Effects of long-term organophosphate exposures on neurological symptoms, vibration sense and tremor amongst South African farm workers

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dc.contributor.authorLondon, Leslie
dc.contributor.authorNell, V
dc.contributor.authorThompson, M L
dc.contributor.authorMyers, J E
dc.date.accessioned2021-10-08T07:16:01Z
dc.date.available2021-10-08T07:16:01Z
dc.date.issued1998
dc.description.abstractOBJECTIVES: This study assessed the relationship between long-term exposure to organophosphate insecticides and neurological symptoms, vibration sense, and motor tremor after control for the effect of past poisoning and acute exposure. METHODS: This cross-sectional study included 164 pesticide applicators and 83 nonspraying reference workers on deciduous fruit farms. The workers were tested on the Vibratron II, on tests of dynamic and static tremor, and for a set of neurological and "dummy" symptoms. Exposure was derived with the use of a job-exposure matrix for pesticides in agriculture. RESULTS: Compared with nonapplicators, current applicators reported significantly more dizziness, sleepiness, and headache and had a higher overall neurological symptom score. This association remained statistically significant after multiple logistic regression analyses controlling for a range of confounders and effect modifiers [odds ratio (OR) 2.25, for current applicators having high neurological score, 95% confidence interval (95% CI) 1.15-4.39]. The average lifetime intensity of organophosphate exposure was nonsignificantly associated with both neurological (OR 1.98, 95% CI 0.49-7.94) and "dummy" symptoms (OR 2.37, 95% CI 0.54-10.35). Previous pesticide poisoning was significantly associated with the neurological scores (OR 4.08, 95% CI 1.48-11.22) but not with the "dummy" symptoms. Vibration sense outcomes were associated with age and height, but not with the organophosphate exposure measures. In the multiple linear regression modeling for tremor intensity in the dominant hand, recent organophosphate exposure in the past 10 days was a significant predictor (partial correlation coefficient = 0.04), but none of the long-term organophosphate exposure measures were significant. CONCLUSIONS: Strong evidence was found for an association between symptom outcomes and past organophosphate poisoning and between symptom outcomes and current spray activity. In contrast to symptoms, there was no association between either past poisoning or current spray activity and vibration sense or tremor outcome. Long-term organophosphate exposure did not appear to predict symptoms, vibration sense, or tremor outcome.
dc.identifier.apacitationLondon, L., Nell, V., Thompson, M. L., & Myers, J. E. (1998). Effects of long-term organophosphate exposures on neurological symptoms, vibration sense and tremor amongst South African farm workers. <i>Scandinavian Journal of Work, Environment & Health</i>, 24(1), 18 - 29. http://hdl.handle.net/11427/34750en_ZA
dc.identifier.chicagocitationLondon, Leslie, V Nell, M L Thompson, and J E Myers "Effects of long-term organophosphate exposures on neurological symptoms, vibration sense and tremor amongst South African farm workers." <i>Scandinavian Journal of Work, Environment & Health</i> 24, 1. (1998): 18 - 29. http://hdl.handle.net/11427/34750en_ZA
dc.identifier.citationLondon, L., Nell, V., Thompson, M.L. & Myers, J.E. 1998. Effects of long-term organophosphate exposures on neurological symptoms, vibration sense and tremor amongst South African farm workers. <i>Scandinavian Journal of Work, Environment & Health.</i> 24(1):18 - 29. http://hdl.handle.net/11427/34750en_ZA
dc.identifier.issn0355-3140
dc.identifier.issn1795-990X
dc.identifier.ris TY - Journal Article AU - London, Leslie AU - Nell, V AU - Thompson, M L AU - Myers, J E AB - OBJECTIVES: This study assessed the relationship between long-term exposure to organophosphate insecticides and neurological symptoms, vibration sense, and motor tremor after control for the effect of past poisoning and acute exposure. METHODS: This cross-sectional study included 164 pesticide applicators and 83 nonspraying reference workers on deciduous fruit farms. The workers were tested on the Vibratron II, on tests of dynamic and static tremor, and for a set of neurological and "dummy" symptoms. Exposure was derived with the use of a job-exposure matrix for pesticides in agriculture. RESULTS: Compared with nonapplicators, current applicators reported significantly more dizziness, sleepiness, and headache and had a higher overall neurological symptom score. This association remained statistically significant after multiple logistic regression analyses controlling for a range of confounders and effect modifiers [odds ratio (OR) 2.25, for current applicators having high neurological score, 95% confidence interval (95% CI) 1.15-4.39]. The average lifetime intensity of organophosphate exposure was nonsignificantly associated with both neurological (OR 1.98, 95% CI 0.49-7.94) and "dummy" symptoms (OR 2.37, 95% CI 0.54-10.35). Previous pesticide poisoning was significantly associated with the neurological scores (OR 4.08, 95% CI 1.48-11.22) but not with the "dummy" symptoms. Vibration sense outcomes were associated with age and height, but not with the organophosphate exposure measures. In the multiple linear regression modeling for tremor intensity in the dominant hand, recent organophosphate exposure in the past 10 days was a significant predictor (partial correlation coefficient = 0.04), but none of the long-term organophosphate exposure measures were significant. CONCLUSIONS: Strong evidence was found for an association between symptom outcomes and past organophosphate poisoning and between symptom outcomes and current spray activity. In contrast to symptoms, there was no association between either past poisoning or current spray activity and vibration sense or tremor outcome. Long-term organophosphate exposure did not appear to predict symptoms, vibration sense, or tremor outcome. DA - 1998 DB - OpenUCT DP - University of Cape Town IS - 1 J1 - Scandinavian Journal of Work, Environment & Health LK - https://open.uct.ac.za PY - 1998 SM - 0355-3140 SM - 1795-990X T1 - Effects of long-term organophosphate exposures on neurological symptoms, vibration sense and tremor amongst South African farm workers TI - Effects of long-term organophosphate exposures on neurological symptoms, vibration sense and tremor amongst South African farm workers UR - http://hdl.handle.net/11427/34750 ER - en_ZA
dc.identifier.urihttp://hdl.handle.net/11427/34750
dc.identifier.vancouvercitationLondon L, Nell V, Thompson ML, Myers JE. Effects of long-term organophosphate exposures on neurological symptoms, vibration sense and tremor amongst South African farm workers. Scandinavian Journal of Work, Environment & Health. 1998;24(1):18 - 29. http://hdl.handle.net/11427/34750.en_ZA
dc.language.isoeng
dc.publisher.departmentDepartment of Statistical Sciences
dc.publisher.facultyFaculty of Science
dc.sourceScandinavian Journal of Work, Environment & Health
dc.source.journalissue1
dc.source.journalvolume24
dc.source.pagination18 - 29
dc.source.urihttps://dx.doi.org/10.5271/sjweh.274
dc.subject.otherOrganophosphorus compounds
dc.subject.otherInsecticide
dc.subject.otherPesticides
dc.subject.otherTremor
dc.subject.otherHuman
dc.subject.otherCentral nervous system
dc.subject.otherSensorial perception
dc.subject.otherVibration
dc.subject.otherToxicity
dc.subject.otherLong term
dc.subject.otherOccupational exposure
dc.subject.otherAgriculture
dc.subject.otherSpraying
dc.subject.otherPublic health
dc.subject.otherOccupational medicine
dc.subject.otherEpidemiology
dc.subject.otherSouth Africa
dc.subject.otherNervous system diseases
dc.subject.otherNeurological disorder
dc.subject.otherInvoluntary movement
dc.subject.otherAfrica
dc.subject.otherOrganophosphoré
dc.subject.otherPesticide
dc.subject.otherTremblement
dc.subject.otherHomme
dc.subject.otherSystème nerveux central
dc.titleEffects of long-term organophosphate exposures on neurological symptoms, vibration sense and tremor amongst South African farm workers
dc.typeJournal Article
uct.type.publicationResearch
uct.type.resourceJournal Article
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