Evaluating how occupational exposure to organophosphates and pyrethroids impacts ADHD severity in Egyptian male adolescents.

BACKGROUND: Attention Deficit/Hyperactivity Disorder (ADHD) is a neurodevelopmental disorder characterized by deficits in attention and hyperactivity/impulsivity that cause impairments to daily living. An area of long-standing concern is understanding links between environmental toxicants, including pesticides, and the development or worsening of ADHD. OBJECTIVES: The present study evaluated associations between occupational pesticide exposure, specifically organophosphate (OP) pesticides, chlorpyrifos (CPF) and the pyrethroids (PYR) alpha-cypermethrin (αCM) and lambda-cyhalothrin (λCH), and symptoms of ADHD in a longitudinal study among Egyptian adolescent males. METHODS: Participants (N = 226, mean age = 17) were Egyptian adolescent males who either applied pesticides or were non-applicators. Urinary trichloro-2-pyridinol (TCPy) was measured as a specific metabolite biomarker of exposure to chlorpyrifos. Urinary 3-phenoxybenzoic acid (3-PBA) was measured as a general metabolite biomarker of exposure to pyrethroids, while urinary cis-3-(2,2- dichlorovinyl)-2,2-dimethylcyclopropane carboxylic acid (cis-DCCA) was measured as a specific biomarker of exposure to αCM and lambda cyhalothric acid (λCH acid) measured as a specific biomarker of exposure to λCH. Ordinal logistic regression models controlling for age were used to determine the likelihood of ADHD development (measured via parent-reported ADHD symptoms) as the level of biomarkers of pesticide exposure increased. RESULTS: Cis-DCCA was the only biomarker associated with higher likelihood ADHD symptoms (> 0.60 vs. 0-0.17 µg/g creatinine; OR = 2.82, 95% CI: 1.29-6.14). All participants reported clinical levels of ADHD symptoms when compared to national norms used in the United States. TCPy, trans-DCCA and λCH acid were not associated with risk of ADHD symptoms after controlling for levels of cis-DCCA. No other metabolites were associated with the number of ADHD symptoms. There were no interaction effects found for exposure to both OPs and Pyrethroids. DISCUSSION: The results suggest that exposure to the pyrethroid αCM is associated with more ADHD symptoms. Methodological and cultural considerations in need of further study are discussed.

Respiratory health disorders among workers in some Egyptian welding enterprises.

Welding fumes contain a complex mixture of metallic oxides that pose a risk to welders' respiratory systems. This study aimed to evaluate respiratory health disorders among workers in some Egyptian welding enterprises and their relationship to the workplace environment. This research was performed from January 1st, 2019 to February 28th, 2021 in welding enterprises in Birket El-Sabaa, a randomly selected district of Menoufia governorate, Egypt. A cross-sectional comparative study was conducted on 110 welders and 110 non-occupationally exposed subjects. Environmental studies were carried out for total welding fumes, respirable dust, and manganese air levels. Spirometric measures and manganese levels in whole blood were applied. Analysis of the personal air samples revealed that the mean values of welding fumes, respirable dust, and manganese air levels were higher than the international permissible levels. Welders had a higher significant prevalence of respiratory manifestations (rhinitis, cough, expectoration, wheezes, dyspnea, and chronic bronchitis) as well as decreased spirometric measures (FVC%, FEV1%, FEV1/FVC%, and FEF25-75%) than controls. The mean value of whole blood manganese level was statistically significantly higher among welders than that of the controls (3.35 ± 0.5 and 1.81 ± 0.79 ng/mL; respectively). A significant relationship was reported between longer work time and the prevalence of respiratory manifestations and decreased spirometric measurements. The use of masks/respirators was associated with a reduced prevalence of respiratory manifestations. Finally, welders that are exposed to welding fumes at concentrations higher than the permissible levels in welding establishments suffer from adverse respiratory problems, as shown by increased prevalence of respiratory manifestations and lower spirometric measurements. Regular use of high-quality personal protective equipment, especially masks, as well as periodic medical examinations for welders, is highly urged.

Evaluation of occupational pesticide exposure on Egyptian male adolescent cognitive and motor functioning.

BACKGROUND: Chronic low-level exposure to organophosphorus pesticides is associated with adverse health effects, including a decline in neurological functioning and long-term impairment. These negative effects may be more detrimental in children and adolescents due to their critical stage in development. Little work has investigated the effects of chronic exposure to pesticides, specifically chlorpyrifos (CPF) during the adolescent period. OBJECTIVES: To examine effects of CPF exposure over a year-long period within a group of male adolescents in Egypt (N = 242, mean age = 17.36), including both pesticide applicators and non-applicators. METHODS: Associations between average CPF exposure (measured via urinary metabolite levels of 3,5,6-trichloro-2-pyridinol [TCPy]) and neurobehavioral functioning were examined in a 1-year longitudinal study. Given previous literature, higher levels of TCPy were expected to be associated with worse neurobehavioral functioning. RESULTS: Using mixed effects linear regression, average TCPy exposure predicted deficits in more complex neurobehavioral tasks (Benton visual retention, digit span reverse, match to sample, serial digit learning, and alternating tapping) with estimates of effects ranging from -0.049 to 0.031. Age (effects ranging from 0.033 to 0.090) and field station (effects ranging from -1.266 to -0.278) were significantly predictive of neurobehavioral functioning over time. An interaction effect was found for field station and TCPy across several neurobehavioral domains. DISCUSSION: Results show that occupational exposure to pesticides may have particularly deleterious effects on complex neurobehavioral domains. Additionally, differences across field stations and the age at which individuals are exposed may be important factors to investigate in future research.

Risk perception and behavior in Egyptian adolescent pesticide applicators: an intervention study.

BACKGROUND: Adolescents are engaged in agricultural work, including pesticide application, around the world. Adolescent pesticide applicators are more likely to be exposed to pesticides than their adult counterparts because of their application practice and hygiene habits surrounding pesticide use. There is a need for low-cost interventions to reduce pesticide exposure. We evaluated a theoretically-based educational intervention to change perceptions about the risk of pesticide use and hygiene habits during and after pesticide application for adolescent and young adult pesticide applicators in Egypt. METHODS: Young adult and adolescent male pesticide applicators were given a one-hour educational intervention to inform them about the risk of pesticide use and how to reduce pesticide exposure. The median age of participants was 18 years old. Changes in perceived susceptibility and effectiveness were measured with a survey pre and post-intervention (n = 119) on the same day. The same survey (n = 95) was given 8-months post-intervention to identify sustained effects. Observational checklists of pesticide application practice were also completed during application seasons before and after the intervention. RESULTS: There was an increase in the proportion of individuals who viewed pesticides as being a long-term health risk (74.7% pre-intervention to 97.9% post-intervention, McNemar test p < 0.001). This change remained significant when surveyed at the 8-month follow-up (90.5%, p < 0.001). There was also a sustained improvement regarding participants' views of proper hygiene practice surrounding pesticide application. Applicators were observed wearing goggles, shoes, and masks more frequently post-intervention. CONCLUSION: This theoretically-based intervention is an example of a low-cost solution that can improve adolescents' and young adults' practices regarding pesticide application and personal hygiene practices during and after pesticide application. The intervention can be applied in other countries with similar safety culture surrounding pesticide application.

Environmental and Health Effects of Benzene Exposure among Egyptian Taxi Drivers.

Objectives: To study environmental exposure to benzene as well as hematological effects of benzene exposure in taxi drivers. Background: Exposure to benzene has been associated with adverse health effects, including haematopoietic disorders. Methods: A retrospective cohort study was carried out from the beginning of April 2017, through the end of June 2018, on 280 taxi drivers (the exposed group) and 120 unexposed matched individuals (controls). The tools included a predesigned self-administered questionnaire which contained questions about personal data (e.g., age, educational level, and smoking) and exposure data (e.g., duration and nature of exposure). Investigations involved complete blood count. Environmental studies for light-chain aromatic hydrocarbons (BTEX components: benzene, toluene, ethylbenzene, and xylene) were done. Results: Mean values (ppm) of ambient concentrations of benzene, toluene, ethylbenzene, and xylene (0.81 ± 0.42, 26.69 ± 0.54, 29.36 ± 2.35, and 25.11 ± 2.06, respectively) in the stations were higher than international permissible levels (P < 0.001). On studying the clinical manifestations during the last two weeks, the prevalence of pallor, dizziness, headache, waist and back pain, fatigue, dry throat, and discomfort was significantly higher in taxi drivers (27.1%, 24.3%, 21.4%, 28.6%, 45.7%, 24.3%, and 25.7%, respectively) than among the controls (6.7%, 4.2%, 6.7%, 10%, 10%, 6.7%, 6.7%, and 9.2%, respectively). For chronic diseases, hypertension was the most prevalent chronic disease among the drivers (17.1%) than the controls (5.8%) (P=0.002). Regarding self-assessment of health status, 20.0% of taxi drivers reported poor health while 31.4% reported very good health (P < 0.001). MCH (pg), TLC (×103/µl), and platelets (×103/µl) were significantly lower among taxi drivers (26.33 ± 2.31, 6.55 ± 1.38, and 189.07 ± 53.25, respectively) (P=0.005, <0.001, and <0.001 respectively). Conclusion: Abnormal hematological findings among taxi drivers were found on exposure to benzene. Health of taxi drivers is generally affected. Setting a clinic for periodic checkup and health education for taxi drivers is highly recommended.

Prevalence and risk factors of hearing impairment among primary-school children in Shebin El-kom District, Egypt.

PURPOSE: This study examined the feasibility of screening hearing loss in rural and urban schools in Egypt, and investigated the prevalence and causes of hearing impairment (HI) in Egyptian primary-school students. METHOD: A total of 555 children (6-12 years of age) from a rural and an urban school in the Shebin El-Kom District of Egypt were screened for HI at their schools. A 2-stage screening procedure was used, and positive cases were referred for a diagnostic hearing assessment at a regional medical facility. Risk factors were investigated through a parent questionnaire and an environmental study consisting of noise, ventilation, and crowding measurements at the schools. RESULTS: The screening failure rate was 25.6%, and the prevalence of confirmed HI was 20.9%. The rate of HI did not differ across the schools. Conductive hearing loss of minimal to mild severity was the most common type of HI. The most important predictors for HI were parent suspicion, otitis media, household smoking, low socioeconomic status, and postnatal jaundice. CONCLUSIONS: The prevalence of HI did not differ across settings and was more common than reported in children from developed countries. The screening results also suggest that professionals with limited audiology background can be trained to implement hearing screening programs in Egyptian schools.

Effects of occupational pesticide exposure on children applying pesticides.

Nearly 40% of the Egyptian workforce is employed in agriculture. The cotton industry relies on children and adolescents, who work seasonally, to apply pesticides to the cotton crops. Although previous research has examined adult pesticide exposures in this workforce in Egypt, no research has examined the health effects in adolescents. This study attempts to systematically replicate findings examining the impact of organophosphate pesticide (OP) exposure in adults on Arabic speaking children working as applicators. The aim of this study was to examine the impact of pesticide exposure on children and adolescents spraying cotton fields. Male children currently applying pesticides between the ages of 9 and 15 (Younger, n=30) and 16 and 19 (Older, n=20) were recruited for the study. They completed a neurobehavioral test battery; personality inventory; work, health, and exposure questionnaires; and medical and neurological screening exams. Blood samples were collected to measure acetylcholinesterase. Children not working in agriculture, matched on age and education, served as controls. Both Younger and Older applicator groups, performed significantly worse than the controls on the majority of neurobehavioral tests controlling for age and years of education. The applicators reported significantly more neurological symptoms than the controls and had lower acetylcholinesterase activity. A dose-effect relationship demonstrated that increased years of exposure to organophosphate pesticides is associated with cognitive deficits. This is one of the several studies demonstrating that functional cognitive effects are positively correlated with increased years of exposure to OP pesticides, though primarily in adult populations, building confidence in the association. Since children around the world are exposed to OP pesticides, these studies suggest that the need to evaluate this potential problem is urgent.