The role of biomarkers in environmental assessment

Abstract

Epidemiology can be defined as the study of the prevalence of disease in a community at a special time and which is produced by special causes not generally present in the affected community. Classical epidemiology has been reactive rather than proactive. The earliest examples, such as nervous disorders among makers of hats (‘mad as a hatter’) and cancer in chimney sweeps, were cases where an abnormally high incidence of disease was noted and traced back to a specific cause.