Documentation
that Pesticides commonly cause ADHD and Developmental Conditions in Infants and
Children, Review – B. Windham (Ed.), 2010
Many
studies have documented the neurological and developmental effects of pesticide
exposure on infants and children(1abcde, etc.). Among the effects are ADHD/ developmental deficits(1abcde)and birth defects/spontaneous abortions(1efh).
Pyrethroid pesticides are becoming more commonly used
as documentation of major effects by the organophosphate pesticides has
accumulated. But pyrethroid pesticides have similar
mechanisms of activity and effects as organophosphates, and studies suggest
that low dose prenatal exposure to pyrethroids has
the potential to produce long lasting developmental and behavioral effects
through effects on the expression of xenobiotic
metabolizing cytochrome P450s in brain and liver of
the offspring as well as DNA damage and other neurological effects(1g).
Likewise
exposure to organochlorine compounds such as PCBs and
DDEs and industrial chemicals(2abcde), as well as
toxic metals such as mercury, lead, arsenic, and cadmium(3abc) have been found
to cause ADHD and other neurological effects and developmental disabilities.
Infants and children are more affected by toxic exposures than adults, but over
200 toxic chemicals have been documented to cause neurological effects on adults(3a). A
National Academy of Sciences study found that over 50% of births during a
recent period resulted in birth defects or developmental conditions, such as
ADHD, learning disabilities, mood disorders, chronic lung conditions, eczema,
chronic allergies, etc. (3c). Most of
these are documented to have been caused by neonatal exposures to toxics, as
per the documentation in this review.
The
urine of 1,139 children between the ages of 8 and 15 were tested for six
pesticide metabolites, with 119 of the children diagnosed with ADHD(1a). Children with a ten-fold increase in metabolites
from the pesticide malathion (found in head lice treatments) were 55 percent more likely to be
diagnosed with ADHD. Children with higher urinary dialkyl
phosphate concentrations, especially dimethyl
alkylphosphate (DMAP) concentrations, were more
likely to be diagnosed as having ADHD. A 10-fold increase in DMAP
concentration was associated with an odds ratio of 1.55 (95%
confidence interval: 1.14–2.10), with adjustment for gender, age,
race/ethnicity, poverty/income ratio, fasting duration, and urinary creatinine concentration. For the most-commonly detected
DMAP metabolite, dimethyl thiophosphate,
children with levels higher than the median of detectable
concentrations had twice the odds of ADHD (adjusted odds ratio: 1.93 ) compared with children with undetectable levels.
Such pesticides are commonly used in the growing of vegetables and fruit, such
as strawberries.
The
insecticide chlorpyrifos has been
one of the most commonly used pesticides in homes. As part of an ongoing
prospective cohort study in an inner-city minority population, neurotoxicant effects of prenatal exposure to chlorpyrifos were evaluated in 254 children through
the first 3 years of life(1b). Highly exposed
children scored, on average, 6.5 points lower on the Bayley
Psychomotor Development Index and 3.3 points lower on the Bayley Mental Development Index at 3 years of
age compared with those with lower levels of exposure. Children
exposed to higher, compared with lower, chlorpyrifos levels were also significantly more
likely to experience Psychomotor Development Index and Mental Development
Index delays, attention problems, attention-deficit/hyperactivity disorder
problems, and pervasive developmental disorder problems at 3 years
of age. The adjusted mean
36-month Psychomotor Development Index and Mental Development Index
scores of the highly and lower exposed groups differed by only 7.1
and 3.0 points, respectively, but the proportion of delayed children
in the high-exposure group, compared with the low-exposure group,
was 5 times greater for the Psychomotor Development Index and 2.4
times greater for the Mental Development Index, increasing the
number of children possibly needing early intervention services.
Corn, wheat, and soy are the foods highest in the pesticide studied in that
particular study. Encouragingly, a study out of Emory University found that
when children with the high levels of pesticides were put on an organic diet,
the blood pesticide levels became undetectable until conventional foods were
reintroduced. Also, a study out of the University of Washington polled and
studied parents who left a food co-op or retail grocer in the Seattle area, and
classified children into a 75% conventional food group, or a 75% organic food
group. Urine samples were collected to look at pesticide exposure.
Switching to an organic diet lowered pesticide exposure.
A study of preschool children in Mexico found the
group exposed to pesticides to have significant behavioral effects including
increased aggression and violence(1e), compared to the control group exposed to
lower levels of pesticides. Students in
an area with high pesticide exposure had significant deficits of energy and
hand/eye coordination, as well as developmental learning deficits, balance
problems, and poorer general health, compared to an area with lower pesticide
exposure. The Yaqui
mothers from the area with higher pesticide exposure also reported more
problems getting pregnant and higher rates of miscarriage, stillbirth, neonatal
death and premature birth(1e).
A
California study found a significant positive correlation between children with
autism and home use of Pyrethroid insecticides by
pregnant women(4).
References:
(g)Long lasting
effects of prenatal exposure to deltamethrin on
cerebral and hepatic cytochrome P450s and behavioral
activity in rat offspring. Johri A, Parmar
D, et al; Eur J Pharmacol.
2006 Aug 21;544(1-3):58-68, & Cypermethrin-induced
DNA damage in organs and tissues of the mouse: evidence from the comet
assay. Patel S, Pandey
AK, et al, Mutat Res. 2006 Sep
5;607(2):176-83; & Effects of Pyrethroid Insecticides, B. Windham (Ed), www.flcv.com/PyrethrR.html; & (h)
Neurological and Developmental Effects of Pesticides, Review, B. Windham (Ed), www.flcv.com/pesticid.html
2.(a)Prenatal organochlorine exposure and behaviors associated with attention deficit hyperactivity disorder in school-aged children. Sagiv SK, Thurston SW, et al, Am J Epidemiol. 2010 Mar 1;171(5):593-601; & (b)[Developmental neurotoxicity of industrial chemicals],[Article in French], Labie D, Med Sci (Paris). 2007 Oct;23(10):868-72; &(c) Exposure to hexachlorobenzene during pregnancy and children's social behavior at 4 years of age. Ribas-Fito N, Sunver J, et al; Environ Health Perspect. 2007 Mar;115(3):447-50; & (d) Toxic threats to neurologic development of children. Schettler T, Environ Health Perspect. 2001 Dec;109 Suppl 6:813-6; & (e)Epidemiologic evidence of relationships between reproductive and child health outcomes and environmental chemical contaminants. Wigle DT, Arbuckle TE, et al, J Toxicol Environ Health B Crit Rev. 2008 May;11(5-6):373-517.
3. (a)Developmental neurotoxicity of industrial chemicals. Grandjean P, Landrigan PJ. Lancet. 2006 Dec 16;368(9553):2167-78; &(b) Epidemiologic evidence of relationships between reproductive and child health outcomes and environmental chemical contaminants. Wigle DT, Arbuckle TE, et al, J Toxicol Environ Health B Crit Rev. 2008 May;11(5-6):373-517; & (c)Developmental Disabilities and Behavioral Effects of Toxic Metal Exposure, Review, B. Windham (Ed), www.flcv.com/tmlbn.html & www.flcv.com/kidshg.html (over 300 peer-reviewed studies reviewed)
4. Introduction to Environmental influence on Psychiatric Disorders in Children and Adolescents, Hertz-Picciotto, I; Epidemiology: November 2008 - Volume 19 - Issue 6 - p S40, http://journals.lww.com/epidem/Fulltext/2008/11001/Introduction_to_Environmental_influence_on.106.aspx
