W12 39 principles of epidemiology and public health Flashcards
What is public health?
The science and art of promoting and protecting health and well-being, preventing ill-health and prolonging life through the organised efforts of society.
What are the 3 pillars of public health?
Health improvement, protection, services
What is epidemiology?
The study of the distribution and determinants of health-related states or events (including disease), and the application of this study to the control of diseases and other health problems.
What is prevalence?
Proportion of individuals in a defined population that have a disease or other health outcome at a specified point in time (point prevalence) or during a specified time period (period prevalence).
Expressed as a proportion or %.
What is incidence?
Measure of the number of NEW cases of a disease or other health outcome that develops in a population at risk during a specified time period. Estimated from cohort studies.
What is incidence risk?
No of new cases of a disease in specified period of time / number of disease free individuals at start
What is incidence rate!
No. of new cases in a given time / person-time at risk
What are the measures of mortality?
Absolute numbers of deaths - hard to compare between populations. Usually rate per 1000 individuals.
Standardised mortality rate - allows for comparison of rates between populations with different age and/or sex.
Standardised mortality ratio - used when age-specific rates are unavailable. Indirect - expected number of deaths are estimated from mortality rates derived from a standard population. SMR = observed mortality / expected mortality. >1 means higher and <1 means lower in your population.
What are DALYs?
Disability adjusted life years. Combines time lives with disability and time lost due to premature death. One DALY = a lost year of healthy life
What are issues with infectious communicable diseases?
New strains
Issues with resistance
Re-emergence of infections eg measles from drop in vaccinations
What is the chain of infection, eg for influenza?
Infectious agent (virus) —> reservoirs (infected human) —> portal of exit (respiratory tract) —> means of transmission (airborne) —> portal of entry (respiratory tract) —> susceptible host (non-immunised elderly contact)
What are the different infection time periods?
Incubation period: time from infection to onset of symptoms
Latent period: time between infection and ability to transmit infection
Infectious period: time during which infection can be transmitted
What are the different modes of transmission?
Direct contact
Respiratory route
Faecal oral
Sexual transmission
Blood borne
Airborne microbial aerosols
Vector borne
What are the types of immunisation?
Inactivated vaccines - eg tetanus, diphtheria, influenza
Live attenuated vaccines - eg MMR, BCG
What is herd immunity?
Protection of individuals who cannot be immunised
