Dose calculations overview

With the data included in the overview of Garg et al. (316), it is possible to calculate that 18 patients need to be treated for 90 days to avoid one death or one hospitalization for congestive heart failure (95% confidence interval [Cl] 16-23). This meta-analysis includes 32 trials with the ACE inhibitors captopril, enalapril, lisinopril, quinapril, ramipril, and perindopril. It is likely that high doses (for instance, lisinopril 35 mg daily) are more effective than low doses (lisinopril 5 mg daily) (302). Treating 30 patients for 4 years with a high dose of lisinopril (95% Cl 16-509) will avoid one hospitalization for cardiovascular reasons or one death in comparison with a low dose, without increasing the number of adverse effects requiring withdrawal from treatment. 

Simple models have been developed to screen for consequences of worst-case exposures (van de Meent et al., 1995 USEPA, 1997b). For example, these models calculate worst-case exposure by dividing the amount of active ingredient by the room size. When better estimates of exposure are needed, simple models are advanced based on mechanistic processes or statistical relations, in conjunction with experiments aimed at quantifying exposnre factors (Jayjock, 1994 Matoba et al., 1998a,c van Veen, 1996) (see the model overview below). These models describe the mechanisms of exposure and inclnde key factors that influence exposure, such as ventilation rates of rooms and vapor pressures of chemicals. In addition, they provide a more precise temporal and spatial scale of exposure and dose. These scales enable identification and exposnre assessment of persons at various distances from the application and of persons having varions time-intervals of contact with the pesticide. 

Overview of Health Effects. Studies in humans and animals indicate that inhalation of asbestos fibers may lead to fibrotic lung disease (asbestosis), pleural plaques and thickening, and cancer of the lung, the pleura, and the peritoneum. It may also increase the risk of cancer at other sites, but the evidence is not strong. Significant effects on other tissues have not been detected. A number of researchers have found that the occurrence of asbestosis and lung cancer correlates with cumulative exposure (that is, the product of concentration [PCM fibers/mL] multiplied by years of exposure). Therefore, human exposures are expressed below as PCM f-yr/mL. Animal data are provided in terms of exposure level (PCM f/mL) and duration, and the cumulative exposure can be found simply by calculating the product. However, due to differences in clearance rates and lifespan as well as other differences, cumulative doses in animals are not expected to be directly comparable to cumulative doses in humans. Studies that provide reliable dose-... 

Galbraith RF, Roberts RG (2012) Statistical aspects of equivalent dose and error calculation and display in OSL dating an overview and some recommendations. Quat Geochronol 11 1-27... 

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