Epidemiology Flashcards

1
Q

Triad of epidemiological questions?

A

How does pattern of disease vary over time?
How does place in which population lives affect disease pattern?
How do personal characteristics of people in a population affect disease pattern?

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2
Q

What does descriptive epidemiology do?

A

Describe pattern of disease

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3
Q

What does analytical epidemiology do?

A

Make associations of observed patterns to make inferences in hypothesis driven manner

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4
Q

What is genetic epidemiology?

A

Epidemiological evaluation of role of inherited causes of disease in families and populations

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5
Q

What did Morton define genetic epidemiology as?

A

Science which deals with etiology, distribution and control of disease in groups of relatives and with inherited causes of disease in populations

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6
Q

Define incidence

A

Number of new cases diagnosed in specified time interval for specified size of population at risk

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7
Q

What determines population size for incidence?

A

Mid-interval population

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8
Q

Give formula for incidence

A

Number of newly diagnosed cases/mid-2014 population at an area

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9
Q

What must new cases include for incidence calculation?

A

Newly diagnosed patients whether cured or dead

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10
Q

What is the advantage of cumulative incidence?

A

Valid in cohort studies where attrition is low

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11
Q

When is cumulative incidence not helpful?

A

High attrition rate - as dropouts are excluded from being counted as new cases

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12
Q

What is used if high attrition rate and need to calculate incidence?

A

Incidence rate

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13
Q

What is incidence rate?

A

Number of new cases per person-year of observation

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14
Q

What is the unit of incidence rate?

A

Time-1

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15
Q

When are incident rate ratios used?

A

When reporting results that compare two groups incidence rates

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16
Q

What is prevalence?

A

Number of existing cases in specified population for period of observation

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17
Q

What is point prevalence?

A

Prevalence in cross-sectional observation

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18
Q

What is period prevalence?

A

Prevalence in longitudinal observation

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19
Q

Which cases are counted in prevalence?

A

New cases

Diagnosed before observation but still suffering disease

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20
Q

What does prevalence not count re cases?

A

Previously diagnosed but now cured or dead

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21
Q

Calculation of point prevalence

A

Number of existing cases/cross sectional population at an area on 11/11/2018

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22
Q

Calculation of period prevalence

A

Number of existing cases/mid year population at an area

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23
Q

Which illnesses will have higher prevalence?

A

Chronic

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24
Q

What formula expresses relationship between incidence and prevalence?

A

Prevalence = incidence x duration of illness

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25
Q

What is lifetime prevalence?

A

Proportion of individuals in the population who have ever manifested a disease who are alive on a given day.

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26
Q

What is lifetime morbid risk?

A

Probability of a person developing the disorder during the entire period of their life (often a specified period)

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27
Q

What does lifetime morbid risk include?

A

Entire lifetime of a birth cohort both past and future

Includes those deceased at time of survey

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28
Q

What is used to calculate lifetime morbid risk for low incidence disorders?

A

Summation of age-specific incidence rates live approximate LMR

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29
Q

What is baseline prevalence?

A

Usual prevalence of a disease in a community

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30
Q

When is a disease said to be endemic?

A

If baseline is low to moderate and continues without significant fluctuation

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31
Q

What is hyperendemic occurrence?

A

A persistent but high baseline

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32
Q

What occurrence are most psychiatric disorders classed as?

A

Low-level endemic

33
Q

What is sporadic occurrence?

A

Irregular pattern of significant fluctuations from baseline

34
Q

What is epidemic?

A

Occurrence within an area clearly exceeds expected level in a given time period

35
Q

What is a pandemic?

A

An epidemic in wide geographical proportion

36
Q

What is a crude rate?

A

Any rate applicable to a while population

37
Q

What is a specific rate?

A

Any rate applicable to a subgroup of a population

38
Q

What is a standardised rate?

A

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

39
Q

What is crude mortality rate?

A

Ratio between number of deaths du to all-cause in a population and total population sie

40
Q

What is case fatality rate?

A

Ratio between number of deaths from specific disease and number of people affected by the disease in population.

41
Q

What is case fatality rate a measure of?

A

Fatal severity of disease studied

42
Q

What is proportionate mortality rate?

A

Ratio between deaths due to specific cause and total number of deaths in a population

43
Q

What is proportionate mortality rate a measure of?

A

Contribution of a disease to societal mortality burden

44
Q

What is years of potential life lost?

A

Sum of the differences between some predetermined end point and ages of death for those who died before that end point

45
Q

What is years of potential life lost a measure of?

A

Impact of premature mortality on a population

46
Q

Most commonly used end points in years of potential life lost?

A

65 years

Average life expectancy

47
Q

What do years of potential life lost give more weight to?

A

Earlier deaths

48
Q

What is disability-adjusted life years (DALY)?

A

Health gap measure that extends the concept of potential years of life lost due to premature death to include equivalent years of healthy life lost in states of disability

49
Q

What does one DALY represent?

A

Loss of one year of equivalent full health

50
Q

What can be used to calculate DALYs?

A

3% time discounting and non-uniform age weights that give less weight to years lived at young and older ages

51
Q

Calculation for DALY

A

Years of life lost due to premature mortality in population (YLL) + years lost due to disability for cases (YLD)

52
Q

Calculation for YLL?

A

Number of deaths x Standard life expectancy at age of death in years (LE)

53
Q

Calculation for YLD

A

Number of incident cases x weight given to disability x average duration of case until remission or death (life until death in years)

54
Q

Define neonatal death

A

Liveborn that dies within 28 days

55
Q

Define early neonatal death

A

Liveborn that dies within 7 days

56
Q

Define late neonatal death

A

Liveborn that dies between 7-28 days

57
Q

Define stillbirth

A

Fetus that dies before birth but after 24 weeks

58
Q

Define perinatal deaths

A

Still births + early neonatal births

59
Q

Define postneonatal deaths

A

Deaths from 1 month to 1 year

60
Q

Define infant deaths

A

Deaths under 1 year

61
Q

What does a frequency polygon show?

A

Frequency distribution

62
Q

How does one create frequency polygon?

A

Mark number of observations within an interval with single point placed at midpoint of interval and then connect these points

63
Q

What can population pyramids be helpful for?

A

Insight into trends in population over time

64
Q

Types of population pyramids

A

Constrictive
Expansive
Stationary

65
Q

What is a constrictive pyramid?

A

Fewer people in younger age categories.

66
Q

Which type of countries have a constrictive pyramid?

A

E.g. USA - baby boom populations shift to more conservative birth dats

67
Q

What is an expansive pyramid?

A

Greater number of people in younger age categories

High birth rates
Low life expectancy

68
Q

Which type of pyramid is seen in developing countries?

A

Expansive

69
Q

What is an expansive pyramid?

A

Equal numbers of people in all categories, tapering towards old age categories

Low, constant birth rate
High QoL

70
Q

How many psychiatric-epidemiological studies belong to first generation?

A

16

71
Q

What defines first psychiatric-epidemiological generation?

A

Studies carried out before World War II

72
Q

What did first generation psychiatric-epidemiological studies focus on?

A

Health care agency registered prevalence of mental disorders in relation to community characteristics

73
Q

How many studies in the second generation of psychiatric-epidemiological studies?

A

60

74
Q

What did second generation psychiatric-epidemiological studies focus on?

A

Diagnostic criteria
Classification
Nomenclature of psychiatric disorder

75
Q

What type of studies were the second generation psychiatric-epidemiological studies?

A

Field surveys in unstructured clinical interviews

76
Q

When did the third generation of psychiatric-epidemiological studies start?

A

1970

77
Q

What was the major objective of third generation psychiatric-epidemiological studies?

A

Increase reliability of psychiatric diagnoses

Obtain precise estimates of prevalence and incidence of MH disorders

78
Q

What does fourth generation of psychiatric-epidemiological studies include?

A

Comprehensive sets of biological markers such as brain imaging, CSF, bloods etc
Large scale cross-sectional surveys e.g. H70 study