Additional CHAPTER 16 Exercises

 

16.5 Here are the short descriptive titles the text uses to identify elements of Hill’s causal inference framework:

 

(1) = Strength ������������������������� (2) = Consistency ������������������� (3) = Specificity ���������������������

(4) = Temporality ������������������� (5) = Biological gradient �������� (6) = Plausibility ��������

(7) = Coherence ��������������������� (8) = Experiment��������������������� (9) = Analogy

 

Use these codes to label each of these descriptions below.

 

a. This element of Hill's framework suggests that the exposure precedes the disease by a reasonable amount of time.

 

b. The risk of having a child with spina bifida decreases progressively with higher-and-higher levels of folic acid supplementation administered during the first trimester of pregnancy. To which of Hill's elements does this speak?

 

c. The relative risk of lung cancer in smokers is about 15. Thus, the element of ____________ has been met.

 

d. This element of Hill's framework suggests that there are similarities in some respect to otherwise different phenomena.

 

e. Studies on oral contraceptives and breast cancer have in different populations have failed to provide similar results and conclusions. Therefore, Hill's element of __________ has NOT been met.

 

f. Diets high in antioxidants may protect against cancer because antioxidants mitigate the oxidative effects of cellular aging and associated chromosomal damage. Which of Hill's elements has been applied?

 

g. This element of Hill's framework suggests that evidence from laboratory studies and trials provide support for the theory.

 

h. This element of Hill's framework suggests that the exposure leads to only one disease and the disease has no other known causes.

 

i. This element of Hill's framework suggests that all available evidence sticks together as a whole.

 

16.6 In the early 1980s, before AIDS was known to have a viral cause, some scientists noticed that some of the groups identified to be at at high risk of AIDS at the time (such as homosexuals and Haitians) were also at high risk of Hepatitis B. Hepatitis B at the time had a known viral cause, and was known to be transmitted sexually This fact emboldened the scientists’ to hypothesize that AIDS also had a viral cause. Which of Hills elements forms the basis of this inference?

 

16.7. John Snow completed many different investigations of study water source and cholera. All these investigations came to the same conclusion: people who drank from fecal contaminated water sources were more likely to develop cholera. Snow used this information to support his water borne theory of disease transmission. Which element of Hill’s framework fits the fact that all such studies came to similar conclusion?

(a) Strength ��������������� (b) Consistency ��������� (c) Specificity ������������ (d) Temporality

16.8 Which element from Hill’s causal inference framework is illustrated by the following example?Smokers have an elevated risk of a disease, and smokers who smoke two packs a day have a much higher risk than smokers who smoke one pack a day.

(a) Strength ��������������� (b) Specificity ����������������������� (c) Temporality����������� (d) Biologic gradient

16.9 A food borne outbreak of Salmonellosis occurred in Rhynedale, California in association with eating barbequed chicken served at a church picnic. Which of the following is an example of temporal evidence?

 

(a) People who experienced more severe symptoms consumed more barbeque chicken.

(b) Cases exhibited symptom 9 to 111 hours after eating at the picnic.

(c) The cases had cramps, diarrhea, nausea, vomiting, chills, and fever, which are typical signs of Salmonellosis.

(d) Laboratory testing of stool samples from affected individuals isolated the salmonella bacteria.

16.10 Large RRs provide firmer evidence than small RRs. Which element is this?

(a) Strength ��� (b) Consistency���������� (c) Plausibility ����������������������� (d) Coherence

16.11 Evidence “sticks together” as a whole. Which element?

(a) Strength ��� (b) Consistency���������� (c) Plausibility ����������������������� (d) Coherence

16.12 Association is consistent with established biological fact. Which element is this?

(a) Strength ��������������� (b) Consistency ��������� (c) Plausibility ����������������������� (d) Coherence