In this assignment I assessed the relationship between soy consumption and breast cancer which has been studied by Sacks et al (2006), Messina & Loprinzi (2001), Wu et al (2008), and Trock et al (2006). I used the Bradford Hill criteria and assess whether soy has an inverse causal relationship with breast cancer.
Contents
Abstract
1. Strength of Association
2. Consistency of Association
3. Specificity of Association
4. Temporality Relationship
5. Dose Response (Biological Gradient)
6. Biological Plausibility
7. Coherence
8. Experiment Evidence
9. Analogy
Conclusion
Objective and Themes
This work assesses whether the association between soy consumption and breast cancer can be interpreted as an inverse causal relationship. It examines published epidemiological and experimental evidence through the Bradford Hill criteria.
- Strength and consistency of associations between soy exposure and breast cancer
- Specificity and the timing of exposure and outcomes
- Dose response and differences in soy intake across populations
- Biological plausibility and experimental evidence
- Interpretation of epidemiological evidence and causation
Excerpt from the Book
2. Consistency of Association
Weed (2000) explained consistency as the extent to which the association is observed in different circumstances, by different investigators, using different study design and in different locations. The relationship between soy consumption is consistent among a large number of studies. From the studies that I reviewed they all showed that there is a relationship between soy exposure and breast cancer. Messina and Loprinzi’s (2001) article was written to highlight studies that pertain mostly to the controversy of the relationship to soy exposure and breast cancer. Although Weed reviewed many studies that reveal a relationship between soy exposure and breast cancer, I will only mention a few of the studies in this assignment. The author explains that several studies examined the effects of different soy products on the development of chemically induced mammary cancer in adult animals. The data are somewhat inconsistent but generally show that in comparison with control diets, the substitution of soy protein for other protein typically found in a standard laboratory diet modestly reduced (25-50%) tumor incidence. Weed mentioned studies that were completed by Barnes et al. (1990), Hakkak et al (2000) and Ohta et al. (2000). Weed also reviewed studies completed by Cohen et al. (2000) and Hsueh (1992) which argued that soy did not show protective effects on breast cancer.
Weed concluded that there is a lack of any convincing information to substantiate either of two extreme and opposing claims which states that soy is protective against breast cancer and that soy is harmful for women with a history of or at high risk for breast cancer. Although the article shows that there are opposing views, all the articles that were reviewed showed that there is a relationship between soy exposure and breast cancer. As a result there is a consistency of relations.
Chapter Summaries
Abstract: The author introduces the assessment of soy consumption and breast cancer using the Bradford Hill criteria.
1. Strength of Association: The discussion considers relative risks, odds ratios and a meta-analysis of soy exposure and breast cancer risk.
2. Consistency of Association: This section considers evidence from different studies and settings, including research on soy products and mammary cancer in animals.
3. Specificity of Association: The author discusses research on soy protein and cardiovascular risk factors in relation to specificity.
4. Temporality Relationship: The discussion considers the timing of soy consumption and breast cancer outcomes, including evidence involving survivors in Shanghai.
5. Dose Response (Biological Gradient): This section considers levels of soy intake and breast cancer risk in Asian and Western populations.
6. Biological Plausibility: The author introduces biological plausibility and discusses research on mammographic density.
7. Coherence: Coherence is briefly related to biological plausibility.
8. Experiment Evidence: This section discusses experimental designs and research on soy consumption and hormonal or breast-cell changes.
9. Analogy: The author identifies analogy as a criterion but does not develop it further.
Conclusion: The author reflects on the reviewed evidence and its implications for assessing causation.
Keywords
Bradford Hill criteria, epidemiology, causation, soy consumption, breast cancer, soy isoflavones, meta-analysis, odds ratio, dose response, temporality, biological plausibility, experimental evidence
Frequently Asked Questions
What is this work about?
It examines the relationship between soy consumption and breast cancer from the perspective of causal assessment in epidemiology.
What are the central themes?
The main themes include strength and consistency of association, temporality, dose response, biological plausibility and experimental evidence.
What is the primary research question?
The author asks whether soy consumption has an inverse causal relationship with breast cancer.
What scientific method does the author use?
The author assesses published studies using the Bradford Hill criteria. The discussion draws on epidemiological research, meta-analyses and experimental evidence.
What does the main discussion cover?
It considers the Bradford Hill criteria in turn, drawing on research about soy exposure, breast cancer and related health outcomes.
Which keywords characterize the work?
Key terms include Bradford Hill criteria, soy consumption, breast cancer, epidemiology, causation, dose response and biological plausibility.
How does the work address differences in soy intake across populations?
The dose-response section discusses research on different levels of soy consumption in Asian and Western populations.
What example is used to discuss temporality?
The author discusses a study of breast cancer survivors in Shanghai that collected information on lifestyle and subsequent outcomes.
- Quote paper
- Carol Benjamin (Author), 2009, Assessment of Causation in Epidemiologic Research, Munich, GRIN Verlag, https://www.grin.com/document/265470
