- Proxy
- Long
82
Objective Measures
-Energy Expenditure
-Indirect Calorimetry
Uses respiratory gas analysis to measure energy expenditure.
Measure oxygen consumption
You’re not actually measuring heat expended
-Doubly-labeled water
Uses biochemical markers to estimate energy expenditure
83
Objetive Monitors
Pedometer
Record steps taken and offer the ability to estimate the distance walked, if stride length is known
Pros: small, cheap, easy, good for large groups, measures walking, can be used in many settings
Cons: does not measure FITD, no context, reactivity, doesn’t measure stride length or intensity, often go with logs
Activity Monitors
Assess the acceleration of the body in one or more planes of movement
Pros: FITD, small, easy, can go directly to the researcher (chip), can measure displacement, intensity
Cons: expensive, large groups?, no context, heavy analysis
84
Heart Rate Monitor (objective monitor(
Heart Rate Monitor
-Heart rate is a direct indicator of one’s physiological response to physical activity and then you can quantify energy expenditure
-Heart rate is used as an indirect estimate of energy expenditure
Due to linear relationship between exercise workload/intensity, heart rate, and energy expenditure
As workload/intensity increases, heart rate and energy expenditure increases
85
Subjective Vs. Objective Measured
Subjective:
Less accurate
Rely on “opinion”
Social Desirability Bias
Objective Measures:
Accurate
Impartial
86
Physical Fitness
A set of attributes that individuals have or can achieve that relates to the ability to perform physical activity.
87
Physical Fitness can be broken down into five (5) major components:
1. Cardiorespiratory fitness
2. Body comp
3. Flexibility
4. Muscular fitness
Strength
Endurance
88
Cardiorespiratory Fitness
Can be measured directly using maximal exercise testing (VO2max) or indirectly using submaximal exercise and field test protocols
Need treadmill mask (any exercise equipment) bike metabolic cart
89
Maximal Oxygen Uptake (VO2max)
```
Often used as an objective measure of CR fitness
VO2max and Epidemiology Studies
Time consuming, resources
Other factors that may influence PA & fitness
Genetics
Gender
Age
Relative weight
```
90
Submaximal VO2 Tests
(Practical) option for large Epidemiological Studies
Use heart rate (HR) to predict O2 consumption
Linear relationship between HR and exercise workload/intensity
As workload/intensity increases, HR increases
Limitations/assumptions
91
Field Test
Prediction Equations to estimate VO2 max using:
Distance covered in a predetermined time
Ex: 20 m shuttle run
92
what is a randomized controlled trial
A study in which people are allocated at random (by chance alone) to receive one of several clinical interventions. One of these interventions is the standard of comparison or control. The control may be a standard practice, a placebo ("sugar pill"), or no intervention at all. Someone who takes part in a randomized controlled trial (RCT) is called a participant or subject. RCTs seek to measure and compare the outcomes after the participants receive the interventions. Because the outcomes are measured, RCTs are quantitative studies.
93
What is a true control
be careful sometimes articles lie cuz usually the control group does have some sort of intervention so its hard to say ur intervention is better than nothing. Can you really say aerobic is better than nothing? No cuz u don’t have a true group that’s really not getting any intervention
94
What is Randomization
Randomization: ensures that the experimental & control groups are comparable with respect to all factors, known or unknown, except for the factor addressed by the experimental intervention. Example: you can use a computer software program or pick out of a hat. Makes sure all groups are even. Want to avoid bias. Don’t choose a group because you think they’ll do better
Identify the specific population
95
Name some challenges to RCT
Motivation to participate if not randomized to intervention
Double-blind: you want this; when no one knows participants and researchers don’t know who is in what group
in exercise hard – obvi they know if they are working out.
Single blind: researches don’t know
Biases: poor compliance, dropout is bad cuz sample size go down, less power in analysis
External validity: sometimes if u have something well controlled, you don’t know if that’s valid in a different setting
Practicality with larger samples
96
What does HEARTY stand for
healthy eating aerobic and resistance training in youth
97
What was the inclusion criteria for theHEARTY trial
14- 18 yrs
Post-pubertal (Tanner stage ≥4) It’s a growth curve
Obesity: >95th BMI percentile (didn’t need risk factor)
OR
Overweight: 85-95th BMI percentile + diabetes risk factor (example: like family history, high insulin or insulin resistant..)
Physical activity: <2 weekly exercise sessions of >20 minutes each
Couldn’t be similar to trial
98
what were the variables measured and the methods used
Total and regional body comp=MRI
Anthropometry=weight, height, waist, hip
RMR=indirect calorimetry
Cardiorespiratory fitness (vo2 peak)=indirect calorimetry (objective measure)
Musculoskeletal fitness= 8 RM and CSEP tests (grip, push up, curl up, sit and reach vertical jump)
Traditional and nom traditional CVD risk factors= fasting blood measures and OGTT
99
What software waas used for the MRI analysis
Slice-o-matic software v 4.3
% body fat was the primary outcome
100
What is the frequency, intensity, type and time of the exercise program
Frequency= 4x/week
intensity= 65-85% HR max aerobic and 1-3 sets 15 RM resistance
type=treadmill, bike, elliptical aerobic and machines/dumbbells resistance
Time- 15-45 min aerobic and 20-45 min resistance
101
What were the conclusions of the HEARTY study
Combined aerobic + resistance training:
Largest in %body fat & waist
↑ Cardiorespiratory & musculoskeletal fitness
Combined training was superior to aerobic training alone:
Greater reductions in body fat, BMI, waist, muscular strength & endurance
102
Which group had the highest drop out rate and what was the reason for the drop outs
The resistance training group had the most drop outs and the main reason for the drop out was self conscious and depressions a lot of mental health predictors
103
What is the adherence rate in adults
50% discontinue within 6 months
