Search This Site

Tuesday, January 06, 2009

Which of the following is not a criteria for judging causality in non communicable diseases

Question 44
Which of the following is not a criteria for judging causality in non communicable diseases
a. Strength of Association
b. Dose Response Relationship
c. Specificity of the association
d. Lack of Temporal Association
3. Lack of Temporal Association
Park 18th Edition Pages 82 to 83
Epidemiology is the branch of medical science that studies the incidence, distribution, cause, and control of disease in a population.  Although epidemiologists prefer to conduct strong experimental research when possible, often their research questions and variables do not lend themselves to experimental research. Perhaps the single most important individual in the development of research methods and analysis in Epidemiology is Sir Austin Bradford Hill (1897-1991). Bradford Hill developed a list
of criteria that continues to be used today.
The Bradford Hill Criteria
1.      Strength of Association. The stronger the relationship between the independent variable and the dependent variable, the less likely it is that the relationship is due to an extraneous variable.
2.      Temporality. It is logically necessary for a cause to precede an effect in time.
3.      Consistency. Multiple observations, of an association, with different people under different circumstances and with different measurement instruments increase the credibility of a finding.
4.      Theoretical Plausibility (Biological Plausibility). It is easier to accept an association as causal when there is a rational and theoretical basis for such a conclusion.
5.      Coherence. A cause-and-effect interpretation for an association is clearest when it does not conflict with what is known about the variables under study and when there are no plausible competing theories or rival hypotheses. In other words, the association must be coherent with other knowledge.
6.      Specificity in the causes. In the ideal situation, the effect has only one cause. In other words, showing that an outcome is best predicted by one primary factor adds credibility to a causal claim.
7.      Dose Response Relationship. There should be a direct relationship between the risk factor (i.e., the independent variable) and people’s status on the disease variable (i.e., the dependent variable).
8.      Experimental Evidence. Any related research that is based on experiments will make a causal inference more plausible.
9.      Analogy. Sometimes a commonly accepted phenomenon in one area can be applied to another area.
The list given in Park lists only 6 factors as it is not the Hill Criteria, but application of Hill Criteria for Smoking and Lung Cancer
Bradford Hill's considerations were first published in 1965

No comments:

Post a Comment

If you cannot locate what you want to find, please search using the box given below