Tag: pesticides

Chronic fatigue and organophosphate pesticides in sheep farming: a retrospective study amongst people reporting to a UK pharmacovigilance scheme

Abstract:

The Department of Health has recently published a report from the CFS/ME Working Group which concluded that chronic fatigue syndrome (CFS) should be recognized as a chronic illness. Symptoms consistent with CFS are often reported by people who consider their health has been affected by exposure to pesticides, but the Working Group concluded that this type of exposure is not a common trigger for the syndrome.

The Veterinary Medicines Directorate (VMD) collects self-assessed reports of ill health in humans associated with veterinary medicines under their Suspected Adverse Reaction Surveillance Scheme. The reporters have mainly been sheep farmers. These reports were used to investigate the possible relationship between chronic fatigue (CF) and exposure to organophosphate pesticides in sheep farming. The overall aim of the study was to investigate a possible association between exposure to organophosphates and the development of CF amongst people who consider their health has been affected by pesticides in sheep farming. The hypothesis investigated was that repeated exposure to organophosphate pesticides in sheep dip may increase the probability of developing CF. A group of mostly sheep farmers who had reported to the VMD surveillance scheme were identified.

We planned to use a retrospective case-control study design but the initial symptoms reports were not sufficiently reliable to enable this. The study population was asked to complete two questionnaires. The first questionnaire was designed to identify the history of exposure of subjects to organophosphate pesticides, and their exposure was then reconstructed using a metric specifically developed for this purpose. The second questionnaire collected detailed information to identify whether the subjects had CF when they originally reported to the VMD and at the time of the survey.

The questionnaire was sent to a total of 206 subjects, of whom 28 had moved home. A total of 37% of the remaining 178 subjects participated. There was a high prevalence of CF amongst those who completed the questionnaire and this has generally persisted since the subjects reported to the VMD. Higher CF scores were associated with higher exposure to organophosphate pesticides.

CF is very common amongst those who consider their health was affected by pesticides and we have shown there is limited evidence of an association between exposure to organophosphates and CF. Further research is needed to investigate the cause of this syndrome amongst farmers exposed to pesticides.

 

Source: Tahmaz N, Soutar A, Cherrie JW. Chronic fatigue and organophosphate pesticides in sheep farming: a retrospective study amongst people reporting to a UK pharmacovigilance scheme. Ann Occup Hyg. 2003 Jun;47(4):261-7. http://annhyg.oxfordjournals.org/content/47/4/261.long (Full article)

 

Multiple chemical sensitivity and chronic fatigue syndrome in British Gulf War veterans

Abstract:

The objective of this study was to measure the prevalence of multiple chemical sensitivity (MCS) and chronic fatigue syndrome (CFS) in British Gulf War veterans and to investigate their association with reported exposures and psychologic morbidity. In 1997–1998, the authors undertook a cross-sectional survey of three cohorts of British military personnel comprising Gulf veterans (n = 3,531), those who had served in Bosnia (n = 2,050), and those serving during the Gulf War but not deployed there (Era cohort, n = 2,614). MCS and CFS were defined according to operational criteria.

The prevalence of MCS in the Gulf, Bosnia, and Era cohorts was 1.3%, 0.3%, and 0.2%, respectively. For CFS, the prevalence was 2.1% (Gulf cohort), 0.7% (Bosnia cohort), and 1.8% (Era cohort). In Gulf veterans, MCS was strongly associated with exposure to pesticides (adjusted odds ratio = 12.3, 95% confidence interval: 5.1, 30.0). Both syndromes were associated with high levels of psychologic morbidity.

These findings suggest that CFS and MCS account for some of the medically unexplained illnesses reported by veterans after deployment to the Gulf. MCS was particularly associated with Gulf deployment and self-reported exposure to pesticides, findings that merit further exploration given the controversial status of this diagnosis and the potential for recall bias in a questionnaire survey.

 

Source: Reid S, Hotopf M, Hull L, Ismail K, Unwin C, Wessely S. Multiple chemical sensitivity and chronic fatigue syndrome in British Gulf War veterans. Am J Epidemiol. 2001 Mar 15;153(6):604-9. http://aje.oxfordjournals.org/content/153/6/604.long (Full article)

 

Neurasthenic fatigue, chemical sensitivity and GABAa receptor toxins

Abstract:

Following observation of fatigue syndromes in people who have been occupationally exposed to pesticides and insecticides which exert their toxicity through the GABAa receptor, we have formulated the hypothesis that fatigue syndromes in general may be secondary to altered sensitivity of the GABAa receptor. We discuss the possible involvement of organochlorine compounds which are widespread in the environment. Organophosphate compounds may have similar toxic effects through damaged cholinergic input to the dentate gyrus of the hippocampus where cholinergic and GABAergic transmission are closely linked.

 

Source: Corrigan FM, MacDonald S, Brown A, Armstrong K, Armstrong EM. Neurasthenic fatigue, chemical sensitivity and GABAa receptor toxins. Med Hypotheses. 1994 Oct;43(4):195-200. http://www.ncbi.nlm.nih.gov/pubmed/7838000