Epidemiology causality

Epidemiological studies of nickel-producing and nickel-using workers seldom indicate excess mortaUty from nonmalignant respiratory disease. Evidence for such effects exists mainly as a few reports of isolated incidents of asthma, pulmonary fibrosis, chronic bronchitis, and emphysema in nickel workers. Nickel may or may not play a causal role in these incidents (131). 

S Greenland. Probability logic and probability induction. Epidemiology 9 322-332, 1998. GM Petersen, G Parmigiam, D Thomas. Missense mutations in disease genes A Bayesian approach to evaluate causality. Am J Hum Genet. 62 1516-1524, 1998. 

Ideally, to establish a causal relationship between caffeine and improved athletic performance, evidence would be obtained from epidemiological population studies, followed by careful, double-blind, placebo controlled experimental protocols isolating the purported etiological agent (caffeine), and eventually culminating with strong laboratory findings... 

Epidemiology evidence is rated as sufficient to establish a causal link to some form of cancer or as limited (a role for bias or confounding cannot be eliminated) or as inadequate (insufficient in quality or quantity for evaluation). Some of the substances for which lARC panels have concluded there is sufficient evidence of a causal role in human cancer are listed in Table 5.1. 

Scientists skilled in epidemiology, toxicology, and related disciplines collect and evaluate all of the scientific literature containing information regarding the types of toxic effect the chemical under review has been shown to produce. Toxic effects include one or more of the many manifestations of toxicity described earlier in this book. The list of adverse health effects produced by the chemical are said to constitute its toxic hazards, and the critical review and evaluation leading to the list is the hazard identification step. A discussion of the extent to which causal associations with human disease or toxic harm have been established is an important aspect of this step. 

In humans, cases of hepatomas have appeared years after acute exposure to carbon tetrachloride, however, none of the cases could establish a causal link between the exposure and development of neoplasms." Epidemiological studies have also given inconclusive results. A cancer mortality study of a population of rubber workers reported a significantly elevated odds ratio relating carbon tetrachloride with lymphatic leukemia, and lymphosarcoma and reticulum cell carcinoma." A recent retrospective cohort mortality study of aircraft maintenance workers found an increased risk of... 

Bond GG, Bodner KM, Cook RR Phenoxy herbicides and cancer Insufficient epidemiological evidence for a causal relationship. Fundam Appl Pharmacol 12 172-188, 1989... 

According to the lARC, sufficient evidence of carcinogenicity for alcoholic beverages has been established in humans." Epidemiological studies clearly indicate that consumption of alcoholic beverages is causally related to cancers of the oral cavity, pharynx, larynx, esophagus, and liver. Since the lARC evaluation, evidence has accumulated for an asso-... 

Strong suspicions of dependence should be reported always. Without such signals improvements in drug use will not be initiated there is no such thing as a false signal Work to establish the nature of the causality and other clinical and epidemiological features of drug adverse reaction relationship will always be necessary. 

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