Relatively
low
levels
of
prenatal
exposure
to
organophosphate
pesticides
showed
no
relationship
with
social
communication
problems
and
other
traits
related
to
autism
in
children,
data
from
the
prospective
ECHO
study
showed.

The
study
assessed
maternal
values
of
six
dialkyl
phosphate
(DAP)
metabolites
and
3,5,6-trichloro-2-pyridinol
(TCPy),
a
specific
metabolite
resulting
from
chlorpyrifos
breakdown.

Neither
was
linked
with
parent-reported
autism-related
traits
(β
per
doubling
of
TCPy
concentration
=
-0.13,
95%
CI
-0.57
to
0.31;
β
per
doubling
of
DAP
=
-0.42,
95%
CI
-1.03
to
0.19),
reported
Haleigh
Cavalier,
PhD,
MPH,
of
NYU
Langone
Health
in
New
York
City,
and
co-authors.

Results
were
consistent
after
adjusting
for
dietary
confounders,
in
different
models
and
sensitivity
analyses,
and
for
both
boys
and
girls,
the
researchers
wrote
in


JAMA
Pediatrics.

Earlier
research
suggested
that
organophosphate
pesticides
raised
children’s
risk
for
neurodevelopmental
issues
like
IQ
loss
and
attention
deficit-hyperactivity
disorder
(ADHD),
they
noted.

“This
study
adds
another
piece
to
a
large
and
complex
puzzle,
bringing
us
closer
to
understanding
how
environmental
exposures
shape
neurodevelopment,”
Cavalier
told

MedPage
Today.

“While
the
findings
suggest
that
organophosphate
pesticides
were
not
a
major
driver
of
autism-related
traits
at
the
exposure
levels
observed
in
our
study,
that
should
not
be
taken
to
mean
these
chemicals
are
safe,”
she
said.
“Rather,
the
results
inform
future
work
that
should
focus
on
chemical
mixtures
and
other
factors
that
may
influence
risk,
such
as
genetic
susceptibility
or
high-exposure
occupations.”

Organophosphate
pesticides
are
widely
used
in
agriculture,
and
their
metabolites
are
frequently
detected
in
U.S.
population
samples.
Diet,
including
pesticide
residues
in
fruits
and
vegetables,
is
the
way
most
people
are
exposed
to
them.

“Conventional
produce
consumption
is
one
of
the
strongest
predictors
of
organophosphate
pesticide
biomarker
concentrations,
and
organophosphate
metabolites
decrease
substantially
after
adoption
of
an
organic
diet,”
Cavalier
and
co-authors
observed.

Chlorpyrifos
is
an
organophosphate
insecticide
used
on
soybeans,
fruit
and
nut
trees,
broccoli,
cauliflower,
and
other
row
crops.
In
2021,
the
Environmental
Protection
Agency
(EPA)
revoked
all
tolerances
for
the
chemical
but
in
2023,
the
U.S.
Court
of
Appeals
for
the
Eighth
Circuit
overturned
the
EPA’s
ban.
In
2026,
the
EPA
issued
a

technical
correction
to
reflect
the
Eighth
Circuit’s
decision.

The
European
Union
banned
chlorpyrifos
sales
in
2020
after
its
food
safety
authority
said
there
was

no
safe
exposure
level.
In
a
2025
study,
high

prenatal
exposure
to
chlorpyrifos
for
pest
control
in
residential
settings
(a
use
now
banned
in
the
U.S.)
was
associated
with
brain
abnormalities
in
children.

A

meta-analysis
suggested
high
prenatal
organophosphate
pesticide
exposure
may
be
a
risk
factor
for
autism,
Cavalier
and
colleagues
noted.
The

CHARGE
study
of
residential
proximity
to
agricultural
pesticides
and
the

CHAMACOS
study
in
Salinas
Valley
reported
links
between
prenatal
exposure
and
neurodevelopment.
Researchers
in

the
Netherlands
did
not
find
a
relationship
with
autistic
traits
or
ADHD,
however.
An

Ohio-based
study
also
showed
no
link
between
exposure
and
autistic
behavior.

“Differences
between
study
populations
likely
reflect
variations
in
exposure
levels,
timing,
and
sources;
the
presence
of
agricultural
co-exposures;
and
differences
in
population
characteristics
or
underlying
risk
factor
distributions,”
Cavalier
and
co-authors
pointed
out.

“Our
results
therefore
contribute
to
an
emerging
pattern:
positive
associations
tend
to
appear
where
exposures
are
high
and
associated
with
an
agricultural
context,
whereas
null
associations
are
more
common
in
general
population
settings
characterized
by
low
exposure
occurring
primarily
through
diet,”
they
wrote.

The
researchers
leveraged
data
from
the
observational

ECHO
cohort
to
study
3,339
mother-child
pairs
in
the
U.S.
Prenatal
exposure
was
measured
by
concentrations
of
TCPy
and
the
sum
of
six
DAP
metabolites
—
three
dimethyl
phosphates
and
three
diethyl
phosphates
—
in
mothers’
urine.
Almost
all
mothers
(99%)
had
detectable
levels
of
organophosphate
pesticides
in
their
urine.

Autism-related
outcomes
were
assessed
when
children
were
an
average
of
6.4
years
old.
Parents
reported
autism-related
traits
in
children
using
the
Social
Responsiveness
Scale
(SRS),
a
measure
that
captures
social
communication
and
autistic
traits.
“In
large
cohorts,
the
SRS
has
demonstrated
predictive
validity
for
autism
spectrum
disorder
diagnoses
and
functional
and
clinical
outcomes
later
in
childhood,”
Cavalier
and
co-authors
noted.

The
analysis
used
several
models
to
estimate
associations
between
metabolite
markers
and
SRS
scores
overall
and
by
child
sex,
adjusting
for
maternal
sociodemographic
and
behavioral
factors.
Half
of
the
children
in
the
study
were
girls.

Urinary
biomarkers
were
derived
mainly
from
single
urine
samples
and
are
subject
to
within-person
variability,
the
researchers
acknowledged.
The
metabolites
measured
in
the
study
are
short-lived,
they
noted.

“Given
the
known
adverse
impacts
of
pesticides
in
other
contexts,
further
research
should
consider
interactions
with
other
factors,
genetic
susceptibility,
higher
exposures,
or
combined
chemical
mixtures,”
they
wrote.

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