A study of neurobehavioural effects of long-term exposure to organophosphates in male tobacco-growing farmers in Bachok, Kelantan
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Date
2001-11
Authors
Abd Rahman, Ariza
Journal Title
Journal ISSN
Volume Title
Publisher
Universiti Sains Malaysia
Abstract
In order to study the knowledge about adverse health effects of pesticides, practice
of safe behaviour related to pesticide use and to investigate the neurobehavioural effects in
male Malaysian tobacco-growing fanners exposed to OP pesticides, a cross-sectional
con1parative study of 45 OP-exposed tobacco-growing fanners and 45 non-exposed
workers was conducted in August and Septeniber 2000. Structured questionnaire on
knowledge and practice and subjective symptoms associated with pesticide use in the local
Malaysian language was developed and pretested. There were 5 sections in . the
questionnaires; 14 questions on sociode1nographic and occupational characteristics, 4
questions on other chemical exposure, 10 questions on general health characteristics, 36
questions on subjective symptoms checklist, and 20 questions on safety behaviours
associated with pesticide use checklist. Seven tests of the NCTB -profile of mood states,
simple reaction time, digit symbol, digit span, Santa Ana manual dexterity, Benton visual
retention, and pursuit aiming tests - were administered to the subjects. Serum
cholinesterase estimation was also undertaken. Results showed that the mean serun1 cholinesterase activity in exposed fanners
(8924. 7± 1754.0 U/1) was significantly lower than non-exposed workers (11421.4 ± 1855.4
U/I) but within nonnal range (5300 to 12900 U/I). Propottion of farmers significantly
reported n1ore subjective symptoms; waking up at night, excessive sweating, upper limb numbness, upper limb \Veakness, tremors, facial numbness, and changes 1n the fa.cial
muscle.
The results of analysis of covariance, in which age, length of education, and
duration of employment (covariates) \:vere controlled in 45 exposed fanners and 45 nonexposed,
sho\ved that the mean scores on the Profile of Mood States-vigour, digit sy1nbol
correct, digit span fonvard and digit span back\vard, Santa Ana non-preferred hand, Benton
visual retention test and pursuit ailning tests were significantly lower in the exposed
farmers than non-exposed workers.
Fanners' knowledge about adverse effects of pesticides is generally good except
about early symptoms of poisoning where there is a proportion of fanners who failed to
recognise nausea, waiting, and breathing difficulty as early symptoms of poisoning.
For practice of storage of pesticide and disposal of container, majority of far~ers
showed unsatisfactory practice as large proportion of farmers failed to provide a special
room for pesticide storage and practice safe disposal of container. The results of stepwise multiple regression analysis revealed that none of the
neurobehavioural tests' score for 45 exposed farmers were significantly related to serum
cholinesterase. However, scores on the digit symbol correct, digit span backward and
pursuit ai1ning tests were significantly related to length of education. We therefore
conclude that chronic effects on the nervous syste1n have occurred in this group of farmers
and that these effects are likely to be associated wiith long-term repeated exposure to
organophosphate pesticides. Measures need to be taken to enhance farmers' knovvledge and
practice of pesticide use.
Description
Keywords
Organophosphate pesticides, long-term exposure, neurobehavioural effects,