Written by Greg Arnold, DC, CSCS. Of the sixty participating field workers previously exposed to organophosphates, those with 20 years of heavy exposure had significantly more nerve conduction damage and fingertip tingling compared to those with moderate exposure.
Organophosphates are a class of insecticides that were among the most common pesticides used in the twentieth century, with 36 organophosphates registered for use in the United States alone 1. Organophosphates work by inactivating an enzyme, acetylcholinesterase (AChE), which leads to an overabundance of the nerve chemical (“neurotransmitter”) acetylcholine between cells and results in uncontrolled stimulation between cells 1.
Early-stage organophosphate poisoning produces symptoms that include headache, nausea and dizziness as well as severe sweating, salivation, eye-tearing and runny nose. As organophosphate poisoning worsens, more severe symptoms surface that include muscle twitching, weakness, tremor, incoordination, vomiting, abdominal cramps and diarrhea 1.
While toxic exposure to organophosphates has been proven to be fatal, research is suggesting that even people working in the midst of organophosphates and wearing protective gear can suffer health problems. A three-year pilot study (1984–1987), conducted in rural communities in Israel, found subtle reversible in-season changes in nerve conduction patterns of 17 field workers out of 214 residents exposed to seasonal drift containing OP’s. Ophir et al in 2014 2 designed a cross-sectional study to investigate a potential association between OP exposure and neurological damage in the 60 individuals, 50 (83%) of whom were males, who were from the original cohort and still residing approximately 40 years later in the same communities.
Sixty field workers in the Hula Valley (50 men, 10 women) between the ages of 40 and 69 completed nerve conduction studies as well as hot/cold threshold tests.
Among the 60 field workers tested, 17 workers had up to 10 years of field work, 13 had 10-20 years of field work, and 30 had more than 20 years of field work. The researchers decided to study Israeli subjects because 87% of the total amount of agricultural pesticides used in Israel in the 1980s were organophosphates 3. They classified the study participants by exposure into three subgroups based on high, moderate, and low exposure.
The researchers noted a significant difference in nerve function in those with heavy organophosphate exposure. Specifically, compared to the light/moderate exposure group, the heavy exposure group had:
- 14.6% slower nerve impulse rates (3.7 versus 3.2 milliseconds, p = 0.03)
- 36.7% weaker nerve strength (“amplitude” – 7.1 vs 11.2 millivolts, p = 0.024)
In addition, 10 of the 30 heavy-exposure subjects reported “fingertip tingling”. Testing of this group showed 11.2% slower nerve conduction speed in their arms and hands compared to the 50 who did not report tingling (49.0 vs. 55.16 ms, p = 0.046). No statistical significance was seen between the groups for hot/cold thresholds.
The researchers concluded that “These findings attest to subtle nerve damage following lifetime low-level exposures to drifts containing organophosphates.” Because pesticides are important for keeping crops protected from insects, the researchers went on to recommend “reduction strategies” to help field workers lower their exposure to organophosphates. These reduction strategies “are the ultimate means for decreasing exposures to organophosphate drifts” and include “long sleeves and pants” as well as “a plastic wrap similar to a poncho could be made to be appropriately open to air but not to spray.”
Source: Ophir, A., I. Karakis, E. D. Richter, J. M. Abarbanel, U. Wormser, M. Aschner, and Y. Finkelstein. “An uncommon pattern of polyneuropathy induced by lifetime exposures to drift containing organophosphate pesticides.” Neurotoxicology 45 (2014): 338-346.
© 2014 Elsevier Inc. All rights reserved.
Posted September 7, 2017.
Greg Arnold is a Chiropractic Physician practicing in Hauppauge, NY. You can contact Dr. Arnold directly by emailing him at PitchingDoc@msn.com or visiting his web site at www.PitchingDoc.com
References:
- AChE DR. Organophosphate Insecticides.
- Ophir A, Karakis I, Richter E, et al. An uncommon pattern of polyneuropathy induced by lifetime exposures to drift containing organophosphate pesticides. Neurotoxicology. 2014;45:338-346.
- Gordon M, Hirsch I. New issues in agricultural spraying in Israel. Aviation, space, and environmental medicine. 1986;57(6):610-612.
