Use of quality-adjusted life year weights with dose-response models for public health decisions: a case study of the risks and benefits of fish consumption

Mercury bioaccessibility in fish and seafood: Effect of method, cooking and trophic level on consumption risk assessment

The bioaccessible Hg fraction in fish and seafood commonly present in the Mediterranean diet was assessed through three distinct in vitro extraction schemes. Each extraction method provided different results, highlighting the lack of a universal methodology to estimate mercury (Hg) bioaccessibility in those matrices. Bioaccessible Hg fractions ranged from 10 to nearly 90% of total mercury (T-Hg) and increased in predator species (Swordfish - Xiphias gladius, Blue Shark - Prionace glauca and Tuna - Thunnus sp.). Among the three extractions tested, the Unified Bioaccessibility Method (UBM) provided the highest estimation of Hg bioaccessibility for consumers. The tested cooking procedures (frying, grilling and steaming) considerably reduced the bioaccessible fraction. Results indicate that bioaccessible Hg found in ingested fish and seafood is far below the levels set by the current safety risk assessment legislation. These findings highlight the importance of integrating bioaccessibility measurements in food safety legislation.

Human health risk-benefit assessment of fish and other seafood: a scoping review

Fish and other seafood are important sources of nutrients, but they are also sources of chemical contaminants that may cause adverse health effects. This article aimed to identify existing risk-benefit assessments (RBA) of fish, shellfish, and other seafood, compare methodologies, discuss differences and commonalities in findings, and identify limitations and ways forward for future studies. We conducted a scoping review of the scientific literature of studies in all languages published from 2000 through April 2019. We identified 106 RBA of fish and other seafood across Europe, Asia, North America, Africa, and at the global level. Studies were heterogeneous in terms of types of fish and other seafood considered, beneficial and adverse compounds assessed, and overall methodology. Collected data showed that a diet consisting of a variety of lean and fatty fish and other seafood is recommended for the overall population and that women of childbearing age and children should limit the consumption of fish and other seafood types that have a high likelihood of contamination. Our review emphasizes the need for evidence-based, up-to-date, and harmonized approaches in RBA in general.

Public health risk-benefit assessment of red meat in France: Current consumption and alternative scenarios

Consumption of red meat has been associated with the risks of colorectal cancer (CRC), cardiovascular disease (CVD), foodborne-pathogen related diseases and with the potential benefit obtained by reduction of iron deficiency anemia (IDA). Based on probabilistic models, current risks and benefit for the French population were aggregated into a single metric, the disability adjusted life years (DALY). In France, per 100,000 people, current red meat consumption was responsible for a mean of 19 DALYs due to CRC, 21 DALYs to CVD and 7 DALYs to foodborne diseases. Current consumption of iron throughout the diet led to a mean of 15 DALYs due to IDA. To mitigate the risks, scenarios were built per sub-population of age and gender. Among adult and elderly population, the big meat eaters would benefit to adhere to the current recommendation (less than 500 g/w): the risks of CRC and CVD would decrease. Regarding IDA (scenario built with fixed ground beef amount), for young population, a consumption of 375g/w would be sufficient to eliminate the burden while for 25-44 years-old females, 455g/w would reduce IDA, but not entirely. This study highlighted the importance of assessing health risk-benefit per sub-populations and the necessity of communicating the results accordingly.

Estimation of the burden of disease attributable to red meat consumption in France: Influence on colorectal cancer and cardiovascular diseases

The consumption of red meat has been associated with colorectal cancer (CRC) and cardiovascular disease (CVD) worldwide. The objective of this study was to assess quantitatively the burden of disease of CRC and CVD due to the consumption of red meat in France. A probabilistic risk assessment model quantifying the risk, deaths and disability adjusted life years (DALY) of both outcomes was built. In the model, uncertainty and variability were propagated separately. The model used data on current CRC and CVD incidence and red meat consumption in France, as well as dose-response from epidemiological studies. Results were given by age class and gender. A total of 19 [95% CI = 8-33] DALY per 100,000 people per year for CRC associated with red meat consumption was estimated. For CVD, 21 [95% CI = 12-32] DALY per 100,000 people per year was estimated. The uncertainty was mainly due to the dose-response, as revealed by a sensitivity analysis. A scenario analysis, performed on red meat intake, highlighted that consumption of less than 65 g per day could limit the risk of CRC and CVD in the most affected sub-populations.

Risk Benefit Assessment of foods: Key findings from an international workshop

Whilst risk management measures, including food policy, are developed for the protection of public health and the environment, they may also lead to a reduction in health benefits. Policy decisions require then consideration of these necessary trade-offs, which leads to an increasing need to apply formal risk-benefit assessment (RBA) of foods. In this context, the European Food Safety Authority sponsored a Risk-Benefit Assessment Workshop on "past, current and future developments within the risk-benefit assessment of foods (RBA)" held in May 2017. The overall aims of the RBA Workshop were to discuss existing methods, challenges and needs within RBA, and to draft a roadmap for future development of RBA. The specific objectives were to i) identify RBA activities in Europe and globally; ii) discuss how to further develop and optimize RBA methodology; iii) identify challenges and opportunities within RBA; and iv) increase collaboration internationally. The two-day workshop gathered 28 participants from 16 institutions in 11 countries. It included technical presentations of RBA methods and case studies, and two break-out sessions for group discussions. All participants agreed that RBA has substantial potential to inform risk-management decisions in the areas of food safety, nutrition and public health. Several activities to optimize further developments within RBA were suggested. This paper provides a summary of workshop presentations, a discussion of challenges that limit progress in this area, and suggestions of next steps for this promising approach supporting a science-based decision process in the area of risk-benefit management of foods.

Development and Application of a Probabilistic Risk-Benefit Assessment Model for Infant Feeding Integrating Microbiological, Nutritional, and Chemical Components

A probabilistic and interdisciplinary risk-benefit assessment (RBA) model integrating microbiological, nutritional, and chemical components was developed for infant milk, with the objective of predicting the health impact of different scenarios of consumption. Infant feeding is a particular concern of interest in RBA as breast milk and powder infant formula have both been associated with risks and benefits related to chemicals, bacteria, and nutrients, hence the model considers these three facets. Cronobacter sakazakii, dioxin-like polychlorinated biphenyls (dl-PCB), and docosahexaenoic acid (DHA) were three risk/benefit factors selected as key issues in microbiology, chemistry, and nutrition, respectively. The present model was probabilistic with variability and uncertainty separated using a second-order Monte Carlo simulation process. In this study, advantages and limitations of undertaking probabilistic and interdisciplinary RBA are discussed. In particular, the probabilistic technique was found to be powerful in dealing with missing data and to translate assumptions into quantitative inputs while taking uncertainty into account. In addition, separation of variability and uncertainty strengthened the interpretation of the model outputs by enabling better consideration and distinction of natural heterogeneity from lack of knowledge. Interdisciplinary RBA is necessary to give more structured conclusions and avoid contradictory messages to policymakers and also to consumers, leading to more decisive food recommendations. This assessment provides a conceptual development of the RBA methodology and is a robust basis on which to build upon.

Fish, a Mediterranean source of n-3 PUFA: benefits do not justify limiting consumption

Fish is an important source of energy, high-quality proteins, fat, vitamins and minerals. Within lipids, n-3 long-chain PUFA (n-3 LC PUFA), mainly EPA and DHA, play an important role in health promotion and disease prevention. In contrast to the potential health benefits of dietary fish intake, certain chemical pollutants, namely heavy metals and some organic compounds, contained in seafood have emerged as an issue of concern, particularly for frequent fish consumers and sensitive groups of populations. The present review summarises the health benefits and risks of fish consumption. n-3 LC-PUFA are key compounds of cell membranes and play an important role in human health from conception through every stage of human development, maturation and ageing. DHA has a major role in the development of brain and retina during fetal development and the first 2 years of life and positively influences neurodevelopment, mainly visual acuity and cognitive functions. n-3 LC-PUFA are also effective in preventing cardiovascular events (mainly stroke and acute myocardial infarction) especially in persons with high cardiovascular risk. By contrast, there is convincing evidence of adverse neurological/neurodevelopmental outcomes in infants and young children associated with methylmercury exposure during fetal development due to maternal fish consumption during pregnancy. Dioxins and polychlorinated biphenyls present in contaminated fish may also develop a risk for both infants and adults. However, for major health outcomes among adults, the vast majority of epidemiological studies have proven that the benefits of fish intake exceed the potential risks with the exception of a few selected species in sensitive populations.

Mercury toxicity and the protective role of selenium in eel, Anguilla anguilla

The aim of the study was to determine the impact trace metals, mainly toxic ones, on the condition of eel (Anguilla anguilla) inhabiting four regions of Poland. Metal concentrations in eel muscle tissues were studied as functions of size, region, and season 2011-2012. The levels of metals were also used for risk assessment on consumer health. Copper and zinc occurred at concentrations that could only have positive impacts on eel condition. Low levels of cadmium and lead did not impair the condition of the fish. However, mercury occurred at high levels and increased with fish length and season. The mercury levels in eels were compared with the threshold of toxicity (500-1,200 μg kg(-1)), which can cause changes in biochemical processes and impair fish reproduction. The concentration of mercury was 1,010 μg kg(-1) in one specimen of the 120 samples examined, and in 16 specimens, it exceeded 500 μg kg(-1). The toxic effects of the mercury could have been attenuated by the selenium in the muscles of the eel, especially in the muscles of smaller specimens in which the Se/Hg molar ratio was higher than 1 with a positive correlation between these two elements. In larger specimens measuring in excess of 70 cm, this coefficient was below 1, and the mercury to selenium correlation was negative, which meant that the protective effects of selenium were weaker. The mercury in the muscles of large specimens at levels exceeding 500 μg kg(-1) could have weakened eel condition and also posed a threat to consumer health. The cadmium and lead in the muscles of the eel did not affect the condition of the fish. Mercury weakened the condition of large eel, A. anguilla. Selenium protected small- and medium-sized eel against the toxic effects of mercury.

Qalibra: a general model for food risk-benefit assessment that quantifies variability and uncertainty

The EU project BRAFO proposed a framework for risk-benefit assessment of foods, or changes in diet, that present both potential risks and potential benefits to consumers (Hoekstra et al., 2012a). In higher tiers of the BRAFO framework, risks and benefits are integrated quantitatively to estimate net health impact measured in DALYs or QALYs (disability- or quality-adjusted life years). This paper describes a general model that was developed by a second EU project, Qalibra, to assist users in conducting these assessments. Its flexible design makes it applicable to a wide range of dietary questions involving different nutrients, contaminants and health effects. Account can be taken of variation between consumers in their diets and also other characteristics relevant to the estimation of risk and benefit, such as body weight, gender and age. Uncertainty in any input parameter may be quantified probabilistically, using probability distributions, or deterministically by repeating the assessment with alternative assumptions. Uncertainties that are not quantified should be evaluated qualitatively. Outputs produced by the model are illustrated using results from a simple assessment of fish consumption. More detailed case studies on oily fish and phytosterols are presented in companion papers. The model can be accessed as web-based software at www.qalibra.eu.

A framework for organizing and selecting quantitative approaches for benefit-harm assessment

BACKGROUND

Several quantitative approaches for benefit-harm assessment of health care interventions exist but it is unclear how the approaches differ. Our aim was to review existing quantitative approaches for benefit-harm assessment and to develop an organizing framework that clarifies differences and aids selection of quantitative approaches for a particular benefit-harm assessment.

METHODS

We performed a review of the literature to identify quantitative approaches for benefit-harm assessment. Our team, consisting of clinicians, epidemiologists, and statisticians, discussed the approaches and identified their key characteristics. We developed a framework that helps investigators select quantitative approaches for benefit-harm assessment that are appropriate for a particular decisionmaking context.

RESULTS

Our framework for selecting quantitative approaches requires a concise definition of the treatment comparison and population of interest, identification of key benefit and harm outcomes, and determination of the need for a measure that puts all outcomes on a single scale (which we call a benefit and harm comparison metric). We identified 16 quantitative approaches for benefit-harm assessment. These approaches can be categorized into those that consider single or multiple key benefit and harm outcomes, and those that use a benefit-harm comparison metric or not. Most approaches use aggregate data and can be used in the context of single studies or systematic reviews. Although the majority of approaches provides a benefit and harm comparison metric, only four approaches provide measures of uncertainty around the benefit and harm comparison metric (such as a 95 percent confidence interval). None of the approaches considers the actual joint distribution of benefit and harm outcomes, but one approach considers competing risks when calculating profile-specific event rates. Nine approaches explicitly allow incorporating patient preferences.

CONCLUSION

The choice of quantitative approaches depends on the specific question and goal of the benefit-harm assessment as well as on the nature and availability of data. In some situations, investigators may identify only one appropriate approach. In situations where the question and available data justify more than one approach, investigators may want to use multiple approaches and compare the consistency of results. When more evidence on relative advantages of approaches accumulates from such comparisons, it will be possible to make more specific recommendations on the choice of approaches.

Fish consumption during child bearing age: a quantitative risk-benefit analysis on neurodevelopment

The fish ingredient N3-docosahexaenoic acid 22:6 n-3 (DHA) stimulates brain development. On the other hand methylmercury (MeHg) in fish disturbs the developing central nervous system. In this Context the IQ score in children is considered as an aggregate measure of in utero brain development. To determine the effect of DHA exposure on prenatal neurodevelopment the maternal DHA intake during pregnancy was compared with its epidemiologically observed effect on the IQ score of children. For MeHg the maternal intake was converted into its accumulation in the maternal body. The maternal body burden then was compared with its epidemiologically observed relationship with the IQ score. Taking the MeHg and DHA content of 33 fish species the net effect of these compounds on the IQ score was quantified. For most fish species the adverse effect of MeHg on the IQ score exceeded the beneficial effect of DHA. In the case of long-living predators a negative effect up to 10 points on the IQ score was found. The results of this study indicate that food interventions aiming at the beneficial effects of fish consumption should focus on fish species with a high DHA content, while avoiding fish species with a high MeHg content.

State of the art in benefit-risk analysis: food and nutrition

Benefit-risk assessment in food and nutrition is relatively new. It weighs the beneficial and adverse effects that a food (component) may have, in order to facilitate more informed management decisions regarding public health issues. It is rooted in the recognition that good food and nutrition can improve health and that some risk may be acceptable if benefit is expected to outweigh it. This paper presents an overview of current concepts and practices in benefit-risk analysis for food and nutrition. It aims to facilitate scientists and policy makers in performing, interpreting and evaluating benefit-risk assessments. Historically, the assessments of risks and benefits have been separate processes. Risk assessment is mainly addressed by toxicology, as demanded by regulation. It traditionally assumes that a maximum safe dose can be determined from experimental studies (usually in animals) and that applying appropriate uncertainty factors then defines the 'safe' intake for human populations. There is a minor role for other research traditions in risk assessment, such as epidemiology, which quantifies associations between determinants and health effects in humans. These effects can be both adverse and beneficial. Benefit assessment is newly developing in regulatory terms, but has been the subject of research for a long time within nutrition and epidemiology. The exact scope is yet to be defined. Reductions in risk can be termed benefits, but also states rising above 'the average health' are explored as benefits. In nutrition, current interest is in 'optimal' intake; from a population perspective, but also from a more individualised perspective. In current approaches to combine benefit and risk assessment, benefit assessment mirrors the traditional risk assessment paradigm of hazard identification, hazard characterization, exposure assessment and risk characterization. Benefit-risk comparison can be qualitative and quantitative. In a quantitative comparison, benefits and risks are expressed in a common currency, for which the input may be deterministic or (increasingly more) probabilistic. A tiered approach is advocated, as this allows for transparency, an early stop in the analysis and interim interaction with the decision-maker. A general problem in the disciplines underlying benefit-risk assessment is that good dose-response data, i.e. at relevant intake levels and suitable for the target population, are scarce. It is concluded that, provided it is clearly explained, benefit-risk assessment is a valuable approach to systematically show current knowledge and its gaps and to transparently provide the best possible science-based answer to complicated questions with a large potential impact on public health.

Mercury and selenium levels in 19 species of saltwater fish from New Jersey as a function of species, size, and season

There are few data on risks to biota and humans from mercury levels in saltwater fish. This paper examines mercury and selenium levels in muscle of 19 species of fish caught by recreational fisherfolk off the New Jersey shore, as a function of species of fish, size, and season, and risk of mercury to consumers. Average mercury levels ranged from 0.01 ppm (wet weight) (Menhaden Brevoortia tyrannus) to 1.83 ppm (Mako Shark Isurus oxyrinchus). There were four categories of mercury levels: very high (only Mako), high (averaging 0.3-0.5 ppm, 3 species), medium (0.14-0.20 ppm, 10 species), and low (below 0.13 ppm, 5 species). Average selenium levels for the fish species ranged from 0.18 ppm to 0.58 ppm, and had lower variability than mercury (coefficient of variation=38.3 vs 69.1%), consistent with homeostatic regulation of this essential element. The correlation between mercury and selenium was significantly positive for five and negative for two species. Mercury levels showed significant positive correlations with fish size for ten species. Size was the best predictor of mercury levels. Selenium showed no consistent relationship to fish length. Over half of the fish species had some individual fish with mercury levels over 0.3 ppm, and a third had fish with levels over 0.5 ppm, levels that pose a human health risk for high end consumers. Conversely several fish species had no individuals above 0.5 ppm, and few above 0.3 ppm, suggesting that people who eat fish frequently, can reduce their risk from mercury by selecting which species (and which size) to consume. Overall, with the exception of shark, Bluefin Tuna (Thunnus thynnus), Bluefish (Pomatomus saltatrix) and Striped Bass (Morone saxatilis), the species sampled are generally medium to low in mercury concentration. Selenium:mercury molar ratios were generally above 1:1, except for the Mako shark.

Consumer responses to integrated risk-benefit information associated with the consumption of food

The risk analysis of the health impact of foods is increasingly focused on integrated risk-benefit assessment, which will also need to be communicated to consumers. It therefore becomes important to understand how consumers respond to integrated risk-benefit information. Quality-adjusted-life-years (QALYs) is one measure that can be used to assess the balance between risks and benefits associated with a particular food. The effectiveness of QALYs for communicating both positive and negative health effects associated with food consumption to consumers was examined, using a 3 × 2 experiment varying information about health changes in terms of QALYs associated with the consumption of fish (n = 325). The effect of this information on consumer perceptions of the usefulness of QALYs for describing health effects, on risk and benefit perceptions, attitudes, and intentions to consume fish was examined. Results demonstrated that consumers perceived QALYs as useful for communicating health effects associated with food consumption. QALYs communicated as a net effect were preferred for food products associated with negative net effects on health, while separate communication of both risks and benefits may be preferred for food products associated with positive or zero net health effects. Information about health changes in terms of QALYs facilitated informed decision making by consumers, as indicated by the impact on risk and benefit perceptions as intended by the information. The impact of this information on actual food consumption choices merits further investigation.

Policy and science implications of the framing and qualities of uncertainty in risks: toxic and beneficial fish from the Baltic Sea

Policy and research issues in the framing and qualities of uncertainties in risks are analyzed, based on the assessments of dioxin-like compounds (DLCs) and other ingredients in Baltic Sea fish, a high-profile case of governance. Risks are framed broadly, to then focus on dioxins and beneficial fatty acids, fish consumption, human health, and science-management links. Hierarchies of uncertainty (data, model, decision rule, and epistemic) and ambiguity (of values) are used to identify issues of scientific and policy contestation and opportunities for resolving them. The associated complexity of risks is illustrated by risk-benefit analyses of fish consumption and by evaluations of guideline values, highlighting value contents and policy factors in presumably scientific decision criteria, and arguments used in multi-dimensional risk and benefit comparisons. These comparisons pose challenges to narrow assessments centered, for e.g., on toxicants or on food benefits, and to more many-sided and balanced risk communication and management. It is shown that structured and contextualized treatment of uncertainties and ambiguities in a reflexive approach can inform balances between wide and narrow focus, detail and generality, and evidence and precaution.

A review of quantitative risk-benefit methodologies for assessing drug safety and efficacy-report of the ISPOR risk-benefit management working group

OBJECTIVE

Although regulatory authorities evaluate the risks and benefits of any new drug therapy during the new drug-approval process, quantitative risk-benefit assessment (RBA) is not typically performed, nor is it presented in a consistent and integrated framework when it is used. Our purpose is to identify and describe published quantitative RBA methods for pharmaceuticals.

METHODS

Using MEDLINE and other Internet-based search engines, a systematic literature review was performed to identify quantitative methodologies for RBA. These distinct RBA approaches were summarized to highlight the implications of their differences for the pharmaceutical industry and regulatory agencies.

RESULTS

Theoretical models, parameters, and key features were reviewed and compared for the 12 quantitative RBA methods identified in the literature, including the Quantitative Framework for Risk and Benefit Assessment, benefit-less-risk analysis, the quality-adjusted time without symptoms and toxicity, number needed to treat (NNT), and number needed to harm and their relative-value-adjusted versions, minimum clinical efficacy, incremental net health benefit, the risk-benefit plane (RBP), the probabilistic simulation method, multicriteria decision analysis (MCDA), the risk-benefit contour (RBC), and the stated preference method (SPM). Whereas some approaches (e.g., NNT) rely on subjective weighting schemes or nonstatistical assessments, other methods (e.g., RBP, MCDA, RBC, and SPM) assess joint distributions of benefit and risk.

CONCLUSIONS

Several quantitative RBA methods are available that could be used to help lessen concern over subjective drug assessments and to help guide authorities toward more objective and transparent decision-making. When evaluating a new drug therapy, we recommend the use of multiple RBA approaches across different therapeutic indications and treatment populations in order to bound the risk-benefit profile.

A tiered approach for risk-benefit assessment of foods

Risk-benefit analyses are introduced as a new paradigm for old problems. However, in many cases it is not always necessary to perform a full comprehensive and expensive quantitative risk-benefit assessment to solve the problem, nor is it always possible, given the lack of required date. The choice to continue from a more qualitative to a full quantitative risk-benefit assessment can be made using a tiered approach. In this article, this tiered approach for risk-benefit assessment will be addressed using a decision tree. The tiered approach described uses the same four steps as the risk assessment paradigm: hazard and benefit identification, hazard and benefit characterization, exposure assessment, and risk-benefit characterization, albeit in a different order. For the purpose of this approach, the exposure assessment has been moved upward and the dose-response modeling (part of hazard and benefit characterization) is moved to a later stage. The decision tree includes several stop moments, depending on the situation where the gathered information is sufficient to answer the initial risk-benefit question. The approach has been tested for two food ingredients. The decision tree presented in this article is useful to assist on a case-by-case basis a risk-benefit assessor and policymaker in making informed choices when to stop or continue with a risk-benefit assessment.

Risk to consumers from mercury in bluefish (Pomatomus saltatrix) from New Jersey: Size, season and geographical effects

Relatively little attention has been devoted to the risks from mercury in saltwater fish, that were caught by recreational fisherfolk. Although the US Food and Drug Administration has issued advisories based on mercury for four saltwater species or groups of fish, there are few data on how mercury levels vary by size, season, or location. This paper examines total mercury levels in muscle of bluefish (Pomatomus saltatrix) collected from coastal New Jersey, mainly by recreational fishermen. Of primary interest was whether there were differences in mercury levels as a function of location, weight and length of the fish, and season, and in what risk mercury posed to the food chain, including people. Selenium was also measured because of its reported protective effects against mercury. Mercury levels averaged 0.35+/-0.02 (mean and standard error)ppm, and selenium levels averaged 0.37+/-0.01ppm (N=206). In this study, 41% of the fish had mercury levels above 0.3ppm, 20% had levels above 0.5ppm, and 4% had levels above 1ppm. Size was highly correlated with mercury levels, but not with selenium. While selenium levels did not vary at all with season, mercury levels decreased significantly. This relationship was not due to differences in the size of fish, since the fish collected in the summer were the smallest, but had intermediate mercury levels. Mercury levels declined from early June until November, particularly for the smaller-sized fish. While there were significant locational differences in mercury levels (but not selenium), these differences could be a result of size. The levels of mercury in bluefish are not sufficiently high to cause problems for the bluefish themselves, based on known adverse health effects levels, but are high enough to cause potential adverse health effects in sensitive birds and mammals that eat them, and to provide a potential health risk to humans who consume them. Fish larger than 50cm fork length averaged levels above 0.3ppm, suggesting that eating them should be avoided by pregnant women, children, and others who are at risk.

Comparison of the nutritional-toxicological conflict related to seafood consumption in different regions worldwide

This article discusses the seafood consumption worldwide as well as the related nutritional-toxicological conflict. An exposure assessment was performed using seafood consumption data from the Global Environment Monitoring System and nutrient and contaminant concentration data. The data indicated that the region of Japan, Korea, Madagascar and Philippines have the highest seafood consumption, followed by the Nordic-Baltic countries and South-East Asia. In Japan, Korea, Madagascar, Philippines and the Nordic-Baltic countries, pelagic marine fishes are highly consumed compared to fresh water fishes in South-East Asia. Because pelagic fishes are oily fishes, Japan, Korea, Madagascar, Philippines and the Nordic-Baltic countries have high omega-3 fatty acids and vitamin D intake. Iodine intake is influenced by the demersal fish consumption. The current intake of these nutrients via seafood consumption is still below the recommendations. From the toxicological side, the data indicate that none of the seafood groups had a median contaminant concentration above the EU maximum limits. Though, the results show that in some regions the contaminant intake exceeded the international health-based guidance values, mainly focussing on sensitive subpopulations. In contrast, when using less stringent guidance values relevant for non-sensitive subpopulations, the results show that the benefits of increased seafood consumption outweigh the risks.

Quantitative approach for incorporating methylmercury risks and omega-3 fatty acid benefits in developing species-specific fish consumption advice

BACKGROUND

Despite general agreement about the toxicity of methylmercury (MeHg), fish consumption advice remains controversial. Concerns have been raised that negative messages will steer people away from fish and omega-3 fatty acid (FA) benefits. One approach is to provide advice for individual species that highlights beneficial fish while cautioning against riskier fish.

OBJECTIVES

Our goal in this study was to develop a method to quantitatively analyze the net risk/benefit of individual fish species based on their MeHg and omega-3 FA content.

METHODS

We identified dose-response relationships for MeHg and omega-3 FA effects on coronary heart disease (CHD) and neurodevelopment. We used the MeHg and omega-3 FA content of 16 commonly consumed species to calculate the net risk/benefit for each species.

RESULTS

Estimated omega-3 FA benefits outweigh MeHg risks for some species (e.g., farmed salmon, herring, trout); however, the opposite was true for others (swordfish, shark). Other species were associated with a small net benefit (e.g., flounder, canned light tuna) or a small net risk (e.g., canned white tuna, halibut). These results were used to place fish into one of four meal frequency categories, with the advice tentative because of limitations in the underlying dose-response information. Separate advice appears warranted for the neurodevelopmental risk group versus the cardiovascular risk group because we found a greater net benefit from fish consumption for the cardiovascular risk group.

CONCLUSIONS

This research illustrates a framework for risk/benefit analysis that can be used to develop categories of consumption advice ranging from "do not eat" to "unlimited," with the caveat that unlimited may need to be tempered for certain fish (e.g., farm-raised salmon) because of other contaminants and end points (e.g., cancer risk). Uncertainties exist in the underlying dose-response relationships, pointing in particular to the need for more research on the adverse effects of MeHg on cardiovascular end points.

Comparative analysis of state fish consumption advisories targeting sensitive populations

OBJECTIVE

Fish consumption advisories are issued to warn the public of possible toxicological threats from consuming certain fish species. Although developing fetuses and children are particularly susceptible to toxicants in fish, fish also contain valuable nutrients. Hence, formulating advice for sensitive populations poses challenges. We conducted a comparative analysis of advisory Web sites issued by states to assess health messages that sensitive populations might access.

DATA SOURCES

We evaluated state advisories accessed via the National Listing of Fish Advisories issued by the U.S. Environmental Protection Agency.

DATA EXTRACTION

We created criteria to evaluate advisory attributes such as risk and benefit message clarity.

DATA SYNTHESIS

All 48 state advisories issued at the time of this analysis targeted children, 90% (43) targeted pregnant women, and 58% (28) targeted women of childbearing age. Only six advisories addressed single contaminants, while the remainder based advice on 2-12 contaminants. Results revealed that advisories associated a dozen contaminants with specific adverse health effects. Beneficial health effects of any kind were specifically associated only with omega-3 fatty acids found in fish.

CONCLUSIONS

These findings highlight the complexity of assessing and communicating information about multiple contaminant exposure from fish consumption. Communication regarding potential health benefits conferred by specific fish nutrients was minimal and focused primarily on omega-3 fatty acids. This overview suggests some lessons learned and highlights a lack of both clarity and consistency in providing the breadth of information that sensitive populations such as pregnant women need to make public health decisions about fish consumption during pregnancy.

Evaluation of the exposure methodology for risk-benefit assessment of seafood consumption

This study evaluated the methodology of using existing, international data to calculate the intake of nutrients and contaminants via seafood consumption on a national level. This was done by combining French seafood consumption data with two different datasets. The results showed that a significant correlation was found between the results obtained by using different data sets and that a high percentage of the population was classified in the same category (above or below the intake reference values). As such, the general conclusion that can be drawn from the results: 'whether a part of the population does exceed the toxicological reference values for certain contaminants and whether a part of the population does not reach the recommended intake for certain nutrients' remains the same for the two approaches. Therefore, it can be concluded that the existing, international probability distributions are useful when aiming to perform a cost-effective risk benefit evaluation of seafood consumption on national or regional level. When this evaluation does indicate that more detailed results are needed because a certain health risk exists, it can be decided that it is worth to spend more time and money for the analyses of national samples in order to collect more detailed results.

Probabilistic intake assessment of multiple compounds as a tool to quantify the nutritional-toxicological conflict related to seafood consumption

Seafood represents a natural source of valuable nutrients (e.g., long chain omega-3 poly-unsaturated fatty acids (LC n-3 PUFAs), vitamin D, and iodine), but the favourable health perception is troubled by the presence of contaminants (e.g., PCBs, dioxin-like compounds, and (methyl) mercury (MeHg)). This dualism forms the basis for an important public health conflict. The objective of this study was to calculate and evaluate the simultaneous intake of multiple beneficial and harmful compounds (LC n-3 PUFAs, vitamin D, iodine, (Me)Hg, PCBs, and dioxin-like compounds) via seafood consumption in Belgium. A methodology and a software module were developed for executing probabilistic assessments of the simultaneous intake of multiple compounds leading to better insight in the problematic nature of food items involving both health benefits and risks. The simulations concerning seafood consumption in Belgium predicted that, as far as only seafood consumption is concerned, the considered populations do not reach a sufficiently high intake for the three nutrients considered (LC n-3 PUFAs, vitamin D, and iodine). Regarding the contaminants, (Me)Hg contamination of seafood on the Belgian market does not seem to be an issue of major toxicological concern. In contrast, for dioxin-like compounds the tolerable daily intake is reached by people with high seafood consumption.

A risk-benefit analysis of French high fish consumption: a QALY approach

The health risk and the nutritional benefit of a food are usually assessed separately. Toxicologists recommend limiting the consumption of certain fish because of methylmercury; while nutritionists recommend eating more oily fish because of omega 3. A common evaluation is imperative to provide coherent recommendations. In order to evaluate the risks along with the benefits related to fish consumption, a common metric based on the quality-adjusted life year (QALY) method has been used. The impact of a theoretical change from a medium n-3 PUFAs intake to a high intake is studied, in terms of the cardiovascular system (CHD mortality, stroke mortality and morbidity) and on fetal neuronal development (IQ loss or gain). This application can be considered as a sensitive analysis of the model used and looks at the impact of changing the dose-response relationships between cardiovascular diseases and n-3 PUFAs intakes. Results show that increasing fish consumption may have a beneficial impact on health. However, the confidence interval of the overall estimation has a negative lower bound, which means that this increase in fish consumption may have a negative impact due to MeHg contamination. Some limits of the QALY approach are identified. The first concerns determination of the dose-response relationships. The second concerns the economic origins of the approach and of individual preferences. Finally, since only one beneficial aspect and one risk element were studied, consideration should be given to how other beneficial and risk components may be integrated in the model.

Fish consumption is a safe solution to increase the intake of long-chain n-3 fatty acids

OBJECTIVES

Dietary intake of long-chain (LC) n-3 PUFA in developed countries is low compared with recommendations. Fish is naturally rich in LC n-3 PUFA, but is also a dietary source of heavy metals and organic pollutants. We investigated whether the recommendation for LC n-3 PUFA could be reached through fish consumption, without exceeding the provisional tolerable weekly intake of methylmercury (MeHg) and the tolerable weekly intake (TWI) of dioxin-like compounds. Also, the contribution of margarines enriched with LC n-3 PUFA was assessed.

DESIGN

Published nutrient and contaminant data were used in a probabilistic model to calculate the simultaneous nutrient and contaminant intake for different fish consumption scenarios.

RESULTS

The Belgian recommendation for EPA + DHA (0.3% of total energy intake) can be reached by consuming fatty fish a minimum of twice a week, or by varying between lean and fatty fish a minimum of three times a week. At this fish consumption level, MeHg intake is not an issue of toxicological concern. The intake of dioxin-like compounds approximates the TWI when consuming fatty fish more than twice a week, this being a potential toxicological risk because other food items also contribute to the weekly intake of dioxin-like compounds. Use of margarine enriched with LC n-3 PUFA can help to increase LC n-3 intake, on average by 159 mg/d.

CONCLUSIONS

Combination of regular fish consumption (twice a week) with important contribution of fatty fish species, in combination with regular consumption of margarine enriched with EPA + DHA, can be advised to achieve the recommendation for LC n-3 intake.

Health impact assessment: a tool to help policy makers understand health beyond health care

Health impact assessment (HIA)--a combination of methods to examine formally the potential health effects of a proposed policy, program, or project--has received considerable interest over the past decade internationally as a practical mechanism for collaborating with other sectors to address the environmental determinants of health and to achieve more effectively the goals of population health promotion. Demand for HIA in the United States seems to be growing. This review outlines the common principles and methodologies of HIA and compares different approaches to HIA. Lessons learned from the related field of environmental impact assessment and from experience with HIA in other countries are examined. Possible avenues for advancing both the field and the broader goals of population health promotion are outlined.

Integrated risk-benefit analyses: method development with folic acid as example

With the introduction of novel and functional foods, there is increasing need for an integrated quantitative risk-benefit assessment of foods. Consensus about a quantitative risk-benefit assessment mirroring the risk assessment approach has been reached during a recent EFSA workshop. In line, we propose a risk-benefit model that consists of: (1) hazard and benefit identification, (2) hazard and benefit characterization through dose-response functions, (3) exposure assessment, and (4) risk-benefit integration. The DALY, which combines morbidity and mortality serves as common health measure. The overall health impact of bread fortified with folic acid in the Netherlands has been simulated. The case study showed how the risk-benefit approach may assist a policy maker in decisions on food fortification programs. It illustrates general problems regarding the data demands, the assumptions and uncertainties. A simple sensitivity analysis showed which assumptions were most crucial. Modest fortification (140 microg/100 g bread) seems reasonable to improve public health but the results hinge on the assumptions one makes for the association between colorectal cancer and high folate intake. A precautious policymaker may very well decide against folic acid fortification. The often debated increase in masked vitamin B(12)-deficiency appears negligible compared to the health gain resulting from prevented neural tube defects.

Risk to consumers from mercury in Pacific cod (Gadus macrocephalus) from the Aleutians: fish age and size effects

While there has been considerable attention devoted to the risks to high level consumers from mercury in freshwater fish, relatively little attention has been devoted to saltwater fish. Although the U.S. Food and Drug Administration has issued advisories based on mercury for four saltwater species or groups of fish, there are few data on mercury levels generally, or on the risk these levels pose to the fish themselves or to consumers of marine fish. We examined total mercury levels in liver and muscle of Pacific cod (Gadus macrocephalus) collected from the northern Pacific and Bering Sea waters around Nikolski, Amchitka, and Kiska Islands in the Aleutian Chain (Alaska). We were interested in whether there were differences in mercury levels as a function of location, weight, length, and age of the fish, and what risk mercury posed to the food chain, including people. Fish were aged by examining otoliths, and we measured selenium because of its reported protective effects against mercury. Regression models indicated that 27% of the variation in levels of mercury was due to tissue examined and age, while 67% of the variation in levels of selenium was due to tissue, length, and age. Mercury levels were significantly higher in the muscle than the liver, and the reverse was true for selenium. Mercury levels were negatively correlated with selenium levels, and positively correlated with length, weight, and age. There were no gender differences in mercury or selenium levels. The mean levels of mercury in muscle (0.17 ppm wet weight) are within the range known to cause adverse effects in sensitive birds and mammals. Only 4% of the Pacific cod samples had mercury levels above 0.5 ppm, the action level promulgated by many states and countries, and none were above the 1 ppm action level of the U.S. FDA.

A probabilistic model for simultaneous exposure to multiple compounds from food and its use for risk-benefit assessment

A model is presented which allows to quantify the simultaneous distribution of the exposure to two compounds, for example a health-risk and a health promoting compound. The model considers the total dietary intake, and can be used as a first step to study the effects on the balance between risks and benefits following changes in the consumption pattern. The exposure is modelled separately for intake probabilities using a betabinomial model, and for intake amounts using a lognormal model, and these parts are afterwards integrated by Monte Carlo simulation. The model is illustrated using the risk-benefit case of dioxins and the omega-3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). High concentrations of both the health adverse compounds and the health promoting compounds are simultaneously present in fatty fish. Calculated exposures were compared with intake limits: the adequate intake for EPA+DHA and the tolerable daily intake (TDI) for dioxins. We estimate the probability that dioxin exposure is below TDI, the probability that EPA+DHA exposure is above the adequate intake, and the probability that both conditions occur simultaneously. We also model the dependence of these probabilities on age. In the studied population the exposure to both compounds is almost completely below the limits. A scenario study in which meat consumption was replaced by fatty fish consumption shows an increase in the fraction of the population with the recommended intake of EPA+DHA, however also the fraction of the population exceeding the TDI for dioxins is increased. For the example scenario the optimal amount of fatty fish consumption is derived.

Socioeconomic consequences of mercury use and pollution

In the past, human activities often resulted in mercury releases to the biosphere with little consideration of undesirable consequences for the health of humans and wildlife. This paper outlines the pathways through which humans and wildlife are exposed to mercury. Fish consumption is the major route of exposure to methylmercury. Humans can also receive toxic doses of mercury through inhalation of elevated concentrations of gaseous elemental mercury. We propose that any effective strategy for reducing mercury exposures requires an examination of the complete life cycle of mercury. This paper examines the life cycle of mercury from a global perspective and then identifies several approaches to measuring the benefits of reducing mercury exposure, policy options for reducing Hg emissions, possible exposure reduction mechanisms, and issues associated with mercury risk assessment and communication for different populations.

Projected health impact of the Los Angeles City living wage ordinance

STUDY OBJECTIVE

To estimate the relative health effects of the income and health insurance provisions of the Los Angeles City living wage ordinance.

SETTING AND PARTICIPANTS

About 10 000 employees of city contractors are subject to the Los Angeles City living wage ordinance, which establishes an annually adjusted minimum wage (7.99 US dollars per hour in July 2002) and requires employers to contribute 1.25 US dollars per hour worked towards employees' health insurance, or, if health insurance is not provided, to add this amount to wages.

DESIGN

As part of a comprehensive health impact assessment (HIA), we used estimates of the effects of health insurance and income on mortality from the published literature to construct a model to estimate and compare potential reductions in mortality attributable to the increases in wage and changes in health insurance status among workers covered by the Los Angeles City living wage ordinance.

RESULTS

The model predicts that the ordinance currently reduces mortality by 1.4 deaths per year per 10,000 workers at a cost of 27.5 million US dollars per death prevented. If the ordinance were modified so that all uninsured workers received health insurance, mortality would be reduced by eight deaths per year per 10,000 workers at a cost of 3.4 million US dollars per death prevented.

CONCLUSIONS

The health insurance provisions of the ordinance have the potential to benefit the health of covered workers far more cost effectively than the wage provisions of the ordinance. This analytical model can be adapted and used in other health impact assessments of related policy actions that might affect either income or access to health insurance in the affected population.

Methodologies for realizing the potential of health impact assessment

Health impact assessment (HIA), a systematic assessment of potential health impacts of proposed public polices, programs, and projects, offers a means to advance population health by bringing public health research to bear on questions of public policy. The United States has been slow to adopt HIA, but considerable strides have been made in many other countries, and under the auspices of the World Health Organization and World Bank. Varied applications in these diverse milieu have given rise to diverse approaches to HIA-quantitative/analytic, participatory, and procedural-each with distinct disciplinary foundations, goals, and methodologies. Suitability of these approaches for different applications and their challenges are highlighted, along with areas in which methodologic work is most needed and most likely to advance the field from theory and infrequent application to more routine practice in the United States.

Mercury in commercial fish: optimizing individual choices to reduce risk

Most attention to the risks from fish consumption has focused on recreational anglers and on fish caught by individuals, but the majority of fish that people eat are purchased from commercial sources. We examined mercury levels in three types of fish (tuna, flounder, bluefish) commonly available in New Jersey stores, sampling different regions of the state, in communities with high and low per capita incomes, and in both supermarkets and specialty fish markets. We were interested in species-specific levels of mercury in New Jersey fish and whether these levels were similar to data generated nationally by the Food and Drug Administration (FDA; mainly from 1990 to 1992) on the same types of fish. Such information is critical for providing public health advice. We were also interested in whether mercury levels in three common species of fish differed by region of the state, economic neighborhood, or type of store. We found significant species differences, with tuna having the highest levels and flounder the lowest levels. There were no significant differences in mercury levels as a function of type of store or economic neighborhood. There was only one regional difference: flounder from fish markets along the Jersey shore had higher mercury levels than flounder bought in other markets. We also examined mercury levels in six other commonly available fish and two shellfish from central New Jersey markets. There were significant differences in availability and in mercury levels among fish and shellfish. Both shrimp and scallops had total mercury levels < 0.02 ppm (wet weight). Large shrimp had significantly lower levels of mercury than small shrimp. For tuna, sea bass, croaker, whiting, scallops, and shrimp, the levels of mercury were higher in New Jersey samples than those reported by the FDA. Consumers selecting fish for ease of availability (present in > 50% of markets) would select flounder, snapper, bluefish, and tuna (tuna had the highest mercury value), and those selecting only for price would select whiting, porgy, croaker, and bluefish (all with average mercury levels < 0.3 ppm wet weight). Flounder was the fish with the best relationship among availability, cost, and low mercury levels. We suggest that state agencies responsible for protecting the health of their citizens should obtain information on fish availability in markets and fish preferences of diverse groups of citizens and use this information to select fish for analysis of contaminant levels, providing data on the most commonly eaten fish that will help people make informed decisions about risks from fish consumption.

Prospects for health impact assessment in the United States: new and improved environmental impact assessment or something different?

Health impact assessment (HIA) has been advanced as a means of bringing potential health impacts to the attention of policy makers, particularly in sectors where health impacts may not otherwise be considered. This article examines lessons for HIA in the United States from the related and relatively well-developed field of environmental impact assessment (EIA). We reviewed the EIA literature and conducted twenty phone interviews with EIA professionals. Successes of EIA cited by respondents included integration of environmental goals into decision making, improved planning, and greater transparency and public involvement. Reported shortcomings included the length and complexity of EIA documents, limited and adversarial public participation, and an emphasis on procedure over substance. Presently, EIAs consider few, if any, health outcomes. Respondents differed on the prospects for HIA. Most agreed that HIA could contribute to EIA in several areas, including assessment of cumulative impacts and impacts to environmental justice. Reasons given for not incorporating HIA into EIA were uncertainties about interpreting estimated health impacts, that EIA documents would become even longer and more complicated, and that HIA would gain little from the procedural and legal emphasis in EIA. We conclude that for HIA to advance, whether as part of or separate from EIA, well-formulated methodologies need to be developed and tested in real-world situations. When possible, HIA should build on the methods that have been utilized successfully in EIA. The most fruitful avenue is demonstration projects that test, refine, and demonstrate different methods and models to maximize their utility and acceptance.

Weighing health benefit and health risk information when consuming sport-caught fish

Fish consumers may incur benefits and risks from eating fish. Health advisories issued by states, tribes, and other entities typically include advice about how to limit fish consumption or change other behaviors (e.g., fish cleaning or cooking) to reduce health risks from exposure to contaminants. Eating fish, however, may provide health benefits. Risk communicators and fish consumers have suggested the importance of including risk comparison information, as well as health risk-benefit comparisons in health advisory communications. To improve understanding about how anglers fishing in waters affected by health advisories may respond to such risk-risk or risk-benefit information, we surveyed Lake Ontario (NY, USA) anglers. We interviewed by telephone 4,750 anglers, 2,593 of which had fished Lake Ontario in the past 12 months and were sent a detailed mail questionnaire (1,245 responded). We posed questions varying the magnitude of health risks and health benefits to be gained by fish consumption, and varied the population affected by these risks and benefits (anglers, children, women of childbearing age, and unborn children). Respondents were influenced by health benefit and health risk information. When risks were high, most respondents would eat less fish regardless of the benefit level. When risks were low, the magnitude of change in fish consumption was related to level of benefit. Responses differed depending on the question wording order, that is, whether "risks" were posed before "benefits." For a given risk-benefit level, respondents would give different advice to women of childbearing age versus children, with more conservative advice (eat less fish) provided to women of childbearing age. Respondents appeared to be influenced more strongly by risk-risk comparisons (e.g., risks from other foods vs. risks from fish) than by risk-benefit comparisons (e.g., risks from fish vs. benefits from fish). Risk analysts and risk communicators should improve efforts to include risk-risk and risk-benefit comparisons in communication efforts, and to clarify to whom the health risks and benefits from fish consumption may accrue.

Comparative risk and policy analysis in environmental health

There is increasing interest in the integration of quantitative risk analysis with benefit-cost and cost-effectiveness methods to evaluate environmental health policy making and perform comparative analyses. However, the combined use of these methods has revealed deficiencies in the available methods, and the lack of useful analytical frameworks currently constrains the utility of comparative risk and policy analyses. A principal issue in integrating risk and economic analysis is the lack of common performance metrics, particularly when conducting comparative analyses of regulations with disparate health endpoints (e.g., cancer and noncancer effects or risk-benefit analysis) and quantitative estimation of cumulative risk, whether from exposure to single agents with multiple health impacts or from exposure to mixtures. We propose a general quantitative framework and examine assumptions required for performing analyses of health risks and policies. We review existing and proposed risk and health-impact metrics for evaluating policies designed to protect public health from environmental exposures, and identify their strengths and weaknesses with respect to their use in a general comparative risk and policy analysis framework. Case studies are presented to demonstrate applications of this framework with risk-benefit and air pollution risk analyses. Through this analysis, we hope to generate discussions regarding the data requirements, analytical approaches, and assumptions required for general models to be used in comparative risk and policy analysis.

Selecting human health metrics for environmental decision-support tools

Environmental decision-support tools often predict a multitude of different human health effects due to environmental stressors. The accounting and aggregating of these morbidity and mortality outcomes is key to support decision making and can be accomplished by different methods that we call human health metrics. This article attempts to answer two questions: Does it matter which metric is chosen? and What are the relevant characteristics of these metrics in environmental applications? Three metrics (quality adjusted life years (QALYs), disability adjusted life years (DALYs), and willingness to pay (WTP)) have been applied to the same diverse set of health effects due to environmental impacts. In this example, the choice of metric mattered for the ranking of these environmental impacts and it was found for this example that WTP was dominated by mortality outcomes. Further, QALYs and DALYs are sensitive to mild illnesses that affect large numbers of people and the severity of these mild illnesses are difficult to assess. Eight guiding questions are provided in order to help select human health metrics for environmental decision-support tools. Since health metrics tend to follow the paradigm of utility maximization, these metrics may be supplemented with a semi-quantitative discussion of distributional and ethical aspects. Finally, the magnitude of age-dependent disutility due to mortality for both monetary and nonmonetary metrics may bear the largest practical relevance for future research.

Tools for comparative analysis of alternatives: competing or complementary perspectives?

A third generation of environmental policy making and risk management will increasingly impose environmental measures, which may give rise to analyzing countervailing risks. Therefore, a comprehensive analysis of all risks associated with the decision alternatives will aid decision-makers in prioritizing alternatives that effectively reduce both target and countervailing risks. Starting with the metaphor of the ripples caused by a stone that is thrown into a pond, we identify 10 types of ripples that symbolize, in our case, risks that deserve closer examination: direct, upstream, downstream, accidental risks, occupational risks, risks due to offsetting behavior, change in disposable income, macro-economic changes, depletion of natural resources, and risks to the manmade environment. Tools to analyze these risks were developed independently and recently have been applied to overlapping fields of application. This suggests that either the tools should be linked in a unified framework for comparative analysis or that the appropriate field of application for single tools should be better understood. The goals of this article are to create a better foundation for the understanding of the nature and coverage of available tools and to identify the remaining gaps. None of the tools is designed to deal with all 10 types of risk. Provided data suggest that, of the 10 types of identified risks, those associated with changes in disposable income may be particularly significant when decision alternatives differ with respect to their effects on disposable income. Finally, the present analysis was limited to analytical questions and did not capture the important role of the decision-making process itself.

Risk characterization: principles and practice

In the field of risk assessment, characterizing the nature and magnitude of human health or environmental risks is arguably the most important step in the analytical process. In this step, data on the dose-response relationship of an agent are integrated with estimates of the degree of exposure in a population to characterize the likelihood and severity of risk. Although the purpose of risk characterizations is to make sense of the available data and describe what they mean to a broad audience, this step is often given insufficient attention in health risk evaluations. Too often, characterizations fail to interpret or summarize risk information in a meaningful way, or they present single numerical estimates of risk without an adequate discussion of the uncertainties inherent in key exposure parameters or the dose-response assessment, model assumptions, or analytical limitations. Consequently, many users of risk information have misinterpreted the findings of a risk assessment or have false impressions about the degree of accuracy (or the confidence of the scientist) in reported risk estimates. In this article we collected and integrated the published literature on conducting and reporting risk characterizations to provide a broad, yet comprehensive, analysis of the risk characterization process as practiced in the United States and some other countries. Specifically, the following eight topics are addressed: (1) objective of risk characterization, (2) guidance documents on risk characterization, (3) key components of risk characterizations, (4) toxicity criteria for evaluating health risks, (5) descriptors used to characterize health risks, (6) methods for quantifying human health risks, (7) key uncertainties in risk characterizations, and (8) the risk decision-making process. A brief discussion is also provided on international aspects of risk characterization. A number of examples are presented that illustrate key concepts, and citations are provided for approximately 100 of the most relevant papers.

An exposure assessment for methylmercury from seafood for consumers in the United States

An exposure model was developed to relate seafood consumption to levels of methylmercury (reported as mercury) in blood and hair in the U.S. population, and two subpopulations defined as children aged 2-5 and women aged 18-45. Seafood consumption was initially modeled using short-term (three-day) U.S.-consumption surveys that recorded the amount of fish eaten per meal. Since longer exposure periods include more eaters with a lower daily mean intake, the consumption distribution was adjusted by broadening the distribution to include more eaters and reducing the distribution mean to keep total population intake constant. The estimate for the total number of eaters was based on long-term purchase diaries. Levels of mercury in canned tuna, swordfish, and shark were based on FDA survey data. The distribution of mercury levels in other species was based on reported mean levels, with the frequency of consumption of each species based on market share. The shape distribution for the given mean was based on the range of variation encountered among shark, tuna, and swordfish. These distributions were integrated with a simulation that estimated average daily intake over a 360-day period, with 10,000 simulated individuals and 1,000 uncertainty iterations. The results of this simulation were then used as an input to a second simulation that modeled levels of mercury in blood and hair. The relationship between dietary intake and blood mercury in a population was modeled from data obtained from a 90-day study with controlled seafood intake. The relationship between blood and hair mercury in a population was modeled from data obtained from several sources. The biomarker simulation employed 2,000 simulated individuals and 1,000 uncertainty iterations. These results were then compared to the recent National Health and Nutrition Examination Survey (NHANES) that tabulated blood and hair mercury levels in a cross-section of the U.S. population. The output of the model and NHANES results were similar for both children and adult women, with predicted mercury biomarker concentrations within a factor of two or less of NHANES biomarker results. However, the model tended to underpredict blood levels for women and overpredict blood and hair levels for children.

Quality adjusted life years (QALYs) and dose-response models in environmental health policy analysis -- methodological considerations

Analyses of competing risks are currently limited by the lack of empirically well-founded and generalizable quantitative methods. Specifically, quantitative methods for comparative risk analysis require the consideration of the population impacted, the duration of impact, the health endpoints at risk, and the impact on individual quality of life. Whereas risk analysis can be used to provide quantitative estimates of disease incidence, environmental health policy analyses do not often account for differences in health impact from alternative disease states. We discuss the methodological issues related to the use of quality adjusted life years (QALY) as a metric for normalizing expected disease incidence to account for health impact. Through a case study of the risks and benefits of fish consumption, we demonstrate the use of QALY weights with dose-response models for environmental health policy decision making. We suggest that, although this approach can be generalized for use in comparative risk and health policy analysis, it is informationally intensive and requires additional assumptions to those used in traditional safety/risk assessment.