| |
4. Other substances
As for substances other than organochlorine compounds,
Schreinemacher et al. (1999) report a higher SSR (1.12, 95% CI =
1.00-1.26) for rural areas, where herbicides such as
ethylenebisdithiocarbamates are used, than urban and forest
areas in the U.S., without, however, describing specific
substances and exposure environment.
Janssens et al. (2001) studied the correlation of the crop
acreage and pesticide use in 1998 with the death rate in 1985-94
for 589 communities in Belgium. The death rate was significantly
correlated with defoliating agent use (P = 0.01) and plant
growth regulator use (P = 0.02). Correlation was not found with
other pesticides.
No report dealt with alkylphenols or bisphenol A.
[Discussion]
Reports on organochlorine compounds have appeared since Jan. 1,
2001. Atrazine was not found to raise the risk for farm workers
in a cohort study. Another cohort study on pesticide plant
employees observed an increase in risk, but this was thought
insignificant considering the results of the subsequent PSA
test. Nested case-control studies and case-control studies on
PCB did not find significant risk increase. Significant risk
increase by heptachlor, lindane and DDE was observed in few
studies only, which does not permit decision on correlation with
exposure. Studies are needed for specific organochlorine
compounds.
Of the five prospective cohort studies (of which two on the same
cohort) on the relationship of prostatic cancer with farm work
or exposure to pesticides published before Dec. 31, 2000, three
observed significant risk increase, and one obtained a lower
limit of the 95% confidence interval of nearly 1.00. The
remaining one does not provide statistical analysis. Risk
increase was always observed for pesticide spraying workers,
although the SIRs obtained are not high (1.1-2.5). Similar
results were reported in the case-control study published after
Jan. 1, 2001 in two reports, but specific pesticide names and
exposure levels are unclear. Meta-analysis by Keller-Byrne et
al. (1997) of 24 studies on the pesticide-prostatic cancer
relationship gave a relative risk of 1.12 (95% CI = 1.01-1.24),
or 1.29 (1.10-1.51) when 13 retrospective studies were taken
into account, or again 0.93 (0.77-1.11) when 11 studies
reporting SMR were considered. Meta-analysis by van Maele-Fabry
et al. provided similar results. Considering that the exposure
level of farm workers may be lower than that of pesticide
spraying operators, professions accompanied by exposure to
pesticide are likely to be associated with small but significant
increase in risk. However, effects of other factors cannot be
excluded and evaluation for specific pesticides is not possible.
Substances other than organochlorine compounds have not been
studied in this context, although such substances include
compounds with androgen-like activities such as bisphenol A.
They also must be studied in relation to prostatic cancer.
No study was found on prostatic cancer as related to DES
exposure in uterus. Male subjects were followed up about
testicular cancer incidence in relation to DES exposure; similar
studies on prostatic cancer may remain unfruitful simply because
the ages of onset are rather old.
Epidemiologic studies on endocrine disruptors in relation to
prostatic cancer are thus increasing in number, but the results
are still indeterminate and do not permit evaluation of
causality. No Japanese subject has been studied. It is
recommended to study the relationship of prostatic cancer in
relation to chemical exposure in Japan.
|
