100+ Free Public Health Physician (China) Practice Questions

Epidemiology and Health Statistics (流行病学与卫生统计学)

In-depth evaluation of epidemiological principles, study designs, causal inference, and biostatistical analysis: (1) Epidemiological Study Designs: Descriptive studies (cross-sectional surveys, ecological studies, surveillance data analysis), Analytical studies (case-control designs, matching 1:1 and 1:M, nested case-control, cohort studies: prospective, retrospective, ambidirectional), Experimental studies (randomized controlled trials RCTs, community intervention trials, field trials); (2) Measures of Disease Frequency & Association: Incidence rate, attack rate, secondary attack rate, prevalence, point vs period prevalence, cumulative incidence, standard mortality ratio (SMR), disability-adjusted life years (DALYs); Relative Risk (RR), Odds Ratio (OR), Attributable Risk / Risk Difference (AR), Attributable Fraction / Etiologic Fraction (AR%), Population Attributable Risk (PAR), Population Attributable Fraction (PAF); (3) Bias, Confounding & Causal Inference: Selection bias (Berkson's bias, healthy worker effect, non-response bias, Neyman's prevalence-incidence bias), Information bias (recall bias, interviewer bias, diagnostic suspicion bias, differential vs non-differential misclassification), Confounding (criteria for confounders, control via restriction, matching, stratification, Mantel-Haenszel pooling, multivariable regression), Effect modification vs confounding, Bradford Hill criteria for causality (temporality, strength, dose-response, biological plausibility, consistency); (4) Screening & Diagnostic Test Evaluation: Sensitivity, specificity, false positive rate (1-specificity), false negative rate (1-sensitivity), positive predictive value (PPV), negative predictive value (NPV), positive/negative likelihood ratios (LR+, LR-), Receiver Operating Characteristic (ROC) curve and Area Under Curve (AUC), Youden index, parallel testing vs serial testing, lead time bias, length bias; (5) Biostatistics & Quantitative Methods: Types of medical data (quantitative/numerical, nominal/categorical, ordinal/ranked), probability distributions (normal distribution, standard normal Z transformation, binomial distribution, Poisson distribution), measures of central tendency (mean, geometric mean, median) and dispersion (standard deviation, variance, interquartile range IQR), parameter estimation (standard error of the mean, 95% confidence intervals), hypothesis testing logic (Type I error alpha, Type II error beta, statistical power 1-beta), parametric tests (one-sample t-test, paired t-test, two independent samples t-test, one-way analysis of variance ANOVA), non-parametric tests (Wilcoxon signed-rank test, Mann-Whitney U test, Kruskal-Wallis H test), Chi-square test (test of independence, goodness of fit, paired McNemar test, Fisher's exact test), Pearson correlation, Spearman rank correlation, simple linear regression, multivariable linear regression, and binary logistic regression.

Environmental Health and Occupational Medicine (环境卫生学与职业卫生学)

Comprehensive knowledge of environmental risk factors, water and air sanitation, and occupational disease prevention: (1) Atmospheric & Indoor Air Hygiene: Criteria air pollutants (PM2.5, PM10, SO2, NO2, CO, Ozone), photochemical smog (formation mechanisms, PAN, secondary pollutants), London-type sulfurous smog vs Los Angeles-type photochemical smog, Air Quality Index (AQI), health effects of ambient particulate matter (respiratory, cardiovascular, pulmonary deposition fractions), indoor air contaminants (formaldehyde, radon and lung cancer risk, benzene, total volatile organic compounds TVOC), sick building syndrome (SBS); (2) Drinking Water Sanitation & Water Resources: Waterborne infectious diseases, natural water self-purification, drinking water treatment train (coagulation using alum/PAC, sedimentation, rapid sand filtration, chlorination/chloramine/ozone/UV disinfection), disinfection byproducts (trihalomethanes THMs, haloacetic acids HAAs), Standards for Drinking Water Quality (GB 5749 mandatory microbiological, toxicological, and sensory indicators), endemic geochemical diseases (endemic fluorosis: dental and skeletal fluorosis, endemic arsenicosis, iodine deficiency disorders IDD); (3) Soil & Waste Management: Soil pollution pathways, heavy metal accumulation (cadmium and Itai-itai disease, mercury and Minamata disease), hazardous waste disposal, landfill leachate management; (4) Occupational Hazards & Toxicology: Occupational exposure limits (OELs: PC-TWA, PC-STEL, MAC under GBZ 2.1), occupational health surveillance (pre-placement, periodic, departure, and emergency medical examinations under GBZ 188); chemical intoxications: Lead poisoning (inhibition of ALAD and ferrochelatase, basophilic stippling, lead line on gums, EDTA/DMSA chelation), Mercury poisoning (erethism, intention tremor, stomatitis, DMPS/DMSA chelation), Benzene poisoning (bone marrow suppression, aplastic anemia, acute myeloid leukemia AML), Carbon monoxide poisoning (carboxyhemoglobin formation, delayed encephalopathy, hyperbaric oxygen therapy), Hydrogen sulfide poisoning ('knockdown' acute respiratory paralysis), Organophosphate pesticide poisoning (AChE inhibition, muscarinic/nicotinic/CNS manifestations, pralidoxime AChE reactivators and atropine); (5) Occupational Dusts & Pneumoconiosis: Silicosis (free silica SiO2 content, dust cell nodule formation, eggshell hilar lymph node calcification), Coal worker's pneumoconiosis (CWP), Asbestosis (chrysotile/amphibole fibers, pulmonary fibrosis, pleural plaques, malignant mesothelioma risk); (6) Physical Hazards: Noise-induced hearing loss (temporary vs permanent threshold shift, 4000 Hz notch on audiogram), Hand-arm vibration disease (HAVD, Raynaud's phenomenon / white finger disease), Heat illness (heat cramps, heat exhaustion, classic and exertional heat stroke), Non-ionizing and ionizing radiation protection (ALARA principle: time, distance, shielding).

Nutrition, Food Hygiene and Toxicology (营养与食品卫生学及卫生毒理学)

Comprehensive examination of human nutrition, food contamination, foodborne disease outbreaks, and toxicological hazard assessment: (1) Human Nutritional Science: Energy balance, Basal Metabolic Rate (BMR); Proteins (essential amino acids, nitrogen balance, protein nutritional quality evaluation: AAS, PER, NPU), Lipids (saturated, monounsaturated, polyunsaturated fatty acids, n-3 vs n-6 PUFAs, EPA, DHA), Carbohydrates (available carbohydrates, dietary fiber, glycemic index GI, glycemic load GL); Vitamins (fat-soluble: A, D, E, K; water-soluble: B1 thiamine and beriberi, B2 riboflavin and angular stomatitis, B3 niacin and pellagra, B9 folate and neural tube defects, B12 cobalamin and pernicious anemia, Vitamin C and scurvy); Minerals and trace elements (calcium, iron: heme vs non-heme, nutritional anemia, zinc, iodine, selenium and Keshan disease); Dietary Reference Intakes (DRIs: Estimated Average Requirement EAR, Recommended Nutrient Intake RNI, Adequate Intake AI, Tolerable Upper Intake Level UL); Chinese Dietary Guidelines and Food Guide Pagoda; (2) Food Contamination & Chemical Food Safety: Mycotoxins (Aflatoxin B1: Aspergillus flavus, hepatocarcinogenicity, AF M1 in milk, Ochratoxin A, Patulin in fruit products, Zearalenone), Chemical contaminants (heavy metals: lead, cadmium, methylmercury, inorganic arsenic; environmental pollutants: dioxins, PCBs; processing contaminants: heterocyclic amines HCAs, polycyclic aromatic hydrocarbons PAHs including benzo[a]pyrene, acrylamide, N-nitrosamines), Food additives (GB 2760 classification, functional classes, ADI, maximum permitted usage levels); (3) Foodborne Diseases & Food Poisoning: Definition and statutory classification of food poisoning; Bacterial food poisonings: Salmonella (enteritis, eggs/poultry), Staphylococcus aureus (heat-stable enterotoxin, rapid incubation 1–6 hours, vomiting), Clostridium botulinum (neurotoxin, flaccid paralysis, home-canned and fermented foods, antitoxin therapy), Vibrio parahaemolyticus (halophilic marine pathogen, seafood), Bacillus cereus (emetic toxin vs diarrheal enterotoxin), Listeria monocytogenes (psychrotrophic, pregnancy risks); Toxic fungal and plant/animal poisonings: Poisonous mushrooms (amatoxins, muscarine, phalloidin), Tetrodotoxin (pufferfish, heat-stable neurotoxin, voltage-gated Na+ channel blockade), Scombroid fish poisoning (histamine), Cyanogenic glycosides (bitter almonds, cassavas); Food poisoning outbreak investigation protocol and sample collection; (4) Fundamentals of Public Health Toxicology: General toxicokinetics: Absorption (gastrointestinal, respiratory, dermal), Distribution (apparent volume of distribution, blood-brain barrier, placental barrier), Biotransformation (Phase I functionalization reactions via Cytochrome P450 CYP enzymes, Phase II conjugation reactions: glucuronidation, sulfation, glutathione conjugation), Excretion (renal, biliary-fecal, pulmonary); Dose-Response relationships (graded vs quantal dose-response, sigmoidal curves, threshold concepts); Toxicity endpoints and testing: Acute toxicity (median lethal dose LD50, LC50, classification of acute chemical toxicity), Subacute and chronic toxicity studies, No Observed Adverse Effect Level (NOAEL), Lowest Observed Adverse Effect Level (LOAEL), Benchmark Dose (BMD/BMDL), Acceptable Daily Intake (ADI) and Reference Dose (RfD) derivation with uncertainty factors (UF); Genotoxicity tests (Ames Salmonella reverse mutation assay, chromosomal aberration assay, in vivo micronucleus assay); Carcinogenicity, teratogenicity, and developmental toxicity testing.

Disease Control, Outbreak Response and Public Health Surveillance (疾病预防控制、突发事件应急与健康监测)

Exhaustive evaluation of communicable disease dynamics, field outbreak response, health surveillance systems, and public health emergency containment: (1) Infectious Disease Dynamics & Control Strategies: The three essential epidemiological links: Source of infection (patients, carriers: asymptomatic, incubatory, convalescent; animal reservoirs / zoonoses), Mode of transmission (airborne/droplet, waterborne, foodborne, contact: direct/indirect, vector-borne, vertical/perinatal, bloodborne), Susceptible population (herd immunity threshold HIT = 1 - 1/R0, passive vs active immunity); Principles of prevention and control: Measures targeting the reservoir (early detection, diagnosis, reporting, isolation, treatment), Measures breaking transmission pathways (disinfection: preventive vs terminal, vector control, sanitation), Measures protecting susceptible hosts (active immunization, post-exposure prophylaxis, chemoprophylaxis); (2) Statutory Infectious Disease Law & Reporting: Law of the PRC on the Prevention and Treatment of Infectious Diseases (《中华人民共和国传染病防治法》); Classification: Class A (甲类: Plague 鼠疫, Cholera 霍乱), Class B (乙类: COVID-19, SARS, Anthrax [pulmonary anthrax managed as Class A], HIV/AIDS, Viral Hepatitis A/B/C/E, Pulmonary TB, Rabies, Dengue, Japanese Encephalitis, Measles, Pertussis, Typhoid/Paratyphoid, Syphilis, Gonorrhea), Class C (丙类: Influenza, Mumps, Rubella, Hand-Foot-and-Mouth Disease HFMD, Acute Hemorrhagic Conjunctivitis, Infectious Diarrhea); Statutory reporting timelines via China Information System for Disease Control and Prevention: Class A and Class B managed as Class A (pulmonary anthrax) must be reported via direct web-reporting within 2 hours; other Class B and Class C diseases within 24 hours; (3) Expanded Programme on Immunization (EPI) & Vaccine Management: National Immunization Programme vaccines (Hepatitis B, BCG, Polio IPV/bOPV, DTaP, MMR, Japanese Encephalitis, Meningococcal AC, Hepatitis A); Vaccine types: live-attenuated vaccines, inactivated whole-cell vaccines, subunit/recombinant protein vaccines, toxoids, conjugate vaccines, mRNA vaccines; Cold chain management (temperature monitoring 2°C–8°C for refrigerated vaccines, -20°C for live polio/freeze-dried vaccines, VVM vaccine vial monitors, shake test for freeze-sensitive vaccines); Adverse Events Following Immunization (AEFI: vaccine reactions vs coincidental events vs injection errors vs psychogenic reactions, AEFI surveillance and investigation); (4) Field Epidemiology & Outbreak Investigation: 10 standard steps of field outbreak investigation (prepare for fieldwork, establish existence of outbreak, verify diagnosis, construct case definition: confirmed, probable, suspected, active case searching, descriptive epidemiology: person-place-time epidemic curves, formulate plausible hypotheses, test hypotheses via analytical epidemiology: retrospective cohort attack rates or case-control odds ratios, implement containment measures, write field report and communicate findings); Types of epidemic curves: point-source outbreak (log-normal distribution, sharp peak within one incubation period), continuous common-source outbreak, propagated / person-to-person spread (progressive series of peaks separated by incubation periods); (5) Public Health Emergencies & Contingency Management: Regulations on Preparedness for and Response to Public Health Emergencies (《突发公共卫生事件应急条例》); Classification of public health emergencies: Major infectious disease outbreaks, mass unexplained diseases, significant food and occupational poisonings, bio-terrorist threats; Four-tiered emergency response grading (Level I Extremely Serious / Red, Level II Serious / Orange, Level III Relatively Serious / Yellow, Level IV General / Blue); Emergency operational workflows, on-site commanding, personal protective equipment (PPE levels: Level 1 to Level 4 biosafety precautions), risk communication; (6) Chronic Non-Communicable Disease (NCD) Prevention: Epidemiology and risk factors for hypertension, type 2 diabetes mellitus, cardiovascular disease, stroke, malignant neoplasms (lung, gastric, colorectal, liver, breast, cervical), and COPD; Three levels of prevention: Primary prevention (health promotion, tobacco control, dietary modification, physical activity), Secondary prevention (early screening, regular health examinations, high-risk group identification, opportunistic screening), Tertiary prevention (clinical management, rehabilitation, complication prevention, disability limitation); (7) Maternal, Child, School Health & Community Surveillance: Key maternal and child health indicators (maternal mortality ratio MMR, infant mortality rate IMR, under-5 mortality rate U5MR), expanded neonatal screening (PKU, congenital hypothyroidism, G6PD deficiency, hearing screening), growth and developmental milestones, school health supervision (myopia prevention, ergonomic school desk/chair standards, adolescent nutrition).