SPEX Preventive Medicine 2 — Questions and Answers
Question 1: Which study design is most appropriate for estimating the prevalence of hypertension in a US county?
- Randomized controlled trial
- Cross-sectional survey (Correct answer)
- Prospective cohort study
- Case-control study
Correct answer: Cross-sectional survey
Cross-sectional surveys measure disease prevalence at a single point in time within a defined population.
Question 2: A vaccine with 80% efficacy is administered to a population where the attack rate without vaccination is 10%. What is the attack rate in vaccinated individuals?
- 2% (Correct answer)
- 4%
- 6%
- 8%
Correct answer: 2%
Vaccine efficacy of 80% means the attack rate is reduced by 80%, so 10% × (1−0.80) = 2%.
Question 3: Which measure best quantifies the public health impact of eliminating a risk factor from a population?
- Relative risk
- Odds ratio
- Population attributable risk percent (Correct answer)
- Number needed to treat
Correct answer: Population attributable risk percent
Population attributable risk percent estimates the proportion of disease in the total population attributable to a given exposure.
Question 4: An employee develops contact dermatitis after working with epoxy resins. Under OSHA regulations, this must be recorded on the OSHA 300 Log if it results in:
- Any skin irritation lasting >1 day
- Days away from work, restricted duty, or medical treatment beyond first aid (Correct answer)
- Any physician visit regardless of treatment
- Loss of productivity documented by a supervisor
Correct answer: Days away from work, restricted duty, or medical treatment beyond first aid
OSHA recordable illnesses include those requiring days away, job transfer/restriction, or medical treatment beyond first aid.
Question 5: The US Preventive Services Task Force recommends annual low-dose CT screening for lung cancer in adults aged 50–80 who have a ___-pack-year smoking history and currently smoke or quit within the past 15 years.
- 10
- 20 (Correct answer)
- 30
- 40
Correct answer: 20
USPSTF recommends annual LDCT for adults 50–80 with ≥20 pack-year history who currently smoke or quit within 15 years.
Question 6: In outbreak investigation, the epidemic curve for a point-source exposure typically shows:
- A gradual rise and prolonged plateau lasting several incubation periods
- A sharp peak within one incubation period followed by rapid decline (Correct answer)
- Multiple peaks separated by one incubation period
- Random clustering with no identifiable peak
Correct answer: A sharp peak within one incubation period followed by rapid decline
A point-source outbreak exposes all cases simultaneously, producing a sharp rise and fall within a single incubation period.
Question 7: Which intervention is classified as tertiary prevention?
- Fluoride supplementation to prevent dental caries
- Mammography screening in asymptomatic women
- Cardiac rehabilitation after myocardial infarction (Correct answer)
- Hepatitis B vaccination of healthcare workers
Correct answer: Cardiac rehabilitation after myocardial infarction
Tertiary prevention reduces the impact of established disease by restoring function and preventing complications, as cardiac rehab does post-MI.
SPEX Preventive Medicine 2
Which study design is most appropriate for estimating the prevalence of hypertension in a US county?