Epidemiology of environmental hazards.

Environmental epidemiology faces major obstacles that are well known in epidemiology in general, though often particularly troublesome in studies of environmental hazards. Major problems include misclassification due to imprecise determination of environmental exposures or poor discrimination of nonspecific effects. New insight into reserve capacities of organ function suggest that better markers of early toxicity could be used in environmental epidemiology along with biological markers of exposure. Also, individual susceptibility, whether genetic or not, needs to be explored as a definite source of variable sensitivity to environmental hazards. Epidemiology is of key importance in identifying environmental hazards and in determining the magnitude of risk. However, environmental epidemiology faces problems that are familiar from the general field of epidemiology, but some of these difficulties are of special concern in studies of environmental hazards. Thus, due to the limited span of the exposure interval, misclassification may occur to a considerable degree. The effects are often nonspecific, and attempts are therefore made to identify early markers of adverse effects. The general population consists of individuals with different degrees of susceptibility to toxicity, and this variation can be a source of confounding bias. Thus, a major objective is to increase the power of environmental epidemiology studies.