<p class="first" id="d551789e263">This cohort study uses data from the National Health
and Nutrition Examination Survey
conducted from 1999 to 2002 to investigate whether exposure to pyrethroid insecticides
is associated with the risk of all-cause, cardiovascular, and cancer mortality in
the general US adult population.
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<h5 class="title" id="d551789e269">Question</h5>
<p id="d551789e271">Is pyrethroid exposure associated with long-term mortality in
the general US adult
population?
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<h5 class="title" id="d551789e274">Findings</h5>
<p id="d551789e276">In this cohort study of a nationally representative sample of
2116 adults in the United
States, higher exposure to pyrethroid insecticides, indicated by higher levels of
general pyrethroid metabolite 3-phenoxybenzoic acid in urine samples, was associated
with a higher risk of death from all causes or cardiovascular disease over 14 years
of observation.
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<h5 class="title" id="d551789e279">Meaning</h5>
<p id="d551789e281">Environmental exposure to pyrethroid insecticides appears to be
associated with an
increased risk of long-term all-cause mortality and cardiovascular mortality in the
US general adult population.
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<h5 class="title" id="d551789e285">Importance</h5>
<p id="d551789e287">Widespread exposure to pyrethroid insecticides has been reported
among the general
population in the United States and worldwide. However, little is known about the
association of pyrethroid exposure with long-term health outcomes in adults.
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<h5 class="title" id="d551789e290">Objective</h5>
<p id="d551789e292">To examine the association of pyrethroid exposure with all-cause
and cause-specific
mortality among adults in the United States.
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<h5 class="title" id="d551789e295">Design, Setting, and Participants</h5>
<p id="d551789e297">The nationally representative cohort included 2116 adults aged
20 years and older
who participated in the US National Health and Nutrition Examination Survey conducted
from 1999 to 2002 and provided urine samples for pyrethroid metabolite measurements.
Participants were linked to mortality data from the survey date through December 31,
2015. Data were analyzed from May to August 2019.
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<h5 class="title" id="d551789e300">Exposures</h5>
<p id="d551789e302">Urinary levels of 3-phenoxybenzoic acid, a general pyrethroid
metabolite and commonly
used biomarker for pyrethroid exposure, were determined by using high-performance
liquid chromatography coupled with electrospray chemical ionization and tandem mass
spectrometry.
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<h5 class="title" id="d551789e305">Main Outcomes and Measures</h5>
<p id="d551789e307">Mortality from all causes, cardiovascular disease, and cancer.</p>
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<h5 class="title" id="d551789e310">Results</h5>
<p id="d551789e312">This cohort study of 2116 adults comprised 1145 women (weighted
proportion, 51.6%)
and 971 men (weighted, 48.4%), with a weighted mean (SE) age of 42.6 (0.5) years;
958 participants (weighted, 68.4%) were of non-Hispanic white ancestry, 646 (weighted,
14.7%) of Hispanic ancestry, 419 (weighted, 11.3%) of non-Hispanic black ancestry,
and 93 (weighted, 5.6%) of other ancestry. During a median of 14.4 years (range, 0.1-16.8
years) of observation, 246 deaths occurred, including 41 associated with cardiovascular
disease and 52 associated with cancer. Participants with higher urinary 3-phenoxybenzoic
acid levels were at a higher risk of death during the follow-up period, with death
occurring in 8.5% (unweighted, 75 of 709), 10.2% (unweighted, 81 of 701), and 11.9%
(unweighted, 90 of 706) of participants across increasing tertiles of urinary 3-phenoxybenzoic
acid levels. After adjustment for age, sex, race/ethnicity, socioeconomic status,
dietary and lifestyle factors, body mass index, and urinary creatinine levels, the
hazard ratios for all-cause mortality, cardiovascular disease mortality, and cancer
mortality among participants with the highest tertile compared with those with the
lowest tertile of urinary 3-phenoxybenzoic acid levels were 1.56 (95% CI, 1.08-2.26),
3.00 (95% CI, 1.02-8.80), and 0.91 (95% CI, 0.31-2.72), respectively.
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<h5 class="title" id="d551789e315">Conclusions and Relevance</h5>
<p id="d551789e317">In this nationally representative sample of US adults, environmental
exposure to pyrethroid
insecticides was associated with an increased risk of all-cause and cardiovascular
disease mortality. Further studies are needed to replicate the findings and determine
the underlying mechanisms.
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