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[Effects on immune functions]
2.13 Effects on immune functions (allergy) [Summary]
Literature survey concerning epidemiology of endocrine
disruptors and allergy was performed. Searching the PubMed
database retrieved 5 reports published up to Oct. 31, 2004,
including 3 cohort studies, 1 case-control study and 1
synchronic study. No Japanese subject was studied in these
reports. The three cohort studies concluded that exposure to
PCBs and dioxins at the background level reduces allergy
incidence, whereas the synchronic study on cord blood IgE and
the case-control study involving a severely exposed group found
that exposure promoted allergy. It may seem that severe PCB
exposure of adults promote allergy while exposure to
background-level PCBs or dioxins of fetuses or infants
counteracts allergy, but the few reports do not provide a good
ground for any conclusion. It is recommended to conduct
prospective epidemiologic studies in Japan on this subject.
[Purpose]
Some of organochlorine compounds, including PCBs and dioxins,
have been suggested to affect the immune system, as reflected
possibly in the recent increase in incident of allergic
diseases. Literature was reviewed to know the present status of
epidemiologic studies on association of organochlorine compounds
or other substances with allergy.
[Method]
The PubMed database (http://www.ncbi.nlm.nih.gov/entrez/query.fcgi)
provided by National Library of Medicine was searched with a
strategy "(allergy OR atopy) AND (insecticides OR pesticides OR
chlorinated hydrocarbons OR PCBs OR phenol OR phthalate OR
styrene OR furan OR organotin OR diethylstilbestrol OR ethinyl
estradiol) AND (human)". From among the citations retrieved,
original papers reporting epidemiologic studies on human
populations were selected, and other articles cited in these
papers or reviews were added. A study on yusho in Taiwan showed
serious PCB exposure associated with high incidence of allergic
diseases. A Slovakian study also observed association of PCB
exposure with increased cord blood IgE level, suggesting
relationship of PCB exposure to allergic diseases. Two cohort
studies (3 reports) from Holland, however, state that exposure
to background-level PCBs or dioxins decreases allergy. Further
studies are obviously needed.
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