Reference no: EM132680995

Question 1:

For each of the following studies indicate whether the results are more likely to be to be due to a spurious or non-causal association or a causal association. In 2-4 sentences each, explain the reasoning behind your answer using the nine guidelines for judging whether an observed association is causal. You do not need to go through each guideline for each study, but select and discuss those that are most relevant to your response.

a. A case-control study found that there was a moderate to strong association between caffeine consumption and death from liver cancer. Other studies have shown that those who drink coffee are more likely to smoke than those who do not drink coffee.

b. A randomized controlled trial showed that consistent phototherapy (light therapy) significantly reduced the adverse effects of Seasonal Affective Disorder among Scandinavian males. This finding was confirmed in subsequent studies.

c. A large epidemiologic study examined the possible association between 20 lifestyle behaviors and teen pregnancy. The study found a significant positive relationship between seatbelt use and teen pregnancy that had not been previously reported in an epi study.

Question 2:

Other than those used in your textbook, provide an example of a necessary but not sufficient cause for a disease. You may choose any cause and disease, but be sure to describe how your example is a necessary but not sufficient cause. You should be able to adequately respond in 2-4 sentences but may write more if you wish.