Odds ratio multiplicity

If the odds ratio for pattern 1 (joint effect of genotype and drug) is significantly greater than the product of odds ratios for patterns 2 (independent effect of genotype) and pattern 3 (independent effect of drug), then there is evidence for statistical (multiplicative) interaction. This analysis can be carried out in the context of multiple regression analysis by the inclusion of an interaction term. 

In Siemiatycki s (1991) population-based case-control study of cancer in Montreal, Canada (see monograph on dichloromethane in this volume), phenol was one of the substances evaluated 1% of the entire study population had been exposed to it at some time. Among the main occupations to which phenol exposure was attributed in this study were electric motor repairmen and foundry workers. The publication reported an association between phenol and pancreatic cancer (odds ratio, 4.8 90% CI, 1.8-12.7 n = 4) for no other site was cancer risk associated with phenol exposure. [The Working Group noted that detailed results for other sites were not provided, because they were based on small numbers, and that workers typically had multiple exposures.]... 

In the Montreal case-control study carried out by Siemiatycki (1991) (see monograph on dichloromethane in this volume), the investigators estimated the associations between 293 workplace substances and several types of cancer. Isocyanates were one of the substances, and it was stated that the most common form in this study was toluene diisocyanates. The main occupations to which isocyanate exposure was attributed in this study were motor vehicle refinishers, motor vehicle mechanics and foundry workers. Only 0.8% of the study subjects had ever been exposed to isocyanates. For most types of cancer examined (oesophagus, stomach, colon, rectum, pancreas, prostate, bladder, kidney, skin melanoma, lymphoma), there was no indication of an excess risk due to isocyanates. For lung cancer, in the population subgroup of French Canadians (the majority ethnic group in this region), based on 10 cases exposed at any level, the odds ratio was 2.2 (90% CI, 0.9-5.3). [The interpretation of the null results has to take into account the small numbers and presumably low exposure levels. Workers had multiple exposures.]... 

In a case-control study within a cohort of 6678 rubber workers in the United States (lARC, 1987) (Wilcosky et al., 1984), one of the substances assessed was xylene, which was analysed as a potential risk factor in relation to each of five cancer types. There were somewhat increased odds ratios (OR) for prostate cancer (OR, 1.5 n = 8), lymphosarcoma (OR, 3.7 n = 4 p < 0.05) and lymphatic leukaemia (OR, 3.3 n = 4). [The Working Group noted that workers were typically exposed to multiple exposures.]... 

A case-control study was performed in a cohort of 29,139 men employed in a chemical manufacturing environment (60). Nested case-control studies of non-Hodgkin s lymphoma, multiple myeloma, nonlymphocytic leukemia, and lymphocytic leukemia were conducted in men from two chemical facilities and a research center. Exposure odds ratios were examined in relation to 21 specific chemicals. The results are difficult to interpret because exposure to vinyl acetate was associated with a decreased risk for nonlymphocytic leukemia (odds ratio ... 

Adjusted odds ratios were derived from a multiple logistic regression analysis in which each odds ratio was adjusted for all other factors listed. An odds ratio higher than 1 indicates that patients with the characteristic have a higher likelihood of having an intracranial hemorrhage than those without the characteristic. 

An example of the outcome of a Fisher exact test is shown in Figure 4.5. A set of MMoA-annotated compounds were screened for inhibition of TNF-a production in lipopolysaccharide-stimulated THP-1 cells. The TNF-a pathway is well characterized and many known protein nodes, such as IKBKB, were identified in the analysis. Target discovery was consistent with a pathway enrichment analysis and, for each protein, a contigency table was constructed with /i-value and odds ratio calculated. To make sure that the / -values identified were significant when testing many different targets, a Bonferroni correction term - a method used to counteract the problem of multiple comparisons, which occurs when a set of statistical inferences are considered simultaneously - was applied. 

For institutional barriers against proliferation, it is proposed that a waste transmutation complex consisting of multiple units of the PEACER be run by an international organization in compliance with the IAEA safeguard procedures. Another approach is related to the denaturing of the fissile materials with isotopes that would complicate the use of the reactor fuel for weapon programmes. As a measure of the extent of denaturing, the odd ratio is defined as follows ... 

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