Paul Candon, Medical Tribune News Service
High levels of pesticide exposure at work decreased fertility in
men by nearly 80 percent, according to a study that examined
in-vitro fertilization success rates.
Among 20 men exposed to pesticides on the job, investigators
identified nine who had moderate exposure -- gardeners, and
livestock, dairy and poultry farmers -- and seven who had high
exposure -- contractors and fruit and flower growers. Information
about the other four was not useful for the study.
The moderately exposed group had about half the fertility rate
of those who were not exposed; the highly exposed group had 22
percent the fertility rate of the unexposed.
``Most people involved in our study had an exposure to
fungicides and herbicides,'' said co-researcher Dick Heederik, of
the department of environmental sciences, environmental and
occupational health group, at Wageningen Agricultural University.
``But some farmers were exposed to as many as 10 to 30 different
agents,'' he said. ``Toxicological [tests] are needed to answer''
the question of which particular agents caused the fertility
problems.
Whether pesticides have the same effect in natural reproduction
is unclear. In another study conducted in the Netherlands, the
researchers were not able to analyze the relationship between
pesticide and in-vivo fertility because of the small number of men
available with pesticide exposure, said Heederik. However, other
research has indicated that pesticide exposure can affect ``'time
to pregnancy', sperm quality, sex ratio and some other reproductive
outcome variables,'' said Heederick.
``Unfortunately, very little attention has been paid to this
issue. I'm glad that this article is addressing the topic,'' said
Dr. Masood Khatamee, clinical professor at New York University
School of Medicine and founder of the Society for the Prevention of
Human Infertility. For years, environmental factors have been known
to affect the male reproductive system, said Khatamee. Over 80
years ago, he said, doctors first began to notice high rates of
testicular cancer and infertility in chimney sweepers. ``Since
then, we have known that pesticides and environmental factors do
have an effect on male fertility.''
Khatamee is working on get funding from Congress to conduct
research to determine which specific pesticides and environmental
factors cause infertility. With this information, he hopes people
can prevent infertility before it occurs.
He pointed out that other factors, such as smoking, stress,
illicit-drug use and heat to the testicles, are believed to affect
fertility too. ``Without a doubt,'' he said, ``environment has an
impact on fertility, male and female.''
However, Dr. Larry Lipshutz, professor of urology at Baylor
College of Medicine in Houston, Texas, said that in his experience,
if workers use the precautions provided by the pesticide companies,
such as the wearing of protective clothing, masks and gloves,
``they're not going to have a [fertility] problem.'' He added that
the study did not report data on sperm quality, so one cannot
conclude whether sperm quality was impaired or whether the men's
sperm count was lower than average.
The report appears in the Aug. 7 edition of The Lancet.
The investigators looked for the effects of other agents on
fertilization as well, but found no significant results. Overall,
questionnaires were given to 836 couples between 1991 and 1998 who
planned to use in-vitro fertilization. Participants were asked to
answer questions about exposure to agents such as organic solvents,
metal dust, metal and welding fumes, and pesticides. Men exposed to
pesticides filled out a second questionnaire, detailing their type
of work and level of exposure.
