Public and Preventative Health

Question 1

infant mortality rate

Answer 1

number of reported deaths among children <1 year of age during a given time period divided by the number of reported live births during the same time period and expressed as per 1000 live births per year

Question 2

incresing the sample size decreases the probability of ____ but does not alter the risk of ___

Answer 2

incresing the sample size decreases the probability of TYPE I AND II ERROR but does not alter the risk of BIAS/CONFOUNDING

Question 3

berkson’s bias

Answer 3

occurs in a case-control study using hospitalized controls, as they may not be representative sample of the population

Question 4

information bias

Answer 4

the way in which information is collected about study participants is inadequate.

Question 5

recall bias

Answer 5

when individuals with disease may be more likely to incorrectly recall/believe they were exposed to a possible risk factor than those who are free of disease.

Question 6

sensitivity calculation

Answer 6

TP/TP+FN

aka true positives/ all the diseased people, whether they tested positive or not (falsely negative)

Question 7

specificity

Answer 7

TN/ (TN+ FP)

Question 8

what is likely hood ratio

Answer 8

likelihood that a given test result would be expected in a patient with disease compared with the likelihood that the same result would be expected in a patient without disease.
LR+ indicates how much the probability of disease increases if the test is positive.
LR- indicates how much the probability of disease decreases if the test is negative

Question 9

LR+ calculation

Answer 9

indicates how much the prbability of disease increases if the test is positive

LR+ = sensitivity/ (1-specificity)

Question 10

LR-

Answer 10

indicates how much the probability decreases if a person tests negative.

LR= (1-sensitivity)/(specificity)

Question 11

positivie predictive value

Answer 11

proportion of people with a positive test who have the disease

PPV = (TP)/ (TP+FP)

Question 12

Negative predictive value

Answer 12

proportion of people with a negative test, who really don’t have the disease.

NPV = (TN)/(TN+FN)

Question 13

efficacy vs effectiveness

Answer 13

efficacy: the extent to which a specific intervention produces a beneficial result nder ideal conditions (RCT)

effectiveness: measures the benefit of an intervention under usual conditions of clinical care: considers both the efficacy of an intervention and its actual impact on the real world.

Question 14

Odds ratio of a case-control study

Answer 14

OR: (A/C) / (B/D) = (AD/BC)

Question 15

number needed to treat

Answer 15

NNT= 1/ (ARR)
where arr= absolute rate reduction = CER-EER
CER is control group event rate
EER is experimental group event rate.

Question 16

prevalence:
#cases/total population
aka burden of disease

Question 17

attack rate

Answer 17

number exposed individuals who became ill/total number of people exposed.

Question 18

If the absolute rate of disease among smokers is 10/1000, and amongst non smokers it is 1/1000, what is relative risk and attributable risk?

Answer 18

RR=10 (ratio of the probability of the event in the exposed group compared to the non-exposred group) aka 10/1.

Attributable risk is the number of cases of a disease among exposured individuals that can be attributed to that exposure aka incidence (exposed) - incidence (unexposed)

therefore 10-1 = 9. 9 per 1000 persons per year.

Question 19

tf case-control designs is better for studying rare diseases than the cohort design.

Answer 19

true; A COHORT STUDY NEED TO BE very large to ensure that enough cases of the rare disease develop.

Question 20

health promotion

Answer 20

enabling peopel to increase control over and to improve their health.