Obtaining information about susceptibility from the epidemiological literature.
Whether people become ill after encountering environmental pollutants depends on the magnitude of their exposure and their capacity to respond. Exposure and intrinsic response capabilities vary within the population. Those that become ill when the general population remains largely unaffected are considered to be highly susceptible. The U.S. Environmental Protection Agency (USEPA), responsible for protecting the public from environmental pollutants, has developed risk assessment procedures to assist in evaluating the likelihood of health effects. However, the Agency's ability to evaluate the risk faced by highly susceptible populations is often hindered by the paucity of adequate health effects data. Response variability can be assessed with animal models and human epidemiological studies. Although animal models are useful when evaluating the effect of gender and developmental stage on susceptibility, inbred rodent strains underestimate the genetic and lifestyle-induced variability in susceptibility found in human populations. Epidemiological approaches are the preferred source of information on variability. This paper reviews the epidemiological literature from the perspective of a risk assessor seeking data suitable for estimating the risk to highly susceptible populations. Epidemiological approaches do not measure the full range of population response variability. Rather, "susceptibility factors" are evaluated either as risk factors or by focusing on the susceptible population, e.g. children. Susceptibility factors due to genetics, developmental stage, gender, ethnicity, disease state and lifestyle are most frequently encountered. Often, the information describing the health impact of the susceptibility factor is incomplete due to, (1) a failure to consider factors modifying susceptibility; (2) inadequate exposure data; (3) a failure to evaluate the health impact of the susceptibility factor. In addition, for a given exposure agent, several susceptibility factors may be relevant. While incomplete data describing susceptibility factors limits the opportunity for quantitative estimations of risk, available information can supplement qualitative evaluations and risk management.
Grassman
J A
JA
School of Public Health, Columbia University, New York USA. grassman@niehs.nich.gov
D000818:Animals; D004198:Disease Susceptibility / Q000453:epidemiology*; D018876:Environmental Illness / Q000453:epidemiology*; D004785:Environmental Pollutants / Q000009:adverse effects*; D006801:Humans; D018570:Risk Assessment; D014481:United States; D014484:United States Environmental Protection Agency
D004785:Environmental Pollutants