Prevalence and interannual changes in multiple chemical sensitivity in Japanese workers
Environ Health Prev Med
Prevalence and interannual changes in multiple chemical sensitivity in Japanese workers
Xiaoyi Cui 0 1
Xi Lu 0 1
Mizue Hiura 0 1
Masako Oda 0 1
Aya Hisada 0 1
Wataru Miyazaki 0 1
Hisamitsu Omori 0 1
Takahiko Katoh 0 1
0 H. Omori Department of Biomedical Laboratory Sciences, Faculty of Life Sciences, Kumamoto University , Kumamoto , Japan
1 X. Cui (&) X. Lu M. Hiura M. Oda A. Hisada W. Miyazaki H. Omori T. Katoh Department of Public Health, Faculty of Life Sciences, Kumamoto University , 1-1-1 Honjou, Chuo-ku, Kumamoto 860-8556 , Japan
Objective We aimed to evaluate the prevalence rates and interannual fluctuations in multiple chemical sensitivity (MCS) in Japanese workers. Methods We assessed MCS using the Quick Environmental Exposure and Sensitivity Inventory, employing both Miller and Japanese criteria. Workers of two manufacturing companies located in Kyushu, Japan, were assessed, with company A surveyed in 2003, 2006 and 2011, and company B in 2003 and 2011. Results In company A, the Miller criteria-based MCS prevalence rate was higher in 2011 than in 2003, and according to the Japanese criteria, it was higher in 2011 than 2006. In company B, the Miller criteria-based MCS prevalence rate was lower in 2011 than in 2003. Conclusion The results indicated that MCS exists among industrial workers in Japan. We found no statistically significant interannual changes in MCS rates.
Multiple chemical sensitivity; Environmental exposure; QEESI; Sick house syndrome; Allergy; Japanese workers
Multiple chemical sensitivity (MCS) is an acquired chronic
disorder in which exposure to low levels of chemicals
causes mild to wholly disabling symptoms [
are usually vague and nonspecific, involving more than one
organ system. In general, the reported symptoms are
attributed to previous chemical exposure, and recur on
subsequent exposure to chemicals at doses below those
known to cause harmful effects in the general population
]. The etiology of MCS, however, remains unclear. It is
difficult to estimate its prevalence because it is derived
from self-reports, which differ from case rates diagnosed
by medical staff—occupational physicians in particular [
MCS patients’ clinical characteristics are usually evaluated
using questionnaires such as the Environmental Exposure
and Sensitivity Inventory (EESI), or clinical interviews that
rely on the individual’s retrospective self-reports [
Miller and Prihoda [
] developed a globally standardized
self-administered questionnaire, the Quick Environmental
Exposure Sensitivity Inventory (QEESI), designed to assist
researchers and clinicians in screening, studying, and
evaluating patients with MCS.
People with environmental sensitivities may be
susceptible to diverse environmental factors. Some of the
more common agents containing chemical compounds that
trigger reactions in such people include pesticides and
volatile organic compounds (VOCs), such as solvents,
perfumes, formaldehyde, and other petrochemicals. These
agents may be contained in workplace building structures,
furnishings, and cleaning products, among other sources
]. A definition of work-related MCS was introduced by
]. Adverse MCS health effects were observed in
workers in subsequent research [
]; the negative effects of
chemical hazards are a longstanding part of occupational
health in the industrialized world [
]. While such issues
initially tended to arise in industrial workers, similar
problems have emerged in residents and workers in tight
buildings in air- and water-polluted communities, and in
persons exposed to various chemicals [
]. We selected
workers employed in two large companies as participants,
because this group allowed for easier follow-ups than
community residents. The response rate may be higher
from the workers who answered the questionnaires as
instructed by company leaders. In addition to our aim of
evaluating MCS prevalence rates and their interannual
change, we assessed the rates of allergies and Sick house
syndrome (SHS) in Japanese workers.
Materials and methods
The present study was carried out at a paper pulp producing
company (company A) in 2003, 2006, and 2011, and at an
automotive company (company B) in 2003 and 2011, both
in Kyushu, Japan. Subjects were asked to complete QEESI
questionnaires, which also cover the respondents’
diagnostic history of allergies and SHS. After excluding invalid
questionnaires, we obtained 832 valid responses in 2003,
729 in 2006, and 144 in 2011 at company A, and 333
responses in 2003 and 426 in 2011 at company B.
We used the Japanese version of the QEESI questionnaire
prepared by Ishikawa and Miyata to assess MCS [
criterion subscale of the QEESI contains 10 questions rated
on a scale from 0 to 10; the total possible score for each
subscale, therefore, ranges from 0 to 100.
We used the Miller criteria to define MCS in workers
according to the scores yielded by three cut-off subscales:
C40 for chemical sensitivity, C25 for other chemicals, and
C40 for symptom severity classified as MCS [
et al. [
] designed a study to establish the cut-off value for
Japanese criteria using the QEESI as an MCS screening
method. We also employed their Japanese criteria of C40
for chemical sensitivity, C20 for symptom severity, and
C10 for life impact classified as MCS.
We collected and used anonymous information for data
analysis. The distribution differences were examined using
Chi square test. The average differences were examined
using t tests. Statistical analyses were carried out using
SPSS version 18 for Windows (SPSS, Japan).
The ethics review boards of Miyazaki University (no. 82;
April 9, 2003) and Kumamoto University (no. 168; May
11, 2011) approved this study, following their ethical
guidelines for human research. All participants provided
written informed consent to participate, and the complete
protection of their personal data was agreed upon in
At the 2003 baseline, SHS diagnostic history rates for
companies A and B were 0.1 and 0.3 %, respectively, and
the allergy diagnostic history rates for companies A and B
were 23.1 and 24.0 %, respectively (Tables 1, 2). The
Miller-criteria-based MCS prevalence rate was 1.1 % in
company A and 2.4 % in company B in 2003 (Figs. 1, 2).
In company A, SHS diagnostic history rate rose in 2011
(2.1 %) compared to 2003 and 2006 (0.1 %). The allergy
diagnostic history rate decreased in 2006 (20.7 %) but rose
in 2011 (39.6 %) (Table 1). In company B, the SHS and
allergy diagnostic history rates (0.5 and 29.3 %,
respectively) increased in 2011 (Table 2). In company A, the
Miller-criteria-based MCS prevalence rate rose in 2011
(1.4 %) in comparison to 2003 and 2006 (1.1 %) (Fig. 1).
However, in company B, Miller-criteria-based MCS
prevalence rates dropped in 2011 (1.6 %) from 2003 (2.4 %)
As the life impact subscale was not employed in 2003,
company A’s QEESI-derived Japanese criteria-based MCS
prevalence rate could only be determined between 2006
and 2011 (Fig. 3). The Japanese criteria-based MCS
prevalence rate increased in 2011 (4.2 %) from 2006
(3.3 %); these prevalence rates were higher than those
derived from the Miller criteria in 2011 (1.4 %) and 2006
(1.1 %) (Fig. 1). Nevertheless, these differences were not
In addition, the mean age of company A employees rose
in 2006 (44.9 ± 10.61 years old) and decreased in 2011
(41.5 ± 11.04 years old) compared to baseline
(42.8 ± 10.34 years old). The proportion of women in
company A in 2011 (16.7 %) grew from 2003 (11.7 %) to
2006 (10.0 %) (Table 1). The mean age of employees in
company B increased in 2011 (44.8 ± 9.78 years old)
when compared to 2003s baseline (40.5 ± 8.65 years old);
the proportion of females also grew from 2003 (0 %) to
2011 (3.1 %) (Table 2).
This study investigated both Miller and Japanese
criteriabased MCS prevalence rates across several years in
Japanese general industrial workers.
Miller and Prihoda American study indicated that the
MCS rate was 7.1 % in 1999 [
]. A larger-scale
investigation by Kreutzer et al. [
] employed a telephone survey,
and found MCS rates of 6.3 %. In line with the present
findings, studies by Uchiyama in 2000 and by Hojo in 2002
showed Japan’s MCS rate to be lower than that of the USA
]. In both companies, allergy diagnostic history rates
rose in 2011 compared to 2003. Our findings were
consistent with the increasing trend of allergy epidemic in
In the work environment, Watanabe et al. [
several at-risk categories of chemicals, especially volatile
compounds such as organic solvents. Many compounds
used daily in manufacturing processes contained such
chemicals, and exposed not only the workers who produced
them, but also those in areas such as construction,
automotive work, textiles, cleaning, and so on [
]. The impact
of environmental sensitivities on workers may range from
mild to severe, even making work impossible in some cases
]. However, as this study’s subjects were workers from
two large companies, it is important to note the selection
bias known as the healthy worker effect (HWE), the
process wherein unhealthy individuals are excluded from the
workplace, as healthy workers are more likely to continue
to work than those who are sick [
]. Some studies have
suggested that incomplete follow-ups with workers who
leave employment and migrate away from their workplace
could be a source of the HWE [
]. Terr comments that
some MCS patients change their jobs because of their
symptoms , Lax and Henneberger later reported a
similar conclusion [
]. A 2-year follow-up of 50 subjects
with MCS showed that most were unchanged or worse by
their final assessment [
]. Follow-up studies show that
people with MCS frequently suffer symptoms for many
years, but may show gradual improvement over time [
As the present study anonymized participants, it was
impossible to confirm how many workers were
continuously checked across several years. We also have found
that it was impossible to follow-up with subjects who
ceased working due to MCS. However, many patients were
overlap in different years, which may indicate that they did
not leave the workplace and were not recovered from MCS
symptoms. The HWE may influence the MCS prevalence
rate found in this study; however, this bias may not have
had a significant impact on the results.
In occupational settings, exposures are often chronic.
This suggests that controlling chemical exposure in the
early phases of MCS may prevent more serious
developments. Even for healthy people, numerous aggravating
exposures may be below legal limits but not within
adequate safety margins to prevent symptoms [
environmental quality in the workplace can promote
worker’s health and productivity. Such workplace
accommodation may include behavior changes, including the use
of the least toxic cleaning products and pest control
practices, and avoidance of scented products [
comparing estimated onset factors between male and
female patients revealed that workplace chemical exposure
was markedly higher in males [
Acknowledgments This work was supported in part by
Grants-inAid for Research on Health Security Control (H24-Kenki-jpan) from
the Ministry of Health, Labor and Welfare of Japan (http://www.
mhlw.go.jp/). We express our sincere appreciation to the staff
members of the Department of Public Health, Faculty of Life Sciences,
Conflict of interest No conflict of interest.
1. Martini A , Iavicoli S , Corso L. Multiple chemical sensitivity and the workplace: current position and need for an occupational health surveillance protocol . Oxid Med Cell Longev . 2013 ; 351457 .
2. Graveling RA , Pilkington A , George JP , Butler MP , Tannahill SN . A review of multiple chemical sensitivity . Occup Environ Med . 1999 ; 56 : 73 - 85 .
3. Saito M , Kumano H , Yoshiuchi K , Kokubo N , Ohashi K , Yamamoto Y , et al. Symptom profile of multiple chemical sensitivity in actual life . Psychosom Med . 2005 ; 67 : 318 - 25 .
4. Miller CS , Prihoda TJ . The Environmental Exposure and Sensitivity Inventory (EESI): a standardized approach for measuring chemical intolerances for research and clinical applications . Toxicol Ind Health . 1999 ; 15 : 370 - 85 .
5. Sears ME . The medical perspective on environmental sensitivities . Can Hum Rights Commission . 2007 ; 16 - 60 .
6. Cullen MR . The worker with multiple chemical sensitivities: an overview . Occup Med . 1987 ; 2 : 655 - 61 .
7. Gibson PR . MCS: a survival guide . New Harbinger: Oakland; 2000 .
8. Moen BE . Chemical sensitivity and the work place environment: research needs . Psychoneuroendocrinology . 2005 ; 30 : 1039 - 42 .
9. Ashford NA , Miller CS . Chemical exposures: low levels and high stakes . New York: Van Nostrand Reinhold; 1997 .
10. Ishikawa S , Miyata M. Multiple chemical sensitivity-criteria and test methods for diagnosis . Allergol Immunol . 1999 ; 6 : 990 - 8 .
11. Hojo S , Sakabe K , Ishikawa S , Miyata M , Kumano H . Evaluation of subjective symptoms of Japanese patients with multiple chemical sensitivity using QEESI(c) . Environ Health Prev Med . 2009 ; 14 : 267 - 75 .
12. Kreutzer R , Neutra RR , Lashuay N. Prevalence of people reporting sensitivities to chemicals in a population-based survey . Am J Epidemiol . 1999 ; 150 : 1 - 12 .
13. Uchiyama I , Murayama R . Multiple chemical sensitivity as seen from the public health . In: Heisei 11 Welfare grant-in-aid for scientific research report . 2000 . pp. 1 - 5 (in Japanese).
14. Hojyo S. Epidemiological study using QEESI in Japan . In: Heisei 13 Welfare grant-in-aid for scientific research report . 2002 . pp. 134 - 152 (in Japanese).
15. Akasawa A. The development factors and medical system evaluation based on epidemiological study about national age prevalence of allergic diseases and treatment guidelines spread effect . In: Heisei 22 Labor and welfare grant-in-aid for scientific research report . 2011 . pp. 245 - 250 (in Japanese).
16. Watanabe M , Tonori H , Aizawa Y. Multiple chemical sensitivity and idiopathic environmental intolerance (part two) . Environ Health Prev Med . 2003 ; 7 : 273 - 82 .
17. Li CY , Sung FC . A review of the healthy worker effect in occupational epidemiology . Occup Med (Lond) . 1999 ; 49 : 225 - 9 .
18. Monson RR. Observations on the healthy worker effect . J Occup Med . 1986 ; 28 : 425 - 33 .
19. Bell CM , Coleman DA . Models of the healthy worker effect in industrial cohorts . Stat Med . 1987 ; 6 : 901 - 9 .
20. Terr AI. Clinical ecology in the workplace . J Occup Med . 1989 ; 31 : 257 - 61 .
21. Lax MB , Henneberger PK . Patients with multiple chemical sensitivities in an occupational health clinic: presentation and follow-up . Arch Environ Health . 1995 ; 50 : 425 - 31 .
22. Terr AI . Environmental illness: a clinical review of 50 cases . Arch Intern Med . 1986 ; 146 : 145 - 9 .
23. Ziem G , McTamney J . Profile of patients with chemical injury and sensitivity . Environ Health Perspect . 1997 ; 105 : 417 - 36 .
24. Hojo S , Ishikawa S , Kumano H , Miyata M , Sakabe K. Clinical characteristics of physician-diagnosed patients with multiple chemical sensitivity in Japan . Int J Hyg Environ Health . 2008 ; 211 : 682 - 9 .