Epidemiological effects studies

In conclusion, phytic acid forms soluble complexes with Ca2+ at intestinal pH under a variety of conditions and fails to inhibit Ca2 bioavailability to mice in our experimental system. Despite the hazard in direct extrapolation of results obtained with animals kept on a well-defined dietary regimen to humans consuming a complex diet, many elements of which affect Ca2+ bioavailability, our data demonstrate the need for a reevaluation of the putative antinutritional properties of dietary phytate. Our further contention that adequate levels of dietary phytate may actually be beneficial due to its food preserving properties and its protection against colonic cancer will warrant a prospective epidemiological human study designed to assess the longterm effects of dietary phytate on mineral bioavailability and inflammatory bowel diseases. 

Chen-Yeung M, Wong R, McLean L, et al Epidemiologic health study of workers in an aluminum smelter in British Columbia Effects on the respiratory system. Am Rev Respir Dis 127 465M-69, 1983... 

Gamble J, et al Epidemiological-environmental study of lead acid battery workers. HI. Chronic effects of sulfuric acid on the respiratory system and teeth. Environ Res 35 30-52, 1984... 

Numerous diagnostic methods have been developed to evaluate female reproductive dysfunction. Although these methods have rarely been used for occupational or environmental toxicological evaluations, they may be helpful in defining biological parameters and mechanisms related to female reproductive toxicity. If clinical observations link exposure to the reproductive effect of concern, these data will aid the assessment of adverse female reproductive toxicity. The following clinical observations include end-points that may be reported in case reports or epidemiological research studies. 

Health effects studies, such as epidemiological studies, utilizing employee health records require that the records be complete, well maintained, and readily accessible, and that they contain comparable information. These requirements apply to records for all sites. Therefore, automation and centralization of the records is practically a necessity. Records from multiple CSDP sites with multiple contractors at each site may be kept in a variety of forms and according to a variety of procedures. Standardized forms and procedures for all sites would ensure that records could be used for health effects studies. Epidemiological studies on occupation-ally related diseases are most meaningful when employee exposure data are available for correlation with the health data. Complete, high-quality health and... 

Gamble, J., WJones, and S.Minshall. 1987. Epidemiological-environmental study of diesel bus garage workers Acute effects of NOj and respirable participate on the respiratory system. Environ. Res. 42(1) 201-214. 

The accuracy of exposure assessment is determined by systematic and random errors in the assessment. For quantitative exposure assessments, important sources of error include measurement errors (i.e. from laboratory and field monitoring techniques), as well as variations in exposure over time and space. For qualitative exposure proxies (e.g. self-reported past exposures, occupational histories or expert evaluations), the most important sources of error are recall bias (systematic differences in exposure recall between cases and controls) and random error, expressed in terms of intra- and inter-rater agreement. Although systematic errors can result in serious misinterpretations of the data, especially due to scaling problems, random errors have received more attention in epidemiology because this type of error is pervasive, and its effect is usually to diminish estimates of association between exposure and disease. The magnitude of random errors can be considerable in epidemiological field studies. 

Perera, F.P., Whyatt, R.M., Jedrychowski, W., Rauh, V., Manchester, D., Santella, R.M., Ottman, R. (1998). Recent developments in molecular epidemiology a study of the effects of environmental polycyclic aromatic hydrocarbons on birth outcomes in Poland. Am. J. Epidemiol. 147 309-14. 

Weight of evidence of all data, including human incidents, epidemiology, and studies conducted in experimental animals, is used to substantiate specific target organ/systemic toxic effects that merit classification. 

Asians, Black Africans, and aboriginal Australians. However, while these particular ethnic groups have an increased incidence of MS, identical twin studies show only a 30% correlation in disease occurrence in individuals sharing the same DNA and environmental factors. Epidemiological genetic studies show a relational rather than a causative effect (Barcellos et al., 2002). While regions of interest have been identified, none have been linked to MS wdth certainty. 

Hexane is currently under review for its carcinogenicity however, it is not classified as a carcinogen at the present time. A US Environmental Protection Agency (EPA) reference concentration of 0.2mgm was calculated based on an epidemiological inhalation study with an uncertainty factor of 300. Critical effects were reported to be neurotoxicity and electrophysiological alterations. 

Both the total fat intake and the ratios between FAs of different classes influence the activity of immune cells. Such information was initially obtained through epidemiological human studies, and studies conducted with cultured cells and animal models. These studies showed that EFAs are required for the growth and maintenance of the immune cells, and free FAs are produced and secreted during the activation of these cells. A number of intervention studies regarding the effects of the amount and composition of dietary fat on human immune response have been conducted, results of which are discussed in the following sections. 

As seen in Figure 3-10, very little quantitative information is available regarding the health effects in humans exposed to selenium compounds via inhalation. The only quantitative inhalation studies in humans that relate selenium exposure levels or selenium body levels to health effects following inhalation exposure are epidemiological cancer studies. Fatalities following inhalation exposure to selenium compounds have not been reported. Despite the large number of cases of reported inhalation exposures in occupational settings, characterization of exposure concentrations and the selenium... 

Saalbach E (1973) The effect of sulphur, magnesium, and sodium on yield and quality of agricultural crops. Pontif Acad Sci Scr Varia 38 541-589. Sasaki N (1980) Epidemiolog.cal studies on hypertension in northeast Japan. In Kesteloot H and Joossens JV, eds. Epidemiology of Arterial Blood Pressure, pp. 367-377. Martinus Nijhoff Publishers The Hague, Boston, London. 

Observations in humans are useful for assessing the relevance of the results of animal studies and for confirming ADls. Studies dealing with epidemiological surveys, clinical experience, anecdotal observations, health effect studies relating to occupational exposure, reports of abuse, and volunteer studies measuring intolerance provide important observations. 

Cross F, Palmer R, Busch R, et al. 1986. An overview of PNL radon experiments with reference to epidemiological data. In Thompson R, Mahaffey J, eds. Life-span radiation effects studies in animals What can they tell us Proceedings 22nd Hanford Life Sciences Symposium, Richland,... 

The wide variety of chemicals produced and very poor overall health and safety statistics, make the assessment of occupationally determined disease and ill-health particularly difficult. Taking this a stage further, other than disasters or accidents, where the effect on workers and the environment can be relatively easy to observe, the long-term impact, particularly from low levels of new or poorly studied materials, is a particular problem. Epidemiology, (the study of social groups and patterns of disease as a means of determining causes ) is difficult due to the varied exposure conditions and the varied significance of other factors. Exposure to chemicals at work is one hazard that can be controlled. 

Epidemiological studies on the prevention of contact dermatitis in the work environment are needed to prove the effectiveness of preventive measures and interventions. Presently, epidemiological intervention studies that evaluate the relative impact of various measures to prevent contact dermatitis, have not been published. 

Gaffey, W. R. 1983b. Recent Epidemiological Studies of PCBs, in Advances in Exposure, Health and Environmental Effects Studies of PCBs, Symposium Proceedings, ed. R. J. Davenport and B. K. Bernard, Report No. LSI-TR-507-1373, NTIS No. PB 84-135771 189-201, Office of Toxic Substances, U.S. EPA, Washington, DC. 

---