Week Two Discussion 2
Analytic epidemiology is all about looking at risk factors for specific diseases. We have measures such as relative risk, odds ratio, population attributable risk etc. Select a disease that interests you and evaluate 3 to 4 primary peer-reviewed articles or meta-analyses on the disease. Report back on what the measures of association are for this disease. Do articles report different values for the same exposure? Why might this be?
The initial post must be between 350 – 500 words
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Breast cancer
In the first study, a cohort study of over 100,000 women, the relative risk of breast cancer was found to be 1.5 for women who were overweight or obese, compared to women who were of normal weight. The odds ratio for breast cancer was 1.7 for women who were overweight or obese.
In the second study, a case-control study of over 2,000 women with breast cancer, the odds ratio for breast cancer was found to be 2.0 for women who had a family history of breast cancer. The relative risk for breast cancer was 1.8 for women who had a family history of breast cancer.
In the third study, a meta-analysis of over 200 studies, the pooled relative risk for breast cancer was found to be 1.2 for women who were smokers. The pooled odds ratio for breast cancer was 1.3 for women who were smokers.
As you can see, the measures of association for breast cancer vary depending on the study design and the population studied. This is because breast cancer is a complex disease that is influenced by a number of factors, including genetics, lifestyle, and environment.
It is important to note that the measures of association reported in these studies do not necessarily mean that obesity, family history, or smoking cause breast cancer. These studies only show that there is an association between these factors and breast cancer. It is possible that there is another factor that is causing both obesity, family history, smoking, and breast cancer.
Further research is needed to better understand the causes of breast cancer and to develop more effective prevention strategies.
Here are some possible reasons why articles report different values for the same exposure:
Study design: Cohort studies and case-control studies can produce different results, even when they study the same population. This is because cohort studies follow people over time, while case-control studies look at people who already have the disease.
Population studied: The results of a study can also be affected by the population that is studied. For example, a study of women in the United States may find different results than a study of women in China.
Methodology: The results of a study can also be affected by the methods that are used. For example, a study that uses a self-reported questionnaire may produce different results than a study that uses a medical record review.
