Browsing by Author "Dalvie, Mohamed Aqiel"
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- ItemOpen AccessA prospective cohort study on ambient air pollution and respiratory morbidities including childhood asthma in adolescents from the western Cape Province: study protocol(2017) Olaniyan, Toyib; Jeebhay, Mohamed; Röösli, Martin; Naidoo, Rajen; Baatjies, Roslynn; KYnzil, Nino; Tsai, Ming; Davey, Mark; de Hoogh, Kees; Berman, Dilys; Parker, Bhawoodien; Leaner, Joy; Dalvie, Mohamed AqielAbstract Background There is evidence from existing literature that ambient air pollutant exposure in early childhood likely plays an important role in asthma exacerbation and other respiratory symptoms, with greater effect among asthmatic children. However, there is inconclusive evidence on the role of ambient air pollutant exposures in relation to increasing asthma prevalence as well as asthma induction in children. At the population level, little is known about the potential synergistic effects between pollen allergens and air pollutants since this type of association poses challenges in uncontrolled real life settings. In particular, data from sub-Sahara Africa is scarce and virtually absent among populations residing in informal residential settlements. Methods/design A prospective cohort study of 600 school children residing in four informal settlement areas with varying potential ambient air pollutant exposure levels in the Western Cape in South Africa is carried-out. The study has two follow-up periods of at least six-months apart including an embedded panel study in summer and winter. The exposure assessment component models temporal and spatial variability of air quality in the four study areas over the study duration using land-use regression modelling (LUR). Additionally, daily pollen levels (mould spores, tree, grass and weed pollen) in the study areas are recorded. In the panel study asthma symptoms and serial peak flow measurements is recorded three times daily to determine short-term serial airway changes in relation to varying ambient air quality and pollen over 10-days during winter and summer. The health outcome component of the cohort study include; the presence of asthma using a standardised ISAAC questionnaire, spirometry, fractional exhaled nitric-oxide (FeNO) and the presence of atopy (Phadiatop). Discussion This research applies state of the art exposure assessment approaches to characterize the effects of ambient air pollutants on childhood respiratory health, with a specific focus on asthma and markers of airway inflammation (FeNO) in South African informal settlement areas by considering also pollen counts and meteorological factors. The study will generate crucial data on air pollution and asthma in low income settings in sub-Sahara Africa that is lacking in the international literature.
- ItemOpen AccessA prospective cohort study on ambient air pollution, airborne pollen (and fungal spores) and respiratory morbidities including childhood asthma in adolescents from the Western Cape Province(2018) Olaniyan, Toyib Adedamola; Dalvie, Mohamed Aqiel; Jeebhay, Mohamed Fareed; Röösli, MartinBackground: The epidemiological studies investigating environmental risk factors associated with asthma among children living in informal settlements are scant as are studies on the independent and co-pollutant effect of short- and long-term exposures to ambient air pollutants as well as fungal spores on asthma-associated outcomes. This study systematically investigated these factors among schoolchildren residing in informal settlements in the Western Cape province of South Africa. Methods: A cohort study of grade-4 schoolchildren (n=590) recruited from six primary schools in four informal settlements was conducted over 12 months. In addition, a panel study, investigated the children for 2 consecutive school weeks in both summer and winter. Spirometry and fractional-exhaled nitric oxide (FeNO) measurements were conducted during the school day, while the International Study on Asthma and Allergy in Children (ISAAC) standardised questionnaire was administered to the parent or guardian at the child’s home at baseline and follow-up. The presence of atopy was determined based on a positive Phadiatop test on sera. In the cohort study, annual NO2 and PM2.5 levels were computed for each child’s address using a land-use regression model. Daily PM10 levels obtained from a stationary monitor near two of the study areas were used for the panel study. Airborne pollen and fungal spore measurements were obtained directly from a stationary monitor placed in each study area. Results: The prevalence of doctor-diagnosed asthma was 3.4% and only half of them were on asthma treatment. The prevalence of wheezing in the past 12 months (12.9%), airway obstruction (17.6%) and airway inflammation (10.2%) was much higher. The presence of damp conditions, visible mould growth, passive smoking as well as paraffin-use for cooking and heating were significant indoor risk factors for asthma. The estimated annual average NO2 level of 16.6 µg/m3 was below the WHO annual exposure standards, however more than a third of children were exposed to annual PM2.5 levels above the 10 µg/m3 WHO standard and the allergic symptom threshold level of 100 spores/m3 for Alternaria spores. In the panel study, daily exposure of schoolchildren to Alternaria and Cladosporium spores independently decreased FEV1 (-27.56 ml, 95% CI: -50.60 to -4.51 ml per 10 spores/m3 increase in Alternaria; and -86.19ml, 95% CI: -131.69 to -40.70 ml per 50 spores/m3 increase in Cladosporium respectively) from lag day-0 to lag day-5, especially in the winter monitoring period. In the cohort study, an interquartile range increase of 14.2 µg/m3 in annual NO2 was associated with an risk of new onset ocular-nasal symptoms (adjusted odds ratio – aOR: 1.63, 95% CI: 1.01 – 2.60), wheezing (aOR: 3.57, 95% CI: 1.18 – 10.92), more than two or more asthma symptom score (aOR: 1.71, 95% CI: 1.02 – 2.86), and airway inflammation defined as FeNO > 35ppb (aOR: 3.10, 95% CI: 1.10 – 8.71), independent of PM2.5 exposures. In addition, an interquartile increase of 83.1 spores/m3 in 24-hour annual Alternaria spore levels was associated with an increased risk of airway inflammation incidence and having a ≥ 10% increase in FeNO at follow-up both in the single-pollutant model and two-pollutant model. Conclusion: This study demonstrated a large proportion of undiagnosed and untreated asthma in schoolchildren living in informal settlements, with both indoor and outdoor mould exposures playing an important role in addition to ambient chemical pollutants. The incidence of new onset asthma symptoms and airway inflammation associated with NO2 at levels below the WHO Air Quality Standards raises the issue of the adequacy of these standards in protecting respiratory health. Raised long-term levels of airborne Alternaria spores contributing to increased airway inflammation is likely to form the basis for the increased risk of acute symptoms and airway effects observed in association with exposure peaks.
- ItemOpen AccessAnthropometric measurements, sexual development and serum reproductive hormonal levels among boys in the rural Western Cape(2016) Mao, Jun; Dalvie, Mohamed AqielBackground: Our previous epidemiological study have investigated the effect of pesticides on growth of boys in the Western Cape rural area, in this cross-sectional study, we extend those initial observation into a more detailed exploration of t he growth pattern in anthropometric variables and hormonal indicators, and its relation to pubertal stage. Reference data in relation to pubertal stage are presented, and compared with other international findings. Objective: To investigate the anthrop ometric growth and reproductive hormones alternation of Western Cape Rural boys who are potentially exposed to agricultural pesticides. Methods: A cross-sectional study of 269 boys was conducted in the rural Western Cape in South Africa. Tests included serum gonadotrophin releasing hormone (GnRH), lutenizing hormone (LH), follicle stimulating hormone (FSH), testosterone, sex hormone binding globulin (SHBG) and estradiol (E2); a physical examination of height, weight and BMI measurements; sexual matura tional assessment and a questionnaire (demographics and general medical history). Median of anthropometric variables and hormone levels by pubertal stage were compared with international references. Results: Median age of pubertal onset is 11.6 years old, later than African American boys and Urban South African boys. Western Cape rural boys were apparently shorter and lighter compared with the CDC and the WHO growth standards in the prepubertal and early pubertal stage, and then catch-up evidently in the mid and late puberty. Compared with previous pubertal hormonal studies, our boys were low in serum levels of testosterone were low and high in oestradiol levels throughout entire pubertal stages and the classic endocrine Negative Feedback Loops in hy pothalamic pituitary gonadal axis were established earlier. Conclusion: The results provide further evidence for the effects potentially from agricultural pesticides exposure in the pattern of growth in height and weight, and hormonal fluctuations dur ing the development of puberty.
- ItemOpen AccessDemographic determinants of chemical safety information recall in workers and consumers in South Africa(2015) Sathar, Farzana; Dalvie, Mohamed Aqiel; Rother, Hanna-AndreaChemical hazard communication is intended to alert users of the potential hazards of chemicals. Apart from the fact that hazard information should be understood, it is also important that it should be recalled. Recall of hazard communication is critical when the written form of the information is not available at the time it is required. A cross-sectional study investigating predictors of the recall of chemical safety information on labels and safety data sheets amongst 315 workers (industry, transport and agriculture sectors) and 87 consumers in two provinces of South Africa was conducted. The recall of participants was tested using two modules (module 2 which relates to the demographics, and module 3 which relates to the recall of the participants) from the Hazard Communication Comprehensibility Testing (CT) Tool developed by the Centre for Environmental and Occupational Health at the University of Cape Town. Respondents were predominantly male (67.7%), the median age was 37 years (IQR: 30-46 years) and less than half of the participants completed high school (47.5%). The majority of participants were blue collar workers outside of industry (55.5%). The skull and crossbones symbol was the label element most recalled, both unprompted (79.6%) and prompted (94.8%), and the first aid and treatment measures the least frequently recalled (6.0%-29.9%). Multivariate analysis showed the predictors that were found to increase the recall of all the label elements were, industrial sector, transport sector, agriculture sector, gender, home language English and Afrikaans, reading English and Afrikaans, completing high school and non-industry white collar occupations. The predictors that were found to decrease recall were further education, not wearing glasses and non-industry blue collar occupations. This study found demographic factors to influence the recall of hazard information. Policy should ensure the implementation of procedures that promote the recall of hazard information to protect workers from hazardous exposures.
- ItemOpen AccessGenetic polymorphisms and organophosphate neurotoxicity amongst emerging farmers in the Western Cape(2016) Glass, Tracy; Dalvie, Mohamed Aqiel; Holtman, Zelda; Ramesar, RajBACKGROUND: Long-term exposure to organophosphates (OPs) can cause chronic neurotoxic effects which may be modulated by genetic polymorphisms of xenobiotic metabolising enzymes (XMEs). No previous study investigated XME modulation of neurotoxicity outcomes. OBJECTIVES: To investigate whether XMEs polymorphisms modulate OP neurotoxicity among emerging farmers. METHODS: A cross-sectional study of 301 emerging farmers was conducted in the rural Western Cape of South Africa. Neurotoxicity testing included the World Health Organisation Core Test Battery (digit span forward and backward) and vibration sensitivity testing. Questionnaire items included demographic data, potential confounders and work history of pesticide exposures. Blood samples were analysed for genetic polymorphisms of the following XMEs; glutathione S-transferases (GST), N-acetyltransferases (NAT) and Paraoxonase (PON1). RESULTS: Median age was 39 (30-48) and most had 9 years of education or less (65.5%). 54% of the participants were OP pesticide applicators. There was a low prevalence of the GST null genotype (GSTT-1% and GSTM-16%) and the GA and GG genotype for NAT (10%). Modulation of OP exposure and neurotoxic outcome relationships by NAT, PON1 at position 192 and GST was indicated in multivariate analysis. The strongest evidence of modification was by NAT on the relationship between pesticide poisoning and impaired vibration sense. Poisoned individuals with the GG genotype were more likely to suffer from impaired vibration sense compared to GA and AA genotypes. CONCLUSION: Genetic polymorphisms of NAT, PON1 (at position 192) and GSTM may modify the relationship between OP exposure and neurotoxicity. Larger longitudinal studies are required to determine whether preventive strategies can be developed to improve health amongst the identified vulnerable groups.
- ItemOpen AccessHealth risk perception of Karoo residents related to fracking, South Africa(2015) Willems, Mieke; Dalvie, Mohamed Aqiel; Rother, Hanna-Andrea; London, LeslieShale gas exploration by means of Hydraulic Fracturing (fracking) has been on the South African (SA) energy agenda since 2010 as a potential alternative energy source to coalmining. Internationally, the desirability of fracking is debated due to increasing evidence of the environmental and health risks fracking poses. However, experts favouring fracking propose this technology as a greener alternative to conventional energy sources such as coal. Limited scientific evidence is available internationally related to knowledge and risk perceptions of fracking and evidence is limited to studies conducted in the United States (US). South African risk perception studies relates to mining, farming, travelling in SA as a foreigner and sexual behaviour. The president of SA called fracking a 'Game-Changer' using industry jargon in the 2014 presidential address. However, SA has failed to produce exploration regulations to date despite oil and gas companies pushing their agendas. Public participation in the process thus far has been limited. This cross sectional study explored the knowledge, health risk perceptions and information sources related to fracking amongst 102 Central Karoo residents through a household survey. Beaufort West municipality was selected as the study site as this is one of the closestareas to Cape Town demarcated for fracking exploration. This study found that 40% of Central Karoo residents do not know what fracking is or the potential risks and benefits thereof. Media is the main information source of 59% of participants. Only half of participants trust their information sources. Those with more trust in their information sources perceived fracking as posing a greater risk. In contrast those believing fracking to pose a low risk were more likely to trust the government and oil and gas companies. More than half of participants (53%) believe that fracking poses an extreme health risk and 78% thought fracking will harm their health. Most commonly listed causes why fracking will make Karoo residents sick includes water pollution (47.4%) and air pollution (19.6%). Higher education was found to have an inverse relationship with trust in the national government A limitation of this study was that farms could not be randomly selected, affecting the representativeness of the sample. There is a major lack of knowledge pertaining to fracking among those living in the Central Karoo which has important implications for managing the process of public participation in the approval of shale gas exploration.
- ItemOpen AccessThe long-term respiratory health effects of the herbicide, paraquat, among Western Cape workers(1996) Dalvie, Mohamed Aqiel; White, Neil; Myers, JonnyObjective: Paraquat is a commonly used herbicide worldwide and is a well-documented cause of pulmonary fibrosis in studies of laboratory animals and in humans following high dose exposure (usually accidental or as parasuicide). The respiratory effects of long-term, low dose paraquat exposure have not been fully evaluated. We set out to evaluate the possible effects of paraquat spraying among deciduous fruit farm workers in the Western Cape, South Africa. Methods: A cross-sectional study of 126 workers was performed. Administered questionnaires generated information on exposure, respiratory symptoms and confounding variables. Spirometry and gas transfer were measured and chest radiographs performed. Oxygen desaturation on exercise testing was by oximetry during a modified stage one exercise test. Results: No association was found between long-term paraquat exposure and reported symptoms, spirometry (FVC, FEVl, FEVl/FVC) and gas transfer (TLco and Kco) or chest radiography. Multivariate analysis showed a significant relationship between measures of long-term paraquat exposure and arterial oxygen desaturation during exercise (p < 0.05). Conclusion: Previous studies have also not shown a significant relationship between measures of paraquat exposure and standard tests of lung function. Arterial oxygen desaturation during exercise represents a more sensitive test. Our findings indicate that working with paraquat under usual field conditions for a long period is associated with abnormal exercise physiology in a dose dependant fashion.
- ItemOpen AccessNeurobehavioural effects of pesticide exposure among emerging farmers in the Western Cape(2013) Holtman, Zelda; London, Leslie; Dalvie, Mohamed AqielThe number of emerging farmers is increasing in South Africa. This study investigated neurotoxic effects resulting from long-term low-level exposure to organophosphate pesticides amongst emerging farmers. A cohort study involving 319 (66% male and 34% female) emerging farmers in the Western Cape was conducted between 2009 and 2010. Testing included a questionnaire exploring demographic details, work history, medical history; the Q16 and the Brief Symptom Inventory (BSI). Additionally, neurobehavioural performance was assessed on the following: Digit span forward and backward, Digit Symbol, Santa Ana Pegboard, Pursuit Aiming, Benton Visual Retention and Vibration sense as measured by vibration sense threshold using a 256 Hz frequency tuning fork. Exposure to OP's was derived from three metrics: (i) OP applicator status, (ii) cumulative OP exposure weighted for task/activity, (iii) diagnosed past poisoning. Two sets of analyses were conducted: a cross-sectional analysis at baseline (N=319), and a cohort analysis (N=273), comparing change in neurobehavioural performance over the 12 month follow up period. The exposure variable for cumulative occupational OP exposure in the baseline cross-section was generated from the job history data in the farmer questionnaire based on the exposure obtained during the current job and preceding three jobs. This represented long-term past OP exposure. In both the baseline cross-section and the cohort analysis, the relationship investigated was between dichotomised outcomes and four models for OP exposure. Three models used each of the metrics for OP exposure and a fourth model used the metric of cumulative OP exposure adjusted for diagnosed past poisoning. The difference between the analysis in the cohort was that both cumulative exposure and acute poisoning were restricted to the 12 months of follow up, whereas the baseline, both cumulative and acute poisoning were based on any past exposure without a time period. Further, for the cohort study (n=273), the outcomes were the difference in scores (measured as the ratio of the repeat measure at one year to the baseline score) which were regressed in the four exposure models outlined above. All models were controlled for confounders including age, gender, schooling, language, current alcohol consumption, previous head injuries, psychological illness and socioeconomic status. Model building led to the inclusion of additional co-variates for some of the analyses.
- ItemOpen AccessThe relationship between environmental exposures to pesticides measured by means of environmental exposure indices and the anthropomentric outcomes of boys living on farms in the rural Western Cape(2011) Ochieng, Anne Achieng; Dalvie, Mohamed AqielFew epidemiological studies have investigated the effect of pesticides on growth of boys and results are conflicting. Pesticide environmental exposure indices have not previously been developed. To investigate the effect of pesticide exposure using environmental exposure indices on pubertal growth of boys...
- ItemOpen AccessThe relationship between pesticide metabolites and asthma outcomes among women farm workers(2013) Mwanga, Hussein Hassan; Jeebhay, Mohamed; Dalvie, Mohamed AqielVarious studies have demonstrated an association between exposure to pesticides and adverse respiratory health outcomes including non-specific respiratory symptoms, rhinitis and asthma. Few studies have investigated the relationship between pesticide metabolites and asthma outcomes and only a limited number have explored mechanisms for allergic and non-allergic airway inflammation in individuals exposed to pesticides. A previous sub-study of this group reported an association between allergic airway inflammation as determined by fractional exhaled nitric oxide (FeNO) and low levels of whole blood cholinesterase among women farm workers. The main objective of this study was to investigate the relationship between exposure to different pesticides (ascertained through pesticide metabolites concentrations in urine) and asthma phenotypes (based on respiratory symptoms, cytokine patterns and exhaled nitric oxide profiles) among rural women in the Western Cape Province.
- ItemOpen AccessRelationship between pesticide residue levels and neurotoxicity among women on farms in the Western Cape(2014) Motsoeneng, Marnonyowe Portia; Dalvie, Mohamed AqielFarm workers and residents living in and around farms are exposed to pesticides. Women are vulnerable to health risks posed by pesticides. To date there are few studies that have investigated the relationship between pesticide residues in human body fluids and neurotoxicity. This study therefore aims to investigate the relationship between urinary pesticide residue levels and neurotoxicity amongst women working in farms in the Western Cape, South Africa.
- ItemOpen AccessThe reproductive health effects of along term DDT exposure on malaria vector control workers in Northern Province, South Africa(2002) Dalvie, Mohamed Aqiel; Myers, JohnnyMetabolites of DDT (1, 1, 1-trichloro-2,2-bis(p-chlorophenyl)ethane), used in many developing countries including South Africa for the control of malaria vectors, have been shown to be endocrine disruptors in vitro and in vivo. The study hypothesis was that male vector control workers highly exposed to DDT in the past should demonstrate clinically significant exposure-related anti-androgenic and/or estrogenic effects reflected in abnormalities in hormone levels, semen, sexual function and fertility. A cross-sectional study of 60 workers from 3 camps situated near Malaria Control Center (MMC) in Tzaneen was performed.
- ItemOpen AccessRespiratory allergy and asthma associated with pesticide exposure amongst women in rural Western Cape(2012) Ndlovu, Vuyelwa; Dalvie, Mohamed Aqiel; Jeebhay, MohamedPesticide exposure has been increasingly associated with adverse respiratory health effects including asthma and allergy. However, few studies have been conducted among women and workers in developing countries. South Africa is one of the largest users of pesticides on the continent and the Western Cape is one of the main agricultural areas in the country, with uncontrolled use posing an increased health risk to farm workers. This study focused on determining the association between pesticide exposure (predominantly organophosphates and carbamates) and the presence of allergy and asthma among women farm workers and residents. A cross-sectional study was conducted on 211 women including those working and living on farms (farm dwellers, n=121) and those residing in neighbouring farm areas (town dwellers, n=90). Outcome measurements included the abbreviated European Community Respiratory Health questionnaire, fractional exhaled nitric oxide (FeNO) levels and immunological tests (a positive Phadiatop test indicating atopy and quantification of specific IgE to house dust mite, storage mite and spider mite). The outcome variables included doctor diagnosed asthma, adult onset asthma, current asthma, allergic sensitisation, allergic airway inflammation and the asthma symptom score. The asthma symptom score was a continuous outcome generated as the sum of positive responses to four questions on asthma symptoms in the last 12 months including wheeze with breathlessness, woken up with chest tightness, attack of shortness of breath at rest and woken by attack of coughing. The asthma symptom score values ranged from from 0 for no symptoms to 4 for all symptoms.
- ItemOpen AccessThe Impact of Extreme Weather Events on Mental Health in Africa: A Mixed-Methods Systematic Review(2022) Deglon, Michaele; Dalvie, Mohamed Aqiel; Abrams, AmberIntroduction: The psychosocial impacts of extreme weather events are contributing to the burden of mental illness, exacerbated by pre-existing vulnerabilities. Despite an emerging global interest in this association, Africa remains poorly represented in the literature. Methods: A mixed-methods systematic review of peer-reviewed studies was conducted to determine the adverse mental health outcomes associated with extreme weather events in Africa (2008-2021). The review was conducted in line with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). Results: A total of 12 204 peer-reviewed articles were identified of which 12 were retained for analysis. These studies were all conducted in 8 countries in Sub-Saharan Africa. Adverse mental health outcomes were identified resulting from flood (n=4), drought (n=4), extreme heat (n=1), bushfire (n=1), and multiple events (n=2). Findings included pathological outcomes with predictable symptomatology including mood disorders; trauma- and stressor-related disorders; and suicide. Additionally, conditions indicating psychological distress which were below the pathological threshold including emotion regulation difficulties, disturbed sleep, alcohol use, stress, and anxiety. The quantitative evidence for the association between extreme weather events and mental health was limited primarily by a lack of longitudinal data, exposure gradient, and comparison to an unaffected group, as well as a failure to provide an objective exposure measure. The qualitative evidence for this association was complimentary but without sufficient clinical measurement these outcomes cannot be verified as psychological morbidities. In addition, this review provided insight into the mental health of vulnerable communities affected by extreme weather events including those living in poverty, farmers, pastoralists, women, and children. Conclusion: This review provided some preliminary evidence for the association between extreme weather events and adverse mental health outcomes for populations in Africa. The review also provides insight to vulnerable populations affected by extreme weather events. Future research with stronger designs and methodologies are recommended.
- ItemOpen AccessThe relationship between urinary organophosphate pesticide residues and reproductive development among boys living in the rural Western Cape(2018) Monate, Pearl Naledi; Dalvie, Mohamed Aqiel; Basera, WisdomBackground: Many contemporary agricultural pesticides are hormonally active, but few previous studies have investigated their effect on the reproductive health and growth of pubertal boys. A previous analysis found significant differences in serum reproductive hormone levels and lower anthropometric measurements as well as non-significant lower sexual maturity ratings and testicular sizes in farm boys compared to non-farm boys from the rural Western Cape in South Africa. Methodology: This analysis included 183 out of 269 school boys residing on farms and neighbouring nonfarming areas who provided urine samples in a cross-sectional study. Measurements included a questionnaire, clinical assessment of sexual maturity development (SMD), anthropometric measurements (height, weight and body mass index (BMI)), serum reproductive hormones (including luteinizing hormone (LH), follicle stimulating hormone (FSH), testosterone and oestradiol (E2)) and urinary levels of 3 dialkyl phosphates (organophosphate pesticide metabolites) including di-ethyl, di-methyl and di-methyl triphosphate (DEP, DMP and DMTP). Results: The median (interquartile range) of age and sum dialkyl phosphates of the school boys was 12 years (9-13 years) and 68.3 ng/mL (27.9-129.5 ng/mL) respectively. There were consistent, mostly non-significant associations with some dose response relationships between urinary levels of dialkyl phosphates and adverse effects on outcomes including SMD, serum reproductive hormones and anthropometric development. The strongest results included a strong positive association and dose response found between serum oestradiol > the 50th percentile and quartiles DMTP (odd ratio and confidence interval for highest and lowest quartile: 7.4; 1.7-32.4) and between BMI <50th percentile and quartiles of DMTP (odd ratio and confidence interval for highest and lowest quartile: 3.2; 1.2-9.0). Conclusion: The results provide some preliminary evidence that organophosphate pesticides exposure could alter the reproductive hormone levels and adversely affect the body size of school boys. There was also lack of evidence of other adverse effects on reproductive development. These findings require further investigation in a larger longitudinal study with seasonal bio-monitoring for pesticides.