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The ultimate public health objective is the ability to predict and prevent disease, and not necessarily to identify an exhaustive list of potential disease risk factors. For any important public health outcome with multiple and potentially interrelated risk factors, an improved understanding of the contribution of individual and combinations of modifiable risk factors to the disease burden is essential for formulating an appropriate public health strategy. Partitioning techniques that divide the combined impact of multiple risk factors into exposure-specific components while taking into account the potential interrelations among those components, have been described in the epidemiological literature. In this article, we review and compare the available methods and options for such apportionment and apply them in a more general public health context as a method of selecting and prioritizing coronary heart disease (CHD) prevention strategies.

This paper attempts to assess possible risks that may result from human exposure to dietary intake of acrylamide.

Detection of heavy metals at trace or higher levels in foods and food ingredients is not unexpected given the widespread unavoidable presence of several metals in nature, coupled with advancement in analytical methods and lowering limits of detection. To assist risk managers with a rapid risk assessment when facing these situations, a metal dietary exposure screening tool (MDEST) was developed. The tool uses food intake rates based on the National Health and Nutrition Examination Survey 2005-2010 consumption data for the U.S. population two+ years and up and for infants age six months to

Abstract: Cumulative risk assessment, concerned with the multiple health effects of chemical mixtures, challenges the utility of existing single-chemical regulatory references. We compare example cumulative risk assessments for 40 HAPs; one based on single-effect toxicological data from EPA, and another based on a multiple-effect toxicological database we developed. For the 40-chemical HAP subset, the multiple effect database contains information on approximately seven effects per chemical and contains a total of 290 toxicological values. Seven health effects are represented in the IRIS data. Seventeen health effects are represented in the multiple-effect data. Respiratory and neurological effects ranked first and second in both cumulative analyses, regardless of the source data. In addition to respiratory and neurological effects, gastro-intestinal/hepatic, renal/kidney, and immunologic effects were identified as effects of concern on the basis of the multiple effect data. Immunologic effects are not found in the 40-chemical IRIS dataset. Cumulative risk assessment has the potential to expand our understanding of the public health impacts of environmental exposures. Advancements in toxicological resources will improve cumulative risk assessment. Cumulative risk assessment will reduce risks to the extent that it can be integrated into prevention strategies to track and protect the public’s health. [Copyright &y& Elsevier]

Data from occupational cohort mortality studies have been used to derive exposure-response curves and general population excess lifetime cancer risks, given low-level, chronic exposure. Using an actuarial method, mortality-based rate ratios associated with cumulative exposures are applied to age-specific background cancer mortality rates for a theoretical population aged birth to 70 years. In one recent U.S. Environmental Protection Agency health assessment, a mortality-based leukemia relative rate model was used with background leukemia incidence rates, rather than mortality rates, to calculate excess lifetime risk of leukemia incidence. We examined the validity and implications of this novel approach, while considering possible bias if a potential leukemogen did not pose equal risk by cell type. Limited sensitivity analyses were also conducted. Our analyses show that using total leukemia mortality-based potency estimates with background incidence rates will introduce a biased estimate of excess lifetime risk, the direction of which varies by potency and the histological type of leukemia. These biases were somewhat increased on adjustment for possible greater susceptibility of children. For potent carcinogens, the traditional approach provides a reasonable approximation of excess lifetime mortality risk for both the more and less fatal forms of leukemia, even after adjustments for children and is, therefore, to be preferred. Less consistency by leukemia cell type and background rate was observed for flatter exposure-response curves. This evaluation illustrates the importance of carefully examining the impact of methodological changes to calculations of excess lifetime risk before implementation. [ABSTRACT FROM AUTHOR]

Twenty-four-hour recall data from the Continuing Survey of Food Intake by Individuals (CSFII) are frequently used to estimate dietary exposure for risk assessment. Food frequency questionnaires are traditional instruments of epidemiological research; however, their application in dietary exposure and risk assessment has been limited. This article presents a probabilistic method of bridging the National Health and Nutrition Examination Survey (NHANES) food frequency and the CSFII data to estimate longitudinal (usual) intake, using a case study of seafood mercury exposures for two population subgroups (females 16 to 49 years and children 1 to 5 years). Two hundred forty-nine CSFII food codes were mapped into 28 NHANES fish/shellfish categories. FDA and state/local seafood mercury data were used. A uniform distribution with minimum and maximum blood-diet ratios of 0.66 to 1.07 was assumed. A probabilistic assessment was conducted to estimate distributions of individual 30-day average daily fish/shellfish intakes, methyl mercury exposure, and blood levels. The upper percentile estimates of fish and shellfish intakes based on the 30-day daily averages were lower than those based on two- and three-day daily averages. These results support previous findings that distributions of “usual” intakes based on a small number of consumption days provide overestimates in the upper percentiles. About 10% of the females (16 to 49 years) and children (1 to 5 years) may be exposed to mercury levels above the EPA's RfD. The predicted 75th and 90th percentile blood mercury levels for the females in the 16-to-49-year group were similar to those reported by NHANES. The predicted 90th percentile blood mercury levels for children in the 1-to-5-year subgroup was similar to NHANES and the 75th percentile estimates were slightly above the NHANES. [ABSTRACT FROM AUTHOR]

One of the most important challenges facing risk mangers in the coming decades is the joint management of chemical and radiological wastes. Born out of different traditions, radiation and chemical risk approaches can differ sharply. Radiation protection generally focuses on establishing effective dose levels across media and utilizes an approach that incorporates the philosophy of ALARA. In contrast, chemical risk management strategies are medium specific and risk based. In practice these differences can complicate decision making and potentially lead to duplicative efforts. We have undertaken a series of case studies to determine the extent and nature of the barriers that exist with regard to the potential harmonization of risk management approaches. Built upon the results of an interactive workshop held in June 1998, these case studies examine how cleanup decisions were made at a series of contaminated sites around the United States. It is anticipated that these case studies will demonstrate (1) the areas of greatestdiscord among chemical and radiological risk management approaches, and (2) how gaps in approaches could be bridged. This presentation will review the important conclusions of these case studies and (if possible) offer suggestions about how chemical and radiation risk management can be harmonized. [ABSTRACT FROM AUTHOR]

4-(2-Hydroxyethyl) morpholine (HEM) is widely used as a building block of macromolecules in the manufacture of pharmaceuticals and dietary supplements and could remain as an impurity in the finished products. An evaluation of HEM was conducted to identify endpoints that could be used to determine the point-of-departure (POD) for use in assessing the potential risk from exposure to HEM. No oral repeated dose toxicological studies of appropriate duration were found for HEM. Therefore, suitable analogue(s) were identified. Although oral repeated dose studies were available for the analogues, the studies were not of sufficient duration for use in the assignment of a POD for risk evaluation. Accordingly, the Threshold of Toxicological Concern (TTC) approach, which proposes that a de minimis value can be derived to qualitatively assess risk, was considered for HEM. To determine the appropriate TTC approach (genotoxic or non-genotoxic), the genotoxicity of HEM and its analogues were evaluated. The weight of the evidence indicated that HEM, and the appropriate analogues, are not genotoxic. Considering the chemical structure of HEM, the non-genotoxic Cramer class III TTC value of 1.5 μg/kg bw/day was determined to be appropriate for use in safety assessment of HEM as an impurity in products intended for human consumption. [ABSTRACT FROM AUTHOR]