TABLE 7.5 Neurobehavioral Effects with History of Past OP Poisoning


Population: Exposed

Population: Control

Health Outcomes or Test Type

OP Insecticide Exposure




Savage et al., 1988

100 male workers from Colorado and Texas registry of OP-insecticide poisonings

100 matched controls recruited from study-subject referrals, businesses, public agencies, investigators

>30 NB tests, including: WAIS, Halstead-Reitan, MMPI-mood, questionnaires; average impairment rating; 9 years after poisoning

History of 10 OPs reported as primary cause of poisoning; methyl parathion, parathion in at least half of poisoned workers; AChE of both groups within normal limits

Paired matching on age, sex, level of education, social class, occupational class, ethnic background (Mexican)

Poisoned workers worse average impairment rating; worse on 18 of 36 NB tests; some impairment of fine motor movements; more anxiety symptoms

No information on past or current exposure of controls; no correction for multiple testing

Steenland et al., 1994

128 people from CA registry of OP-insecticide poisoning; 28% hospitalized for one night

90 friends of poisoned workers “not currently working with pesticides,” 19% in agriculture

Eight NB tests from NES2 in English and Spanish, including mood scales; 1–9 years after poisoning

History of OP use; 83 also found to have significant decrease in AChE at time of poisoning; specific OPs named but limited insecticide-specific analyses because of small numbers

Poisoned workers, controls similar in mean grade level, race, preferred language, percentage of drinkers; regression to adjust for confounding

Hospitalized OP-poisoned workers significantly worse on two of 10 NB tests (continuous-performance test and digit-symbol); for all poisoned workers together, even worse performance in those with more severe poisonings; mood scales worse for tension and confusion

No information on past OP exposure of controls; no formal correction for multiple comparison

Rosenstock et al., 1991

36 men hospitalized and treated for OP poisoning in Nicaragua

25 male friends of study subjects with no prior OP poisoning; 69% with prior OP-pesticide exposure

Six of seven NB subtests from WHO battery, including BSI, CNS symptoms; Spanish-translated tests; 1–3 years after poisoning

History of OP hospitalization; no pesticide use within 3 months before testing

Matching on age, sex; testers blinded to exposure status; analysis and adjustment for premorbid intellectual functional difference in vocabulary scores

Exposed group had worse performance on five or six NB domains, more CNS symptoms (7.2 vs 4.7, p<.01); no difference in mood symptoms from BSI

Association strengthened by controls having prior OP pesticide exposure

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