Epidemiology & Prevention USMLE Step 1 Practice Questions
53 board-style USMLE Step 1 questions in Biostatistics & Behavioral Science. Each question shows the correct answer; create a free account for the full explanation and adaptive practice.
- USMLE Step 1 · medium1. A 45-year-old woman with no significant medical history presents for routine breast cancer screening mammography. The examination is interpreted as BI-RADS 4 (suspicious for mal…
- USMLE Step 1 · medium2. In a clinical trial evaluating a new antihypertensive medication, researchers randomly assign 1,000 patients to either drug or placebo. At baseline, the drug group has a mean sy…
- USMLE Step 1 · medium3. A case-control study examines the relationship between oral contraceptive use and venous thromboembolism (VTE) in women aged 25-45 years. Researchers enroll 200 women with newly…
- USMLE Step 1 · easy4. A 58-year-old man with a 40 pack-year smoking history presents with a 3-month history of productive cough and occasional hemoptysis. Vital signs are stable and oxygen saturation…
- USMLE Step 1 · hard5. A screening program for colorectal cancer detects 95% of cases in people with the disease and correctly identifies 90% of people without the disease as disease-free. In the gene…
- USMLE Step 1 · medium6. A 45-year-old man with a 20-year smoking history presents to the emergency department with acute anterior wall myocardial infarction. His initial vital signs are BP 148/92 mmHg,…
- USMLE Step 1 · hard7. Researchers conduct a study to evaluate the effectiveness of a newly licensed rotavirus vaccine in a developing country. They vaccinate 8,000 children aged 6-24 months in a rura…
- USMLE Step 1 · medium8. A researcher conducting a cross-sectional survey finds that patients with depression have higher rates of chronic pain compared to those without depression (OR = 3.2, 95% CI 2.1…
- USMLE Step 1 · medium9. A 15-year prospective cohort study enrolls 5,000 asymptomatic adults aged 40-60 years and follows them for cardiovascular disease (CVD) outcomes. Baseline measurements include t…
- USMLE Step 1 · medium10. A randomized controlled trial comparing two antihypertensive agents (amlodipine vs. lisinopril) enrolls 300 patients with Stage 2 hypertension. Patients are randomized 1:1 using…
- USMLE Step 1 · medium11. A case-control study investigates risk factors for type 2 diabetes mellitus in a primary care population. Researchers identify 500 patients with newly diagnosed type 2 diabetes…
- USMLE Step 1 · easy12. A 10-year prospective cohort study enrolls 10,000 current smokers (mean age 55, smoking ≥1 pack daily for ≥30 years) and 10,000 age-matched never-smokers to assess lung cancer r…
- USMLE Step 1 · medium13. A state epidemiologist is reviewing surveillance data for pertussis (Bordetella pertussis infection) across a region. The reported incidence increased from 4 cases per 100,000 p…
- USMLE Step 1 · medium14. A 45-year-old woman with stage 2 hypertension is enrolled in a randomized controlled trial comparing a new ACE inhibitor (lisinopril-amlodipine combination) to standard monother…
- USMLE Step 1 · easy15. A 59-year-old asymptomatic woman with a 20 pack-year smoking history presents for preventive care. Vital signs are normal (BP 128/82, HR 72, RR 14, Temp 98.6°F). She denies coug…
- USMLE Step 1 · medium16. A local health department identifies 12 cases of hepatitis A linked to a restaurant over 10 days. Affected patients present with fever (38.5°C), jaundice, and elevated transamin…
- USMLE Step 1 · medium17. Over a 24-hour period, 42 employees at an office develop vomiting and diarrhea after a luncheon. The epidemic curve shows a sharp rise and fall in cases over a single incubation…
- USMLE Step 1 · hard18. A 58-year-old male smoker presents with chronic productive cough and dyspnea. Vital signs show BP 138/82, HR 92, RR 18, temperature 37.2°C, SpO2 92% on room air. Chest X-ray rev…
- USMLE Step 1 · medium19. A hospital develops a two-step screening program for a rare but serious endocrine cancer. A 52-year-old woman presents with fatigue and weight loss; initial laboratory work show…
- USMLE Step 1 · easy20. A 52-year-old man with a 30-pack-year smoking history presents with BP 138/86, HR 82, RR 16, and SpO2 98% on room air. He denies dyspnea, cough, or chest pain. Spirometry shows…
- USMLE Step 1 · easy21. A 7-year-old boy with acute lymphoblastic leukemia currently receiving chemotherapy (HR 102, BP 98/62, temp 37.2°C) has an absolute neutrophil count of 800/μL and cannot receive…
- USMLE Step 1 · medium22. A 45-year-old woman participates in a randomized influenza vaccine trial. She receives the inactivated influenza vaccine and remains asymptomatic throughout the season with norm…
- USMLE Step 1 · medium23. A college student develops meningococcal meningitis and lives in a house with 12 roommates. Two roommates were already febrile and symptomatic on the same day as the index patie…
- USMLE Step 1 · medium24. After a wedding reception, 96 guests are interviewed about acute gastroenteritis. Of the 60 guests who ate the shrimp appetizer, 36 became ill. Of the 36 guests who did not eat…