Prevalence of People Reporting Sensitivities to Chemicals in a Population based Survey
Am J Epidemiol
Number 0 1
Prevalence of People Reporting Sensitivities to Chemicals in a Population- based Survey 0 1
Richard Kreutzer 0 1
Raymond R. Neutra 0 1
Nan Lashuay 0 1
0 Received for publication November 11 , 1997, and accepted for publication August 26, 1998. Abbreviations: MCS, multiple chemical sensitivity; BRFS , Behavioral Risk Factor Survey; CASRO, Council of American Survey Research Organizations. From the Environmental Health Investigations Branch, Department of Health Services , Emeryville, CA. Reprint requests to Dr. Richard Kreutzer , Department of Health Services, Environmental Health Investigations Branch , 1515 Clay Street, Suite 1700, Berkeley, CA 94612
1 School of Hygiene and Public Health
Sponsored by the Society for Epidemiologic Research To describe the prevalence and correlates of reports about sensitivities to chemicals, questions about chemical sensitivities were added to the 1995 California Behavior Risk Factor Survey (BRFS). The survey was administered by telephone to 4,046 subjects. Of all respondents, 253 (6.3%) reported doctor-diagnosed "environmental illness" or "multiple chemical sensitivity" (MCS) and 643 (15.9%) reported being "allergic or unusually sensitive to everyday chemicals." Sensitivity to more than one type of chemical was described by 11.9% of the total sample population. Logistic regression models were constructed. Hispanic ethnicity was associated with physician-diagnosed MCS (adjusted odds ratio (OR) = 1.82, 95% confidence interval (Cl) 1.21-2.73). Female gender was associated with individual self-reports of sensitivity (adjusted OR = 1.63, 95% Cl 1.23-2.17). Marital status, employment, education, geographic location, and income were not predictive of reported chemical sensitivities or reported doctor diagnosis. Surprising numbers of people believed they were sensitive to chemicals and made sick by common chemical exposures. The homogeneity of responses across race-ethnicity, geography, education, and marital status is compatible with a physiologic response or with widespread societal apprehensions in regard to chemical exposure. Am J Epidemiol 1999;150:1-12. asthma; multiple chemical sensitivity; tobacco smoke pollution
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ORIGINAL CONTRIBUTIONS
There is great controversy over the notion of a
disorder in which the victim develops wide-ranging
symptoms to many unrelated chemicals at
conventionally subtoxic exposure levels, but through toxicologic
mechanisms (1-13). The notion implies that many
common chemical exposures are pathologic (i.e., that
structure or function are altered) for a subset of people
and, in order for the pathology to occur, processes of
sensitization and/or amplification occur. Proponents of
this concept call the phenomenon multiple chemical
sensitivity (MCS), environmental illness, 20th century
disease, environmental hypersensitivity, or other
names. Other investigators have advised labeling the
condition "idiopathic environmental intolerance" (14).
For ease of reference, we will refer to the phenomenon
as MCS in this paper.
This controversy has large political, social, and
psychological costs. MCS's existence could theoretically
alter, on a fundamental level, society's relation to
chemicals (15). Despite the fact that there is little
substantive research supporting a toxicologic explanation
for this condition, and that medical researchers
disagree vigorously about its nature and etiology, MCS is
rapidly becoming an established diagnosis on the basis
of public belief and political fiat. Workers
compensation claims for this diagnosis have been successful.
The Department of Housing and Urban Development
has provided housing assistance to persons with
reported chemical sensitivities. MCS sufferers have
sought their inclusion under the Americans with
Disabilities Act (16, 17).
Most of the literature describing people who report
symptoms attributed to low level chemical exposure
comes from occupational or environmental clinics or
personal accounts. There is little peer-reviewed
literature that has demonstrated sufficiently strong objective
correlates of reported symptoms, nor is there literature
demonstrating a new mechanism for symptom
causation from chemical exposure despite some creative
speculation about exposure routes in the body,
sensitive tissues, and amplification processes (18-30). As a
result, causal hypotheses for MCS range widely
between psychological and physiological mechanisms.
As state health department officials, we are frequently
asked about chemical sensitivities following chemical
spills, during hazardous waste site remediation, during
"sick building" investigations, and concerning pesticide
exposures at the agricultural/residential interface. To
help us develop ways to study MCS, we convened an
advisory committee of national experts representing the
full spectrum of opinion on this controversy. Within this
diverse group, consensus was reached about the lack of
information on the population prevalence of people w (...truncated)