Public Health, Health Promotion and Disease Prevention
Core concepts
Understand the levels of prevention - primary (prevent onset), secondary (early detection), tertiary (limit disability). Know the principles of health promotion (Ottawa Charter: build healthy public policy, create supportive environments, strengthen community action, develop personal skills, reorient health services). Familiarise yourself with epidemiology basics: incidence versus prevalence, risk factors, screening principles (sensitivity, specificity, predictive value), and immunisation schedules. Recognise the pharmacist's public-health role: vaccination, screening, health education, smoking cessation, and antimicrobial stewardship.
Traps
Incidence (new cases over time) versus prevalence (all existing cases) is a classic trap. Sensitivity (true positives) versus specificity (true negatives); positive predictive value depends on prevalence. Primary prevention is before disease; secondary is early detection; tertiary is rehabilitation. Screening is not the same as diagnosis. Do not confuse health promotion with disease prevention - they overlap but are distinct.
Worked example
A screening test with high sensitivity but low specificity produces many false positives, especially in low-prevalence populations - so positive predictive value falls. Questions often ask why a good test yields many false alarms: the answer is low prevalence, not a faulty test.
Exam strategy
Classify each intervention by prevention level, then apply the epidemiological measure (incidence, prevalence, sensitivity, specificity, PPV).