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 · easy25. A tropical region has consistently reported 15 to 20 malaria cases per 100,000 people annually for over a decade with minimal year-to-year variation. Recent surveillance data co…
- USMLE Step 1 · easy26. A 59-year-old woman with hypertension (BP 148/92 mmHg) and hyperlipidemia presents for routine evaluation. She is asymptomatic with normal vital signs otherwise (HR 78/min, RR 1…
- USMLE Step 1 · medium27. A local health department identifies 12 cases of hepatitis A (ALT 850 U/L, anti-HAV IgM positive) linked to a restaurant over 10 days. Affected patients present with jaundice, f…
- USMLE Step 1 · medium28. 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 · hard29. A 58-year-old male smoker with a 40-pack-year history presents with productive cough and dyspnea. Vital signs show BP 145/88, HR 98, RR 22, SpO2 88% on room air. A longitudinal…
- USMLE Step 1 · hard30. A researcher compares crude mortality rates between a retirement community (mean age 78 years) and a nearby university town (mean age 22 years). The retirement community demonst…
- USMLE Step 1 · medium31. A 52-year-old woman presents with weight loss and palpitations. Vital signs: BP 142/88, HR 108, RR 18, Temp 37.2°C, SpO2 98%. Laboratory studies show elevated free T4 (28 pg/mL)…
- USMLE Step 1 · easy32. A 52-year-old man with a 30-pack-year smoking history presents for preventive counseling. Vital signs are BP 138/82 mmHg, HR 88 bpm, RR 16, SpO2 98% on room air. He denies curre…
- USMLE Step 1 · easy33. A 7-year-old boy with acute lymphoblastic leukemia currently receiving chemotherapy presents to clinic with vital signs: BP 105/68, HR 92, RR 20, Temp 37.1°C, SpO2 98%. Recent l…
- USMLE Step 1 · medium34. A 45-year-old woman participates in a randomized influenza vaccine trial. She receives the inactivated flu vaccine and remains asymptomatic throughout the season with normal vit…
- USMLE Step 1 · medium35. 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 · medium36. 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…
- USMLE Step 1 · easy37. A city with baseline measles incidence of 2-3 cases annually reports 84 confirmed cases this month, predominantly in unvaccinated children (MMR serology positive). Affected pati…
- USMLE Step 1 · easy38. A tropical region in Southeast Asia has consistently reported 15 to 20 malaria cases per 100,000 people annually for the past 8 years with minimal year-to-year variation. Serolo…
- USMLE Step 1 · medium39. Investigators are designing an observational study comparing fracture risk in chronic glucocorticoid users and nonusers. They are particularly concerned that age and sex differ…
- USMLE Step 1 · hard40. A 32-year-old female presents with left leg swelling and pain. She uses oral contraceptives and smokes one pack daily. Vital signs: BP 118/76, HR 92, RR 16, Temp 37°C, SpO2 98%.…
- USMLE Step 1 · medium41. A epidemiologic study examining 5,000 patients (mean age 62, 55% male) finds coffee consumption associated with lung cancer (RR 2.1, p<0.05). Chest CT confirms adenocarcinoma in…
- USMLE Step 1 · medium42. A prospective cohort study follows 200 night-shift workers and 400 day-shift workers for 5 years to assess new onset hypertension. By the end of follow up, 40 night-shift worker…
- USMLE Step 1 · medium43. Investigators study a possible association between a pesticide and Parkinson disease. They enroll 120 patients with Parkinson disease and 200 controls without Parkinson disease.…
- USMLE Step 1 · medium44. A 58-year-old woman undergoes mammography screening and is found to have a 1.2-cm breast mass with negative axillary lymph nodes on imaging. Her vital signs are stable (BP 128/8…
- USMLE Step 1 · medium45. A 62-year-old man with 45 pack-year smoking history presents for routine follow-up. CT chest screening reveals a 1.2-cm nodule (Lung-RADS 3); PET-CT shows no hypermetabolic acti…
- USMLE Step 1 · medium46. A 34-year-old woman presents to the emergency department in July with fever (38.5°C), cough, and myalgias for 2 days. Vital signs: BP 118/76, HR 92, RR 18, SpO2 98% on room air.…
- USMLE Step 1 · medium47. A rapid screening test for celiac disease has the same sensitivity and specificity in all populations. A family medicine clinic uses the test in asymptomatic adults, whereas a g…
- USMLE Step 1 · easy48. A 62-year-old man presents with a 3-month history of intermittent hematochezia. Vital signs: BP 128/82, HR 92, RR 16, Temp 37.2°C, SpO2 98% on room air. A screening blood test f…