I have completed question one, I want question two one and half pages
- In one page present one criticism for each of Bradford Hill’s causal criteria
- In two pages based on the following papers which explore the relationship between soy consumption and breast cancer by Sacks et al (2006), Mezzina and Loprinzi (2001), wu et al (2008), and trock et al (2006). Rank order which Bradford Hill criteria are most closely met and provide a brief explanation as to why.
Expert Solution Preview
Introduction:
As a medical professor, I am responsible for creating college assignments and evaluating student performance. It is my duty to design and conduct lectures, provide feedback through examinations and assignments. The following answers will be focused on one criticism for each of Bradford Hill’s causal criteria and analyzing the relationship between soy consumption and breast cancer by ranking the criteria, which are closely met by the research papers.
Answer 1:
Bradford Hill’s causal criteria are widely used in determining the causality of an observation or a study. However, these criteria are not perfect, and each of the criteria has certain limitations. One criticism for each of Bradford Hill’s causal criteria is as follows:
1. Strength of Association: Although the strength of association criterion is significant, it does not consider the impact of confounding factors in the association between two variables. For instance, if an environmental factor has a strong association with a health outcome, it does not necessarily mean that the environmental factor is the cause.
2. Consistency: This criterion can be criticized that different studies may have different contexts, sample sizes, and follow-up periods, making it difficult to compare and assess consistency.
3. Specificity: This criterion has limitations, as it assumes that one cause leads to one effect, while in reality, several causes can lead to one outcome.
4. Temporality: This criterion can be criticized that it is difficult to determine the temporal relationship between cause and effect in studies with long follow-up periods.
5. Biological Plausibility: This criterion can be criticized that it is limited by the extent of scientific knowledge, and the lack of knowledge can lead to dismissing plausible theories.
6. Coherence: This criterion assumes that the cause-effect relationship proposed in a study should be consistent with what is already known about the disease. However, this assumption can have limitations as knowledge about a particular disease can evolve over time.
7. Experimental Evidence: This criterion can be criticized that not all disease outcomes can be studied experimentally, and the ethical and practical limitations of conducting experiments limit the use of this criterion.
8. Analogy: The analogy criterion can be criticized for being subjective and lacks a clear set of guidelines on how to evaluate analogies.
Answer 2:
The four papers explore the relationship between soy consumption and breast cancer. Based on these papers, Bradford Hill’s causal criteria can be ranked in the following order:
1. Biological plausibility: All the papers discussed the biological mechanism of soy and its effect on breast cancer. The biological mechanism proposed in the studies was consistent with known biology, and there was a plausible rationale for a causal relationship, ranking this criterion first.
2. Temporality: In the studies, soy consumption was measured at baseline, and breast cancer incidence was assessed during follow-up. Therefore, temporality criterion is closely met by all studies.
3. Strength of association: In the studies, a significant inverse association between soy consumption and breast cancer was observed in both Asian and American populations. However, the magnitude of the association was modest; therefore, ranking the criterion third.
4. Consistency: Different studies found a significant inverse association between soy consumption and breast cancer in both Asians and Americans. However, the studies had differences in sample sizes, methods, and results, ranking the criterion fourth.
5. Coherence: There is coherence between the studies and prior knowledge about breast cancer, as soy is known to have anti-cancer properties and may play a role in reducing the risk of breast cancer. Therefore, coherence is ranked fifth.
6. Analogy: The analogy criterion is not applicable in this case.
7. Specificity: The studies did not explore a specific type of breast cancer associated with soy consumption, so the specificity criterion is not well met.
8. Experimental evidence: The studies were observational and did not involve experiments, so this criterion is not met.
In summary, based on the four research papers, biological plausibility and temporality are the two criteria most closely met. However, further experimental studies could clarify whether soy consumption may have a causal relationship with breast cancer.
