Understanding Public Health

WHO definition of health

A state of complete physical, mental, and social well-being, and not merely the absence of disease or infirmity.

APHA definition of public health

A science-based, evidence-backed field that promotes and protects the health of all people and their communities where they live, learn, work, and play.

Social Determinants of Health (SDOH)

Non-medical factors and broader systems (economic policies, social norms, climate change, political structures) shaping the conditions in which people are born, grow, live, work, and age.

Equality

An approach where each individual or group is given the exact same resources or opportunities, regardless of their specific needs.

Equity

An approach that recognizes varying circumstances and allocates the specific resources needed to reach an equal outcome.

Justice

An approach that fixes or removes structural barriers at the systems level to create long-term, sustainable, equitable access.

Health Inequalities

Measurable differences or uneven distributions of health status or resources between groups, focusing on what differences exist without determining if they are fair.

Health Inequities

Systematic differences in health outcomes between population groups that are unfair, unjust, and avoidable, focusing on why those differences exist.

Downstream public health approach

Interventions targeted at individual disease management, personal risk reduction, and behavior change (e.g., individual screening or treatment).

Upstream public health approach

Interventions targeted at environmental, structural, and social determinants to prevent health issues at the population level (e.g., sanitation, clean water, smoke-free laws).