Causation cases

Case-control studies retrospectively compare the frequency of breast implantation in women with and without the outcomes of interest. If, for example, connective tissue disorders were more likely to occur among women with breast implants, this would constitute some evidence for causation. Case-control studies typically require less time and resources than cohort studies. However, they are susceptible to many more biases than cohort studies [62]. The primary reason not to perform a case-control study here, however, is that a separate case-control study would be required for each of the outcomes of interest, i.e., a case-control study of systemic sclerosis, a case-control study of rheumatoid arthritis, etc. The... 

The book begins with a discussion of the theories of error causation and then goes on to describe the various ways in which data can be collected, analyzed, and used to reduce the potential for error. Case studies are used to teach the methodology of error reduction in specific industry operations. Finally, the book concludes with a plan for a plant error reduction program and a discussion of how human factors principles impact on the process safety management system. 

In the shorter case studies, only the immediate causes of the errors are described. However, the more extended examples in the latter part of the appendix illustrate two important points about accident causation. First, the precondihons for errors are often created by incorrect policies in areas such as training, procedures, systems of work, communications, or design. These "root causes" underlie many of the direct causes of errors which are described in this section. Second, the more comprehensive examples illustrate the fact that incidents almost always involve more than one cause. These issues will... 

The mucopolysaccharidoses share a common mechanism of causation, as illustrated in Figure 48-10. They are inherited in an autosomal recessive manner, with Hurler and Hunter syndromes being perhaps the most widely studied. None are common. In some cases, a family history of a mucopolysaccharidosis is obtained. Specific laboratory investigations of help in their diagnosis are urine testing for the presence of increased... 

Figure 48-15. Simplified scheme of the causation of achondroplasia (MIM 100800). In most cases studied so far, the mutation has been a G to A transition at nucleotide 1138. In a few cases, the mutation was a G to C transversion at the same nucleotide. This particular nucleotide is a real "hot spot" for mutation. Both mutations result in replacement of a Gly residue by an Arg residue in the transmembrane segment of the receptor. A few cases involving replacement of Gly by Cys at codon 375 have also been reported.

Figure SOS. Tentative scheme of the main events in causation of primary hemochromatosis (MIM 235200). The two principal mutations are CY282Y and H63D (see text). Mutations in genes other than HFE are also involved in some cases.

Figure 52-7. Simplified scheme of the sequence of events involved in the causation of chronic granulomatous disease (MIM 306400). Mutations in any of the genes for the four polypeptides involved (two are components of cytochrome b55gand two are derived from the cytoplasm) can cause the disease. The polypeptide of 91 kDa is encoded by a gene in the X chromosome approximately 60% of cases of chronic granulomatous disease are X-linked, with the remainder being inherited in an autosomal recessive fashion.

Muir T, Zegarac M (2001) Societal costs of exposure to toxic substances economic and health costs of four case studies that are candidates for environmental causation. Environ Health Perspect 109(Suppl 6) 885-903... 

To obtain the mass emissions of pollutants from e-waste recycling processes, it is essential that the inputs of pollutants are truly e-waste related. To fulfill this requirement, a causal analysis is desirable. However, the concept of causation is rather problematic because causal mechanisms are complex [26]. Nonetheless, we are compelled to identify causes, in an attempt to minimize the uncertainties associated with our estimates. In this chapter, the strict empiricist, David Hume s empirical criterion, was adopted. This approach requires only a combination of (1) e-waste processing and environmental pollution are associated in space and time (contiguity) (2) e-waste processing precede to environmental pollution (temporal succession) and (3) e-waste processing is always conjoined with environmental pollution (consistent conjunction). These are always the cases judged from a number of previous studies [6, 27-35]. 

Similar remarks can be made about accident reports, it was observed that the focus of the majority is on the direct safety related deviations in the accident causation path, and almost no attention is given to the indirect safety related deviations. Indirect safety related deviations were mentioned but no attention was given to the fact that these deviations were in the causal path, re-occurring, and often present for a long time prior to the accident. Korvers (Korvers et al., 2002) gave some good examples by showing ten cases in which identical indirect safety related deviations present prior to accidents repeatedly caused similar accidents. 

In addition to quantitative approach, qualitative identification can be of value in appropriate instances. In some cases of ADRs, more than one of the six methods of drug linkage that are listed in Figure 20.4 may be used in causation analysis. In fact, multiple methods in the same case strengthens either the confirmation of the rejection of an ADR and its etiology. 

A demonstration of this nature is said to establish an association between the factor and the excess cancers. Two events - in this case the factor and the excess cancers - are said to be associated when they occur together more frequently than they should if chance alone were operating. We need to turn to statisticians to figure out whether the odds are greater than those associated with a chance occurrence. Association is not causation, but demonstrating that an association exists gets the epidemiologist part of the way to an answer. 

Return now to a point made early in this section. Statistical associations, the existence of which cohort and case-control studies can reveal to us, are not, of themselves, evidence of causation. If found, and even if they are strong - large relative risk or odds-ratio - they do not establish that the phenomena being investigated, the phenomena that are associated (disease and some exposure or other factor) are causally related. To see most easily why this is so, it is best to examine the difficulties that need to be overcome to move from association to any conclusion about the existence of a causal link. 

Another type of biological evidence that supports a case for causation derives from experimental work with animals if the substance under consideration is carcinogenic in animals, associations seen in epidemiology studies become biologically supportable. Sometimes it is possible to conduct a study after intervening to remove the suspect substance if risk declines following such an intervention, the case for causation strengthens (recall Pott s chimney sweeps). 

Even when Mr. Z s expert makes the case for specific causation, it remains possible that there are other medical and exposure issues that make alternative causes even more likely than benzene. Possible alternative causes are always in the spotlight, at least among defendants. 

Theoretical incident concepts and associated models have evolved from investigations into the how and why of case histories. Resulting insights have made it possible to better explain and understand incident causation. There are many other incident causation theories besides the ones presented in this chapter, such as the Process Theory. (See the additional references for this chapter.) Key theories on incident causation discussed in this overview are ... 

This book will outline what forensic pharmacology is and how it is used in similar cases in the real world. Chapter 2 will describe principles used by forensic pharmacologists to establish causation, namely pharmacokinetics and pharmacodynamics. Chapter 3 will describe the tools used by forensic scientists to identify and quantify chemicals in bodily fluids and tissues. Chapter 4 will describe current trends in drug abuse, focusing... 

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