PH 150A MT2 EXAM WITH CORRECT SOLUTIONS
What two study designs are used to measure if a disease is associated with an
exposure? - ANSWER 1. Cohort
2. Case-control
Define risk. - ANSWER Probability of an event occurring (such as development of
disease or death over a specified observation window).
Why is incidence a greater measure of risk than prevelance? - ANSWER Prevalence can
also be affected by disease duration. Researchers are usually interested in things that
cause onset or acquisition of disease.
Define absolute risk. - ANSWER - Incidence of disease (mortality) in a population.
- Does NOT take into account the risk of disease in NON-exposed individuals but can
indication magnitude of risk in a group of people WITH exposure.
- does not indicate if exposure is ASSOCIATED with risk of disease (or death)
What are the two ways to calculate measures of association? - ANSWER 1. Difference in
absolute risks (incidence or death) = ABSOLUTE measure
2. Ratio of absolute risks (incidence or death) = RELATIVE measure
What are the three ways to calculate relative risk? - ANSWER 1. Incidence Density Ratio
(IDR) = relative rate (rate ratio)
2. Cumulative incidence ratio (CIR) = relative risk (risk ratio)
3. Odds Ratio (OR)
How do you calculate Incidence Density Ratio (IDR)? - ANSWER rate ratio = ID
exposed/ID unexposed
How do you calculate Cumulative incidence ratio (CIR)? - ANSWER risk ratio = CI
exposed/CI unexposed
How do you calculate Odds Ratio (OR)? - ANSWER Odds exposure diseased/odds
exposure not diseased
How do you calculate absolute risk? - ANSWER diseased population (exposed &
uneposed)/ total population
How do you calculate Relative Risk (RR)? - ANSWER Relative risk ratio = incidence in
exposed/incidence in unexposed
,What does it mean id RR = 1? - ANSWER Risk in exposed is equal to risk in unexposed
(no association)
What does it mean if RR>1? - ANSWER Risk in exposed is greater than the risk in
unexposed (positive association)
What does it mean if RR<1? - ANSWER Risk in exposed is less than risk in unexposed
(negative association)
In positive association, R ___ 1 ? - ANSWER >
In negative association, R ___ 1 ? - ANSWER <
Cohort Study Design - ANSWER non-randomly divide population into exposed and
unexposed
Case-Control Study Design - ANSWER Cases have the disease while controls do not
have the disease
True or False: Risk of disease can directly be estimated from a case-control study -
ANSWER False. Myst have values for incidence in exposed and non-exposed
What can you calculate in a case control study? - ANSWER Odds
What can you calculate in a cohort study? - ANSWER Risk
How do you calculate odds? - ANSWER - number of times event occurred/ number of
times the event did not occur
- odds of exposure in diseased individuals/odds of exposure in control individuals
- (a/c)/(b/d) = (ad)/(b/c)
How do you calculate odds using probability? - ANSWER p/(1-p) where p is the
probability of exposure or event occurring
What is the range of odds? - ANSWER 0(nobody has the event) to infinity (everyone has
the event)
What does it mean if OR=1? - ANSWER odds of exposure in cases is equal to odds in
control (no association)
What does it mean if OR>1? - ANSWER odds of exposure in cases is greater than odds of
exposure in controls (positive association)
What does it mean if OR<1? - ANSWER odds of exposure in controls is greater than odds
of exposure in cases (negative association)
What happens in matched-pairs case-control studies? - ANSWER controls are selected
by matching each one to a case according to variables that are known to be related to
disease risk i.e. age, sex, race/ethnicity
, What are the four type of case-control pairs that are observed? - ANSWER 1.
exposed-exposed
2. unexposed-unexposed
3. exposed-unexposed
4. unexposed-exposed
What are concordant pairs? - ANSWER - exposed-exposed
- unexposed-unexposed
What are discordant pairs? - ANSWER - exposed-unexposed
- unexposed-exposed
How do you calculate matched pairs odds ratio? - ANSWER exposed case
discordant/unexposed case discordant
1 in ___ adults will have depression at some time in their life - ANSWER 6
Each year, ~____ million American adults experience depression - ANSWER 16
What are effective treatments for depression? - ANSWER - psychosocial therapy such
as cognitive-behavioral, interpersonal or problem solving
- psychosocial support
- anti-depressant medication
In the US, mental disorders are commonly diagnosed using the? - ANSWER Diagnostic
and Statistical Manual of Mental Disorders (DSM-5) published by the American
Psychiatric Association
In depression, the individual must be experiencing ___ or more symptoms during the
same ____ week period - ANSWER 5; 2
Where does mental health data come from? - ANSWER - Substance Abuse and Mental
Health Services Administration (SAMHSA)
- National Survey on Drug Use and Health (NSDUH)
What are the major risk factors for depression? - ANSWER - family history
- major life events, trauma, or stress
- certain physical illnesses and medications
What two study designs are used to measure if a disease is associated with an
exposure? - ANSWER 1. Cohort
2. Case-control
Define risk. - ANSWER Probability of an event occurring (such as development of
disease or death over a specified observation window).
Why is incidence a greater measure of risk than prevelance? - ANSWER Prevalence can
also be affected by disease duration. Researchers are usually interested in things that
cause onset or acquisition of disease.
Define absolute risk. - ANSWER - Incidence of disease (mortality) in a population.
- Does NOT take into account the risk of disease in NON-exposed individuals but can
indication magnitude of risk in a group of people WITH exposure.
- does not indicate if exposure is ASSOCIATED with risk of disease (or death)
What are the two ways to calculate measures of association? - ANSWER 1. Difference in
absolute risks (incidence or death) = ABSOLUTE measure
2. Ratio of absolute risks (incidence or death) = RELATIVE measure
What are the three ways to calculate relative risk? - ANSWER 1. Incidence Density Ratio
(IDR) = relative rate (rate ratio)
2. Cumulative incidence ratio (CIR) = relative risk (risk ratio)
3. Odds Ratio (OR)
How do you calculate Incidence Density Ratio (IDR)? - ANSWER rate ratio = ID
exposed/ID unexposed
How do you calculate Cumulative incidence ratio (CIR)? - ANSWER risk ratio = CI
exposed/CI unexposed
How do you calculate Odds Ratio (OR)? - ANSWER Odds exposure diseased/odds
exposure not diseased
How do you calculate absolute risk? - ANSWER diseased population (exposed &
uneposed)/ total population
How do you calculate Relative Risk (RR)? - ANSWER Relative risk ratio = incidence in
exposed/incidence in unexposed
,What does it mean id RR = 1? - ANSWER Risk in exposed is equal to risk in unexposed
(no association)
What does it mean if RR>1? - ANSWER Risk in exposed is greater than the risk in
unexposed (positive association)
What does it mean if RR<1? - ANSWER Risk in exposed is less than risk in unexposed
(negative association)
In positive association, R ___ 1 ? - ANSWER >
In negative association, R ___ 1 ? - ANSWER <
Cohort Study Design - ANSWER non-randomly divide population into exposed and
unexposed
Case-Control Study Design - ANSWER Cases have the disease while controls do not
have the disease
True or False: Risk of disease can directly be estimated from a case-control study -
ANSWER False. Myst have values for incidence in exposed and non-exposed
What can you calculate in a case control study? - ANSWER Odds
What can you calculate in a cohort study? - ANSWER Risk
How do you calculate odds? - ANSWER - number of times event occurred/ number of
times the event did not occur
- odds of exposure in diseased individuals/odds of exposure in control individuals
- (a/c)/(b/d) = (ad)/(b/c)
How do you calculate odds using probability? - ANSWER p/(1-p) where p is the
probability of exposure or event occurring
What is the range of odds? - ANSWER 0(nobody has the event) to infinity (everyone has
the event)
What does it mean if OR=1? - ANSWER odds of exposure in cases is equal to odds in
control (no association)
What does it mean if OR>1? - ANSWER odds of exposure in cases is greater than odds of
exposure in controls (positive association)
What does it mean if OR<1? - ANSWER odds of exposure in controls is greater than odds
of exposure in cases (negative association)
What happens in matched-pairs case-control studies? - ANSWER controls are selected
by matching each one to a case according to variables that are known to be related to
disease risk i.e. age, sex, race/ethnicity
, What are the four type of case-control pairs that are observed? - ANSWER 1.
exposed-exposed
2. unexposed-unexposed
3. exposed-unexposed
4. unexposed-exposed
What are concordant pairs? - ANSWER - exposed-exposed
- unexposed-unexposed
What are discordant pairs? - ANSWER - exposed-unexposed
- unexposed-exposed
How do you calculate matched pairs odds ratio? - ANSWER exposed case
discordant/unexposed case discordant
1 in ___ adults will have depression at some time in their life - ANSWER 6
Each year, ~____ million American adults experience depression - ANSWER 16
What are effective treatments for depression? - ANSWER - psychosocial therapy such
as cognitive-behavioral, interpersonal or problem solving
- psychosocial support
- anti-depressant medication
In the US, mental disorders are commonly diagnosed using the? - ANSWER Diagnostic
and Statistical Manual of Mental Disorders (DSM-5) published by the American
Psychiatric Association
In depression, the individual must be experiencing ___ or more symptoms during the
same ____ week period - ANSWER 5; 2
Where does mental health data come from? - ANSWER - Substance Abuse and Mental
Health Services Administration (SAMHSA)
- National Survey on Drug Use and Health (NSDUH)
What are the major risk factors for depression? - ANSWER - family history
- major life events, trauma, or stress
- certain physical illnesses and medications
