Epidemiology causation

Loue S (2000) Epidemiological causation in the legal context substance and procedures. In Gastwirth JL (ed.). Statistical Science in the Courtroom. Springer, New York, pp. 4430—4387, 98997-98998. 

Hsu B 1980 Recent progress in antineoplastic drug research in China, (review). In Marks, PA (ed.) Cancer Research In The People s Republic Of China And The United States of America -Epidemiology, Causation and Approaches to Therapy. Grune and Stratton, New York NY p. 235-250... 

Halogenated compounds, found in high concentrations in seaweeds consumed in Japan and Hawaii, have been suspected of being carcinogenic, largely based on epidemiological extrapolation (high incidences of hepatic carcinoma). However, direct human causation has not been estabUshed (107). 

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). 

When epidemiological evidence is limited, and insufficient to establish causation, it may remain important in the hazard identification step if it is supported by reliable animal data. Within the regulatory context, convincing animal evidence of toxicity, even in the absence of strong epidemiological evidence, or indeed any epidemiological evidence, will still be used for hazard characterization. 

In contrast to the documented effect of cotton dust on acute responses, the causation of chronic respiratory effects in occupationally exposed subjects has not been established. The OSHA cotton dust standard is based on the premise that sustained exposure may result in chronic respiratory problems. To test this hypothesis, the pertinent literature is reviewed and discussed in an attempt to decide if convincing epidemiological documentation exists to support a cause and effect connection between prolonged dust exposure and chronic respiratory impairment. There appears to be a need for additional studies to clarify this important aspect of occupational medicine. 

Overinterpretation of laboratory and epidemiologic studies of cancer causation can make cancer-prevention regulations inefficient and ineffective. Similarly, it can lead to unjust resolution of cancer-related toxic torts. In this book VanDoren explains how these difficulties arise and gives valuable insight into how they can be reduced or eliminated by market-driven choices of individuals and companies. ... 

Oxidative stress is now recognized as an important etiological factor in the causation of several chronic diseases including cancer, cardiovascular diseases, osteoporosis, and diabetes. Antioxidants play an important role in mitigating the damaging effects of oxidative stress on cells. Lycopene, a carotenoid antioxidant, has received considerable scientific interest in recent years. Epidemiological, tissue culture, and animal studies provide... 

Cancer of the esophagus is not amenable to satisfactory surgical or chemical intervention and must therefore be addressed by searching for preventative measures. This type of neoplasm provides a unique epidemiologic model for the study of cancer causation and offers a means to learn more about initiation and promotion of this unique tumor. 

There has been some epidemiological confirmation of the probability of a significant death rate. A law passed in Texas in the early 1990s required the reporting of death within 2 weeks after ECT. From June 1993 through August 1994, 8 deaths were reported among nearly 1,700 patients subjected to shock treatment. Controversy surrounds causation, and critics of ECT attempted without success to obtain more autopsy details (Smith, 1995). 

Community exposure studies typically included concomitant exposures to particles, so the studies have limited utility in defining causation sulfur dioxide was but one of several agents contributing to observed effects. The epidemiologic studies suggest that the respiratory effects of exposure to sulfur dioxide in combination with particles, are greater than are the effects caused by sulfur dioxide alone in healthy individuals-especially in the elderly and those with preexisting cardiac or respiratory disease (WHO 1979). 

Concern over haphazard and unrecognized transfer of preponderance of evidence or more likely than not standards from the burden of persuasion to the burden of factual proof (burden of production) involves more than idle semantics. The adverse effects of failure to undertake a deliberate, two-step probabilistic analysis include (a) undue preference for particular probabilities of causation found in one epidemiologic study, especially when meta-analysis of multiple studies is not possible or available (b) unrecognized lowering of the burden of production with concomitant stiffening of the burden (standard) of persuasion (c) inappropriate fixation on simplistic quantitative rules such as the >50% likelihood rule and (d) poorly reasoned opinions because courts fail to explain exactly how they apply the >50%, more-likely than-not rule. 

Epidemiology has made the major contribution to our current understanding of the roles of individual environmental substances in human cancer causation, so that is why this space has been reserved for a discussion of the epidemiologic method and its limitations. 

The problem of apparent as against true inconsistencies also comes up when comparisons are made between the results of epidemiology studies and experimental animal studies. Dinitrochickenwire (DNC) causes cancer in rats, but there is no evidence that it does so in humans. This statement could be uttered for several hundred chemicals. But before it is accepted at face value, it is critical to inquire whether the speaker means that no epidemiology data exist for DNC (in which case the speaker has committed a sin of omission), or whether he means that epidemiology studies have been conducted and are negative in regard to causation. If the latter is the case, it is important to inquire further whether the studies were sufficiently powerful to rule out a risk the size of the one that DNC produced in animals. If they were sufficiently... 

Cartcer Epidemiology, Biomarkers and Prevention. 1991-. Philadelphia, PA AACR. Monthly. pISSN 1055-9965. URL http //cebp.aacrjoumals.org/. Cancer causation, mechanisms of carcinogenesis, prevention, and survivorship descriptive, analytical, biochemical, and molecular epidemiology use of biomarkers to study neoplastic and preneoplastic processes... 

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