Prevalence of Protozoan Pathogens Among Diarrheic Children Under 5 Years in Public Hospital of Ethiopia During the Global COVID 19 Pandemic

Acute childhood diarrhea is one of the leading causes of childhood morbidity and mortality in sub-Saharan African countries. Entamoeba histolytica and Giardia lamblia are the common cause of childhood diarrhea in the region. However, there are only few studies on protozoa causing diarrhea in sub-Saharan African countries. This study was conducted to investigate the relative prevalence and explore risk factors of E. histolytica and G. lamblia among diarrheic children of under 5 years in a public hospital of Ethiopia. A retrospective study was conducted among diarrheic children at Hiwot Fana hospital, Ethiopia. Records of all diarrheic children less than 5 years who had sought medical treatment in the hospital from September 1, 2020 to December 31, 2022 were included. Data were collected from 1257 medical records of the children using a structured data-collection format. Data were entered into an Excel sheet and exported into SPSS version 22 for data processing and analysis. Descriptive statistical tests, Chi-square, and logistic region analysis were applied to determine predictors of protozoa infections. Of the 1257 cases, 962 (76.5%) had watery diarrhea and the remaining 239 (19.0%) had dysentery. The combined prevalence of E. histolytica and G. lamblia among diarrheic children was 11.8% (95% CI: 9.6-13.4). As the age of children increased, the frequency of these two protozoan infections was significantly increased compared to children with other causes. There were more diarrhea cases during the summer season including those associated with E. histolytica and G. lamblia. This study revealed that 1 in 10 causes of diarhhea among young children in the study area was likely caused by E. histolytica and G. lamblia. These findings call for community-based safe water and food safety interventions in order to reduce childhood diarrhea caused by protozoan infections in resource-poor settings.

A proposal for further developing fatigue-related post COVID-19 health states for burden of disease studies

Previous efforts to estimate the burden of fatigue-related symptoms due to long COVID have a very high threshold for inclusion of cases, relative to the proposed definition from the World Health Organization. In practice this means that milder cases, that may be occurring very frequently, are not included in estimates of the burden of long COVID which will result in underestimation. A more comprehensive approach to modelling the disease burden from long COVID, in relation to fatigue, can ensure that we do not only focus on what is easiest to measure; which risks losing focus of less severe health states that may be more difficult to measure but are occurring very frequently. Our proposed approach provides a means to better understand the scale of challenge from long COVID, for consideration when preventative and mitigative action is being planned.

Burden of disease attributable to risk factors in European countries: a scoping literature review

OBJECTIVES

Within the framework of the burden of disease (BoD) approach, disease and injury burden estimates attributable to risk factors are a useful guide for policy formulation and priority setting in disease prevention. Considering the important differences in methods, and their impact on burden estimates, we conducted a scoping literature review to: (1) map the BoD assessments including risk factors performed across Europe; and (2) identify the methodological choices in comparative risk assessment (CRA) and risk assessment methods.

METHODS

We searched multiple literature databases, including grey literature websites and targeted public health agencies websites.

RESULTS

A total of 113 studies were included in the synthesis and further divided into independent BoD assessments (54 studies) and studies linked to the Global Burden of Disease (59 papers). Our results showed that the methods used to perform CRA varied substantially across independent European BoD studies. While there were some methodological choices that were more common than others, we did not observe patterns in terms of country, year or risk factor. Each methodological choice can affect the comparability of estimates between and within countries and/or risk factors, since they might significantly influence the quantification of the attributable burden. From our analysis we observed that the use of CRA was less common for some types of risk factors and outcomes. These included environmental and occupational risk factors, which are more likely to use bottom-up approaches for health outcomes where disease envelopes may not be available.

CONCLUSIONS

Our review also highlighted misreporting, the lack of uncertainty analysis and the under-investigation of causal relationships in BoD studies. Development and use of guidelines for performing and reporting BoD studies will help understand differences, avoid misinterpretations thus improving comparability among estimates.

REGISTRATION

The study protocol has been registered on PROSPERO, CRD42020177477 (available at: https://www.crd.york.ac.uk/PROSPERO/ ).

Harmonized approach to estimate the burden of disease of dietary exposure to four chemical contaminants - A French study

Exposure to chemical contaminants found in foods has been associated with various adverse health effects. Burden of disease studies are increasingly used to estimate the public health impact of such exposures. The aims of this study were to estimate the burden of disease due to dietary exposure to four chemicals in France in 2019 (lead (Pb), cadmium (Cd), methylmercury (MeHg), and inorganic arsenic (i-As)), and to develop harmonized methods that can be applied for other chemicals and countries. We used national food consumption data from the third French national food consumption survey, chemical food monitoring data from the Second French Total Diet Study (TDS), dose-response data and disability weights from scientific literature, and disease incidence and demographics from national statistics. We adopted a risk assessment approach to estimate disease burden, incidence, mortality, and Disability-Adjusted Life Years (DALYs) attributable to dietary exposure to the chemicals. In all models, we harmonized food classification and exposure assessment. We propagated uncertainty through the calculations using Monte Carlo simulation. We estimated that, among these chemicals, i-As and Pb were responsible for the highest disease burden. i-As was estimated to cause 820 DALYs, or approximately 1.25 DALYs per 100,000 inhabitants. The estimated burden of Pb was 1834 to 5936 DALYs, or 2.7 (lower bound) to 8.96 (upper bound) DALYs/100,000. The burden of MeHg (192 DALYs), and Cd (0 DALY) was substantially lower. The foods contributing most to disease burden was drinks (30 %), "other foods" (mostly composite dishes) (19 %), and fish and seafood (7 %). Interpretation of estimates needs to consider all underlying uncertainties, linked with data and knowledge gaps. The harmonized models are the first to make use of data from TDS, which are available in several other countries. Thus, they can be applied to estimate the burden and to rank food-associated chemicals at national level.

Estimating the Under-ascertainment of COVID-19 cases in Toronto, Ontario, March to May 2020

Background

Public health surveillance data do not always capture all cases, due in part to test availability and health care seeking behaviour. Our study aimed to estimate under-ascertainment multipliers for each step in the reporting chain for COVID-19 in Toronto, Canada.

Design and methods

We applied stochastic modeling to estimate these proportions for the period from March 2020 (the beginning of the pandemic) through to May 23, 2020, and for three distinct windows with different laboratory testing criteria within this period.

Results

For each laboratory-confirmed symptomatic case reported to Toronto Public Health during the entire period, the estimated number of COVID-19 infections in the community was 18 (5th and 95th percentile: 12, 29). The factor most associated with under-reporting was the proportion of those who sought care that received a test.

Conclusions

Public health officials should use improved estimates to better understand the burden of COVID-19 and other similar infections.

The increasing significance of disease severity in a burden of disease framework

Recent estimates have reiterated that non-fatal causes of disease, such as low back pain, headaches and depressive disorders, are amongst the leading causes of disability-adjusted life years (DALYs). For these causes, the contribution of years lived with disability (YLD) - put simply, ill-health - is what drives DALYs, not mortality. Being able to monitor trends in YLD closely is particularly relevant for countries that sit high on the socio-demographic spectrum of development, as it contributes more than half of all DALYs. There is a paucity of data on how the population-level occurrence of disease is distributed according to severity, and as such, the majority of global and national efforts in monitoring YLD lack the ability to differentiate changes in severity across time and location. This raises uncertainties in interpreting these findings without triangulation with other relevant data sources. Our commentary aims to bring this issue to the forefront for users of burden of disease estimates, as its impact is often easily overlooked as part of the fundamental process of generating DALY estimates. Moreover, the wider health harms of the COVID-19 pandemic have underlined the likelihood of latent and delayed demand in accessing vital health and care services that will ultimately lead to exacerbated disease severity and health outcomes. This places increased importance on attempts to be able to differentiate by both the occurrence and severity of disease.

Reporting guidelines for burden of disease studies: why and how?

Background

The Disability Adjusted Life Year (DALY) is a frequently used metric to assess burden of disease (BoD). Many independent BoD studies have been performed across Europe, showing wide variations and inconsistencies in the application and reporting of DALY specific methods. The European Burden of Disease Network (burden-eu) aims to develop guidelines for reporting DALY calculation studies which may enhance transparency and comparability of BoD estimates across Europe and beyond.

Methods

A burden-eu working group of experts generated a list of potential reporting items based on existing literature, guidance for developing guidelines and consultations with BoD experts. To pilot the drafted product, we asked BoD experts and non-experts to apply it to existing BoD studies. We received feedback and we revised the guidelines accordingly.

Results

The guide for DALY calculation studies comprises about 25 items that should be reported in BoD studies. We included information about the study setting, data input sources including methods for data corrections, DALY-specific methods (e.g., YLL life table, YLD approach, disability weights etc), data analyses, and data limitations. We also included information on how users can compare their new estimates with previously available BoD estimates.

Conclusions

We introduced a reporting instrument for DALY calculations that can be used to document input data and methodological design choices in BoD studies. The application of such guidelines will enhance usability of BoD estimates for decision-makers as well as global, regional, and national health experts.

Key messages

Risk–Benefit assessment of foods: Development of a methodological framework for the harmonized selection of nutritional, microbiological, and toxicological components

Investigating the impact of diet on public health using risk–benefit assessment (RBA) methods that simultaneously consider both beneficial and adverse health outcomes could be useful for shaping dietary policies and guidelines. In the field of food safety and nutrition, RBA is a relatively new approach facing methodological challenges and being subject to further developments. One of the methodological aspects calling for improvement is the selection of components to be considered in the assessment, currently based mainly on non-harmonized unstandardized experts’ judgment. Our aim was to develop a harmonized, transparent, and documented methodological framework for selecting nutritional, microbiological, and toxicological RBA components. The approach was developed under the Novel foods as red meat replacers—an insight using Risk-Benefit Assessment methods (NovRBA) case study, which attempted to estimate the overall health impact of replacing red meat with an edible insect species, Acheta domesticus. Starting from the compositional profiles of both food items, we created a “long list” of food components. By subsequently applying a series of predefined criteria, we proceeded from the “long” to the “short list.” These criteria were established based on the occurrence and severity of health outcomes related to these components. For nutrition and microbiology, the occurrence of health outcomes was evaluated considering the presence of a component in the raw material, as well as the effect of processing on the respective component. Regarding toxicology, the presence and exposure relative to reference doses and the contribution to total exposure were considered. Severity was graded with the potential contribution to the background diet alongside bioavailability aspects (nutrition), the disability-adjusted life years per case of illness of each hazard (microbiology), and disease incidence in the population, potential fatality, and lifelong disability (toxicology). To develop the “final list” of components, the “short list” was refined by considering the availability and quality of data for a feasible inclusion in the RBA model. The methodology developed can be broadly used in food RBA, to guide and reinforce a harmonized selection of nutritional, microbiological, and toxicological components and will contribute to facilitating RBA implementation, enabling the generation of transparent, robust, and comparable outcomes.

Methodological considerations in injury burden of disease studies across Europe: a systematic literature review

Background

Calculating the disease burden due to injury is complex, as it requires many methodological choices. Until now, an overview of the methodological design choices that have been made in burden of disease (BoD) studies in injury populations is not available. The aim of this systematic literature review was to identify existing injury BoD studies undertaken across Europe and to comprehensively review the methodological design choices and assumption parameters that have been made to calculate years of life lost (YLL) and years lived with disability (YLD) in these studies.

Methods

We searched EMBASE, MEDLINE, Cochrane Central, Google Scholar, and Web of Science, and the grey literature supplemented by handsearching, for BoD studies. We included injury BoD studies that quantified the BoD expressed in YLL, YLD, and disability-adjusted life years (DALY) in countries within the European Region between early-1990 and mid-2021.

Results

We retrieved 2,914 results of which 48 performed an injury-specific BoD assessment. Single-country independent and Global Burden of Disease (GBD)-linked injury BoD studies were performed in 11 European countries. Approximately 79% of injury BoD studies reported the BoD by external cause-of-injury. Most independent studies used the incidence-based approach to calculate YLDs. About half of the injury disease burden studies applied disability weights (DWs) developed by the GBD study. Almost all independent injury studies have determined YLL using national life tables.

Conclusions

Considerable methodological variation across independent injury BoD assessments was observed; differences were mainly apparent in the design choices and assumption parameters towards injury YLD calculations, implementation of DWs, and the choice of life table for YLL calculations. Development and use of guidelines for performing and reporting of injury BoD studies is crucial to enhance transparency and comparability of injury BoD estimates across Europe and beyond.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12889-022-13925-z.

Disability adjusted life years associated with COVID-19 in Denmark in the first year of the pandemic

Background

Burden of disease studies measure the public health impact of a disease in a society. The aim of this study was to quantify the direct burden of COVID-19 in the first 12 months of the epidemic in Denmark.

Methods

We collected national surveillance data on positive individuals for SARS-CoV-2 with RT-PCR, hospitalization data, and COVID-19 mortality reported in the period between 26^th of February, 2020 to 25^th of February, 2021. We calculated disability adjusted life years (DALYs) based on the European Burden of Disease Network consensus COVID-19 model, which considers mild, severe, critical health states, and premature death. We conducted sensitivity analyses for two different death-registration scenarios, within 30 and 60 days after first positive test, respectively.

Results

We estimated that of the 211,823 individuals who tested positive to SARS-CoV-2 by RT-PCR in the one-year period, 124,163 (59%; 95% uncertainty interval (UI) 112,782–133,857) had at least mild symptoms of disease. The total estimated disease burden was 30,180 DALYs (95% UI 30,126; 30,242), corresponding to 520 DALYs/100,000. The disease burden was higher in the age groups above 70 years of age, particularly in men. Years of life lost (YLL) contributed with more than 99% of total DALYs. The results of the scenario analysis showed that defining COVID-19-related fatalities as deaths registered up to 30 days after the first positive test led to a lower YLL estimate than when using a 60-days window.

Conclusion

COVID-19 led to a substantial public health impact in Denmark in the first full year of the epidemic. Our estimates suggest that it was the the sixth most frequent cause of YLL in Denmark in 2020. This impact will be higher when including the post-acute consequences of COVID-19 and indirect health outcomes.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12889-022-13694-9.

Practicalities of implementing burden of disease research in Africa: lessons from a population survey component of our multi-partner FOCAL research project

Background

Collaborative research is being increasingly implemented in Africa to study health-related issues, for example, the lack of evidence on disease burden, in particular for the presumptive high load of foodborne diseases. The FOCAL (Foodborne disease epidemiology, surveillance, and control in African LMIC) Project is a multi-partner study that includes a population survey to estimate the foodborne disease burden in four African low- and middle-income countries (LMICs). Our multi-partner study team had members from seven countries, all of whom contributed to the project from the grant application stage, and who play(ed) specific roles in designing and implementing the population survey.

Main text

In this paper, we applied Larkan et al.’s framework for successful research partnerships in global health to self-evaluate our project’s collaboration, management, and implementation process. Our partnership formation considered the interplay and balance between operations and relations. Using Larkan et al.’s seven core concepts (i.e., focus, values, equity, benefit, communication, leadership, and resolution), we reviewed the process stated above in an African context.

Conclusion

Through our current partnership and research implementing a population survey to study disease burden in four African LMICs, we observed that successful partnerships need to consider these core concepts explicitly, apply the essential leadership attributes, perform assessment of external contexts before designing the research, and expect differences in work culture. While some of these experiences are common to research projects in general, the other best practices and challenges we discussed can help inform future foodborne disease burden work in Africa.

Burden of non-communicable disease studies in Europe: a systematic review of data sources and methodological choices

BACKGROUND

Assessment of disability-adjusted life years (DALYs) resulting from non-communicable diseases (NCDs) requires specific calculation methods and input data. The aims of this study were to (i) identify existing NCD burden of disease (BoD) activities in Europe; (ii) collate information on data sources for mortality and morbidity; and (iii) provide an overview of NCD-specific methods for calculating NCD DALYs.

METHODS

NCD BoD studies were systematically searched in international electronic literature databases and in grey literature. We included all BoD studies that used the DALY metric to quantify the health impact of one or more NCDs in countries belonging to the European Region.

RESULTS

A total of 163 BoD studies were retained: 96 (59%) were single-country or sub-national studies and 67 (41%) considered more than one country. Of the single-country studies, 29 (30%) consisted of secondary analyses using existing Global Burden of Disease (GBD) results. Mortality data were mainly derived (49%) from vital statistics. Morbidity data were frequently (40%) drawn from routine administrative and survey datasets, including disease registries and hospital discharge databases. The majority (60%) of national BoD studies reported mortality corrections. Multimorbidity adjustments were performed in 18% of national BoD studies.

CONCLUSION

The number of national NCD BoD assessments across Europe increased over time, driven by an increase in BoD studies that consisted of secondary data analysis of GBD study findings. Ambiguity in reporting the use of NCD-specific BoD methods underlines the need for reporting guidelines of BoD studies to enhance the transparency of NCD BoD estimates across Europe.

Characteristics of Settings and Etiologic Agents of Foodborne Disease Outbreaks - China, 2020

Introduction

Foodborne diseases are a growing public health problem and have caused a large burden of disease in China. This study analyzed epidemiological characteristics of foodborne diseases in China in 2020 to provide a scientific basis for prevention and control measures.

Methods

Data were collected from 30 of 31 provincial-level administrative divisions (PLADs) in the mainland of China, excluding Xizang (Tibet) Autonomous Region, via the National Foodborne Disease Outbreaks Surveillance System. The number and proportion of outbreaks, illnesses, hospitalizations, deaths by setting, pathogen-food category pairs and etiology were calculated.

Results

In 2020, 7,073 foodborne disease outbreaks were reported, resulting in 37,454 illnesses and 143 deaths. Among the identified pathogens, microbial pathogens were the most common confirmed etiology, accounting for 41.7% of illnesses. Poisonous mushrooms caused the largest proportion of outbreaks (58.0%) and deaths (57.6%). For venues where foodborne disease outbreaks occur, household had the highest number of outbreaks (4,140) and deaths (128), and catering service locations caused the largest proportion of illnesses (59.9%). Outbreaks occurring between June and September accounted for 62.8% of total outbreaks.

Conclusions

Foodborne disease outbreaks mainly occurred in households. Microbial pathogens remained the top cause of outbreak-associated illnesses. Poisonous mushrooms were ranked the top cause of deaths in private homes in China. The supervision and management of food safety and health education should be strengthened to reduce the burden of foodborne diseases. Publicity should be increased to reduce the incidence of mushroom poisonings in families, and supervision and management of food should be strengthened to reduce microbial contamination.

Risk-Benefit Assessment of Cereal-Based Foods Consumed by Portuguese Children Aged 6 to 36 Months-A Case Study under the RiskBenefit4EU Project

Cereal-based foods, including breakfast (BC) and infant cereals (IC), are among the first solid foods introduced to infants. BC and IC are sources of macro and micronutrients that have beneficial effects on health, but can also be sources of harmful chemical and microbiological contaminants and nutrients that may lead to adverse health effects at high consumption levels. This study was performed under the RiskBenefit4EU project with the aim of assessing the health impact associated with consumption of BC and IC by Portuguese children under 35 months. Adverse effects associated with the presence of aflatoxins, Bacillus cereus, sodium and free sugars were assessed against the benefits of fiber intake. We applied a risk–benefit assessment approach, and quantified the health impact of changes in consumption of BC and IC from current to various alternative consumption scenarios. Health impact was assessed in terms of disability-adjusted life years. Results showed that moving from the current consumption scenario to considered alternative scenarios results in a gain of healthy life years. Portuguese children can benefit from exchanging intake of IC to BC, if the BC consumed has an adequate nutritional profile in terms of fiber, sodium and free sugars, with levels of aflatoxins reduced as much as possible.

Risk-Benefit Assessment of Consumption of Rice for Adult Men in China

Objective: To evaluate the health impact of current and alternative patterns of rice consumption in Chinese adult men (40-79 years of age). Methods: We applied a risk-benefit assessment (RBA) model that took into account the health effects of selenium (Se), cadmium (Cd), and inorganic arsenic (i-As). The health effects included the prevention of prostate cancer associated with exposure to Se, and an increased risk of lung, bladder, and skin cancer for i-As and chronic kidney disease (CKD) for Cd. We defined the baseline scenario (BS) as the current individual mean daily consumption of rice in the population of interest and two alternative scenarios (AS): AS1 = 50 g/day and AS2 = 200 g/day. We estimated the health impact for different age groups in terms of change in Disability-Adjusted Life Years (ΔDALY). Results: The BS of rice consumption was 71.5-105.4 g/day in different age groups of adult men in China. We estimated that for AS1, the mean ΔDALY was -2.76 to 46.2/100,000 adult men of 40-79 years old. For AS2, the mean ΔDALY was 41.3 to 130.8/100,000 individuals in this population group. Conclusion: Our results showed that, based on associated exposure to selenium, cadmium, and i-As in rice, the current consumption of rice does not pose a risk to adult men in China. Also, a lower (50 g/day) or higher (200 g/day) rice consumption will not bring larger beneficial effects.

Prevalence of Antimicrobial Resistant of Vibrio parahaemolyticus Isolated from Diarrheal Patients - Six PLADs, China, 2016-2020

What is already known on this topic?

Vibrio parahaemolyticus (V. parahaemolyticus) is frequently resistant to common antimicrobials such as ampicillin and generally highly susceptible to most clinically used antimicrobials.

What is added by this report?

V. parahaemolyticus were highly resistant to cefazolin and ampicillin: 94.4% and 37.0%, respectively. However, it was below 3% resistance to all 10 other antimicrobials including clinically relevant agents and even imipenem. The overall levels of antimicrobial resistance and multidrug resistance were 95.1% and 3.3%, respectively. The distribution of antimicrobial resistance and the multidrug resistance had regional, temporal, sexual, and isolated source strain variation.

What are the implications for public health practice?

This study provides data on drug resistance of V. parahaemolyticus in Chinese clinical settings, which will help develop a public health strategy.

Mushroom Poisoning Outbreaks - China, 2010-2020

Introduction: Mushroom poisoning was the leading cause of foodborne disease outbreaks and outbreak-associated deaths in China. Mushroom poisoning outbreak surveillance can provide insight into the epidemiological characteristics of mushroom poisonings and guide policymaking and health education to reduce illnesses and deaths.

Methods: Foodborne Disease Outbreak Surveillance System was upgraded in 2011 to collect foodborne disease outbreaks in China. Mushroom poisoning outbreaks during 2010-2020 were selected to analyze geographical distribution, seasonal distribution, and setting of food preparation.

Results: A total of 10,036 outbreaks, which resulted in 38,676 illnesses and 788 deaths, were reported in this period. Mushroom poisonings occurred all over the country, but with highest incidence in the southwest and central China. Overall, 84.6% outbreaks were associated with food prepared in households, followed by 8.7% in street stalls, and 2.5% in canteens. Mushroom poisoning outbreaks clearly exhibited seasonality, and the peak season was summer through autumn. Outbreaks occurring between May and October accounted for 94.1% of total outbreaks, 92.4% illnesses, and 97.2% deaths.

Conclusions: Mushroom poisoning is a food safety issue of higher concern in China. Targeted health education is essential to reduce mushroom poisoning, especially in southwest China. Citizens are advised to not collect or eat wild mushrooms.

Burden of foodborne diseases: think global, act local

National burden of foodborne disease (FBD) studies are essential to establish food safety as a public health priority, rank diseases, and inform interventions. In recent years, various countries have taken steps to implement them. Despite progress, the current burden of disease landscape remains scattered, and researchers struggle to translate findings to input for policy. We describe the current knowledge base on burden of FBDs, highlight examples of well-established studies, and how results have been used for decision-making. We discuss challenges in estimating burden of FBD in low-resource settings, and the experience and opportunities deriving from a large-scale research project in these settings. Lastly, we highlight the role of international organizations and initiatives in supporting countries to develop capacity and conduct studies.

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.

The burden of disease of three food-associated heavy metals in clusters in the Danish population - Towards targeted public health strategies

Lifestyle and sociodemographics are likely to influence dietary patterns, and, as a result, human exposure to chemical contaminants in foods and their associated health impact. We aimed to characterize subgroups of the Danish population based on diet and sociodemographic indicators, and identify those bearing a higher disease burden due to exposure to methylmercury (MeHg), cadmium (Cd) and inorganic arsenic (i-As). We collected dietary, lifestyle, and sociodemographic data on the occurrence of chemical contaminants in foods from Danish surveys. We grouped participants according to similarities in diet, lifestyle, and sociodemographics using Self-Organizing Maps (SOM), and estimated disease burden in disability-adjusted life years (DALY). SOM clustering resulted in 12 population groups with distinct characteristics. Exposure to contaminants varied between clusters and was largely driven by intake of fish, seafood and cereal products. Five clusters had an estimated annual burden >20 DALY/100,000. The cluster with the highest burden had a high proportion of women of childbearing age, with most of the burden attributed to MeHg. Individuals belonging to the top three clusters had higher education and physical activity, were mainly non-smokers and lived in urban areas. Our findings may facilitate the development of preventive strategies targeted to the most affected subgroups.

Food Safety Implications of Transitions Toward Sustainable Healthy Diets

Despite increased political attention, foodborne diseases still cause a substantial public health, economic, and social burden worldwide. Children younger than 5 years, people living in developing regions, and in the poorest areas of the world are disproportionally affected, bearing a large proportion of the global burden of foodborne disease. Yet, food safety is a prerequisite to ensuring food security globally: Foods that are responsible for important food safety problems are also crucial to ensure food security in some regions and are essential sources of nutrition. Moreover, together with calls for action to meeting international sustainable development goals, global efforts to promote food security and healthy diets have now highlighted the need to modify food systems globally. This article therefore explores the food safety dimensions of transitions toward food systems that promote sustainable healthy diets. The current body of evidence points to the combined health and environmental benefits of shifting toward a more plant-based diet, including vegetables and fruits, nuts, pulses, and whole grains. As a shift toward more plant-based diets may also lead to higher exposures to chemicals or pathogens present in these foods, an evaluation of food safety implications of such transitions is now imperative. We conclude that several synergies between public health, environmental, and food safety strategies can be identified to support dietary transitions.

Unscattering the burden of disease landscape: supporting interaction between existing burden of disease efforts

The burden of disease landscape in Europe is currently scattered with experts from diverse professional backgrounds, ranging from experts in infectious diseases, non-communicable diseases, injuries and risk factors, to experts in more comprehensive national, regional and global burden of disease studies. Currently there is little interaction between these experts and existing burden of disease efforts. The European burden of disease network (burden-eu) COST Action aims to bring together expertise across different domains and professional backgrounds. During the course of the burden-eu COST Action, several steps will be taken to facilitate interaction between existing burden of disease efforts. First, a survey has been sent around to all members of the EU burden of disease network to map burden of disease studies that have been carried out in their country. Apart from general details about the year of the study and cause of disease categories, items of the survey included data sources, methodological approach and collaborations with institutes of other countries. In the first month, the survey has been completed for over 70 studies that have been carried out in twelve countries. Second, comparison of existing burden of disease initiatives allows for the identification of the various domains for which burden of disease has been assessed, highlight methodological differences as well as similarities, and

facilitate improvements and harmonization of methods and approaches. Furthermore, the data collected from the survey will be included in a continuously updated burden of disease database that lists all past and current burden of disease activities. Lastly, burden-eu will facilitate regular meetings and workshops. Each of these steps will make it possible to move beyond the currently scattered burden of disease landscape and increase interaction between professionals and burden of disease efforts.

Risk-Benefit Assessment of Foods

Food is an elementary requirement for human life, providing nutrients and essential energy needed for optimal health. But at the same time, food can also be a vehicle of hazardous substances or pathogens that could affect human health negatively. Risk‐benefit assessment (RBA) of foods, a relatively new methodology for decision support, integrates nutrition, toxicology, microbiology, chemistry and human epidemiology for a comprehensive health impact assessment. By integrating health risks and benefits related to food consumption, RBA facilitates science‐based decision‐making in food‐related areas and the development of policies and consumer advice. The present work programme aimed to allow the fellow to become acquainted with the process of RBA and the associated tools needed to assess quantitatively the risks and the benefits through three main activities (i) to learn the different methodologies used for RBA; (ii) to apply these methodologies to a specific case‐study – RBA of raw milk consumption; and (iii) to participate in the main activities of the Risk‐Benefit research group at DTU Food regarding risk‐benefit issues. For the RBA of raw milk consumption, microbiological pathogens (Listeria monocytogenes, Salmonella spp., Campylobacter jejuni and Shiga toxin‐producing Escherichia coli), probiotic bacteria and nutritional components (vitamins B2 and A) were considered, as well as the potential impact of raw milk consumption in the reduction of the allergies’ prevalence. Two major approaches were applied: the bottom‐up (estimating the disease incidence due to the exposure) and the top‐down (using epidemiological and incidence data to the estimate the number of cases attributable to a certain exposure). Through all the training and hands‐on activities performed, the present work programme enabled the fellow to extend the knowledge on the quantitative RBA, specifically in the context of raw milk consumption. EU‐FORA programme also provided an exceptional opportunity of networking and establishment of future research lines of collaboration.

Population vulnerability to COVID-19 in Europe: a burden of disease analysis

BACKGROUND

Evidence has emerged showing that elderly people and those with pre-existing chronic health conditions may be at higher risk of developing severe health consequences from COVID-19. In Europe, this is of particular relevance with ageing populations living with non-communicable diseases, multi-morbidity and frailty. Published estimates of Years Lived with Disability (YLD) from the Global Burden of Disease (GBD) study help to characterise the extent of these effects. Our aim was to identify the countries across Europe that have populations at highest risk from COVID-19 by using estimates of population age structure and YLD for health conditions linked to severe illness from COVID-19.

METHODS

Population and YLD estimates from GBD 2017 were extracted for 45 countries in Europe. YLD was restricted to a list of specific health conditions associated with being at risk of developing severe consequences from COVID-19 based on guidance from the United Kingdom Government. This guidance also identified individuals aged 70 years and above as being at higher risk of developing severe health consequences. Study outcomes were defined as: (i) proportion of population aged 70 years and above; and (ii) rate of YLD for COVID-19 vulnerable health conditions across all ages. Bivariate groupings were established for each outcome and combined to establish overall population-level vulnerability.

RESULTS

Countries with the highest proportions of elderly residents were Italy, Greece, Germany, Portugal and Finland. When assessments of population-level YLD rates for COVID-19 vulnerable health conditions were made, the highest rates were observed for Bulgaria, Czechia, Croatia, Hungary and Bosnia and Herzegovina. A bivariate analysis indicated that the countries at high-risk across both measures of vulnerability were: Bulgaria; Portugal; Latvia; Lithuania; Greece; Germany; Estonia; and Sweden.

CONCLUSION

Routine estimates of population structures and non-fatal burden of disease measures can be usefully combined to create composite indicators of vulnerability for rapid assessments, in this case to severe health consequences from COVID-19. Countries with available results for sub-national regions within their country, or national burden of disease studies that also use sub-national levels for burden quantifications, should consider using non-fatal burden of disease estimates to estimate geographical vulnerability to COVID-19.

Health impact of substituting red meat by fish: addressing variability in risk-benefit assessments

Background

Sufficient intake of fish and limited red meat intake is commonly encouraged by national dietary guidelines to prevent various lifestyle diseases. One way to fulfill these guidelines would be to substitute red meat by fish. However, quantitative evidence of the public health gain of such substitution is lacking. Moreover, contaminants in these foods may compromise nutritional benefits. We aimed to estimate the health impact of substituting red meat by fish in the Danish diet in a risk-benefit assessment (RBA). Our study can support policy makers in defining evidence-based public health strategies.

Methods

We quantified the health impact of substituting red meat by fish among Danish adults in terms of Disability-Adjusted Life Years (DALY) using data from a national dietary survey and food monitoring. We investigated the use of probabilistic methods to model variability in individual substitution behaviors and to assess health impact distributions in RBA of food.

Results

Health impact of the substitution varied largely by the type of fish consumed and by age and sex of the consumer. We estimated that 134 (95% uncertainty interval: 102; 169) DALYs/100,000 could be averted per year if a mix of lean and fatty fish is consumed in the Danish recommended amounts and intake of red meat decreased among Danish adults. The highest benefit was estimated for women in the childbearing age and for men above 50 years of age. However, a small fraction of women were assigned an overall health loss due to methylmercury exposure during pregnancy and the associated adverse effects in unborn children.

Conclusions

Our study estimated an overall health gain of substituting red meat by fish in the general Danish adult population, while providing insight in the variability in health impact at the level of individual consumers. Our approach can be applied in other RBAs and the results support the need for targeted public health strategies to ensure consumer health and safety.

Key messages

The health impact of substituting red meat by fish in Danish adults was quantified in terms of disability-adjusted life years (DALYs), while accounting for variability between individuals. We estimated that young women and men above 50 years of age will experience the largest health gain while a small fraction of the women were assigned a health loss due to chemical exposure.

Burden of disease of heavy metals in population clusters: towards targeted public health strategies

Background

Humans are exposed to heavy metals from certain foods, thus specific dietary patterns may lead to high burden of disease (BoD). By identifying diet, lifestyle and socio-demographic characteristics of population groups with highest BoD, targeted preventive strategies can be developed. We aimed at identifying clusters and characteristics of Danish individuals with highest BoD due to food exposure to three heavy metals: methylmercury (MeHg), cadmium and inorganic arsenic.

Methods

We collected diet, lifestyle and socio-demographic information of 3,946 individuals in the Danish National Survey of Diet and Physical Activity. Occurrence of heavy metals in food was obtained from Danish food monitoring. We applied machine learning self-organizing maps to group individuals according to similarities in diet, lifestyle and socio-demographics, and estimated BoD due to metal exposure in terms of Disease-Adjusted Life Years (DALY). We will present calculation steps of our approach in a tutorial-like way and demonstrate its applicability to other cases.

Results

We identified 13 population subgroups with distinct dietary and lifestyle characteristics. The estimated BoD varied largely between subgroups, with five subgroups experiencing a BoD > 10 DALY/100,000. The cluster bearing the highest BoD (26.2 (95% uncertainty interval (UI): 10.3, 50.6) DALY/100,000) was significantly different from the cluster with the lowest BoD (5.1 (95% UI: 2.5, 9.2) DALY/100,000) (preliminary). BoD was higher in subgroups with diet and lifestyle considered healthy. Most of the BoD was due to MeHg, particularly in female-dominant subgroups.

Conclusions

Linking machine learning, exposure assessment and burden of disease metrics, this novel approach identified population subgroups with higher BoD due to exposure to three heavy metals. It can be expanded to estimate BoD of other chemicals, and used to develop targeted preventive strategies to reduce BoD in more affected subgroups.

Estimating the burden of disease of exposure to chemical contaminants in food in Denmark

Background

Recent global estimates have shown that dietary exposure to chemical contaminants cause over 56,000 deaths and 9 million healthy life years lost each year. However, the contribution of causative agents varies greatly between world regions and countries due to local food consumption and contamination. To prioritize public health interventions to reduce disease burden, national-level risk ranking evidence is needed. The overall aims of this project are to estimate the burden of disease (BoD) of selected chemical hazards in foods consumed in Denmark, and to identify the relative contribution of foods.

Methods

We identified chemicals on the basis of their presumed public health impact. The final list of chemicals was defined in agreement with the Danish Veterinary and Food Administration, and included: methylmercury, inorganic arsenic, cadmium, acrylamide, dioxin/dioxin-like PCBs and lead. We estimated BoD in terms of disability adjusted life years (DALY) in a model combining exposure assessment with dose response models to derive probabilities of health effects, taking an incidence-based approach. Data were collected from the Danish National Survey of Diet and Physical Activity, food monitoring, literature, and national statistics.

Results

We estimated that methylmercury, inorganic arsenic, cadmium and acrylamide lead to a BoD of 514 DALY (95% uncertainty interval: 185, 990) in 2016 (preliminary results). Estimates for lead and dioxin/dioxin-like PCBs are pending. Methylmercury exposure from fish was the greatest contributor to overall burden (478 DALY), and acrylamide from potato products the second (30 DALY). The health outcomes leading to highest burden were intellectual disability and cancer.

Conclusions

Our estimates will assist public health managers identifying the chemical contaminants in foods with the highest impact on public health in Denmark. Future research should focus on estimating the effect of mitigation strategies on the disease burden.

Key messages

We provide national quantitative evidence of the health impact of chemical exposures from foods. Information on the relative contribution of foods and population groups affected may focus mitigation.

Seroprevalence of Toxoplasma gondii in domestic pigs, sheep, cattle, wild boars, and moose in the Nordic-Baltic region: A systematic review and meta-analysis

Background

Toxoplasma gondii is an important foodborne zoonotic parasite. Meat of infected animals is presumed to constitute a major source of human infection and may be a driver of geographical variation in the prevalence of anti-T. gondii antibodies in humans, which is substantial in the Nordic-Baltic region in northern Europe. However, data on seroprevalence of T. gondii in different animal species used for human consumption are scattered.

Methods

We conducted a systematic review of seroprevalence studies and meta-analysis to estimate the seroprevalence of T. gondii in five animal species that are raised or hunted for human consumption in the Nordic-Baltic region: domestic pigs (Sus scrofa domesticus), sheep (Ovis aries), cattle (Bos taurus), wild boars (Sus scrofa), and moose (Alces alces). We searched for studies that were conducted between January 1990 and June 2018, and reported in articles, theses, conference abstracts and proceedings, and manuscripts. Subgroup analyses were performed to identify variables influencing the seroprevalence.

Findings

From a total of 271 studies identified in the systematic review, 32 were included in the meta-analysis. These comprised of 13 studies on domestic pigs, six on sheep, three on cattle, six on wild boars, and four on moose. The estimated pooled seroprevalence of T. gondii was 6% in domestic pigs (CI_95%: 3–10%), 23% in sheep (CI_95%: 12–36%), 7% in cattle (CI_95%: 1–21%), 33% in wild boars (CI_95%: 26–41%), and 16% in moose (CI_95%: 10–23%). High heterogeneity was observed in the seroprevalence data within each species. In all host species except wild boars, the pooled seroprevalence estimates were significantly higher in animals >1 year of age than in younger animals. Not all studies provided information on animal age, sensitivity and specificity of the serological method employed, and the cut-off values used for defining an animal seropositive.

Conclusions

A substantial proportion of animals raised or hunted for human consumption in the region had tested positive for T. gondii. This indicates widespread exposure to T. gondii among animals raised or hunted for human consumption in the region. Large variations were observed in the seroprevalence estimates between the studies in the region; however, studies were too few to identify spatial patterns at country-level.

A probabilistic approach for risk-benefit assessment of food substitutions: A case study on substituting meat by fish

Accounting for substitution of foods is inevitable when evaluating health impact of dietary changes. But substitution behavior and the associated health impact may vary between individuals. We therefore propose the use of probabilistic methods to model substitution and assess health impact distributions in risk-benefit assessment (RBA) of foods. We investigated the health impact of substituting red and processed meat with fish in the Danish adult population and the variability in health impact. We applied probabilistic approaches in modeling the substitution to reflect variability between individual substitution behaviors. Furthermore, when multiple intake scenarios are compared, we propose a method for adjusting intake differences for individual day-to-day variability. We estimated that 134 (95% UI: 102; 169) Disability-Adjusted Life Years/100,000 were averted per year by the substitution. The health impact varied considerably by age and sex, with the largest health benefit of the substitution observed for young women in the child-bearing age and for the older generation, mainly men. This study provides further insight in how the health impact of substituting meat by fish varies between individuals and suggests a framework to be applied in RBAs of other food substitutions. Our results are relevant for policy makers in defining targeted public health strategies.

Probabilistic approach for assessing cancer risk due to benzo[a]pyrene in barbecued meat: Informing advice for population groups

BACKGROUND

Consumption of meat prepared by barbecuing is associated with risk of cancer due to formation of carcinogenic compounds including benzo[a]pyrene (BaP). Assessment of a population's risk of disease and people's individual probability of disease given specific consumer attributes may direct food safety strategies to where impact on public health is largest. The aim of this study was to propose a model that estimates the risk of cancer caused by exposure to BaP from barbecued meat in Denmark, and to estimate the probability of developing cancer in subgroups of the population given different barbecuing frequencies.

METHODS

We developed probabilistic models applying two dimensional Monte Carlo simulation to take into account the variation in exposure given age and sex and in the individuals' sensitivity to develop cancer after exposure to BaP, and the uncertainty in the dose response model. We used the Danish dietary consumption survey, monitoring data of chemical concentrations, data on consumer behavior of frequency of barbecuing, and animal dose response data.

FINDINGS

We estimated an average extra lifetime risk of cancer due to BaP from barbecued meat of 6.8 × 10-5 (95% uncertainty interval 2.6 × 10-7 - 7.0 × 10-4) in the Danish population. This corresponds to approximately one to 4,074 extra cancer cases over a lifetime, reflecting wide uncertainty. The impact per barbecuing event on the risk of cancer for men and women of low body weight was higher compared to higher bodyweight. However, the difference due to sex and bodyweight between subgroups are dwarfed by the uncertainty.

INTERPRETATION

This study proposes a model that can be applied to other substances and routes of exposure, and allows for deriving the change in risk following a specific change in behaviour. The presented methodology can serve as a valuable tool for risk management, allowing for the formulation of behaviour advice targeted to specific sub-groups in the population.

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.

Use of Mathematical Optimization Models to Derive Healthy and Safe Fish Intake

Background

Recommended fish intake differs substantially from observed fish intake. In Denmark, ∼15% of the population consumes the state-recommended fish intake. How much fish individuals eat varies greatly, and this variation cannot be captured by considering the fish intake of the average population.

Objective

We developed a method intended to provide realistic and achievable personalized dietary recommendations based on an individual's body weight and current fish intake. The objective of the study was to propose specific fish intake levels for individuals that meet the recommendations for eicosapentaenoic acid, docosahexaenoic acid, and vitamin D without violating the permitted intake recommendations for methyl mercury, dioxins, and polychlorinated biphenyls.

Methods

Two mathematical optimization models were developed that apply quadratic programming to model personalized recommended fish intake, fulfilling criteria on nutrients and contaminants, while simultaneously deviating as little as possible from observed individual intake. A recommended intake for 8 fish species was generated for each individual in a group of 3016 Danes (1552 women and 1464 men, aged 18-75 y), whose fish intakes and body weights were known from a national dietary survey.

Results

Individual, personal dietary recommendations were successfully modeled. Modeled fish intake levels were compared to observed fish intakes. For women, the average proposed increase in fish intake was 14 g/wk for lean fish and 63 g/wk for fatty fish; and for men these numbers were 12 and 55 g/wk, respectively.

Conclusions

Using fish intake as an example, we show how quadratic programming models may be used to advise individual consumers how to optimize their diet, taking both benefits and risks into account. This approach has the potential to increase compliance with dietary guidelines by targeting the individual consumers and minimizing the need for large and ultimately unrealistic behavior changes.

The disease burden of congenital toxoplasmosis in Denmark, 2014

BACKGROUND

Congenital toxoplasmosis (CT) causes a substantial disease burden worldwide. The aim of this study was to estimate the disease burden of CT in Denmark, a developed country with free public healthcare and nationwide data available.

METHODS

Using data primarily from two public health surveillance programmes conducted between 1992 and 2007, we estimated the incidence, occurrence of sequelae, mortality and the burden of disease in terms of disability-adjusted life years (DALYs) of CT in Denmark in 2014.

FINDINGS

We estimated that 14 children were born with CT in 2014, of which six will have developed sequelae by the age of 12. CT resulted in a total disease burden of 123 DALYs (95% uncertainty interval [UI], 100-148), of which 78 (95% UI, 64-94) were due to foetal loss and 2 (95% UI, 1-3) were due to neonatal death; the remaining burden was due to moderate to severe life-long sequelae. A comparison of the estimated incidence of CT with the number of reported CT cases in 2008-2014 indicated that for each reported CT case, at least five other CT cases could be expected to have occurred and gone unreported.

INTERPRETATION

Early onset, severity, and life-long duration of sequelae have a major effect on the disease burden of CT. Our data suggest that CT is under-diagnosed or under-reported in Denmark. The estimated disease burden and public health impact in Denmark is lower than in other European countries, highlighting the need for country-specific studies.

Application of Molecular Typing Results in Source Attribution Models: The Case of Multiple Locus Variable Number Tandem Repeat Analysis (MLVA) of Salmonella Isolates Obtained from Integrated Surveillance in Denmark

Salmonella is an important cause of bacterial foodborne infections in Denmark. To identify the main animal-food sources of human salmonellosis, risk managers have relied on a routine application of a microbial subtyping-based source attribution model since 1995. In 2013, multiple locus variable number tandem repeat analysis (MLVA) substituted phage typing as the subtyping method for surveillance of S. Enteritidis and S. Typhimurium isolated from animals, food, and humans in Denmark. The purpose of this study was to develop a modeling approach applying a combination of serovars, MLVA types, and antibiotic resistance profiles for the Salmonella source attribution, and assess the utility of the results for the food safety decisionmakers. Full and simplified MLVA schemes from surveillance data were tested, and model fit and consistency of results were assessed using statistical measures. We conclude that loci schemes STTR5/STTR10/STTR3 for S. Typhimurium and SE9/SE5/SE2/SE1/SE3 for S. Enteritidis can be used in microbial subtyping-based source attribution models. Based on the results, we discuss that an adjustment of the discriminatory level of the subtyping method applied often will be required to fit the purpose of the study and the available data. The issues discussed are also considered highly relevant when applying, e.g., extended multi-locus sequence typing or next-generation sequencing techniques.

Methodological Framework for World Health Organization Estimates of the Global Burden of Foodborne Disease

BACKGROUND

The Foodborne Disease Burden Epidemiology Reference Group (FERG) was established in 2007 by the World Health Organization to estimate the global burden of foodborne diseases (FBDs). This paper describes the methodological framework developed by FERG's Computational Task Force to transform epidemiological information into FBD burden estimates.

METHODS AND FINDINGS

The global and regional burden of 31 FBDs was quantified, along with limited estimates for 5 other FBDs, using Disability-Adjusted Life Years in a hazard- and incidence-based approach. To accomplish this task, the following workflow was defined: outline of disease models and collection of epidemiological data; design and completion of a database template; development of an imputation model; identification of disability weights; probabilistic burden assessment; and estimating the proportion of the disease burden by each hazard that is attributable to exposure by food (i.e., source attribution). All computations were performed in R and the different functions were compiled in the R package 'FERG'. Traceability and transparency were ensured by sharing results and methods in an interactive way with all FERG members throughout the process.

CONCLUSIONS

We developed a comprehensive framework for estimating the global burden of FBDs, in which methodological simplicity and transparency were key elements. All the tools developed have been made available and can be translated into a user-friendly national toolkit for studying and monitoring food safety at the local level.

World Health Organization Estimates of the Global and Regional Disease Burden of 22 Foodborne Bacterial, Protozoal, and Viral Diseases, 2010: A Data Synthesis

BACKGROUND

Foodborne diseases are important worldwide, resulting in considerable morbidity and mortality. To our knowledge, we present the first global and regional estimates of the disease burden of the most important foodborne bacterial, protozoal, and viral diseases.

METHODS AND FINDINGS

We synthesized data on the number of foodborne illnesses, sequelae, deaths, and Disability Adjusted Life Years (DALYs), for all diseases with sufficient data to support global and regional estimates, by age and region. The data sources included varied by pathogen and included systematic reviews, cohort studies, surveillance studies and other burden of disease assessments. We sought relevant data circa 2010, and included sources from 1990-2012. The number of studies per pathogen ranged from as few as 5 studies for bacterial intoxications through to 494 studies for diarrheal pathogens. To estimate mortality for Mycobacterium bovis infections and morbidity and mortality for invasive non-typhoidal Salmonella enterica infections, we excluded cases attributed to HIV infection. We excluded stillbirths in our estimates. We estimate that the 22 diseases included in our study resulted in two billion (95% uncertainty interval [UI] 1.5-2.9 billion) cases, over one million (95% UI 0.89-1.4 million) deaths, and 78.7 million (95% UI 65.0-97.7 million) DALYs in 2010. To estimate the burden due to contaminated food, we then applied proportions of infections that were estimated to be foodborne from a global expert elicitation. Waterborne transmission of disease was not included. We estimate that 29% (95% UI 23-36%) of cases caused by diseases in our study, or 582 million (95% UI 401-922 million), were transmitted by contaminated food, resulting in 25.2 million (95% UI 17.5-37.0 million) DALYs. Norovirus was the leading cause of foodborne illness causing 125 million (95% UI 70-251 million) cases, while Campylobacter spp. caused 96 million (95% UI 52-177 million) foodborne illnesses. Of all foodborne diseases, diarrheal and invasive infections due to non-typhoidal S. enterica infections resulted in the highest burden, causing 4.07 million (95% UI 2.49-6.27 million) DALYs. Regionally, DALYs per 100,000 population were highest in the African region followed by the South East Asian region. Considerable burden of foodborne disease is borne by children less than five years of age. Major limitations of our study include data gaps, particularly in middle- and high-mortality countries, and uncertainty around the proportion of diseases that were foodborne.

CONCLUSIONS

Foodborne diseases result in a large disease burden, particularly in children. Although it is known that diarrheal diseases are a major burden in children, we have demonstrated for the first time the importance of contaminated food as a cause. There is a need to focus food safety interventions on preventing foodborne diseases, particularly in low- and middle-income settings.

Source attribution of human salmonellosis: an overview of methods and estimates

Reducing the burden of foodborne salmonellosis is challenging. It requires identification of the most important food sources causing disease and prioritization of effective intervention strategies. For this purpose, a variety of methods to estimate the relative contribution of different sources of Salmonella infections have been applied worldwide. Each has strengths and limitations, and the usefulness of each depends on the public health questions being addressed. In this study, we reviewed the source attribution methods and outcomes of several studies developed in different countries and settings, comparing approaches and regional differences in attribution estimates. Reviewed results suggest that illnesses and outbreaks are most commonly attributed to exposure to contaminated food, and that eggs, broiler chickens, and pigs are among the top sources. Although most source attribution studies do not attribute salmonellosis to produce, outbreak data in several countries suggest that exposure to raw vegetables is also an important source. International travel was also a consistently important exposure in several studies. Still, the relative contribution of specific sources to human salmonellosis varied substantially between studies. Although differences in data inputs, methods, and the point in the food system where attribution was estimated contribute to variability between studies, observed differences also suggest regional differences in the epidemiology of salmonellosis.

Assessing the applicability of currently available methods for attributing foodborne disease to sources, including food and food commodities

A variety of approaches to attribute foodborne diseases to specific sources are available, including hazard occurrence analysis, epidemiological methods, intervention studies, and expert elicitations. The usefulness of each method to attribute disease caused by a foodborne hazard depends on the public health question being addressed, on the data requirements, on advantages and limitations of the method, and on the data availability of the country or region in question. Previous articles have described available methods for source attribution, but have focused only on foodborne microbiological hazards. These articles have described strengths and weaknesses of each method, but no guidance on how to choose the most appropriate tool to address different public health questions has thus far been provided. We reviewed available source attribution methods; assessed their applicability to attribute illness caused by enteric, parasitic, and chemical foodborne hazards to the responsible sources; and renamed some of the approaches. The main objective was to make recommendations on the most appropriate method(s) to attribute human disease caused by different foodborne hazards. We concluded that the proportion of disease that can be attributed to specific foods items or transmission routes may be estimated for the majority of the evaluated hazards by applying one or more of the source attribution methods assessed. It was also recognized that the use of source attribution methods may be limited to specific countries, reflecting the data availability.

Attributing human foodborne illness to food sources and water in Latin America and the Caribbean using data from outbreak investigations

Foodborne pathogens are responsible for an increasing burden of disease worldwide. Knowledge on the contribution of different food sources and water for disease is essential to prioritize food safety interventions and implement appropriate control measures. Source attribution using outbreak data utilizes readily available data from outbreak surveillance to estimate the contribution of different sources to human disease. We developed a probabilistic model based on outbreak data that attributes human foodborne disease by various bacterial pathogens to sources in Latin America and the Caribbean (LA&C). Foods implicated in outbreaks were classified by their ingredients as simple foods (i.e. belonging to one single food category), or complex foods (i.e. belonging to multiple food categories). For each agent, the data from simple-food outbreaks were summarized, and the proportion of outbreaks caused by each category was used to define the probability that an outbreak was caused by a source. For the calculation of the number of outbreaks attributed to each source, simple-food outbreaks were attributed to the single food category in question, and complex-food outbreaks were partitioned to each category proportionally to the estimated probability. We analysed all bacterial pathogens together, focused on important bacterial pathogens separately, and, when data were sufficient, performed analyses by country, decade and location. Between 1993 and 2010, 6313 bacterial outbreaks were reported by 20 countries. In general, the most important sources of bacterial disease were meat, dairy products, water and vegetables in the 1990s, and eggs, vegetables, and grains and beans in the 2000s. We observed fluctuations of the most important sources of disease for each pathogen between decades and countries, which may be a consequence of changes in the control of zoonotic disease over the years, of changes in food consumption habits, or of changes in public health focus and availability of data of different pathogens. This study identified data gaps in the region and highlighted the importance of effective surveillance systems to identify sources of disease. Still, the application of this method for source attribution in the LA&C region was successful, and we concluded that this approach can be used to attribute disease to food sources and water in other regions, including developing regions with limited data on the public health impact of foodborne diseases.