Pesticide illness, farm practices, and neurological symptoms among farm residents in Colorado

The purpose of this study is to evaluate the association between pesticides and neurological symptoms among a population exposed to organophosphate chemicals as a result of agricultural use. Chronic sequelae of acute pesticide poisoning from organophosphate compounds include a variety of neurological symptoms including restlessness, irritability, and trouble sleeping. Individuals who have had an acute pesticide poisoning have been reported to suffer a wide range of neurological symptoms that occur from weeks to months after the initial episode. Data for this study came from a cross-sectional survey of farmers and their spouses conducted in an eight-county area in north-eastern Colorado. Neurological characteristics were assessed to determine their relationship with previously reported pesticide-related illnesses. Symptoms that were significantly associated with a previous poisoning were difficulty concentrating [OR 2.07, 95% confidence interval (CI) 1.22, 3.50]; relatives noticing person had trouble remembering things (OR 2.54, 95% CI 1.47, 4.39); making notes to remember things (OR 2.18, 95% CI 1.20, 3.97); finding it hard to understand the meaning of newspapers, magazines, and books (OR 1.90, 95% CI 1.01, 3.60); felt irritable (OR 1.84, 95% CI 1.08, 3.12); felt depressed (OR 2.82, 95% CI 1.65, 4.81); had heart palpitations without exertion (OR 2.83, 95% CI 1.22, 6.54); sleeping more than usual (OR 3.58, 95% CI 1.95, 6.58); difficulty moving fingers or grasping things (OR 2.08, 95% CI 1.06, 3.24); and headaches at least once a week (OR 1.85, 95% CI 1.06, 3.24). Stepwise regression was used to identify the best explanatory model of pesticide-related illness. Variables that were associated with increased odds of illness were being male, being depressed, sleeping too much, and using crop organophosphates.     

Acute symptoms following work with pesticides

BACKGROUND: Serious accidental poisoning by pesticides is rare in the UK, but more minor pesticide-related illness may be under-reported. Anecdotally, use of sheep dip has been linked with flu-like symptoms. AIM: To explore the frequency, nature and determinants of acute symptoms following work with pesticides. METHODS: A postal survey of men in three rural areas of England and Wales provided data on occupational use of five categories of pesticide, occurrence of 12 specified symptoms within 48 h of using pesticides and tendency to somatize. Risk factors for pesticide-related symptoms were assessed by modified Cox regression. RESULTS: Of 10 765 responders (response rate = 31%), 4108 had at some time used pesticides occupationally, including 935 (23%) who reported symptoms following such work on at least one occasion. In two areas, acute symptoms were most frequent following use of sheep dip (29 and 32% of users), but in the third area the rate was significantly lower (13% of users). The relative frequency of symptoms was similar for all five categories of pesticide, and flu-like symptoms did not cluster unusually among users of sheep dip. Risk of pesticide-related symptoms increased with somatizing tendency (prevalence ratio for highest versus lowest category 2.4, 95% confidence interval 2.0-3.0) and was higher in men who had used pesticides most often or handled concentrate. CONCLUSION: Acute symptoms are common following work with pesticides, but in many cases the illness may arise through psychological rather than toxic mechanisms.     

Pesticide poisoning of farm workers-implications of blood test results from Vietnam

Information on the health impacts of pesticides is quite limited in many developing countries, with many surveys relying solely on farmer self-assessments of their health status. To test the reliability of self-reported data, an acetyl cholinesterase enzyme (AChE) blood test was conducted for 190 rice farmers in the Mekong Delta, Vietnam. Results reveal a high prevalence of pesticide poisoning by organophosphate and carbamate exposure, where over 35% of test subjects experienced acute pesticide poisoning (a reduction of AChE >25%), and 21% chronically poisoned (>66% AChE reduction). Using the medical test results as benchmarks, we find that farmers' self-reported symptoms have very weak associations with actual poisoning. To investigate the possible determinants of pesticide poisoning, a probit model was constructed with pesticide amount, toxicity, training, and the use of protective measures as explanatory variables. The results indicate that although the absolute amount of pesticides used does not increase the probability of poisoning, a 1% increase in the use of highly hazardous pesticides (WHO Ia or Ib) increases the probability of poisoning by 3.9% and an increased use of protective measures decreases the probability of poisoning by 44.3%. We also find significant provincial differences in poisoning incidence after we control for individual factors. The provincial effects highlight the potential importance of negative externalities, and suggest that future research on pesticide-related damage should include information on local water, air and soil contamination.     

An epidemiological study on occupational acute pyrethroid poisoning in cotton farmers.

A cross sectional survey on the prevalence of acute pyrethroid poisoning in cotton farmers was conducted in 1987 and 1988. A total of 3113 pyrethroid spraymen (2230 men (71.6%) and 883 women (28.4%] were interviewed after spraying and followed up for 72 hours. Adverse effects of pyrethroid exposure were found in 834 of them (26.8%) manifested as abnormal facial sensations, dizziness, headache, fatigue, nausea, or loss of appetite. Only 10 subjects, who developed significant systemic symptoms and had signs of listlessness or muscular fasciculation, were diagnosed as having mild occupational acute pyrethroid poisoning with a prevalence of 0.31% in subjects exposed to pure pyrethroids and 0.38% in subjects exposed to pyrethroid organophosphate mixtures. Measurements of pyrethroid concentrations in the air of the breathing zone, in skin pads, and in urine samples showed that dermal contamination is the main route of exposure to pyrethroids in cotton growers. Preventive measures are recommended.     

Structural Equation Modeling of the Relationships Between Pesticide Poisoning,Depressive Symptoms and Safety Behaviors Among Colorado Farm Residents

Abstract

Purpose: To use structural equation modeling (SEM) to test the theory that a past pesticide poisoning may act as a mediator in the relationship between depression and safety practices. Depression has been associated with pesticide poisoning and was more strongly associated with safety behaviors than workload, social support or health status of farm residents in a previously published report.

Methods: A cross-sectional survey of farmers and their spouses was conducted in eight counties in northeastern Colorado. Depressive symptoms were assessed using the Center for Epidemiologic Studies-Depression (CES-D) scale. Exploratory and confirmatory factor analyses were used to identify symptoms most correlated with risk factors for depression and safety practices. SEM was used to examine theoretical causal models of the relationship between depression and poor health, financial difficulties, a history of pesticide poisoning, and safety practices.

Results: Exploratory factor analysis identified three factors in the CES-D scale. The SEM showed that poor health, financial difficulties and a history of pesticide poisoning significantly explained the depressive symptoms. Models with an excellent fit for the safety behaviors resulted when modeling the probability that the pesticide poisoning preceded depression, but no fit was possible when reversing the direction and modeling depression preceding pesticide poisoning.

Conclusions: Specific depressive symptoms appeared to be significantly associated with pri marily animal handling and farm machinery. The order of events, based on SEM results, was a pesti cide poisoning preceding depressed mood in relation to safety behaviors.     

An epidemiological study on occupational acute pyrethroid poisoning in cotton farmers

A cross sectional survey on the prevalence of acute pyrethroid poisoning in cotton farmers was conducted in 1987 and 1988. A total of 3113 pyrethroid spraymen (2230 men (71.6%) and 883 women (28.4%] were interviewed after spraying and followed up for 72 hours. Adverse effects of pyrethroid exposure were found in 834 of them (26.8%) manifested as abnormal facial sensations, dizziness, headache, fatigue, nausea, or loss of appetite. Only 10 subjects, who developed significant systemic symptoms and had signs of listlessness or muscular fasciculation, were diagnosed as having mild occupational acute pyrethroid poisoning with a prevalence of 0.31% in subjects exposed to pure pyrethroids and 0.38% in subjects exposed to pyrethroid organophosphate mixtures. Measurements of pyrethroid concentrations in the air of the breathing zone, in skin pads, and in urine samples showed that dermal contamination is the main route of exposure to pyrethroids in cotton growers. Preventive measures are recommended.     

Pesticide use and pesticide-related symptoms among black farmers in the Agricultural Health Study

BACKGROUND: Health effects of pesticides have not been well studied in black farmers. We describe agricultural practices and pesticide-related symptoms in North Carolina black and white farmers participating in the Agricultural Health Study. METHODS: Self-administered questionnaires were completed by 891 black and 11,909 white farmers licensed to apply restricted pesticides. Regression models were used to compare characteristics by race. RESULTS: Black farmers reported lower lifetime pesticide use, less use of each class of pesticides (e.g., herbicides, insecticides), less use of high exposure application methods, and fewer pesticide-related symptoms such as headaches or dizziness, skin irritation, chest discomfort and feeling nervous or depressed than did white farmers. CONCLUSIONS: Differences between black and white farmers may be explained by farm characteristics or economics. Despite lower use of pesticides, black farmers may have other work practices that affect exposure and risk.     

Structural Equation Modeling of Pesticide Poisoning,Depression, Safety,and Injury

ABSTRACT

The role of pesticide poisoning in risk of injuries may operate through a link between pesticide-induced depressive symptoms and reduced engagement in safety behaviors. The authors conducted structural equation modeling of cross-sectional data to examine the pattern of associations between pesticide poisoning, depressive symptoms, safety knowledge, safety behaviors, and injury. Interviews of 1637 Colorado farm operators and their spouses from 964 farms were conducted during 1993–1997. Pesticide poisoning was assessed based on a history of ever having been poisoned. The Center for Epidemiologic Studies—Depression scale was used to assess depressive symptoms. Safety knowledge and safety behaviors were assessed using ten items for each latent variable. Outcomes were safety behaviors and injuries. A total of 154 injuries occurred among 1604 individuals with complete data. Pesticide poisoning, financial problems, health, and age predicted negative affect/somatic depressive symptoms with similar effect sizes; sex did not. Depression was more strongly associated with safety behavior than was safety knowledge. Two safety behaviors were significantly associated with an increased risk of injury. This study emphasizes the importance of financial problems and health on depression, and provides further evidence for the link between neurological effects of past pesticide poisoning on risk-taking behaviors and injury.     

A clinical neurological,neurophysiological, and neuropsychological study of sheep farmers and dippers exposed to organophosphate pesticides

Objectives: To classify clinical diseases of the subjects with abnormal indices of peripheral neuropathy identified in field studies of sheep farmers and dippers exposed to organophosphate pesticides. To explore what neuropsychological profiles, if any, may be associated with neurophysiological damage in these subjects. Methods: A case-control study (79 subjects) nested within the cross sectional study (685 subjects) of sheep farmers from the field study. Three groups with no, possible, and probable or definite neuropathy according to field studies were recruited. Investigations comprised symptoms of neuropathy, neurologial signs, motor and sensory nerve conduction, electromyography, quantitative sensory testing, and neuropsychological tests. Results: The incidence of clinical neuropathy increased from 7% in the no neuropathy group to 52% in the probable or definite neuropathy group based on nerve conduction measurements or presence of neurological signs. Sensory abnormalities were found more often than motor deficits. Small diameter nerve fibres were also affected more than large fibres. Conclusions: The neuropathy is predominantly sensory and is characteristic of distal, chronic neuropathy with no acute features. Small fibre populations are affected more than large fibre populations. Increasing severity of neuropathy was associated with anxiety and depression as measured in the neuropsychological tests.     

The Association of Sleep Duration and Depressive Symptoms in Rural Communities of Missouri,Tennessee, and Arkansas

Purpose: To determine the association between sleep duration and depressive symptoms in a rural setting. Methods: We conducted a cross‐sectional study using data from Wave 3 of the Walk the Ozarks to Wellness Project including 12 rural communities in Missouri, Arkansas, and Tennessee (N = 1,204). Sleep duration was defined based on average weeknight and weekend hours per day: short (<7), optimal (7‐8), and long (>8). The primary outcome was self‐reported elevated depressive symptoms. Multivariable logistic regression was used to estimate adjusted prevalence odds ratios (aPOR) and 95% confidence intervals (95% CI). Findings: Elevated depressive symptoms were common in this rural population (17%). Depressive symptoms were more prevalent among subjects with short (26.1%) and long (24%) sleep duration compared to those with optimal (11.8%) sleep duration. After adjusting for age, gender, race, education, employment status, income, and BMI, short sleep duration was associated with increased odds of elevated depressive symptoms (aPOR = 2.12, 95% CI: 1.49, 3.01), compared to optimal sleep duration. Conversely, the association between long sleep duration and depressive symptoms was not statistically significant after covariate adjustment. Similar findings were observed when we excluded individuals with insomnia symptoms for analysis. Conclusions: This study suggests that short sleep duration (<7 hours per night) and depressive symptoms are common among rural populations. Short sleep duration is positively associated with elevated depressive symptoms. The economic and health care burden of depression may be more overwhelming among rural populations, necessitating the need to target modifiable behaviors such as sleep habits to improve mental health.     

The health impacts of pesticide use on sugarcane farmers in Fiji

A survey conducted among sugarcane farmers in Fiji found significant differences in the incidence of chronic illness and disease between users of pesticides and a nonuser control group. Though average production of sugarcane was markedly higher among pesticide users, average annual medical expenditures were also significantly higher. Advanced technological methods including chemical pesticides require a system of institutional support to provide, inter alia, information for an effective transition from traditional to modern agricultural practices. Without that support the ad hoc application of technology may result in inefficiency and, in the case of pesticides, increased health risks among the farm population. Besides practical handling and application advice farmers require information describing the chronic health impacts of pesticide exposure to allow their weighing of the full costs of pesticide use against the production benefits.     

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

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.     

Knowledge,attitudes and practices (KAP) among agricultural extension workers concerning the reduction of the adverse impact of pesticides in agricultural areas in Tanzania

BACKGROUND: Extension workers are educated locally to enable them to train farmers in using improved local farming methods and imported technology, such as pesticides, to increase crop production. However, the extension workers are not adequately trained in health aspects of pesticides and hence are unable to provide adequate services to farmers with regard to safe use of pesticides. OBJECTIVE: The present study assessed the knowledge, attitudes and practices of agricultural extension workers with respect to health effects of pesticides in order to develop strategies for the control of pesticide exposure and prevention of pesticide poisoning in Tanzania. METHODS: A survey of Tanzanian agricultural extensionists was undertaken in 1991-1994 using a standardized questionnaire in face-to-face interviews. Extensionists who were district agricultural officers, assistant agricultural officers, agricultural assistants, and field assistants, working in the coffee and cotton growing areas (N = 61) within a radius of 15 km of farm, estate or village under farm worker study (reported elsewhere) were included in the survey. RESULTS: The majority of extensionists knew that pesticides could enter the human body but only a quarter perceived pesticides as a major problem in the community they served. The majority showed awareness of potential health hazards of the different pesticides used in their service areas, but they did not recognize what pesticides were responsible for poisoning. A high proportion was familiar with first aid procedures in case of pesticide poisoning; however, many procedures described were not appropriate for pesticide poisoning. CONCLUSIONS: The survey indicated that training of agricultural workers in health aspects of pesticide exposure is an important task for adequate provision of service to farmers with regard to safe use of pesticides in Tanzania. Nevertheless, the appropriate role of extensionists in reducing the health impact of pesticides would be to advocate pesticides of low toxicity or non-chemical pest control.     

Depressive symptoms in farm women: effects of health status and farming lifestyle characteristics,behaviors, and beliefs

A multitude of responsibilities, environmental and social influences, and stressors place farm women at high risk for depressive symptoms. This cross sectional survey design study examines demographic, health status, and farm lifestyle characteristics, behaviors and beliefs as risk factors contributing to depressive symptoms among farm women in southeast Louisiana. The study was conducted in a stratified, random sample of 657 women 18 years and older. Factors predictive of depressive symptoms in adjusted logistic regression included those who experience poor health, perceive hazards associated with farming, experience recent farm-related injuries and engage in farming over longer periods of time. These findings help target interventions toward women at risk for depressive symptoms.     

Pesticides and respiratory symptoms among farmers

OBJECTIVE: Despite the intensive use of pesticides in agriculture there are few studies assessing the risk of respiratory conditions from this exposure. The study aimed at quantifying the prevalence of respiratory symptoms among farmers and evaluating its relationship with occupational use of pesticides and the prevalence of respiratory symptoms. METHODS: A cross-sectional study was conducted among 1,379 farmers from two municipalities of Southern Brazil in 1996. Frequency and type of chemical exposure and pesticide poisoning were recorded for both sexes. All subjects aged 15 years or older with at least 15 weekly hours of agricultural activity were interviewed. An adapted questionnaire developed by the American Thoracic Society was used for the assessment of respiratory symptoms. Multivariate logistic regression analysis was carried out. RESULTS: More than half (55%) of interviewees were male. The prevalence of asthma symptoms was 12% and chronic respiratory disease symptoms was 22%. Higher odds ratios for both asthma (OR=1.51; 95% CI: 1.07-2.14) and chronic respiratory disease (OR=1.34; 95% CI 1.00-1.81) symptoms were found in women. Logistic regression analysis identified associations between many forms of exposure to pesticides and increased respiratory symptoms. Occurrence of pesticide poisoning was associated with higher prevalence of asthma symptoms (OR=1.54; 95% CI: 1.04-2.58) and chronic respiratory disease symptoms (OR=1.57; 95% CI: 1.08-2.28). CONCLUSIONS: In spite of causality limitations, the study results provide evidence that farming exposure to pesticides is associated with higher prevalence of respiratory symptoms, especially when the exposure is above two days per month.     

Neurotoxicity among pesticide applicators exposed to organophosphates.

OBJECTIVES--An epidemiological study of 90 male pesticide applicators licensed in New York was conducted to investigate the effect of exposure to organophosphate pesticides on the peripheral nervous system. METHODS--A cohort of farmers and pesticide applicators from New York State were questioned off season (November 1988-February 1989) and again during the spraying season (April 1989-August 1989) about the presence of several acute signs and symptoms. Short term exposure was validated by measuring the concentration of dimethylthiophosphate (DMTP), a metabolite of guthion, in urine. Chronic signs of subtle peripheral nerve damage were determined by vibration threshold sensitivity of the farmers and applicators tested during November 1988-February 1989 and compared with controls drawn from the general population who were tested during the same time period the next year (November 1989-February 1990). Vibration threshold sensitivity was determined for both the hands and feet. Long term exposure to pesticides was determined by questionnaire. RESULTS--Paired t tests show that mean vibration threshold scores were significantly higher for the dominant (P < 0.00) and non-dominant (P < 0.04) hands among pesticide applicators when compared with scores for population based controls individually matched on age, sex, and county of residence. CONCLUSIONS--A significant increase in mean vibration threshold sensitivity for the dominant and non-dominant hand suggests previous organophosphate exposure among pesticide applicators was associated with a loss of peripheral nerve function.     

Probabilistic assessment of acute health symptoms related to pesticide use under intensified Nepalese agriculture

Agriculture intensification has pushed farmers to use pesticides for maintaining agricultural productivity and to increase income. However, pesticide use has a significant negative impact on farmers' health. In Nepal, uses of pesticides have been already documented in agriculturally intensified areas, however, little is known on health impacts. Weekly interviews were conducted during 2005 to assess the emerging pesticide problems, estimate the magnitude of pesticide-related acute illness, and identify associated risk factors. The study showed that very few farmers have adopted safety gear during pesticide spraying. The safety measures regression shows that warm temperature and drinking habits significantly reduced adoption of safety gear, whereas, integrated pest management (IPM) training and farm experience increased its adoption. The dose-response analyses showed that use of insecticides or fungicides, spray duration and mixing pesticides significantly affect farmer's health, which could be reduced either by educating farmers, increasing the use of safety gear, or reducing mixtures applications.     

Relationship between neighbourhood social participation and depression among older adults: A longitudinal study in China

Previous research has found a negative linkage between neighbourhood social participation and depressive symptoms in Western countries, but the cross‐sectional design of these studies limits the ability to infer causality. Little attention has been paid to socio‐psychological pathways linking neighbourhood social participation to depressive symptoms among older adults in China. This study aimed to examine the impact of neighbourhood social participation on depressive symptoms among older adults in China. It also further explored the mediating roles of physical activity, social contact among neighbours, and contact with own children in the relationship between social participation and depressive symptoms. Data obtained through three waves (2011, 2013, and 2015) of the China Health and Retirement Longitudinal Study were used. The sample consisted of 10,105 individuals aged 60 and above and 24,623 person‐year records captured during these three waves. Depressive symptoms were assessed using the Center for Epidemiology Studies of Depression scale. Results showed that respondents' depression decreased with an increasing level of neighbourhood social participation, more time spent on physical activities, and a higher frequency of contact with neighbours and with own children. These factors were found to partly mediate the relationship between neighbourhood social participation and depression. The negative relationships between social contact and depression and contact with own children and depression were both strengthened by neighbourhood social participation. In conclusion, physical activity, social contact among neighbours and contact with own children are mechanisms through which neighbourhood social participation lowers the risk of depression among older adults in China.     

中学生抑郁症状与父母受教育程度关系随访分析

目的了解中学生抑郁症状变化趋势和父母受教育水平的关系,为制定中学生抑郁症状的干预措施提供依据。方法采取整群抽样方法,于2009年及2010年采用抑郁自评量表(SDS)对南京市5所学校53个班级初一和高一年级2 202名在校中学生进行2次问卷调查。基线调查2 160名中学生,1 a后随访调查2 118名中学生,随访率为98.1%。结果随访共检出抑郁症状学生974名,检出率为46.0%,其中轻、中、重度抑郁的比例分别为29.4%,13.4%和3.3%。父母为初中及以下文化程度的中学生SDS标准总分、抑郁症状检出率均最高,且中度及重度抑郁症状所占比例也较高。多因素Logistic回归分析显示,父母受教育程度均与中学生的抑郁症状呈负关联,仅父亲受教育程度差异有统计学意义。结论父母受教育程度尤其是父亲受教育程度是中学生抑郁症状的重要影响因素。