# Study Guide Flashcards

1
Q

Odds Ratio? (formula)
Self-reported cross-sectional data obtained via questionnaire between 1993 and 1997 from 31,173 wives were used. Wives were asked about current and past use of specific pesticides and groups of pesticides based on function (fungicides, herbicides, insecticides, and fumigants).
Among 31,173 wives surveyed, 8.2% of 281 women with retinal degeneration and 4.7 % of those without retinal degeneration reported ever use of fungicides.

Create a table, fill it in, and find the odds ratio?

A
```A. 23
B. 1452
C. 258
D. 29440
Total of those w/ fungicide: 1475
Total of those w/o fungicide: 29698
Total: 31,173
Total of those w/ RD: 281
Total of those w/o RD: 30892
Odds ratio: (a*d)/(b*c)= (23*29440)/(1452*258)= 1.8
Interpret?: 1.8-1*100= 80%```
2
Q

Relative Risk? (RR)
In a study of radiation exposure and breast cancer, 500 participants with breast cancer and 1000
participants without breast cancer are compared. It is learned that 400 of the participants with breast
cancer and 600 of the participants without breast cancer were exposed to radiation for prolonged
period of time at some point in their life, prior to diagnosis. We later learned from a government report
that the incidence of breast cancer in the total population is 30% and the prevalence to radiation
exposure is 50% .
Create a 2 x 2 table.

A

a/(a+b) / c/(c+d)

3
Q

Attributable Risk?

A

a/(a+b) - c/(c+d)

4
Q

Attributable Fraction? (AF)

A

RR-1 /RR

5
Q

Pop. Attributable Fraction? (PAF)

A

The proportion of cases for an outcome that can be attributed to a certain risk factor for the whole pop.
P(R-1) / P(R-1)+1

6
Q

Sensitivity?

A

true positive rate. the proportion of samples that are genuinely positive and give a positive result
Ex: a test that identifies all positive samples in a panel is very sensitive
a/a+c (vertical)

7
Q

Specificity?

A

true negative rate. the proportion of samples that test negative
-Ex: a test that identifies all healthy people as negative for a specific illness
d/b+d

8
Q

Positive Predictive Value? (PPV)

A

a/a+b

9
Q

Negative Predictive Value? (NPV)

A

d/c+d

10
Q

Cause specific death rate?

A

(# of deaths from a specified cause/total pop.)* 100,000

11
Q

Case fatality Ratio?

A

(# of cases who died/total # of cases)* 100

12
Q

Disadvantages of this study design include the following: should not be used to study disease etiology and exposure-disease temporality not ascertained

A

Cross sectional study

13
Q

Which study design’s unit of observation is a group and uses existing study data?

A

Ecologic study

14
Q

This study design cannot directly measure risk and instead uses the odds ratio

A

Case control

15
Q

The main type of bias with this study design is selection bias

A

Cohort

16
Q

This study design is useful for studying rare diseases

A

Case control

17
Q

This is a quick and inexpensive study design and often uses data from surveys

A

Cross sectional

18
Q

In this type of study, participants are given a new medication but not randomized

A

Intervention or Quasi Experimental

19
Q

In this study, a team of investigators gathered data on a group of individuals who were exposed to secondhand smoke about 10 years ago. Then the team determines if any developed different types of cancers.

A

Retrospective cohort

20
Q

Insulin to prevent the complications of diabetes. What kind of prevention?

A

Tertiary

21
Q

Healthy eating to prevent diabetes. Prevention?

A

Primary

22
Q

Blood glucose testing to detect diabetes. Prevention?

A

Secondary

23
Q

True or false: Specificity is affected by the prevalence of a given disease

A

False; PPV and NPV are influenced by prevalence of a disease