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Year 2 Medicine > Causation & Study Design: HIV & AIDS > Flashcards

Causation & Study Design: HIV & AIDS Flashcards

1
Q

Study designs

  • Which study design is reflected in each? (A-D)
A
  • Which study design is reflected in each? (A-D)
    • A = Cross-Sectional
    • B = Case-control
    • C = Cohort
    • D = Randomised Control Trial
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2
Q

Study designs

  • Which study design is reflected in each? (A-D)
A
  • Which study design is reflected in each? (A-D)
    • A = Cross-Sectional
    • B = Case-control
    • C = Cohort
    • D = Randomised Control Trial
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3
Q

Study designs

  • Which study design is reflected in each? (A-D)
A
  • Which study design is reflected in each? (A-D)
    • A = Cross-Sectional
    • B = Case-control
    • C = Cohort
    • D = Randomised Control Trial
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4
Q

Study designs

  • Which study design is reflected in each? (A-D)
A
  • Which study design is reflected in each? (A-D)
    • A = Cross-Sectional
    • B = Case-control
    • C = Cohort
    • D = Randomised Control Trial
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5
Q

Cross-sectional study

  • A defined population is surveyed to simultaneously measure
    • …/ … status
    • …
  • Sample selected using inclusion and exclusion criteria
    • Different to case-control (sample selected based on outcome status)
    • Different to cohort (sample based on exposure status)
  • Could be general population or clinic-based
  • Prevalence is reported for the population as a whole, and often for subgroups
A
  • A defined population is surveyed to simultaneously measure
    • Disease/ condition status (e.g. infertility)
    • Exposure (e.g. sedentary lifestyle, alcohol intake)
  • Sample selected using inclusion and exclusion criteria
    • Different to case-control (sample selected based on outcome status)
    • Different to cohort (sample based on exposure status)
  • Could be general population or clinic-based
  • Prevalence is reported for the population as a whole, and often for subgroups
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6
Q

Cross-sectional study

  • A defined population is surveyed to simultaneously measure
    • Disease/ condition status (e.g. infertility)
    • Exposure (e.g. sedentary lifestyle, alcohol intake)
  • Sample selected using … and … criteria
    • Different to case-control (sample selected based on outcome status)
    • Different to cohort (sample based on exposure status)
  • Could be general … or …-based
  • Prevalence is reported for the population as a whole, and often for subgroups
A
  • A defined population is surveyed to simultaneously measure
    • Disease/ condition status (e.g. infertility)
    • Exposure (e.g. sedentary lifestyle, alcohol intake)
  • Sample selected using inclusion and exclusion criteria
    • Different to case-control (sample selected based on outcome status)
    • Different to cohort (sample based on exposure status)
  • Could be general population or clinic-based
  • Prevalence is reported for the population as a whole, and often for subgroups
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7
Q

Cross-sectional study

  • A defined population is surveyed to simultaneously measure
    • Disease/ condition status (e.g. infertility)
    • Exposure (e.g. sedentary lifestyle, alcohol intake)
  • Sample selected using inclusion and exclusion criteria
    • Different to case-control (sample selected based on … status)
    • Different to cohort (sample based on exposure status)
  • Could be general population or clinic-based
  • Prevalence is reported for the population as a …, and often for …
A
  • A defined population is surveyed to simultaneously measure
    • Disease/ condition status (e.g. infertility)
    • Exposure (e.g. sedentary lifestyle, alcohol intake)
  • Sample selected using inclusion and exclusion criteria
    • Different to case-control (sample selected based on outcome status)
    • Different to cohort (sample based on exposure status)
  • Could be general population or clinic-based
  • Prevalence is reported for the population as a whole, and often for subgroups
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8
Q

Cross-sectional study

  • A defined population is surveyed to simultaneously measure
    • Disease/ condition status (e.g. infertility)
    • … (e.g. sedentary lifestyle, alcohol intake)
  • Sample selected using inclusion and exclusion criteria
    • Different to case-control (sample selected based on outcome status)
    • Different to cohort (sample based on … status)
  • Could be general population or clinic-based
  • Prevalence is reported for the population as a whole, and often for subgroups
A
  • A defined population is surveyed to simultaneously measure
    • Disease/ condition status (e.g. infertility)
    • Exposure (e.g. sedentary lifestyle, alcohol intake)
  • Sample selected using inclusion and exclusion criteria
    • Different to case-control (sample selected based on outcome status)
    • Different to cohort (sample based on exposure status)
  • Could be general population or clinic-based
  • Prevalence is reported for the population as a whole, and often for subgroups
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9
Q

Cohort study

  • Used to
    • calculate … (new onset cases of a disease/condition/outcome)
    • identify … (risk factors) for particular outcome
  • Participants selected into exposed vs non-exposed group (no allocation made by the researcher)
  • Two groups as similar as possible (e.g. age, gender, occupation, stage of illness, etc.)
    • Variables not of interest are matched (i.e. potential confounders) at selection
    • Exposures of interest are not measured or matched at selection
  • At study end, relative numbers of new disease occurrences compared across groups
  • Retrospective or prospective
A
  • Used to
    • calculate incidence (new onset cases of a disease/condition/outcome)
    • identify exposures (risk factors) for particular outcome
  • Participants selected into exposed vs non-exposed group (no allocation made by the researcher)
  • Two groups as similar as possible (e.g. age, gender, occupation, stage of illness, etc.)
    • Variables not of interest are matched (i.e. potential confounders) at selection
    • Exposures of interest are not measured or matched at selection
  • At study end, relative numbers of new disease occurrences compared across groups
  • Retrospective or prospective
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10
Q

Cohort study

  • Used to
    • calculate incidence (new onset cases of a disease/condition/outcome)
    • identify exposures (risk factors) for particular outcome
  • Participants selected into … vs non-… group
  • Two groups as … as possible (e.g. age, gender, occupation, stage of illness, etc.)
    • Variables not of interest are matched (i.e. potential confounders) at selection
    • Exposures of interest are not measured or matched at selection
  • At study end, relative numbers of new disease occurrences compared across groups
  • Retrospective or prospective
A
  • Used to
    • calculate incidence (new onset cases of a disease/condition/outcome)
    • identify exposures (risk factors) for particular outcome
  • Participants selected into exposed vs non-exposed group (no allocation made by the researcher)
  • Two groups as similar as possible (e.g. age, gender, occupation, stage of illness, etc.)
    • Variables not of interest are matched (i.e. potential confounders) at selection
    • Exposures of interest are not measured or matched at selection
  • At study end, relative numbers of new disease occurrences compared across groups
  • Retrospective or prospective
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11
Q

Cohort study

  • Used to
    • calculate … (new onset cases of a disease/condition/outcome)
    • identify exposures (risk factors) for particular outcome
  • Participants selected into exposed vs non-exposed group (no allocation made by the researcher)
  • Two groups as similar as possible (e.g. age, gender, occupation, stage of illness, etc.)
    • Variables not of interest are matched (i.e. potential confounders) at selection
    • Exposures of interest are not measured or matched at selection
  • At study end, relative numbers of new disease occurrences compared across …
  • Retrospective or prospective
A
  • Used to
    • calculate incidence (new onset cases of a disease/condition/outcome)
    • identify exposures (risk factors) for particular outcome
  • Participants selected into exposed vs non-exposed group (no allocation made by the researcher)
  • Two groups as similar as possible (e.g. age, gender, occupation, stage of illness, etc.)
    • Variables not of interest are matched (i.e. potential confounders) at selection
    • Exposures of interest are not measured or matched at selection
  • At study end, relative numbers of new disease occurrences compared across groups
  • Retrospective or prospective
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12
Q

Cohort study

  • Used to
    • calculate incidence (… … cases of a disease/condition/outcome)
    • identify exposures (… …) for particular outcome
  • Can be …spective or ….spective
A
  • Used to
    • calculate incidence (new onset cases of a disease/condition/outcome)
    • identify exposures (risk factors) for particular outcome
  • Can be retrospective or prospective
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13
Q

Case-control study

  • Used to identify relevant … (not used to calculate …)
  • Two groups of participants are selected – one with condition (cases) and one without (controls)
  • Controls selected to be as similar as possible to the cases (e.g. age, gender, occupation, stage of illness, etc.)
    • Variables not of interest are matched (i.e. potential confounders) at selection
    • Exposures of interest are not measured or matched at selection
  • Always …→Past exposure/s in both groups
    • E.g. interview/survey, historical records
A
  • Used to identify relevant exposures (not used to calculate incidence)
  • Two groups of participants are selected – one with condition (cases) and one without (controls)
  • Controls selected to be as similar as possible to the cases (e.g. age, gender, occupation, stage of illness, etc.)
    • Variables not of interest are matched (i.e. potential confounders) at selection
    • Exposures of interest are not measured or matched at selection
  • Always retrospective→Past exposure/s in both groups
    • E.g. interview/survey, historical records
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14
Q

Case-control study

  • Used to identify relevant exposures (not used to calculate incidence)
  • Two groups of participants are selected – one with condition (…) and one without (…)
  • Controls selected to be as … as possible to the … (e.g. age, gender, occupation, stage of illness, etc.)
    • Variables not of interest are matched (i.e. potential confounders) at selection
    • Exposures of interest are not measured or matched at selection
  • Always retrospective→Past exposure/s in both groups
    • E.g. interview/survey, historical records
A
  • Used to identify relevant exposures (not used to calculate incidence)
  • Two groups of participants are selected – one with condition (cases) and one without (controls)
  • Controls selected to be as similar as possible to the cases (e.g. age, gender, occupation, stage of illness, etc.)
    • Variables not of interest are matched (i.e. potential confounders) at selection
    • Exposures of interest are not measured or matched at selection
  • Always retrospective→Past exposure/s in both groups
    • E.g. interview/survey, historical records
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15
Q

Case-control study

  • Used to identify relevant exposures (not used to calculate incidence)
  • Two groups of participants are selected – one with condition (cases) and one without (controls)
  • Controls selected to be as similar as possible to the cases (e.g. age, gender, occupation, stage of illness, etc.)
    • Variables not of interest are matched (i.e. potential …) at selection
    • Exposures of interest are … … or matched at selection
  • Always retrospective→Past exposure/s in both groups
    • E.g. interview/survey, historical records
A
  • Used to identify relevant exposures (not used to calculate incidence)
  • Two groups of participants are selected – one with condition (cases) and one without (controls)
  • Controls selected to be as similar as possible to the cases (e.g. age, gender, occupation, stage of illness, etc.)
    • Variables not of interest are matched (i.e. potential confounders) at selection
    • Exposures of interest are not measured or matched at selection
  • Always retrospective→Past exposure/s in both groups
    • E.g. interview/survey, historical records
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16
Q

Case-control study

  • Used to identify relevant exposures (not used to calculate …)
  • Two groups of participants are selected – one with condition (cases) and one without (controls)
  • Controls selected to be as similar as possible to the cases (e.g. age, gender, occupation, stage of illness, etc.)
    • Variables not of interest are matched (i.e. potential confounders) at selection
    • Exposures of interest are not measured or matched at selection
  • Always retrospective→… …/s in both groups
    • E.g. interview/survey, historical records
A
  • Used to identify relevant exposures (not used to calculate incidence)
  • Two groups of participants are selected – one with condition (cases) and one without (controls)
  • Controls selected to be as similar as possible to the cases (e.g. age, gender, occupation, stage of illness, etc.)
    • Variables not of interest are matched (i.e. potential confounders) at selection
    • Exposures of interest are not measured or matched at selection
  • Always retrospective→Past exposure/s in both groups
    • E.g. interview/survey, historical records
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17
Q

Cohort studys can be retrospective or prospective, but case-control studies are always …

A

retrospective

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18
Q

RCT

  • Used to test the … and …/… of interventions
  • Participants selected and then randomly allocated to either receive the intervention of interest or to receive a control (or no) intervention
  • Random allocation should ensure that the two groups are essentially identical before provision of intervention or control
  • Outcomes are compared across the two groups at the end of the trial
A
  • Used to test the safety and efficacy/effectiveness of interventions
  • Participants selected and then randomly allocated to either receive the intervention of interest or to receive a control (or no) intervention
  • Random allocation should ensure that the two groups are essentially identical before provision of intervention or control
  • Outcomes are compared across the two groups at the end of the trial
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19
Q

RCT

  • Used to test the safety and efficacy/effectiveness of interventions
  • Participants selected and then … allocated to either receive the …. of interest or to receive a …
  • Random allocation should ensure that the two groups are essentially identical before provision of intervention or control
  • Outcomes are compared across the two groups at the end of the trial
A
  • Used to test the safety and efficacy/effectiveness of interventions
  • Participants selected and then randomly allocated to either receive the intervention of interest or to receive a control (or no) intervention
  • Random allocation should ensure that the two groups are essentially identical before provision of intervention or control
  • Outcomes are compared across the two groups at the end of the trial
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20
Q

RCT

  • Used to test the safety and efficacy/effectiveness of interventions
  • Participants selected and then randomly allocated to either receive the intervention of interest or to receive a control (or no) intervention
  • Random allocation should ensure that the two groups are essentially … before provision of intervention or control
  • Outcomes are … across the two groups at the end of the trial
A
  • Used to test the safety and efficacy/effectiveness of interventions
  • Participants selected and then randomly allocated to either receive the intervention of interest or to receive a control (or no) intervention
  • Random allocation should ensure that the two groups are essentially identical before provision of intervention or control
  • Outcomes are compared across the two groups at the end of the trial
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21
Q

RCT

  • Used to test the … and …/effectiveness of interventions
  • Participants selected and then randomly allocated to either receive the intervention of interest or to receive a control (or no) intervention
  • … allocation should ensure that the two groups are essentially identical before provision of intervention or control
  • Outcomes are compared across the two groups at the end of the trial
A
  • Used to test the safety and efficacy/effectiveness of interventions
  • Participants selected and then randomly allocated to either receive the intervention of interest or to receive a control (or no) intervention
  • Random allocation should ensure that the two groups are essentially identical before provision of intervention or control
  • Outcomes are compared across the two groups at the end of the trial
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22
Q

Why do we need to think about causation?

A
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23
Q

Differences between study designs

A
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24
Q

Differences between study designs

  • List in order (top to bottom) - Cohort, Cross-sectional, Case control, RCT, Case Study
A
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25
Q

Which study design gives the best evidence for causal association?

A

RCT

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26
Q

A … is a variable that influences both the dependent variable and independent variable causing a spurious association

A

A confounder is a variable that influences both the dependent variable and independent variable causing a spurious association

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27
Q

Confounding

  • Influences both … and …
A
  • Influences both exposure and disease
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28
Q

Causal criteria

  • … postulates – causal factors in infectious disease
  • …-Hill criteria – causal factors in sickness, injury and occupation
A
  • Koch’s postulates – causal factors in infectious disease
  • Bradford-Hill criteria – causal factors in sickness, injury and occupation
29
Q

Causal criteria

  • Koch’s … – causal factors in … disease
  • Bradford-… criteria – causal factors in …, injury and occupation
A
  • Koch’s postulates – causal factors in infectious disease
  • Bradford-Hill criteria – causal factors in sickness, injury and occupation
30
Q

Causal criteria

  • Koch’s postulates – causal factors in … disease
  • Bradford-Hill criteria – causal factors in sickness, … and occupation
A
  • Koch’s postulates – causal factors in infectious disease
  • Bradford-Hill criteria – causal factors in sickness, injury and occupation
31
Q

Causal criteria

  • … postulates – causal factors in infectious disease
  • Bradford-Hill criteria – causal factors in sickness, injury and …
A
  • Koch’s postulates – causal factors in infectious disease
  • Bradford-Hill criteria – causal factors in sickness, injury and occupation
32
Q

Bradford-Hill criteria

33
Q

Bradford-Hill criteria

34
Q

Bradford-Hill criteria

35
Q

Koch’s postulates

36
Q

Koch’s postulates

  • The bacteria must be … in … case of the disease.
  • The bacteria must be isolated from the host with the disease and grown in pure culture.
  • The specific disease must be reproduced when a pure culture of the bacteria is inoculated into a healthy susceptible host.
  • The bacteria must be recoverable from the experimentally infected host.
A
  • The bacteria must be present in every case of the disease.
  • The bacteria must be isolated from the host with the disease and grown in pure culture.
  • The specific disease must be reproduced when a pure culture of the bacteria is inoculated into a healthy susceptible host.
  • The bacteria must be recoverable from the experimentally infected host.
37
Q

Koch’s postulates

  • The bacteria must be present in every case of the disease.
  • The bacteria must be … from the host with the disease and … in pure culture.
  • The specific disease must be reproduced when a pure culture of the bacteria is inoculated into a healthy susceptible host.
  • The bacteria must be recoverable from the experimentally infected host.
A
  • The bacteria must be present in every case of the disease.
  • The bacteria must be isolated from the host with the disease and grown in pure culture.
  • The specific disease must be reproduced when a pure culture of the bacteria is inoculated into a healthy susceptible host.
  • The bacteria must be recoverable from the experimentally infected host.
38
Q

Koch’s postulates

  • The bacteria must be present in every case of the disease.
  • The bacteria must be isolated from the host with the disease and grown in pure culture.
  • The specific disease must be … when a pure culture of the bacteria is inoculated into a … susceptible host.
  • The bacteria must be recoverable from the experimentally infected host.
A
  • The bacteria must be present in every case of the disease.
  • The bacteria must be isolated from the host with the disease and grown in pure culture.
  • The specific disease must be reproduced when a pure culture of the bacteria is inoculated into a healthy susceptible host.
  • The bacteria must be recoverable from the experimentally infected host.
39
Q

Koch’s postulates

  • The bacteria must be present in every case of the disease.
  • The bacteria must be isolated from the host with the disease and grown in pure culture.
  • The specific disease must be reproduced when a pure culture of the bacteria is inoculated into a healthy susceptible host.
  • The bacteria must be … from the … infected host.
A
  • The bacteria must be present in every case of the disease.
  • The bacteria must be isolated from the host with the disease and grown in pure culture.
  • The specific disease must be reproduced when a pure culture of the bacteria is inoculated into a healthy susceptible host.
  • The bacteria must be recoverable from the experimentally infected host.
40
Q

HIV/AIDS

  • … … Virus infection / Acquired Immune Deficiency Syndrome (HIV/AIDS)
  • A spectrum of conditions caused by infection with the … … Virus (HIV)
  • HIV targets cells within the immune system, causing immunodeficiency→disease and opportunistic infections which would typically normally be neutralised
  • Discovered in 1981 in USA – the AIDS crisis
  • Global pandemic, responsible for at least 35 million deaths worldwide; c. 350,000 men and women in the USA died between 1987 and 1998
A
  • Human Immunodeficiency Virus infection / Acquired Immune Deficiency Syndrome (HIV/AIDS)
  • A spectrum of conditions caused by infection with the Human Immunodeficiency Virus (HIV)
  • HIV targets cells within the immune system, causing immunodeficiency→disease and opportunistic infections which would typically normally be neutralised
  • Discovered in 1981 in USA – the AIDS crisis
  • Global pandemic, responsible for at least 35 million deaths worldwide; c. 350,000 men and women in the USA died between 1987 and 1998
41
Q

HIV/AIDS

  • Human Immunodeficiency Virus infection / Acquired Immune Deficiency Syndrome (HIV/AIDS) A spectrum of conditions caused by infection with the Human Immunodeficiency Virus (HIV)
  • HIV targets cells within the immune system, causing …→disease and opportunistic infections which would typically normally be …
  • Discovered in 1981 in USA – the AIDS crisis
  • Global pandemic, responsible for at least 35 million deaths worldwide; c. 350,000 men and women in the USA died between 1987 and 1998
A
  • Human Immunodeficiency Virus infection / Acquired Immune Deficiency Syndrome (HIV/AIDS) A spectrum of conditions caused by infection with the Human Immunodeficiency Virus (HIV)
  • HIV targets cells within the immune system, causing immunodeficiency→disease and opportunistic infections which would typically normally be neutralised
  • Discovered in 1981 in USA – the AIDS crisis
  • Global pandemic, responsible for at least 35 million deaths worldwide; c. 350,000 men and women in the USA died between 1987 and 1998
42
Q

HIV/AIDS

  • Human Immunodeficiency Virus infection / Acquired Immune Deficiency Syndrome (HIV/AIDS) A spectrum of conditions caused by infection with the Human Immunodeficiency Virus (HIV)
  • HIV targets cells within the immune system, causing immunodeficiency→disease and opportunistic infections which would typically normally be neutralised
  • Discovered in … in USA – the AIDS crisis
  • Global pandemic, responsible for at least … million deaths worldwide; c. 350,000 men and women in the USA died between 1987 and 1998
A
  • Human Immunodeficiency Virus infection / Acquired Immune Deficiency Syndrome (HIV/AIDS) A spectrum of conditions caused by infection with the Human Immunodeficiency Virus (HIV)
  • HIV targets cells within the immune system, causing immunodeficiency→disease and opportunistic infections which would typically normally be neutralised
  • Discovered in 1981 in USA – the AIDS crisis
  • Global pandemic, responsible for at least 35 million deaths worldwide; c. 350,000 men and women in the USA died between 1987 and 1998
43
Q

HIV/AIDS

  • Human Immunodeficiency Virus infection / Acquired Immune Deficiency Syndrome (HIV/AIDS) A spectrum of conditions caused by infection with the Human Immunodeficiency Virus (HIV)
  • HIV targets cells within the immune system, causing immunodeficiency→disease and … infections which would typically normally be neutralised
  • Discovered in 1981 in USA – the AIDS crisis
  • Global …, responsible for at least 35 million deaths worldwide; c. 350,000 men and women in the USA died between 1987 and 1998
A
  • Human Immunodeficiency Virus infection / Acquired Immune Deficiency Syndrome (HIV/AIDS) A spectrum of conditions caused by infection with the Human Immunodeficiency Virus (HIV)
  • HIV targets cells within the immune system, causing immunodeficiency→disease and opportunistic infections which would typically normally be neutralised
  • Discovered in 1981 in USA – the AIDS crisis
  • Global pandemic, responsible for at least 35 million deaths worldwide; c. 350,000 men and women in the USA died between 1987 and 1998
44
Q

AIDS: Contribution of study designs

  • … … help when disease is new, when first cases are being discovered
  • After this - which study design?
  • Then -
A
  • Case studies help when disease is new, when first cases are being discovered
  • After this - which study design - Cross-sectional
  • Then - Case control
45
Q

AIDS: Contribution of study designs

  • Which study design for each?
A
  • Case studies
  • Cross-sectional
  • Case control
46
Q

AIDS Cohort studies

  • Immediately after initial recognition of AIDS, epidemiologists in the United States, Denmark, and the Netherlands established cohort studies of … men, injection drug users, and people with …
  • Then the larger Multicenter AIDS Cohort Study (MACS) which was launched in 1984
    • 1) describe the early pathophysiologic events in the course leading to AIDS-related conditions [and] AIDS…,
    • 2) define and quantify the factors suspected of initiating or modulating the immunopathologic process leading to AIDS…,
    • [and] 3) provide access to a repository of biologic specimens with detailed epidemiologic data for investigators with promising ideas for research
A
  • Immediately after initial recognition of AIDS, epidemiologists in the United States, Denmark, and the Netherlands established cohort studies of homosexual men, injection drug users, and people with hemophilia
  • Then the larger Multicenter AIDS Cohort Study (MACS) which was launched in 1984
    • 1) describe the early pathophysiologic events in the course leading to AIDS-related conditions [and] AIDS…,
    • 2) define and quantify the factors suspected of initiating or modulating the immunopathologic process leading to AIDS…,
    • [and] 3) provide access to a repository of biologic specimens with detailed epidemiologic data for investigators with promising ideas for research
47
Q

AIDS Cohort studies

  • Immediately after initial recognition of AIDS, epidemiologists in the United States, Denmark, and the Netherlands established cohort studies of homosexual men, injection drug users, and people with hemophilia
  • Then the larger Multicenter AIDS Cohort Study (…) which was launched in …
    • 1) describe the early pathophysiologic events in the course leading to AIDS-related conditions [and] AIDS…,
    • 2) define and quantify the factors suspected of initiating or modulating the immunopathologic process leading to AIDS…,
    • [and] 3) provide access to a repository of biologic specimens with detailed epidemiologic data for investigators with promising ideas for research
A
  • Immediately after initial recognition of AIDS, epidemiologists in the United States, Denmark, and the Netherlands established cohort studies of homosexual men, injection drug users, and people with hemophilia
  • Then the larger Multicenter AIDS Cohort Study (MACS) which was launched in 1984
    • 1) describe the early pathophysiologic events in the course leading to AIDS-related conditions [and] AIDS…,
    • 2) define and quantify the factors suspected of initiating or modulating the immunopathologic process leading to AIDS…,
    • [and] 3) provide access to a repository of biologic specimens with detailed epidemiologic data for investigators with promising ideas for research
48
Q

AIDS Cohort studies

  • Immediately after initial recognition of AIDS, epidemiologists in the United States, Denmark, and the Netherlands established cohort studies of homosexual men, injection drug users, and people with hemophilia
  • Then the larger Multicenter AIDS Cohort Study (MACS) which was launched in 1984
    • 1) describe the early … events in the course leading to AIDS-related conditions [and] AIDS…,
    • 2) define and quantify the … suspected of initiating or modulating the immunopathologic process leading to AIDS…,
    • [and] 3) provide access to a repository of biologic specimens with detailed epidemiologic data for investigators with promising ideas for research
A
  • Immediately after initial recognition of AIDS, epidemiologists in the United States, Denmark, and the Netherlands established cohort studies of homosexual men, injection drug users, and people with hemophilia
  • Then the larger Multicenter AIDS Cohort Study (MACS) which was launched in 1984
    • 1) describe the early pathophysiologic events in the course leading to AIDS-related conditions [and] AIDS…,
    • 2) define and quantify the factors suspected of initiating or modulating the immunopathologic process leading to AIDS…,
    • [and] 3) provide access to a repository of biologic specimens with detailed epidemiologic data for investigators with promising ideas for research
49
Q

AIDS Cohort studies

  • Immediately after initial recognition of AIDS, epidemiologists in the United States, Denmark, and the Netherlands established cohort studies of homosexual men, injection drug users, and people with hemophilia
  • Then the larger Multicenter AIDS Cohort Study (MACS) which was launched in 1984
    • 1) describe the early pathophysiologic events in the course leading to AIDS-related conditions [and] AIDS…,
    • 2) define and quantify the factors suspected of initiating or modulating the … process leading to AIDS…,
    • [and] 3) provide access to a repository of biologic … with detailed epidemiologic data for investigators with promising ideas for research
A
  • Immediately after initial recognition of AIDS, epidemiologists in the United States, Denmark, and the Netherlands established cohort studies of homosexual men, injection drug users, and people with hemophilia
  • Then the larger Multicenter AIDS Cohort Study (MACS) which was launched in 1984
    • 1) describe the early pathophysiologic events in the course leading to AIDS-related conditions [and] AIDS…,
    • 2) define and quantify the factors suspected of initiating or modulating the immunopathologic process leading to AIDS…,
    • [and] 3) provide access to a repository of biologic specimens with detailed epidemiologic data for investigators with promising ideas for research
50
Q

The contribution of MACS

  • Over 1,500 papers, 4 which have been cited more than 1000 times;
    • Fahey et al. (1990), in which researchers validated serum levels of neopterin and β2-microglobulin, in combination with the CD4 T-cell count, as biomarkers of AIDS risk;
    • Dean et al. (1996), in which they described the profound protection against HIV infection by a genetic variant of a co-receptor for HIV on CD4 T-cells;
    • Mellors et al. (1996), in which the authors identified the level of HIV circulating in plasma (i.e., HIV viral load) as a strong prognostic indicator; and
    • Mellors et al. (1997), in which they established the combined measurement of HIV viral load and CD4 T- cell count as a highly accurate predictor of prognosis.
  • MACS is being combined with a …-focused cohort WIHS-CISS which still continues to date.
A
  • Over 1,500 papers, 4 which have been cited more than 1000 times;
    • Fahey et al. (1990), in which researchers validated serum levels of neopterin and β2-microglobulin, in combination with the CD4 T-cell count, as biomarkers of AIDS risk;
    • Dean et al. (1996), in which they described the profound protection against HIV infection by a genetic variant of a co-receptor for HIV on CD4 T-cells;
    • Mellors et al. (1996), in which the authors identified the level of HIV circulating in plasma (i.e., HIV viral load) as a strong prognostic indicator; and
    • Mellors et al. (1997), in which they established the combined measurement of HIV viral load and CD4 T- cell count as a highly accurate predictor of prognosis.
  • MACS is being combined with a female-focused cohort WIHS-CISS which still continues to date.
51
Q

The contribution of MACS

  • Over 1,500 papers, 4 which have been cited more than 1000 times;
    • Fahey et al. (1990), in which researchers validated serum levels of neopterin and β2-microglobulin, in combination with the CD4 T-cell count, as biomarkers of AIDS risk;
    • Dean et al. (1996), in which they described the profound protection against HIV infection by a genetic variant of a co-receptor for HIV on CD4 T-cells;
    • Mellors et al. (1996), in which the authors identified the level of HIV circulating in plasma (i.e., HIV viral load) as a strong prognostic indicator; and
    • Mellors et al. (1997), in which they established the combined measurement of HIV viral load and CD4 T- cell count as a highly accurate predictor of prognosis.
  • MACS is being combined with a female-focused cohort WIHS-CISS which still continues to date.
A
  • Over 1,500 papers, 4 which have been cited more than 1000 times;
    • Fahey et al. (1990), in which researchers validated serum levels of neopterin and β2-microglobulin, in combination with the CD4 T-cell count, as biomarkers of AIDS risk;
    • Dean et al. (1996), in which they described the profound protection against HIV infection by a genetic variant of a co-receptor for HIV on CD4 T-cells;
    • Mellors et al. (1996), in which the authors identified the level of HIV circulating in plasma (i.e., HIV viral load) as a strong prognostic indicator; and
    • Mellors et al. (1997), in which they established the combined measurement of HIV viral load and CD4 T- cell count as a highly accurate predictor of prognosis.
  • MACS is being combined with a female-focused cohort WIHS-CISS which still continues to date.
52
Q

Causation and confounding

A
  • Close association between male circumcision and HIV/AIDS prevalence
    • 1) male circumcision causes a reduction in the chance of contracting HIV/AIDS
  • OR
    • 2) some other factor increases chance of being uncircumcised and chance of contracting HIV/AIDS
53
Q

Causation and cofounding - HIV/AIDs and male circumcision

  • Close association between male circumcision and HIV/AIDS prevalence
    • 1) male circumcision … a … in the chance of contracting HIV/AIDS
  • OR
    • 2) some other … increases chance of being … and chance of contracting HIV/AIDS
  • Can it tell us if either, or both or not?
A
  • Close association between male circumcision and HIV/AIDS prevalence
    • 1) male circumcision causes a reduction in the chance of contracting HIV/AIDS
  • OR
    • 2) some other factor increases chance of being uncircumcised and chance of contracting HIV/AIDS
  • Can’t tell us - RCT come in handy here
54
Q

Causation and confounding - Male circumcision and HIV/AIDS

  • Analytic - experimental
    • 3 RCTs; South Africa (N= 3274), Uganda (N= 4996), and Kenya (N= 2784) Does Adult male circumcision reduce risk of HIV acquisition in men?
      • RR of 0.50 at 12 months [CIs 0.34, 0.72]
    • Meta-analysis secondary outcomes (Cochrane Review)
      • Suggested only one sig. difference in sexual behaviour in one trial (circumcised men 1 more sexual contact at 12m)
  • Why?
    • Foreskin increases risk of micro tears during sex
    • Foreskin provides hospitable environment for pathogen survival
A
  • Analytic - experimental
    • 3 RCTs; South Africa (N= 3274), Uganda (N= 4996), and Kenya (N= 2784) Adult male circumcision reduces risk of HIV acquisition in men by c. 60%
      • RR of 0.50 at 12 months [CIs 0.34, 0.72]
    • Meta-analysis secondary outcomes (Cochrane Review)
      • Suggested only one sig. difference in sexual behaviour in one trial (circumcised men 1 more sexual contact at 12m)
  • Why?
    • Foreskin increases risk of micro tears during sex
    • Foreskin provides hospitable environment for pathogen survival
55
Q

Causation and confounding - Male circumcision and HIV/AIDS

  • Analytic - experimental
    • 3 RCTs; South Africa (N= 3274), Uganda (N= 4996), and Kenya (N= 2784) Does Adult male circumcision reduce risk of HIV acquisition in men?
A
  • Analytic - experimental
    • 3 RCTs; South Africa (N= 3274), Uganda (N= 4996), and Kenya (N= 2784) Adult male circumcision reduces risk of HIV acquisition in men by c. 60%
      • RR of 0.50 at 12 months [CIs 0.34, 0.72]
    • Meta-analysis secondary outcomes (Cochrane Review)
      • Suggested only one sig. difference in sexual behaviour in one trial (circumcised men 1 more sexual contact at 12m)
  • Why?
    • Foreskin increases risk of micro tears during sex
    • Foreskin provides hospitable environment for pathogen survival
56
Q

Causation and confounding - Male circumcision and HIV/AIDS

  • Analytic - experimental
    • 3 RCTs; South Africa (N= 3274), Uganda (N= 4996), and Kenya (N= 2784) Adult male circumcision reduces risk of HIV acquisition in men by c. 60%
      • RR of 0.50 at 12 months [CIs 0.34, 0.72]
    • Meta-analysis secondary outcomes (… Review)
      • Suggested only … sig. difference in sexual behaviour in one trial
  • Why?
    • Foreskin increases risk of micro tears during sex
    • Foreskin provides hospitable environment for pathogen survival
A
  • Analytic - experimental
    • 3 RCTs; South Africa (N= 3274), Uganda (N= 4996), and Kenya (N= 2784) Adult male circumcision reduces risk of HIV acquisition in men by c. 60%
      • RR of 0.50 at 12 months [CIs 0.34, 0.72]
    • Meta-analysis secondary outcomes (Cochrane Review)
      • Suggested only one sig. difference in sexual behaviour in one trial (circumcised men 1 more sexual contact at 12m)
  • Why?
    • Foreskin increases risk of micro tears during sex
    • Foreskin provides hospitable environment for pathogen survival
57
Q

Causation and confounding - Male circumcision and HIV/AIDS

  • Analytic - experimental
    • 3 RCTs; South Africa (N= 3274), Uganda (N= 4996), and Kenya (N= 2784) Adult male circumcision reduces risk of HIV acquisition in men by c. 60%
      • RR of 0.50 at 12 months [CIs 0.34, 0.72]
    • Meta-analysis secondary outcomes (Cochrane Review)
      • Suggested only one sig. difference in sexual behaviour in one trial (circumcised men 1 more sexual contact at 12m)
  • Why?
    • Foreskin increases risk of … … during sex
    • Foreskin provides … environment for pathogen …
A
  • Analytic - experimental
    • 3 RCTs; South Africa (N= 3274), Uganda (N= 4996), and Kenya (N= 2784) Adult male circumcision reduces risk of HIV acquisition in men by c. 60%
      • RR of 0.50 at 12 months [CIs 0.34, 0.72]
    • Meta-analysis secondary outcomes (Cochrane Review)
      • Suggested only one sig. difference in sexual behaviour in one trial (circumcised men 1 more sexual contact at 12m)
  • Why?
    • Foreskin increases risk of micro tears during sex
    • Foreskin provides hospitable environment for pathogen survival
58
Q

Koch’s posulates - HIV/AIDS

59
Q

Koch’s posulates - HIV/AIDS

60
Q

Bradford-Hill criteria - HIV/AIDS

61
Q

Bradford-Hill criteria - HIV/AIDS

62
Q

Bradford-Hill criteria - HIV/AIDS

63
Q

Summary - Causation and Study Design - HIV/AIDS

  • Four key types of study design- ….
    • … (3) = analytic-observational, … = analytic-experimental, … = best
  • evidence for causal association between exposure/s and outcome/s
  • When a study finds an association between one thing and another thing, it does not mean one thing caused the other to happen
  • Koch’s postulates; presence of microorganism in diseased organism, microorganism can be isolated and cultured, introduction of microorganism to healthy organism leads to disease, microorganism can be re-isolated from inoculated, disease organism and identified as identical to the original agent
  • Bradford-Hill criteria; Strength of association, Consistency, Specificity, Temporality, Biological gradient, Plausibility, Coherence, Experimental evidence, Analogy
  • We can use different study designs to satisfy causal factors and determine the likelihood of an exposure being causative of a disease outcome
A
  • Four key types of study design- cross-sectional, cohort (retro/prospective), case control, RCT
    • Cross-sectional, cohort, case control = analytic-observational, RCT = analytic-experimental, RCT = best
  • evidence for causal association between exposure/s and outcome/s
  • When a study finds an association between one thing and another thing, it does not mean one thing caused the other to happen
  • Koch’s postulates; presence of microorganism in diseased organism, microorganism can be isolated and cultured, introduction of microorganism to healthy organism leads to disease, microorganism can be re-isolated from inoculated, disease organism and identified as identical to the original agent
  • Bradford-Hill criteria; Strength of association, Consistency, Specificity, Temporality, Biological gradient, Plausibility, Coherence, Experimental evidence, Analogy
  • We can use different study designs to satisfy causal factors and determine the likelihood of an exposure being causative of a disease outcome
64
Q

Summary - Causation and Study Design - HIV/AIDS

  • Four key types of study design- cross-sectional, cohort (retro/prospective), case control, …
    • Cross-sectional, cohort, case control = analytic-observational, … = analytic-experimental, … = best
  • evidence for causal association between exposure/s and outcome/s
  • When a study finds an association between one thing and another thing, it does not mean one thing caused the other to happen
  • … postulates; presence of microorganism in diseased organism, microorganism can be isolated and cultured, introduction of microorganism to healthy organism leads to disease, microorganism can be re-isolated from inoculated, disease organism and identified as identical to the original agent
  • …-Hill criteria; Strength of association, Consistency, Specificity, Temporality, Biological gradient, Plausibility, Coherence, Experimental evidence, Analogy
  • We can use different study designs to satisfy causal factors and determine the likelihood of an exposure being causative of a disease outcome
A
  • Four key types of study design- cross-sectional, cohort (retro/prospective), case control, RCT
    • Cross-sectional, cohort, case control = analytic-observational, RCT = analytic-experimental, RCT = best
  • evidence for causal association between exposure/s and outcome/s
  • When a study finds an association between one thing and another thing, it does not mean one thing caused the other to happen
  • Koch’s postulates; presence of microorganism in diseased organism, microorganism can be isolated and cultured, introduction of microorganism to healthy organism leads to disease, microorganism can be re-isolated from inoculated, disease organism and identified as identical to the original agent
  • Bradford-Hill criteria; Strength of association, Consistency, Specificity, Temporality, Biological gradient, Plausibility, Coherence, Experimental evidence, Analogy
  • We can use different study designs to satisfy causal factors and determine the likelihood of an exposure being causative of a disease outcome
65
Q

Summary - Causation and Study Design - HIV/AIDS

  • Four key types of study design- cross-sectional, cohort (retro/prospective), case control, RCT
    • Cross-sectional, cohort, case control = analytic-…, RCT = analytic-…, RCT = best
  • evidence for … … between exposure/s and outcome/s
  • When a study finds an association between one thing and another thing, it does not mean one thing … the other to happen
  • Koch’s postulates; presence of microorganism in diseased organism, microorganism can be isolated and cultured, introduction of microorganism to healthy organism leads to disease, microorganism can be re-isolated from inoculated, disease organism and identified as identical to the original agent
  • Bradford-Hill criteria; Strength of association, Consistency, Specificity, Temporality, Biological gradient, Plausibility, Coherence, Experimental evidence, Analogy
  • We can use different study designs to satisfy causal factors and determine the likelihood of an exposure being causative of a disease outcome
A
  • Four key types of study design- cross-sectional, cohort (retro/prospective), case control, RCT
    • Cross-sectional, cohort, case control = analytic-observational, RCT = analytic-experimental, RCT = best
  • evidence for causal association between exposure/s and outcome/s
  • When a study finds an association between one thing and another thing, it does not mean one thing caused the other to happen
  • Koch’s postulates; presence of microorganism in diseased organism, microorganism can be isolated and cultured, introduction of microorganism to healthy organism leads to disease, microorganism can be re-isolated from inoculated, disease organism and identified as identical to the original agent
  • Bradford-Hill criteria; Strength of association, Consistency, Specificity, Temporality, Biological gradient, Plausibility, Coherence, Experimental evidence, Analogy
  • We can use different study designs to satisfy causal factors and determine the likelihood of an exposure being causative of a disease outcome
66
Q

Summary - Causation and Study Design - HIV/AIDS

  • Four key types of study design- cross-sectional, cohort (retro/prospective), case control, RCT
    • Cross-sectional, cohort, case control = analytic-observational, RCT = analytic-experimental, RCT = best
  • evidence for causal association between exposure/s and outcome/s
  • When a study finds an association between one thing and another thing, it does not mean one thing caused the other to happen
  • Koch’s postulates; presence of … in diseased organism, microorganism can be … and cultured, introduction of microorganism to … organism leads to disease, microorganism can be … from inoculated, disease organism and identified as identical to the original agent
  • Bradford-Hill criteria; Strength of association, Consistency, Specificity, Temporality, Biological gradient, Plausibility, Coherence, Experimental evidence, Analogy
  • We can use different study designs to satisfy causal factors and determine the likelihood of an exposure being causative of a disease outcome
A
  • Four key types of study design- cross-sectional, cohort (retro/prospective), case control, RCT
    • Cross-sectional, cohort, case control = analytic-observational, RCT = analytic-experimental, RCT = best
  • evidence for causal association between exposure/s and outcome/s
  • When a study finds an association between one thing and another thing, it does not mean one thing caused the other to happen
  • Koch’s postulates; presence of microorganism in diseased organism, microorganism can be isolated and cultured, introduction of microorganism to healthy organism leads to disease, microorganism can be re-isolated from inoculated, disease organism and identified as identical to the original agent
  • Bradford-Hill criteria; Strength of association, Consistency, Specificity, Temporality, Biological gradient, Plausibility, Coherence, Experimental evidence, Analogy
  • We can use different study designs to satisfy causal factors and determine the likelihood of an exposure being causative of a disease outcome
67
Q

Summary - Causation and Study Design - HIV/AIDS

  • Four key types of study design- cross-sectional, cohort (retro/prospective), case control, RCT
    • Cross-sectional, cohort, case control = analytic-observational, RCT = analytic-experimental, RCT = best
  • evidence for causal association between exposure/s and outcome/s
  • When a study finds an association between one thing and another thing, it does not mean one thing caused the other to happen
  • Koch’s postulates; presence of microorganism in diseased organism, microorganism can be isolated and cultured, introduction of microorganism to healthy organism leads to disease, microorganism can be re-isolated from inoculated, disease organism and identified as identical to the original agent
  • Bradford-Hill criteria; … of association, Consistency, …, Temporality, Biological gradient, …, Coherence, … evidence, Analogy
  • We can use different study designs to satisfy causal factors and determine the likelihood of an exposure being causative of a disease outcome
A
  • Four key types of study design- cross-sectional, cohort (retro/prospective), case control, RCT
    • Cross-sectional, cohort, case control = analytic-observational, RCT = analytic-experimental, RCT = best
  • evidence for causal association between exposure/s and outcome/s
  • When a study finds an association between one thing and another thing, it does not mean one thing caused the other to happen
  • Koch’s postulates; presence of microorganism in diseased organism, microorganism can be isolated and cultured, introduction of microorganism to healthy organism leads to disease, microorganism can be re-isolated from inoculated, disease organism and identified as identical to the original agent
  • Bradford-Hill criteria; Strength of association, Consistency, Specificity, Temporality, Biological gradient, Plausibility, Coherence, Experimental evidence, Analogy
  • We can use different study designs to satisfy causal factors and determine the likelihood of an exposure being causative of a disease outcome
68
Q

Summary - Causation and Study Design - HIV/AIDS

  • Four key types of study design- cross-sectional, cohort (retro/prospective), case control, RCT
    • Cross-sectional, cohort, case control = …-observational, RCT = …-experimental, RCT = best
  • evidence for causal association between exposure/s and outcome/s
  • When a study finds an association between one thing and another thing, it does not mean one thing caused the other to happen
  • Koch’s postulates; presence of microorganism in diseased organism, microorganism can be isolated and cultured, introduction of microorganism to healthy organism leads to disease, microorganism can be re-isolated from inoculated, disease organism and identified as identical to the original agent
  • Bradford-Hill criteria; Strength of association, Consistency, Specificity, …, … gradient, Plausibility, …, Experimental evidence, …
  • We can use different study designs to satisfy causal factors and determine the likelihood of an exposure being causative of a disease outcome
A
  • Four key types of study design- cross-sectional, cohort (retro/prospective), case control, RCT
    • Cross-sectional, cohort, case control = analytic-observational, RCT = analytic-experimental, RCT = best
  • evidence for causal association between exposure/s and outcome/s
  • When a study finds an association between one thing and another thing, it does not mean one thing caused the other to happen
  • Koch’s postulates; presence of microorganism in diseased organism, microorganism can be isolated and cultured, introduction of microorganism to healthy organism leads to disease, microorganism can be re-isolated from inoculated, disease organism and identified as identical to the original agent
  • Bradford-Hill criteria; Strength of association, Consistency, Specificity, Temporality, Biological gradient, Plausibility, Coherence, Experimental evidence, Analogy
  • We can use different study designs to satisfy causal factors and determine the likelihood of an exposure being causative of a disease outcome

Year 2 Medicine (162 decks)

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