Epidemiology

Question 1

Descriptive epidemiology

Answer 1

-deals with describing the pattern of diseases

Question 2

Analytical epidemiology

Answer 2

-attempts to make associations of observed patterns in order to make inferences in a hypothesis driven manner

Question 3

Genetic epidemiology

Answer 3

-the epidemiological evaluation of the role of inherited causes of disease in families and in populations

Question 4

Incidence

Answer 4

• number of newly diagnosed people in a specific time interval for a specified size of the population at risk
• measured against time

Question 5

Cumulative incidence

Answer 5

• most common measurement of incidence
• valid in cohort studies where attritition is low
• due to attrition, incidence density (incidence rate) is aused

Question 6

Incidence density

Answer 6

• aka incidence rate
• expresses the number of new cases per person-year of observation
• measured in time-1

Question 7

Prevalence

Answer 7

-the number of existing cases in a specified population for a period of observation

Question 8

Point prevalence

Answer 8

-cross sectional observation of prevalence (at any one time)

(No of existing (both new and old-dead and cured))/ cross sectional population of that area on that date

Question 9

Period prevalence

Answer 9

• prevalence over a specified time frame

- number of existing (both new and old- dead and cured)/ mid year population at an area

Question 10

Prevalence and incidence

Answer 10

incidence x duration of illness

Question 11

Lifetime prevalence

Answer 11

• proportion of individuals in the population who have ever manifested a disorder who are alive on a given day
• has someone ever in their life had the illness- prone to recall bias

Question 12

Lifetime morbid risk

Answer 12

• LMR
• probability of a person developing the disorder during their entire life period
• includes the entire lifetime of a birth cohort both past and future and includes those deceased at time of survey

Question 13

Baseline prevalence

Answer 13

-usual prevalence of a disease in a community

Question 14

Endemic

Answer 14

• if baseline is low to moderate and continues without significant fluctuation then the disease is endemic in the community

Question 15

Hyperendemic

Answer 15

• a persistent but high level of the baseline

- most psychiatric disorders are low level endemic disorders

Question 16

Epidemic

Answer 16

-occurrence within an area clearly exceeds the expected level in a given time period

Question 17

Pandemic

Answer 17

-epidemic in wide geographical proportion

Question 18

Crude rate

Answer 18

-rate applicable to whole population

Question 19

Specific rate

Answer 19

-rate applicable to a subgroup of a population

Question 20

Standardised rate

Answer 20

-a rate applicable to a hypothetical population with an adjusted variable e.g age

Question 21

Crude mortality rate

Answer 21

-ratio between number of deaths due to all-cause in a population and total population size

Question 22

Cause-specific mortality rate

Answer 22

• e.g alcohol specific mortality

- refers to the ration between number of deaths due to alcohol in a population and total population size

Question 23

Case fatality rate

Answer 23

• ratio between number of deaths due to a specific disease and number of persons affected by the disease in a population
• measure of fatal severity of the disease

Question 24

Proportionate mortality rate

Answer 24

• measure of the contribution of a disease to the societal mortality burden
• ratio between deaths due to specific cause and total number of deaths in a population

Question 25

Years of potential life lost (YPLL)

Answer 25

- a measure of the impact of premature mortality on a population - calculated as the sum of the differences between some predetermined end point and the ages of death for those who died before that end point - most common end points are age 65 and the average life expectancy - measure gives more weight to an earlier death than later deaths

Question 26

Disability adjusted life years

Answer 26

-DALY -one DALY represents the loss of one year of equivalent full health DALY= YLL+ YLD YLL= years of life lost due to premature mortality in the population YLD= years lost due to disability for cases

Question 27

YLL

Answer 27

-years of life lost due to premature mortality in the population -YLL= Nx LE N= number of deaths LE= standard life expectancy

Question 28

YLD

Answer 28

-years lost due to disability for cases -YLD= Ix DWxLD -I= number of incident cases DW= weight given to the disability LD= average duration of the case until remission or death (life until death in years)

Question 29

Neonatal death

Answer 29

-a liveborn that dies within 28 days

Question 30

Early neonatal death

Answer 30

-live born that dies within 7 days

Question 31

Late neonatal death

Answer 31

-liveborn that dies between 7 and 28 days

Question 32

Stillbirth

Answer 32

-foetus dies before birth but after 24 weeks of gestation

Question 33

Perinatal death

Answer 33

-still births+ early neonatal births

Question 34

Postneonatal deaths

Answer 34

-deaths from 1 month to one year

Question 35

Infant deaths

Answer 35

-deaths under 1 year

Question 36

Constrictive pyramid

Answer 36

-fewer people in the younger age categories e.g US

Question 37

Expansive pyramid

Answer 37

- large number of people in a younger age categories | - typical of developing countries

Question 38

Stationary pyramid

Answer 38

- roughly equal numbers of people in each category but tapering towards older categories e. g Sweden

Question 39

First generation epidemiological studies

Answer 39

- before world war 2 | - 16 studies looking at prevalence of mental disorders in relation to community characteristics

Question 40

Second generation epidemiological studies

Answer 40

-looked at diagnosis, classification and numenclature after world war 2

Question 41

Third generation epidemiological studies

Answer 41

-started in 1970 with more effort into increasing the reliability of psychiatric diagnoses

Question 42

Fourth generation studies

Answer 42

- current phase | - includes studies into biological markers, csf etc in large cross sectional surveys e.g H70 study