Terminology of the course

Public health

Public Health is the science and practice of preventing disease, prolonging life and promoting health through organised efforts of society Central elements are - the dual character of Public Health as science and practice - integration an simulatneity of the five pillars of public health

Five pillars of Public Health - Health promotion - Prevention - Treatment - Rehabilitation - Long-term care

Planetary Health

Planetary health describes how human health depends on the health of ecosystems. The consequences of global climate change, species extinction, threats to oceans and air pollution call for a rethink of the health sector - Key concepts are - Adaption - Mitigation

Health policy

Health pilicy id defined as the decisions, plans and actions that are undertaken to achive specific healthcare goals within a society

Epidemiology

Epidemiology studies how diseases spread amongst human and non-human populations, of often disease occur in different groups of people and why

Evidence

Findings from research and other knowledge that may serve as a basis for decision-making in Public health and healthcare What counts as evidence is context-dependent and is often broader that the knowledge produced through the scientific method.

Evidence synthesis

Is a type of research method that allows researchers to bringt together all relevant information on a research question

Bradford-Hill criteria

Measures of effect and association

Relationships between exposures and outcomes are measured by measures of effect, which are statistics that estimate the direction and magnitude of associations among variables

Disease occurrence/frequency

Prevalence

Occurence of existing cases It is important that you have a representative sample otherwise you just have a proportion.

\[ \text{Prevalence} = {\text{number of existing cases} \over \text{number of people in a population at a definded persiod of time}} \]

Incidence

Occurence of new cases

Incidence risk

The incidence when the nominator is the same as the denominator

\[ \text{Incidence risk} = {\text{number of new cases over a period of time} \over \text{number of people at risk at the beginning of the time period}} \]

Incidence rate

The incidence whent the denominator is a time \[ \text{Incidence rate} = {\text{number of new cases over a period of time} \over \text{number of people at risk during the time period}} \]

Risk

likelihood, thatt an event of interest will occur in a subject in a spedivied period of follow-up time The risk is a probability The risk must be between 0 and 1 The denominator ist the population at the beginng

Rates

Measures of the speed of something occuring of developing disease/events occurring in a population A rate ist not a probability The rate is always non negative with no upper limit

Mortality

Mortality is a special measure of incidence rate The mortality is a rate and thus has time in the denominator (usually expressed as person years)

\[ \text{Mortality} = {\text{number of deaths} \over \text{number of people per unit of time}} \]

Measures of effect

There are ratio measures (e.g., Odds Ratio, Risk Ratio, Rate Ratio) and difference measures (e.g., Risk difference, Attributable Risk, …)
Ratio measures are used in etiologic studies of health outcomes
Difference measures are used to quantify population impact & public health importance of risk or protective factors that determine health outcomes (size of problem)

Odds ratio

\[ \text{Odds ratio} = {\text{probability of event} \over 1- \text{probability of event}} \]

Risk ratio

\[ \text{Relative risk} = {\text{Incidence in exposed} \over \text{Incidence in the not-exposed}} \]

Rate ratio

ratio of two average rates

Internal validity

Internal validity relates to risk of bias within a study - See Internal and external validity: can you apply research study results to your patients?

External validity

The extent to which the conclusions of an empicircal investigation remain true when different research methods and research paricipants or subjects are used. - External validity addresses generalizability or applicability of study results - Whether our sample is generalizable to the general population.