My name is Catherine Metayer, I am a
professor at the School of Public Health at
University of California Berkeley
I'll be talking to you today about the
work that we're doing to investigate
exposure to pesticide in homes
and the risk of childhood leukemia.
So why are we interested pesticides?
Pesticides are everywhere in our
environment; we use them at home,
we could be exposed through any nearby
areas that are using pesticides, and
children could also be exposed at home.
Another route of exposure could be
through diet where
water, food, or breast milk could be
contaminated with
pesticides. We at the California
childhood leukemia study have surveyed
many houses to document that yes,
families are routinely using pesticides
and storing pesticides in their home. So,
that the potential for a child to be
exposed to this compound is very high.
Most of the time pesticides used in homes
are those to kill insects
and the main family of pesticide that
was found is called pyrethoid.
Herbicides to some extent are also used
and found in the house that were
visited. So what are the challenges
to investigate the potential association
between
exposure to pesticides at home and the
risk of leukemia in children?
First off, when we talk about pesticides
we should understand that this includes
a wide
variety of active ingredients that do
have different chemical structures
and properties.
In the United States there are over
800 registered active ingredients
and for most of them, we believe have a potential
impact on cancer and development of
cancer
not only in adults, but also in children.
So what do we know today?
Epidemiologic stuides do support the role of pesticides, and those have been based on
interviews asking about pesticide use,
and there is strong evidence of different 
studies throughout the world that
exposure to home and garden pesticide
use
is associate with an elevated risk of
childhood leukemia.
Most of the studies have investigated
the role of insecticides, and to a lesser
extent herbicides.
We at the California childhood leukemia
study
documented about ten years ago that
exposure to indoor insecticide increases
the risk of childhood leukemia.
through our different critical windows of the
child development, including pregnancy
and early years of life,
we were one among many studies
around the world: France, Germany,
Brazil, to document this
association. This slide is showing you a
summary of
those resources that have been
published
over the past ten, fifteen years and
any association would be represented
by
little square that is above
one on the scale that is on the
cartoon showing
that use of pesticides
lead to an increased risk of childhood
leukemia
and it appears that, most of
the time it's in the range of a two-fold risk.
Same overall conclusion although based
on smaller
numbers of studies do document that
use of herbicide may increase.
the risk of childhood leukemia, but the
range of
1.5 fold risk. So what are the practical
recommendations?
Although we do not know what specific
pesticides are
increasing the risk of childhood
leukemia, it is safe to say that families
should decrease
their exposure to pesticides during
pregnancy and after the childbirth, as
much as possible.
This could have benefits on reducing
the risk of childhood leukemia but on
the condition, that may be associated
with pesticide.
We also believe that the next generation
of studies will be able to
investigate the levels of those
pesticide in the blood or urine,
in order to have a better
understanding of the association between
pesticides and childhood leukemia.
