NHPC BPH cheat sheet

Core functions of public health: assessment (monitor health, diagnose and investigate), policy development (inform, educate, mobilize, develop policies), and assurance (enforce laws, link to services, assure workforce, evaluate, research).

Ten Essential Public Health Services map onto the three core functions; assessment covers services 1-2, policy development covers 3-5, assurance covers 6-10.

Primary prevention acts before disease onset (immunization, fluoridation); secondary prevention is early detection (screening); tertiary prevention limits disability (rehabilitation).

Historical markers: John Snow's 1854 Broad Street pump investigation linked cholera to contaminated water; the 1848 UK Public Health Act and 1851 Louisiana Sanitary Commission preceded it in sanitary reform.

Health determinants: socioeconomic status, physical environment, genetics, individual behavior, and health services; socioeconomic and environmental factors account for the largest share of population health variation.

The 1978 Alma-Ata Declaration defined primary health care as the key to Health for All; the 1986 Ottawa Charter set out health promotion action areas.

Public health vs. clinical medicine: public health focuses on populations, prevention, and upstream determinants; clinical medicine focuses on individuals, diagnosis, and treatment.

Epidemiologic transition: high mortality from infectious disease shifts to high burden of chronic disease as countries develop; demographic transition follows the same pattern.

Incidence measures new cases over a period (person-time incidence rate = new cases / total person-time at risk); prevalence measures all existing cases at a point in time.

Attack rate = new cases / population at risk during an outbreak; secondary attack rate = new cases among susceptible contacts / total susceptible contacts.

Relative risk (RR) = incidence in exposed / incidence in unexposed; RR > 1 indicates increased risk; attributable risk = incidence in exposed minus incidence in unexposed.

Odds ratio (OR) approximates RR when disease is rare; OR = (a/c)/(b/d) = ad/bc in a 2x2 table.

Case fatality rate = deaths from a disease / diagnosed cases of that disease; crude mortality rate = deaths / total population, usually per 1,000 or 100,000.

Sensitivity = TP/(TP+FN); specificity = TN/(TN+FP); positive predictive value = TP/(TP+FP); PPV rises as prevalence rises.

Herd immunity threshold = 1 - 1/R0; for measles (R0 around 12-18) this requires roughly 92-95% coverage.

Surveillance types: passive (routine reporting), active (health workers seek cases), sentinel (selected sites), and syndromic (monitoring symptom patterns).

Bias types: selection bias, information bias, and confounding; confounding is addressed by randomization, stratification, or multivariable adjustment.

Mean is sensitive to outliers and is used for symmetric data; median is robust and preferred for skewed data; mode is the most frequent value.

Standard deviation measures spread around the mean; standard error of the mean = SD / sqrt(n) and shrinks as sample size grows.

95% confidence interval for a mean = sample mean +/- 1.96 x SE; a 95% CI for a ratio excludes the null (1.0) when the interval does not contain 1.

Type I error (alpha) is rejecting a true null hypothesis; type II error (beta) is failing to reject a false null; power = 1 - beta.

p-value is the probability of observing data at least as extreme as the observed, given the null hypothesis is true; it is not the probability the null is true.

Chi-square test compares observed and expected frequencies in categorical data; t-test compares means of two groups; ANOVA compares means of three or more groups.

Correlation (r) ranges from -1 to +1 and measures linear association; correlation does not establish causation.

Sensitivity, specificity, and predictive values are calculated from a 2x2 table; prevalence affects predictive values but not sensitivity or specificity.

Sample size increases with variance and desired power and decreases with the minimum detectable difference.

Environmental health hazard categories: biological, chemical, physical (radiation, noise, heat), and psychosocial.

Dose-response relationship: response increases with dose; the threshold dose is the lowest dose producing an effect; the no-observed-adverse-effect level (NOAEL) informs acceptable daily intake.

Air pollutants of concern: particulate matter (PM2.5, PM10), ozone, nitrogen dioxide, sulfur dioxide, carbon monoxide, and lead; PM2.5 penetrates deep into the alveoli.

Water quality indicators: fecal coliforms and E. coli signal fecal contamination; residual chlorine maintains disinfection in distribution systems.

Occupational hierarchy of controls: elimination, substitution, engineering controls, administrative controls, and personal protective equipment, in that order of preference.

Occupational exposure limits: TLV (threshold limit value), PEL (permissible exposure limit), and TWA (time-weighted average) define allowable workplace exposure.

Vector control: environmental management (drainage, larviciding), biological control, and chemical control (indoor residual spraying, insecticide-treated nets).

Climate change health effects: heat-related illness, vector range expansion, waterborne disease, food insecurity, and air pollution-related respiratory disease.

Ottawa Charter action areas: build healthy public policy, create supportive environments, strengthen community action, develop personal skills, and reorient health services.

Health Belief Model constructs: perceived susceptibility, perceived severity, perceived benefits, perceived barriers, cues to action, and self-efficacy.

Transtheoretical (Stages of Change) model: precontemplation, contemplation, preparation, action, maintenance, and termination.

Social Cognitive Theory: behavior is shaped by personal, behavioral, and environmental factors (reciprocal determinism); self-efficacy and observational learning are central.

PRECEDE-PROCEED model: PRECEDE diagnoses social, epidemiological, behavioral, and environmental factors; PROCEED covers implementation and evaluation.

Diffusion of Innovations: innovators, early adopters, early majority, late majority, and laggards; adoption follows an S-curve.

Health literacy is the capacity to obtain, process, and understand basic health information to make appropriate health decisions.

Evaluation types: formative (during program development), process (implementation), impact (short-term change), and outcome (long-term health status).

Health system building blocks (WHO): service delivery, health workforce, health information, access to essential medicines, financing, and leadership/governance.

Universal health coverage means all people receive needed health services without financial hardship; it has three dimensions: population covered, services covered, and cost sharing.

Health financing functions: revenue collection, pooling of funds, and purchasing of services; out-of-pocket payment is the least protective financing mechanism.

Beveridge model: tax-funded, government-provided services; Bismarck model: social insurance funded by employer-employee contributions; national health insurance and out-of-pocket models complete the typology.

Cost-effectiveness analysis compares cost per unit of health outcome (e.g., cost per DALY averted); cost-benefit analysis values outcomes in monetary terms.

QALY combines length of life and quality of life; DALY combines years of life lost and years lived with disability.

Moral hazard, adverse selection, and supplier-induced demand are market failures that justify public financing and regulation of health care.

Equity vs. equality: equity allocates resources according to need; equality allocates identical resources to all.

Antenatal care: WHO recommends at least eight contacts; components include screening for anemia, HIV, syphilis, and hypertension, plus tetanus toxoid and iron-folic acid supplementation.

Skilled birth attendance and emergency obstetric care (EmOC) are the main interventions for reducing maternal mortality.

Direct causes of maternal death: hemorrhage, hypertensive disorders, sepsis, obstructed labor, and unsafe abortion; hemorrhage is the leading cause globally.

Essential newborn care: immediate drying and warming, delayed cord clamping, early initiation of breastfeeding within one hour, and exclusive breastfeeding for six months.

Childhood immunization schedule (WHO): BCG and hepatitis B at birth; pentavalent (DPT-HepB-Hib) and OPV at 6, 10, and 14 weeks; measles-rubella at 9 and 15 months.

Integrated Management of Childhood Illness (IMCI) targets pneumonia, diarrhea, malaria, measles, and malnutrition in children under five.

Adolescent health: puberty, mental health, substance use, sexual and reproductive health, and injury prevention are priority domains; HPV vaccination targets adolescent girls.

Postpartum care: at least four visits within 24 hours, day 3, week 1-2, and week 6; monitor for hemorrhage, infection, and depression.

Modes of transmission: direct contact, droplet, airborne, vector-borne, vehicle-borne, and vertical (mother to child).

Chain of infection: infectious agent, reservoir, portal of exit, mode of transmission, portal of entry, and susceptible host; breaking any link interrupts transmission.

TB control: DOTS strategy with directly observed therapy, sputum smear microscopy or GeneXpert, and multidrug regimens; MDR-TB requires second-line drugs.

HIV prevention: condom use, voluntary testing and counseling, pre-exposure prophylaxis (PrEP), prevention of mother-to-child transmission, and antiretroviral therapy.

Malaria control: insecticide-treated nets, indoor residual spraying, artemisinin-based combination therapy, and intermittent preventive treatment in pregnancy.

Non-communicable disease risk factors: tobacco use, harmful alcohol use, unhealthy diet, physical inactivity, and obesity; these drive cardiovascular disease, cancer, diabetes, and chronic respiratory disease.

Screening criteria for NCDs: the condition must be an important health problem, have a detectable latent stage, an acceptable test, and effective treatment.

Vector-borne disease control depends on vector ecology; dengue control relies on eliminating standing water breeding sites.

Macronutrients: carbohydrates (4 kcal/g), protein (4 kcal/g), and fat (9 kcal/g); micronutrients include vitamins and minerals.

Protein-energy malnutrition presents as marasmus (severe wasting without edema) or kwashiorkor (edema, low albumin, often with adequate calorie intake).

Micronutrient deficiencies of public health importance: iron (anemia), vitamin A (blindness, infection), iodine (goiter, cretinism), and zinc (diarrhea, stunting).

Exclusive breastfeeding for six months, then complementary feeding with continued breastfeeding to two years; complementary foods should be nutrient-dense and hygienic.

Food safety: the five keys are keep clean, separate raw and cooked, cook thoroughly, keep food at safe temperatures, and use safe water and raw materials.

Water, sanitation, and hygiene (WASH): safe drinking water, adequate sanitation, and handwashing with soap reduce diarrheal disease; handwashing is a low-cost high-impact intervention.

Foodborne pathogens of concern: Salmonella, Campylobacter, E. coli O157:H7, Listeria, and Staphylococcus aureus; Listeria is a particular risk in pregnancy.

Growth monitoring uses weight-for-age, height-for-age, and weight-for-height z-scores; stunting reflects chronic undernutrition, wasting reflects acute undernutrition.

Core ethical principles: autonomy, beneficence, non-maleficence, and justice; public health adds solidarity, reciprocity, and stewardship.

Informed consent requires capacity, disclosure, understanding, voluntariness, and authorization; exceptions include emergencies and legally mandated public health actions.

Public health ethics balances individual liberty against collective welfare; the harm principle and least-restrictive-means principle guide restrictive measures.

Confidentiality protects identifiable health data; public health reporting and surveillance may require disclosure under law, with the minimum necessary information shared.

Research ethics: the Nuremberg Code (1947) and Declaration of Helsinki (1964) established voluntary consent and review by ethics committees.

Leadership competencies in public health: systems thinking, political awareness, communication, collaboration, and ethical decision-making.

Professional practice: evidence-based decision-making, continuing education, interprofessional collaboration, and quality improvement.

Conflict of interest management requires disclosure, recusal, and transparency in policy and procurement decisions.

Epidemiological study designs ranked by evidence strength: systematic review, randomized controlled trial, cohort, case-control, cross-sectional, case series, case report.

Cohort studies measure incidence and relative risk; case-control studies measure odds ratios and are suited to rare diseases.

Ecological fallacy: inferring individual-level associations from group-level data.

Screening program evaluation requires the condition to be important, the test acceptable and accurate, and treatment effective; lead-time bias can falsely suggest benefit.

Public health surveillance cycle: data collection, analysis, interpretation, dissemination, and action.

Outbreak investigation steps: verify the diagnosis, confirm the outbreak, define cases, find cases, generate hypotheses, test hypotheses, implement control, and communicate.

Health equity: differences in health status that are avoidable, unjust, and unfair; measuring equity requires disaggregated data by sex, age, income, and geography.

Program planning uses needs assessment, priority setting, resource allocation, implementation, and monitoring and evaluation.

Standardization of rates removes the effect of age structure when comparing populations; direct standardization applies the study population's age-specific rates to a standard population.

Incidence density uses person-time at risk in the denominator; cumulative incidence uses the number at risk at the start of follow-up.

Number needed to treat (NNT) = 1 / absolute risk reduction; number needed to harm (NNH) = 1 / absolute risk increase.

Sensitivity and specificity are properties of the test; predictive values depend on prevalence.

Randomization reduces confounding by distributing known and unknown confounders equally between groups.

Intention-to-treat analysis includes all randomized participants in their assigned groups, preserving the benefits of randomization.

Surveillance indicators: timeliness, completeness, sensitivity, positive predictive value, and representativeness.

Case definition components: person, place, time, and clinical and laboratory criteria.

Normal distribution: about 68% of values fall within one SD of the mean, 95% within two SDs, and 99.7% within three SDs.

Parametric tests assume normality and equal variance; nonparametric tests (Mann-Whitney, Wilcoxon, Kruskal-Wallis) are used when assumptions fail.

Linear regression estimates the relationship between a continuous outcome and predictors; logistic regression is used for binary outcomes and reports odds ratios.

Survival analysis uses Kaplan-Meier curves and Cox proportional hazards models to estimate hazard ratios.

Multiple comparisons increase the risk of type I error; Bonferroni correction adjusts the alpha level by dividing by the number of tests.

Missing data handling: complete-case analysis, multiple imputation, and sensitivity analysis; missingness mechanisms are MCAR, MAR, and MNAR.

Data visualization: bar charts for categorical data, histograms for distributions, line graphs for trends, and scatter plots for association.

Statistical significance is not the same as clinical or public health importance; effect size and confidence intervals must be interpreted.

Water treatment steps: coagulation, flocculation, sedimentation, filtration, and disinfection.

Sanitation ladder: open defecation, unimproved, shared, basic, and safely managed sanitation.

Air quality standards set allowable concentrations of pollutants over averaging times (e.g., 24-hour and annual means for PM2.5).

Occupational health surveillance includes pre-employment, periodic, and exit medical examinations and biological monitoring.

Ergonomic hazards: repetitive motion, awkward postures, forceful exertion, and vibration; controls include workstation redesign and job rotation.

Solid waste management hierarchy: prevention, reuse, recycling, recovery, and disposal.

Environmental impact assessment identifies health and environmental effects before project approval.

Climate adaptation measures in health include early warning systems, heat action plans, and vector surveillance.

Health education methods: lectures, group discussions, demonstrations, role play, and mass media; selection depends on audience literacy and setting.

Behavior change techniques: goal setting, self-monitoring, feedback, social support, and environmental restructuring.

Community mobilization engages local leaders, schools, and religious institutions to sustain behavior change.

Social marketing uses the marketing mix (product, price, place, promotion) to promote healthy behaviors.

Formative research uses focus groups, key informant interviews, and surveys to design culturally appropriate messages.

Precede-Proceed phases: social diagnosis, epidemiological diagnosis, behavioral and environmental diagnosis, educational and ecological diagnosis, administrative and policy diagnosis, implementation, process evaluation, impact evaluation, and outcome evaluation.

Health communication principles: clear language, audience segmentation, pretesting, and use of multiple channels.

Program sustainability requires local ownership, capacity building, and integration into existing systems.

Health system performance frameworks assess access, quality, efficiency, equity, and responsiveness.

Health insurance mechanisms: risk pooling, community-based insurance, social health insurance, and private insurance.

Cost-sharing mechanisms: user fees, co-payments, and deductibles; they can deter necessary care, especially for poor households.

Human resources for health: density of doctors, nurses, and midwives per 1,000 population is a key indicator; WHO threshold is 4.45 skilled health workers per 1,000.

Pharmaceutical policy: essential medicines list, generic substitution, procurement, and rational drug use.

Health information systems: DHIS2 and civil registration and vital statistics (CRVS) systems provide routine data for planning.

Decentralization transfers authority to local governments; it can improve responsiveness but risks inequity without adequate financing.

Economic evaluation types: cost-minimization, cost-effectiveness, cost-utility, and cost-benefit analysis.

Family planning methods: barrier, hormonal, intrauterine devices, and permanent methods; effectiveness is measured by the Pearl index.

Emergency contraception is most effective when used as soon as possible after unprotected intercourse.

Antenatal screening includes hemoglobin, blood group, HIV, syphilis, hepatitis B, and glucose tolerance testing.

Partograph monitoring tracks cervical dilation, fetal heart rate, and maternal vital signs during labor to detect obstructed labor.

Kangaroo mother care: skin-to-skin contact, exclusive breastfeeding, and early discharge for low-birth-weight infants.

Child growth standards: WHO median weight-for-age at birth is about 3.3 kg; under-five mortality is reported per 1,000 live births.

Adolescent-friendly health services: confidentiality, privacy, provider training, and youth involvement.

Reproductive health includes family planning, maternal health, safe abortion where legal, and prevention of sexually transmitted infections.

Elimination vs. eradication: elimination reduces cases to zero in a defined area; eradication permanently reduces global cases to zero.

Smallpox was declared eradicated in 1980; polio eradication remains a global goal.

Antimicrobial resistance is driven by inappropriate antibiotic use; stewardship programs promote appropriate prescribing.

Vaccine types: live attenuated, inactivated, toxoid, subunit, and mRNA; live vaccines are generally contraindicated in immunocompromised persons.

Cold chain maintains vaccine potency from manufacture to administration; temperature monitoring is essential.

NCD prevention: tobacco control (MPOWER), salt reduction, physical activity promotion, and alcohol control.

Cancer screening: cervical (HPV test or Pap smear), breast (mammography), and colorectal (fecal occult blood or colonoscopy).

Diabetes control: HbA1c monitoring, lifestyle modification, and medication adherence.

Body mass index (BMI) = weight (kg) / height (m)^2; underweight <18.5, normal 18.5-24.9, overweight 25-29.9, obese >=30.

Dietary diversity scores count food groups consumed; higher scores indicate better diet quality.

Food fortification adds micronutrients to staple foods (e.g., iodized salt, iron-fortified flour); supplementation provides direct nutrient doses.

Foodborne outbreak investigation: interview cases, collect food histories, identify the vehicle, and implement control measures.

Water quality testing uses membrane filtration or most probable number (MPN) methods for coliforms.

Sanitation and hygiene behavior change uses community-led total sanitation (CLTS) to end open defecation.

Food security has four dimensions: availability, access, utilization, and stability.

Nutritional assessment includes anthropometry, biochemical tests, clinical examination, and dietary surveys (the ABCD approach).

Ethical frameworks: consequentialism (outcomes), deontology (duties), virtue ethics (character), and principlism (four principles).

Public health emergencies may justify restrictive measures if they are necessary, proportionate, transparent, and time-limited.

Data ethics: privacy, consent, anonymization, and secondary use of health data require governance.

Professional codes of conduct require honesty, integrity, accountability, and respect for diversity.

Team leadership: situational leadership adapts style to follower readiness; transformational leadership inspires shared vision.

Quality improvement models: Plan-Do-Study-Act (PDSA) cycles and root cause analysis.

Advocacy and policy engagement require evidence synthesis, stakeholder mapping, and clear communication.

Research integrity: avoiding fabrication, falsification, plagiarism, and undisclosed conflicts of interest.