SMLE Community Medicine & Preventive Health 1 — Questions and Answers
Question 1: Which of the following statistics is the BEST indicator of the overall quality of healthcare in a country?
- Crude birth rate
- Total fertility rate
- Infant mortality rate (Correct answer)
- Crude death rate
Correct answer: Infant mortality rate
Infant mortality rate is the most sensitive indicator of healthcare quality as it reflects nutrition, sanitation, maternal care, and the overall effectiveness of the health system.
Question 2: A screening test has a sensitivity of 85% and specificity of 90%. If the prevalence of the disease increases in the tested population, what happens to the positive predictive value (PPV)?
- PPV decreases
- PPV remains unchanged
- PPV becomes equal to sensitivity
- PPV increases (Correct answer)
Correct answer: PPV increases
As disease prevalence increases, the proportion of true positives among all positive tests rises, so PPV increases accordingly.
Question 3: According to the Saudi National Immunization Program, which two vaccines are administered at birth?
- BCG and Hepatitis A
- OPV and Hepatitis B
- BCG and Hepatitis B (Correct answer)
- Rotavirus and BCG
Correct answer: BCG and Hepatitis B
The Saudi immunization schedule administers BCG (to prevent tuberculosis) and Hepatitis B vaccine at birth.
Question 4: A 35-year-old asymptomatic woman undergoes a Pap smear test for cervical cancer detection. This is an example of which level of prevention?
- Primordial prevention
- Primary prevention
- Secondary prevention (Correct answer)
- Tertiary prevention
Correct answer: Secondary prevention
Secondary prevention involves early detection of disease in asymptomatic individuals through screening, such as Pap smears for cervical cancer.
Question 5: In a case-control study investigating the association between a risk factor and a disease, which measure of association is typically calculated?
- Relative risk
- Odds ratio (Correct answer)
- Attributable risk
- Population attributable risk percent
Correct answer: Odds ratio
Odds ratio is used in case-control studies because incidence data is not directly available; it approximates relative risk when disease prevalence is low.
Question 6: In a clinical trial, neither the participants nor the investigators know who received the active treatment or the placebo. This study design is called:
- Open-label trial
- Single-blind trial
- Triple-blind trial
- Double-blind trial (Correct answer)
Correct answer: Double-blind trial
In a double-blind trial, both participants and investigators are unaware of treatment allocation, reducing performance and detection bias.
Question 7: Which of the following is the MOST important Wilson and Jungner criterion for a disease to be suitable for a screening program?
- The disease must have a high case fatality rate
- The test must use invasive techniques for high accuracy
- An effective treatment must be available and early treatment must improve outcomes compared to late treatment (Correct answer)
- The disease must be highly infectious
Correct answer: An effective treatment must be available and early treatment must improve outcomes compared to late treatment
Screening is only justified if early detection leads to better patient outcomes; if treating early confers no advantage over treating at symptom onset, screening provides no benefit.
SMLE Community Medicine & Preventive Health 1
Which of the following statistics is the BEST indicator of the overall quality of healthcare in a country?