A detailed review of research findings and methodological concepts that can guide efforts to characterize the susceptibility of the aged population to the harmful effects of environmental chemicals. Noting that few, if any, of the hundreds of thousands of environmental chemicals have been tested for increased toxicity in the elderly, the book uses knowledge from the fields of gerontology and toxicology to propose methodological principles for investigating the elderly as a population at special risk. Particular attention is given to methods for determining chronic effects, including cancer, linked to the long-term exposures that may characterize this age group. Findings from close to 700 epidemiological, clinical, and experimental studies were critically assessed. The book has four main chapters. The first introduces and discusses the many complex factors that complicate efforts to link chemical exposure to adverse effects on the health of the elderly. Problems considered include the lack of a unified theory of aging, the inability to distinguish intrinsic aging from either disease or toxic response, and the difficulty of determining exposures and doses that have accumulated over decades. The chapter also categorizes classes of chemicals according to their relevance to the aged population, discusses demographic trends, and points to several distinctive life-style variables in the elderly that influence their susceptibility to environmental chemicals. The second chapter provides a detailed review of age-related changes at the genetic, molecular and cellular level, and in individual tissues, organs and systems. For each organ or system discussed, emphasis is placed on age-related changes in structure which might alter functional responses to environmental insults, including chemicals. The third chapter, focused on the basis of altered sensitivity, explores age-related changes in chemical sensitivity as reflected in altered pharmacokinetics and changes in the pharmacodynamics of the central nervous system, endocrine system, kidney, immune system, and other systems and tissues. Theories for explaining the interactions of chemicals and diseases in the aging organism are also reviewed, together with the influence of modifying factors, such as nutrition, alcohol intake, and smoking. The fourth chapter describes the special methodological requirements that need to be met when investigating the effects of chemicals on the aged population. Guidelines are provided for experimental, epidemiological, and clinical approaches, and for the development of biomarkers of aging. The book concludes that the adverse effects of chemical exposure on the aged population will become a health care issue of growing importance.

eng rus.

WHODOC

WHO monograph

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