Epidemiology

Question 1

Bias introduced when screening detects a dz earlier and thus lengthens the time from dx to death

Answer 1

Lead-time bias

Question 2

If you want to know if geographical location affects infant mortality rate but most variation in infant mortality is predicted by SES, then SES is a ___.

Answer 2

Confounding variable

Question 3

(#TP)/(#pts with the dz)

Answer 3

Sensitivity

Question 4

Sensitive tests have few FN and are use to rule __ a dz.

Answer 4

Out

Question 5

PPD reactivity is used as a screening test bc most ppl with TB (except those who are anergic) will have a (+) PPD. Highly sensitive or specific?

Answer 5

Highly sensitive for TB

Question 6

Chronic dzs such as SLE: higher prevalence or incidence?

Answer 6

Higher prevalence

Question 7

Epidemics such as influenza: higher prevalence or incidence?

Answer 7

Higher incidence

Question 8

Cross-sectional survey: incidence or prevalence?

Answer 8

Prevalence

Question 9

Cohort study: incidence or prevalence?

Answer 9

Incidence and prevalence

Question 10

Case-control study: incidence or prevalence?

Answer 10

Neither

Question 11

Describe a test that consistently gives identical results but the results are wrong.

Answer 11

High reliability, low validity

Question 12

Difference between a cohort and case-control study

Answer 12

• Cohort studies: can be used to calculate relative risk (RR), incidence, and/or odds ratio (OR)
• Case-control studies: can be used to calculate an OR

Question 13

Attributable risk

Answer 13

(Incidence rate (IR) of a dz in exposed) - (IR of a dz in unexposed)

Question 14

Relative risk (RR)

Answer 14

(Incidence rate (IR) of a dz in a population exposed to a particular factor) / (IR in those not exposed)

Question 15

Odds ratio (OR)

Answer 15

WRONG!!!!

Likelihood of a dz among individuals exposed to a RF compared to those who have not been exposed

Question 16

Number needed to treat (NNT)

Answer 16

1 / (rate in untxed group - rate in txed group)

Question 17

In which pts do you initiate CRC screening early?

Answer 17

• Have IBD
• Have FAP/HNPCC
• Have 1st-degree relatives with adenomatous polyps (less than 60 yo) or CRC

Question 18

1. MC CA in M

2. MCC of death from CA in M

Answer 18

1. Prostate CA (MC CA in M)

2. Lung CA (MCC CA deaths in M)

Question 19

The % of cases within 1 SD of the mean? 2 SDs? 3 SDs?

Answer 19

68%

95. 4%
96. 7%

Question 20

Birth rate

Answer 20

live births (LBs) per 1000 population in 1 yr

Question 21

Fertility rate

Answer 21

LBs per 1000 females (15-44 yo) in 1 yr

Question 22

Mortality rate

Answer 22

deaths per 1000 population in 1 yr

Question 23

Neonatal mortality rate

Answer 23

deaths from birth - 28 days per 1000 LBs in 1 yr

Question 24

Postnatal mortality rate

Answer 24

deaths from 28 days - 1 yr per 1000 LBs in 1 yr

Question 25

Infant mortality rate

Answer 25

deaths from birth - 1 yr per 1000 LBs in 1 yr (neonatal + postnatal mortality)

Question 26

Fetal mortality rate

Answer 26

deaths from 20 wks gestation - birth per 1000 total births in 1 yr

Question 27

Perinatal mortality rate

Answer 27

deaths from 20 wks gestation - 1 mo per 1000 total births in 1 yr

Question 28

Maternal mortality rate

Answer 28

deaths during pregnancy - 90 days PP per 100,000 LBs in 1 yr

Question 29

Bias introduced into a study when a clinician is aware of the pt’s tx type

Answer 29

Observational bias