Unit Test 1 Flashcards
1
Q
epidemiology
A
the study of health in populations specific to diseases and conditions and how they’re acquired
2
Q
goals of epidemiology:
A
- describe distribution of a disease
- identify risk factors for the disease
- prevent the disease
3
Q
epidemic
A
larger than normal outbreak of a disease within a certain region
4
Q
pandemic
A
if a disease outbreak spreads to other parts of the world
5
Q
who is the father of epidemiology?
A
John Snow, english physician: the first to determine that cholera epidemic in London was a result of the lambeth company water supply contamination from the Thames river
6
Q
John Snow’s legacy
A
paved the way for:
- cleaning the water supply in London
- Germ theory
- population and preventative medicine
7
Q
what is the leading cause of death in first world countries?
A
chronic disease where it used to be infection, acute disease, etc.
8
Q
behavioural epidemiology
A
the observation and study of behaviours that lead to health related states
- also the distribution of these behaviours
9
Q
comorbidity
A
having more than one disease at a time
10
Q
3 goals of physical activity epidemiology:
A
- examine the relationship b/w morbidity and mortality
- identify patterns and determinants of PA
- use evidence to determine things for disease prevention
11
Q
morbidity
A
having a diseased state
12
Q
mortality
A
dying
13
Q
PA can be considered a burden in canada for a few reasons. what are some direct and indirect costs?
A
direct: drugs, hospitals, physician care
indirect: work loss due to disability, things don’t get done when people are sick
14
Q
physical benefits of PA on morbidity
A
- decreased risk of CVD, colon cancer and type 2 diabetes
- protects against breast and prostate cancer, osteoporosis
- prevents and reduces obesity
15
Q
the most healthcare dollars are spent on these diseases
A
coronary artery disease stroke colon cancer breast cancer type 2 diabetes hypertension
16
Q
psychological benefits of PA
A
relieved symptoms of depression, anxiety
improves mood, body image and quality of life
17
Q
history of PA and health
A
see slide pack for this one bc wow this is a lot
18
Q
what are the landmark studies in epi?
A
they provide evidence that PA and health outcomes are related
- London bus study
- Framingham heart study
- Longshoremen study
- Harvard alumni study
19
Q
London bus study
A
1950s UK by Jerry Morris
- a retrospective study
examined link b/w occupations PA and health by measuring heart disease in double decker bus drivers vs conductors
20
Q
what is myocardial infarction?
A
heart attack
21
Q
results of london bus study
A
found that conductors were at lower risk of heart disease than drivers regardless of their age
22
Q
what were some limitations of the london bus study?
A
we can’t conclude anything based on this evidence.
- we don’t know about their leisure activities, daily activities (eating, smoking)
- job stress?
- self selection for the job, could this be just coincidence that lazy people get CVD and choose to be bus drivers than conductors
23
Q
Framingham heart study
A
1949 to present in the US in small town Massachusetts
- a prospective study that followed people over time to see what happens
is there a link b/w lifestyle and health,
>5000 people : men and women, predominantly white, testing and surveyed every 2 years
24
Q
whats the difference between a retrospective study and a prospective study?
A
retrospective: take what you know now and look into history to find out more
prospective: follows people over time and see what happens
25
results of framingham heart study
there were controllable and uncontrollable risk factors
- most things were controllable: smoking, diet, PA rates, alcohol and obesity levels
- uncontrollable: gender, genetics, ethnicity
26
limitations of framingham heart study
only white people, not a very ethnically diverse pop
| - this has changed now to incorporate a more diverse pop of people but initially not
27
Longshoremen study
3500 longshoremen studied in 1951-1972
prospective cohort study
- dockworkers vs supervisors; looked at PA throughout the day
28
results from the longshoremen study
8500kcal/week reduced risk of death due to CHD (coronary heart disease) by 50% WOW
29
limitations of longshoremen study
all men
we don't know about leisure time activities
had some screenings tests but people weren't self selecting which jobs they had
30
Harvard alumni study
1960s
retrospective but also kept track over time prospectively
- researchers sent questionnaires to alum. about PA habits
31
results from harvard alumni study
3 hrs/week of PA could reduce overall death rates by 50%
- even walking helped decrease rate by 33%
- active men lived 2 years longer than inactive men
32
limitations of harvard alumni study
white men all of high socioeconomic status (they were in uni)
33
PA guidelines
| ** these are important **
WHO in 2011
" 150 min mod-intensity PA/week or 75 min vigorous PA/week " - in bouts of 10 mins or more
increase moderate PA to 300 min/week over time or 150 vigorous PA/week but w/e
-- resistance exercise 2 or more days/week
34
risk factor
not necessarily cause of disease but increases the probability of getting that disease, compared to groups that don't have that characteristic
35
incidence
new cases of a health related state that occurs in a population during a specific time period
36
prevalence
number of existing cases (new and old) in a population at a specific point in time
37
how to calculate prevalence rate:
```
# of cases in pop/
# of people in the pop
```
38
why is it not particularly useful to know the number of incidence or prevalence rates
- it doesn't give any info about total pop or if this is a good or bad thing
THUS, it's more important to know the rates of incidence or prevalence
39
how should we express prevalence rates?
as a percent or per 100, 1000, 10,000, etc
40
what does it mean when prevalence rates are high?
bad: lots of people have the disease
good: people aren't dying from the disease
41
how to calculate incidence rates:
```
# of new cases/
# of people in the pop
```
42
categories of rates
crude, specific, and standardized (adjusted)
43
crude rates
- based on total pop w/o considering pop characteristics
44
specific rates
- computed separately for different sub-populations
| ex. diseases that only affect women/men
45
standardized rates
are adjusted so that they make sense by factoring in the effects of some known population characteristics
-- used for comparing 2 or more populations
46
what is the scientific method?
a systematic way of collecting data so we can have fact based explanations about things
- results need to be reproducible
47
what is research design?
an analytic approach used to evaluate a research question
| - how you set up a study to examine the assoc b/w 2 or more variables
48
what are the 4 steps in the scientific method?
1. developing and defining the problem
2. formulating the hypothesis
3. gathering data
4. analyzing and interpreting the results
49
dependent vs independent variables
dependent: is observed and measured, does not receive manipulation
independent: is manipulated by the researcher and looked at change it causes to the DV
50
hypothesis
a prediction that involves facts and guides observations
| - the prediction must be testable
51
how does the process of publishing scientific research work?
- submit research to a journal, the more reputable the better
- article is peer reviewed and avoids conflicts of interest
- study is accepted or rejected
- - once published, it can't be removed, it can only be retracted
52
primary vs. secondary source articles
primary: actual research study that's been run
secondary: summarize a lot of research out there based on keyword searches and put it all together
53
what is the goal of research design in PA epidemiology?
to answer the research question and:
- determine the effect PA has on a particular disease or condition
- determine the consequences PA has on env't, personality char, etc
54
what are the 2 general types of study designs?
observational designs and experimental designs
55
observational study designs
and ex.
examine the association b/w IV and DV as they occur naturally
ex. cross sectional study, prospective cohort study, case-control study
56
experimental study designs
and ex.
the investigator manipulates the IV and looks at the effects on the DV
ex. randomized control trials
57
cross-sectional studies
looks at one pop at a particular point in time
advantages: fast and easy to conduct
* * disadvantages: can't determine direction of assoc (what caused what)
- also can't determine cause and effect
58
case-control studies
pops of people w similar char. are compared to to people in a diseased pop and looks at events that may have put them at risk for the disease
adv: cheap and easy, good for studies of rare things
disadv: can't determine cause and effect
can't determine incidence rates bc not following over time
recall bias - sub can't remember correctly 10 ya
59
prospective cohort studies
follows a group of people over time and sees what diseases they dev'p
adv: can study many outcomes simultaneously AND can measure incidence
disadv: can't determine cause and effect
v. resource intensive, also problem w loss of follow up
60
randomized control trials
randomly assign people to experimental and control groups, change IV in exp group and don't in control
adv: GOLD STANDARD bc can determine cause and effect
disadv: v. expensive, ethical concerns (don't ask tough questions), loss of follow up, hard to examine rare outcomes
61
relative risk (RR)
aka risk ratio
| - risk of disease in people exposed to a risk factor relative to the people not exposed to the risk factor
62
what are threats to determining cause and effect in epi studies?
confounding variables and effect modifiers
63
how do we determine causes in epi studies?
5 criteria (Mills Cannons): determines if data has statistical significance
- temporal sequence
- strength of association
- consistency
- dose-response relationship
- biological/conceptual plausibility
64
what is a confounding variable?
no relationship b/w A and B, it's actually a separate variable that has an effect
65
effect modifiers
alters the relationship b/w A and B but a relationship still exists
66
physical activity definition
any body movement produced by skeletal muscle that results in energy expenditure
ex. beings asleep then getting up
67
exercise def
any form of PA w an objective such as improving health, fitness, etc
68
what is physical fitness?
physical attributes relating to one's morphological, muscular, motor, cardioresp and metabolic capabilities
ex. fit but fat
it is the number one predictor of risk!
69
sedentary behaviour
any waking activity (not asleep) char by energy expenditure of or less than 1.5 METS (metabolic equivalents)
70
risk difference
aka attributable risk
- what's actually attributed to the risk itself
== risk of diseased among exposed - risk of disease among non exposed
- shows how much of the risk is attributable to the disease
71
how many METs of energy are we using at rest?
about 1 MET
72
what are some challenges of measuring PA?
- its a complex construct with many varying aspects
ie. FITT - Frequency, Intensity, Type, Time can all change
- there are diff ways people do PA (occupational, leisure, activities of daily living)
73
3 things a study must be:
valid
reliable
feasible
74
reliability
a study is reliable if it produces the same results over and over again
75
validity
a study is valid if it actually measures what you think you're measuring
- the most valid measures are often v. expensive, making them less feasible
76
feasibility
is the measurement tool you've chosen realistic to use with the resources you've got available
77
3 types of measures
subjective/self report
objective
criterion
- validity increases as you go down the list
- feasibility decreases as you go down the list
78
subjective measures of PA
get info through interview questionnaires or activity diaries
79
advantages and disadvantages of subjective measures of PA
adv: can be done on large scale, recording a variety of measures, cheap, easy to administer and add up data
disadv: social desirability, recency effects have an influence on whether person is honest
- sometimes confusion w questionnaires
80
objective measures of PA
you measures someone's PA w some type of tool collecting data
includes heart rate monitors, pedometers, accelerometers
81
advantages and disadvantages of heart monitors
is an objective measure of PA, as you increase your HR you typically use more energy
adv: valid, easy to collect data and see change over time, small, noninvasive and fairly cheap
disadv: can't use on large scale studies, only measures HR, not intensity of PA
82
criterion measures of PA
reference methods/gold standards
- measure things like kcals used and energy expenditure throughout the day
include: direct observation, doubly labeled water, indirect calorimetry
83
advantages and disadvantages of pedometers
an objective measure of PA, where # of steps = distance travelled = general amount of energy used
adv: get immediate feedback, CHEAP
disadv: can't tell the difference b/w types, intensity, duration of PA, if worn on hip it only monitors activities when moving up and down
84
advantages and disadvantages of accelerometers
an objective measure of PA, that measures acceleration in different planes
adv: small, moderate price range, not intrusive, memory GPS avail
disadv: error is wearing on your wrist bc not accurate for activities when you move your arms a lot
- not as good if not research grade
85
advantages and disadvantages of behavioural observation
criterion measure of PA, where 2 trained observers watch and record daily activities
adv: non-invasive, valid, accurate
disadv: expensive to pay people to observe, people may be more motivated to do more activity, not an option for large pop. studies and better for short durations
86
advantages and disadvantages of double labeled water
criterion measure of PA, considered to be the gold standard for measuring energy expenditure (4-7% error)
- ingesting H and O isotope drink and measure CO2 production from urine output
adv: stays accurate for 3 weeks
disadv: VERY expensive (drink, urinalysis) all you know is total energy expenditure for the day
ideal for small experimental studies and establishing validity of other measures such as part of a pop survey
87
advantages and disadvantages of indirect calorimetry
adv: very accurate, gives info re: intensity and duration of PA in a lab setting
disadv: costly and invasive where you have to wear a mask
88
direct vs indirect calorimetry
both criterion measures of PA
direct: uses bomb calorimeter where energy expenditure=heat production from a sealed chamber
- very expensive
indirect: analysis of O2 consumption and CO2 production in expired air
- like a VO2max test
89
factors affecting physical fitness
genetics: some people have to do v little PA to improve their PF, some people who do PA get worse PF
type and amount of PA- those more active generally have better physical fitness, certain types of PA are good for different aspects of physical fitness
90
reasons epidemiologist measure physical fitness:
to determine if PF is:
1. an outcome of PA
2. a mediator of PA
3. a moderator of PA
91
explain fitness as an outcome of physical activity
questions how PA has an impact on fitness variables directly
92
explain fitness as a mediator of PA
as a middle step, PA changes the fitness variable and the fitness variable the determinant of risk
ex. PA -> PF factors -> risks of certain disease
93
explain fitness as a modifier of PA
aka as an effect modifier
94
how is PA prevalence studied in the world?
most developed nations use surveillance but its hard to compare a lot of the data
- so the WHO has created a standardized survey used in 40 countries
95
how is PA prevalence studied in the US?
BRFSS - behavioural risk factor surveillance system
| a randomized telephone survey about inactivity levels, diet, smoking, alcohol, etc
96
how is Canadian PA data collected?
the canadian physical activity monitor takes national telephone surveys
respondents are 51% and most are females w a uni degree
97
canada health measures survey
an accelerometer study found that surveys weren't actually true about 50% of canadians being accurate, it was more like 15%
98
Factors related to PA levels
1. age: older get less exercise
2. gender: men exercise more
3. ethnicity
4. income
5. education level
99
what does ethnicity have to do w PA levels?
- lowest PA rates in Asian Canadians
| - highest PA rates in Aboriginal Canadians
100
what does income have to do w PA levels?
it affects your ability to participate in organized PA
| use sports as socialization
