IARC Scientific Publications

Sample variation is often the largest error in determining concentrations of mycotoxins in food commodities. The worldwide safety evaluation of mycotoxins requires sampling plans that give acceptably accurate values for the levels of contamination in specific batches or lots of a commodity. Mycotoxin concentrations show a skewed or uneven distribution in foods and feeds, especially in whole kernels (or nuts), so it is extremely difficult to collect a sample that accurately represents the mean batch concentration...

This chapter provides information about the chemical and physical properties of the mycotoxins considered in this book: aflatoxins; fumonisins; ochratoxin A; trichothecenes, especially deoxynivalenol and nivalenol; zearalenone; and ergot alkaloids. This information about structures reveals the chemical diversity of mycotoxins, which is relevant to the wide range of toxicological effects in animals and humans discussed later in the book.

Mycotoxins are secondary metabolites of microfungi that are known to cause sickness or death in humans or animals. Although many such toxic metabolites are known, it is generally agreed that only a few are significant in causing disease: aflatoxins, fumonisins, ochratoxin A, deoxynivalenol, zearalenone, and ergot alkaloids. These toxins are produced by just a few species from the common genera Aspergillus, Penicillium, Fusarium, and Claviceps. All Aspergillus and Penicillium species either are commensals, growing in crops without obvious signs of pathogenicity, or invade crops after harvest and produce toxins during drying and storage...

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This chapter first discusses the urgent need for prevention of childhood diseases that impose a huge and growing burden on families and society. It provides a review of recent research in this area to illustrate both the strengths and limitations of molecular epidemiology in drawing needed links between environmental exposures and illness in children. For illustration, three of the major diseases in children are discussed: asthma, cancer and developmental disorders. All three impose significant difficulties, have increased in recent decades, and are thought to be caused in substantial part by environmental factors, such as toxic exposures due to lifestyle choices (i...

This chapter focuses on biomarkers of reproductive health and disease that have been developed in the past 15 years. Due to the gender- and age-dependency of most of the advances in measuring reproductive health status and outcomes, these biomarkers have been categorized with respect to the unique member of the reproductive triad of interest (i.e. mother, father, conceptus). Biomarkers of female and male puberty, female reproductive function, fetal and infant development, and male reproductive function are discussed...

The adverse effects of obesity support the use of biomarkers to help elucidate disease mechanism, therapeutic interventions, and preventive strategies. Emerging biomarkers for obesity-associated cardiovascular disease (CVD), type 2 diabetes and cancer play diverse roles in biological pathways including immune modulation and fat metabolism. Animal and in vitro data support the association of these biomarkers with obesity-associated diseases, but evidence in humans is still lacking. In humans, plasma levels of biomarkers are widely used to determine risk, but many studies are limited by ethnicity/race, gender or sample size...

Molecular tools have enhanced our understanding of the epidemiology of infectious diseases by describing the transmission system, including identifying novel transmission modes and reservoirs, identifying characteristics of the infectious agent that lead to transmission and pathogenesis, identifying potential vaccine candidates and targets for therapeutics, and recognizing new infectious agents. Applications of molecular fingerprinting to public health practice have enhanced outbreak investigation by objectively confirming epidemiologic evidence, and distinguishing between time-space clusters and sporadic cases...

Degenerative diseases of the nervous system impose substantial medical and public health burdens on populations throughout the world. Alzheimer's disease (AD), Parkinson's disease (PD), and amyotrophic lateral sclerosis (ALS) are three of the major neurodegenerative diseases. The prevalence and incidence of these diseases rise dramatically with age; thus the number of cases is expected to increase for the foreseeable future as life spans in many countries continue to increase. Causal contributions from genetic and environmental factors are, with some exceptions, poorly understood...

Work-related respiratory diseases affect people in every industrial sector, constituting approximately 60% of all disease and injury mortality and 70% of all occupational disease mortality. There are two basic types: interstitial lung diseases, that is the pneumoconioses (asbestosis, byssinosis, chronic beryllium disease, coal workers' pneumoconiosis (CWP), silicosis, flock workers' lung, and farmers' lung disease), and airways diseases, such as work-related or exacerbated asthma, chronic obstructive pulmonary disease and bronchiolitis obliterans (a disease that was recognized in the production of certain foods only 10 years ago)...

Until recently, the potential relevance of genetic, biochemical and lifestyle factors to coronary heart disease have been studied in relative isolation from one another. Although this approach has yielded some major insights, it has resulted in a fragmented and incomplete understanding of the relative importance and interplay of nature and nurture in the development of coronary risk. New opportunities for more integrated, powerful and comprehensive approaches have been opened by major developments, including: establishment, collation and maturation of relevant population bioresources; emergence of technologies that enable rapid and accurate assessment of many genetic and biochemical factors, without necessitating assumptions about biological mechanisms; and advances in statistical analytical methods...

Molecular epidemiology was introduced in the study of cancer in the early 1980s, with the expectation that it would help overcome some important limitations of epidemiology and facilitate cancer prevention. The first generation of biomarkers has indeed contributed to our understanding of mechanisms, risk and susceptibility as they relate largely to genotoxic carcinogens, resulting in interventions and policy changes to reduce risk from several important environmental carcinogens. New and promising biomarkers are now becoming available for epidemiological studies, including alterations in gene methylation and gene expression, proteomics and metabolomics...

The rapidly growing number of molecular epidemiology studies is providing an enormous, often multidimensional, body of evidence on the association of various disease outcomes and biomarkers. The testing and validation of statistical hypotheses in genetic and molecular epidemiology presents a major challenge requiring methodological rigor and analytical power. The non-replication of many genetic and other biomarker association studies suggests that there may be an abundance of spurious findings in the field...

Biomarkers have been used in clinical medicine for decades. With the rise of genomics and other advances in molecular biology, biomarker studies have entered a whole new era and hold promise for early diagnosis and effective treatment of many diseases. A biomarker is a characteristic that is objectively measured and evaluated as an indicator of normal biological processes, pathogenic processes or pharmacologic responses to a therapeutic intervention (1). They can be classified into five categories based on their application in different disease stages: 1) antecedent biomarkers to identify the risk of developing an illness, 2) screening biomarkers to screen for subclinical disease, 3) diagnostic biomarkers to recognize overt disease, 4) staging biomarkers to categorise disease severity, and 5) prognostic biomarkers to predict future disease course, including recurrence, response to therapy, and monitoring efficacy of therapy (1)...

This chapter describes basic principles in study design, data analysis, and interpretation of epidemiological studies of genetic polymorphisms and disease risk, including the assessment of gene-environment interactions. The case-control design (hospital-based, population-based or nested within a prospective cohort) is frequently used to study common genetic variants and disease risk. Because of their widespread use, the analysis of case-control data will be the focus of this chapter. Two key considerations in the study design will be addressed: the selection of genetic markers to be evaluated, and sample size considerations to ensure adequate power to detect associations with disease risk...

Family-based designs are used for a variety of reasons in genetic epidemiology, including the initial estimation of the strength of genetic effects for a disease, genetic linkage analysis by which genetic causes can be sublocalized to chromosomal regions, as well as to perform association studies that are not confounded by ethnic background. This chapter describes some of the approaches that are followed in the initial characterizing of genetic components of disease and family-based designs for association analysis and linkage with genetic markers...

This chapter will discuss design considerations for epidemiological studies that use biomarkers in the framework of etiologic investigations. The main focus will be on describing the incorporation of biomarkers into the main epidemiologic study designs, including cross-sectional or short-term longitudinal designs to characterize biomarkers, and prospective cohort and case-control studies to evaluate biomarker-disease associations. The advantages and limitations of each design will be presented, and the impact of study design on the feasibility of different approaches to exposure assessment and biospecimen collection and processing will be discussed...

This chapter will present some general background material on the cellular, biochemical, and genetic mechanisms of the immune system, then focus on specific examples that illustrate the promise and pitfalls of using immune biomarkers as tools for molecular epidemiologic research and public health practice. Some of the most exciting frontiers in medical science will be discussed: early detection of cancer through autoimmunity; malignancies that arise from the immune system itself; newborn screening for lethal immune deficiencies and latent autoimmune disorders; and neurodevelopmental disabilities that could result from maternal immune responses, which protect the mother but harm the fetus...

The hormonal milieu has been hypothesized to play a role in a range of human diseases, and therefore has been a topic of much epidemiologic investigation. Hormones of particular interest include: sex steroids; growth hormones; insulin-like growth factors; stress hormones, such as cortisol; and hormones produced by the adipose tissue, termed adipokines. Depending on the hormone, levels may be measured in plasma or serum, urine, saliva, tissue, or by assessing genetic variation in the hormone or hormone metabolizing genes...

Though dietary factors are implicated in chronic disease risk, assessment of dietary intake has limitations, including problems with recall of complex food intake patterns over a long period of time. Diet and nutrient biomarkers may provide objective measures of dietary intake and nutritional status, as well as an integrated measure of intake, absorption and metabolism. Thus, the search for an unbiased biomarker of dietary intake and nutritional status is an important aspect of nutritional epidemiology. This chapter reviews types of biomarkers related to dietary intake and nutritional status, such as exposure biomarkers of diet and nutritional status, intermediate endpoints, and susceptibility...