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J E Myers

Publications and source records attributed to J E Myers.

At least 19 recordsLinked to original sources
PubMed2006

Tuberculosis and silica exposure in South African gold miners.

AIMS: To examine the effect of silica exposure, in the absence of silicosis, on the prevalence of pulmonary tuberculosis (PTB), which is epidemic among South African gold miners. METHODS: Cross-sectional study of 520 gold miners over 37 years of age. Length of service, and cumulative and average dust and quartz exposure indices were derived for each miner. Chest radiographs were read for PTB by two NIOSH "B" readers. PTB was defined as a self-reported history of PTB or PTB on chest radiograph. Logistic regression was used to adjust for age, smoking, and silicosis. PTB effects of different exposure metrics for silica, scaled on their interquartile range (IQR), were compared. RESULTS: Means (ranges) were: age 46.7 (37.1-59.9) years; length of service 21.8 (6.3-34.5) years; average intensity of respirable quartz 0.053 (0-0.095) mg/m3. PTB prevalence was 19.4% (95% CI 16.0 to 22.8) on history alone, and 35.2% (95% CI 31.1 to 39.3) on history or on chest radiograph. Length of service was poorly predictive of PTB, while all exposure indices which included dust or quartz yielded prevalence odds ratios (PORs) of approximately 1.4 (95% CI approximately 1.1 to 1.8) for changes of one interquartile range in exposure. Controlling for silicosis--by adjustment or restriction--did not modify these results. Drillers and winch operators had the highest PTB prevalences and the highest dust and silica exposures. CONCLUSION: Older in-service gold miners in South Africa have a high prevalence of PTB, which is significantly associated with dust and silica exposure, even in the absence of silicosis. Limitations include a survivor workforce and the use of cumulative exposures based on current exposures. Dust control is an important component in control of the PTB epidemic in South African gold mines.

Adult↗
PubMed2005

Evaluating and interpreting exposure-response relationships for manganese and neurobehavioral outcomes.

Exposure-response relationships (ERRs) are of interest in many areas of epidemiology. In occupational and environmental epidemiology in particular, the nature of such associations may have practical implications for policy and the setting of standards. We use a study undertaken to estimate the association between neurobehavioral test scores and manganese exposure to illustrate that tests for linear trend may be significant in the presence of highly non-linear ERRs. We illustrate this point further with simulated data where the form of the ERR is known. We provide guidelines for exploring the nature of ERRs, in the absence of a priori knowledge of the response of the outcome of interest to exposure.

Algorithms↗
PubMed2005

The nervous system effects of occupational exposure to manganese--measured as respirable dust--in a South African manganese smelter.

OBJECTIVES: A major recent review of occupational exposure limits for manganese (Mn) has proposed a respirable dust level of 0.1 mg/m3. There is, however, no theoretical basis for using this exposure metric to estimate the systemic effects of Mn, and little in the way of empirical data relating respirable Mn to neurobehavioural and other non-pulmonary effects. Cross-sectional data from a study showing few and unconvincing neurobehavioural effects of inhalable dust in Mn smelter workers published just prior to this review were reanalyzed here using respirable Mn. The hypotheses tested were that respirable Mn exposure is a more appropriate predictor of neurobehavioural effects than inhalable Mn where such effects exist, and that there should be no observed effects at respirable dust levels below 0.1 mg/m3. METHODS: Five hundred and nine production workers and 67 external referents were studied. Exposure measures from personal sampling included the Mn content of respirable dust as a concentration-time integrated cumulative exposure index (CEI) and as average intensity (INT) over a working lifetime. Neurobehavioural endpoints included items from the Swedish nervous system questionnaire (Q16), World Health Organisation neurobehavioural core test battery (WHO NCTB), Swedish performance evaluation system (SPES), Luria-Nebraska (LN), and Danish Product Development (DPD) test batteries, and a brief clinical examination. RESULTS: The median respirable Mn exposure was 0.058 mg/m3 (range=0-0.51; IQR=0.02-0.16) amongst the exposed, with 30% having average intensities above the proposed 0.1 mg/m3 and 44% above the proposed supplemental limit of 0.5 mg/m3 inhalable dust. As in the study of inhalable Mn effects, there were few respirable Mn effects showing clear continuity of response with increasing exposure. CONCLUSION: These data did not provide empirical support for a respirable, as opposed to an inhalable, dust metric being more sensitive in the identification of Mn effects. Neither metric showed convincing effects within the exposure range studied. Further study is needed to determine a threshold for respirable Mn effects, if such exist, and to verify our findings.

Adult↗
PubMed2004

Syncytiotrophoblast degradation and the pathophysiology of the malaria-infected placenta.

Malaria is associated with excessive parasitic infection of the placenta and a reduction in neonatal birthweight. This study has investigated placental cell death in women with active and past malarial infection. Term placentae, with and without malarial pathology, were obtained from women in The Gambia. Active and past malaria infections were identified in placental sections and histological examination was used to determine the number of villi, the incidence of apoptosis, syncytial degradation, fibrinoid deposition and the frequency of syncytial knots. Placentae with active malaria infection showed erythrocyte adhesion of infected cells to syncytiotrophoblast, syncytial degradation, increased syncytial knotting and, in rare cases, localized destruction of the villi. Past malarial infection was characterized by syncytiotrophoblast disruption and fibrin-type fibrinoid (FTF) deposition. Perivillous FTF deposition was consistent with increased syncytial lesions and both increased lesions and syncytial knots were associated with birthweight reductions. Active malaria infection produced no alteration in placental apoptosis. The numbers of chorionic villi remained unchanged and infiltration of inflammatory cells, although not measured directly, appeared to be non-pervasive within the infected tissue. These observations establish a direct link between malaria parasitic infection and syncytiotrophoblast damage. The placental rejection of parasite-affected syncytia may invoke structural changes to compensate for inadequate placental exchange. Syncytial destruction could have serious implications; impairing fetal growth and in some rare cases, providing a previously unrecognized pathway to congenital infection.

Adolescent↗
PubMed2001

Public health lessons from a pilot programme to reduce mother-to-child transmission of HIV-1 in Khayelitsha.

OBJECTIVE: Short-course antiretroviral therapy (ART) has been shown to be effective in reducing mother-to-child transmission (MTCT) of HIV-1. This article details the public health lessons learnt from a district-based pilot programme where a short-course zidovudine (ZDV) regimen has been used in a typical South African peri-urban setting. METHODS: The pilot programme was initiated at two midwife obstetric units in January 1999. Lay counsellors conducted pre- and post-test counselling and nurses took blood for HIV enzyme-linked immunosorbent assay (ELISA) testing. Short-course ZDV was administered antenatally (from 36 weeks' gestation) and during labour. Mother-infant pairs were followed up at eight child health clinics where free formula feed was dispensed weekly. Infants received co-trimoxazole prophylaxis and were ELISA tested for HIV at 9 and 18 months. After 17 months protocol changes aimed at eliminating weaknesses included initiation of ZDV at 34 weeks, self-administration of the first dose of ZDV with the onset of labour, and rapid HIV testing for both mothers and infants. RESULTS: Voluntary counselling and testing was shown to be highly acceptable, with individual counselling more effective than group counselling. Based on less than optimal availability of records, ZDV utilisation was encouraging with up to 59% of subjects initiating treatment, 3 weeks' median duration of ZDV use, and up to 88% receiving at least one intrapartum ZDV dose. Self-administration of the intrapartum dose reached 41%. CONCLUSIONS: Short-course antenatal and intrapartum ART to prevent MTCT of HIV1 was shown to be feasible.

AIDS Serodiagnosis↗
PubMed2001

Screening for primary aldosteronism--normal ranges for aldosterone and renin in three South African population groups.

OBJECTIVE: To establish normal ranges for plasma aldosterone, renin and aldosterone/renin (A/R) ratio in South African normotensives under typical outpatient conditions, and to estimate the prevalence of primary aldosteronism (PA) among hypertensives in primary care settings. DESIGN AND METHODS: One hundred and thirty-six normotensive subjects and 154 sex- and age-matched hypertensives at three primary care clinics had measurements of blood pressure, plasma creatinine, K+, aldosterone, plasma renin activity, and spot urine for urinary Na+/creatinine ratio. Medication was not withdrawn before testing. RESULTS: Mean plasma renin activity in black normotensive subjects (0.95 +/- 1.25 ng/ml/h, mean +/- standard deviation (SD)) was significantly lower than in white (2.09 +/- 1.12 ng/ml/h; P < 0.0001) and coloured (1.81 +/- 1.86 ng/ml/h, P = 0.013) normotensives. Mean plasma aldosterone in black normotensives (306 +/- 147 pmol/l) was also significantly lower than in white (506 +/- 324 pmol/l, P = 0.0002) and coloured (418 +/- 304 pmol/l, P = 0.0148) normotensives. In hypertensives, there were no significant differences in renin or aldosterone levels between the three population groups. Urinary Na+/creatinine ratios, an index of Na+ intake, were not significantly different in the three population groups. None of the normotensives had an A/R ratio > or = 1,000 plus aldosterone > or = 750, while 7.1% of hypertensives exceeded these levels, suggesting that they are appropriate criteria for screening for PA. CONCLUSIONS: A large fraction of black normotensive subjects had low renin and aldosterone levels compared with whites, suggesting a salt-retaining tendency in black subjects. These results have important implications for the interpretation of plasma renin and aldosterone levels in hypertensive patients. In primary care settings, 7.1% of hypertensives had biochemical results indicating the need for investigation of PA.

Aldosterone↗
PubMed2001

Risperidone: review of its therapeutic utility in depression.

There is extensive evidence to implicate dysregulation of noradrenergic, serotonergic, and dopaminergic neurotransmission in the pathophysiology of mood disorders. The receptor profile for risperidone, an atypical antipsychotic with demonstrated efficacy in schizophrenia, is consistent with possible antidepressant activity. Specifically, risperidone is a potent antagonist of central 5-HT2A receptors, addressing symptoms such as insomnia, agitation, and weight loss and may indirectly enhance 5-HT1A-mediated neurotransmission. A search of the worldwide medical literature published through December 2000 revealed 24 publications pertinent to the clinical use of risperidone in the treatment of patients with depressive symptomatology. In schizophrenia, in which depression is a common comorbid condition, the results of eight randomized, blinded, and controlled trials consistently demonstrated that treatment with risperidone significantly reduced scores on various measures of depressive symptoms. Moreover, these effects were distinct from improvements in negative and positive symptoms. Antidepressant effects also were observed in two large meta-analyses of trials in patients with schizophrenia or schizoaffective disorder. Observations from uncontrolled studies and case reports of risperidone therapy of other psychiatric disorders were similarly suggestive of antidepressant activity. Collectively, the evidence we present in this review indicates that risperidone's therapeutic benefits in psychiatric medicine extend beyond potent and effective antipsychotic activity and may include effectiveness in treating depression and related affective disorders. Systematic studies are now needed to evaluate the utility of concomitant therapy with an atypical antipsychotic in psychotic, bipolar, and treatment-resistant depressive syndromes.

Animals↗
PubMed2000

Essentiality, expression, and characterization of the class II 3-hydroxy-3-methylglutaryl coenzyme A reductase of Staphylococcus aureus.

Sequence comparisons have implied the presence of genes encoding enzymes of the mevalonate pathway for isopentenyl diphosphate biosynthesis in the gram-positive pathogen Staphylococcus aureus. In this study we showed through genetic disruption experiments that mvaA, which encodes a putative class II 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase, is essential for in vitro growth of S. aureus. Supplementation of media with mevalonate permitted isolation of an auxotrophic mvaA null mutant that was attenuated for virulence in a murine hematogenous pyelonephritis infection model. The mvaA gene was cloned from S. aureus DNA and expressed with an N-terminal His tag in Escherichia coli. The encoded protein was affinity purified to apparent homogeneity and was shown to be a class II HMG-CoA reductase, the first class II eubacterial biosynthetic enzyme isolated. Unlike most other HMG-CoA reductases, the S. aureus enzyme exhibits dual coenzyme specificity for NADP(H) and NAD(H), but NADP(H) was the preferred coenzyme. Kinetic parameters were determined for all substrates for all four catalyzed reactions using either NADP(H) or NAD(H). In all instances optimal activity using NAD(H) occurred at a pH one to two units more acidic than that using NADP(H). pH profiles suggested that His378 and Lys263, the apparent cognates of the active-site histidine and lysine of Pseudomonas mevalonii HMG-CoA reductase, function in catalysis and that the general catalytic mechanism is valid for the S. aureus enzyme. Fluvastatin inhibited competitively with HMG-CoA, with a K(i) of 320 microM, over 10(4) higher than that for a class I HMG-CoA reductase. Bacterial class II HMG-CoA reductases thus are potential targets for antibacterial agents directed against multidrug-resistant gram-positive cocci.

Amino Acid Sequence↗
PubMed2000

Utility of vibration sense testing for use in developing countries: comparison of extinction time on the tuning fork to vibration thresholds on the Vibratron II.

The measurement of vibration sense loss is a useful tool to detect early impacts of neurotoxic chemicals. Measurement methods are needed for developing countries that are culturally unbiased, and which can be used under field conditions where electricity may be unavailable. Extinction time on a 256 Hz tuning fork was compared to vibration threshold measured on the Vibratron II for precision and agreement amongst 306 fruit farm workers as part of a study investigating neurobehavioural impacts of organophosphates in South Africa in 1993. Simultaneous data were also available from a 1 g accelerometer attached to the post of the Vibratron for comparisons. Precision of the tuning fork and Vibratron II appeared comparable and CVs (2.5 to 8.9%) were lower than that reported in the literature. Agreement of the tuning fork with the Vibratron was moderate (Spearmans correlation coefficient of the order of 0.39 to 0.42) whereas agreement between Vibratron and Accelerometer was high (Spearmans correlation of coefficient of the order of 0.78 to 0.83). Height, age and schooling were predictors of vibration sense for the Vibratron and accelerometer but only schooling for extinction time on the tuning fork. Height modified the variability of the Vibratron and accelerometer. Delays in application of the tuning fork to the base of the medial malleolus of 3 seconds or more were associated with average increases in extinction time of 1.7 s. The tuning fork, as standardised in this study, represents a relatively quick, easy and low-technology device with good utility, that is relatively resistant to the usual confounders for vibration threshold measurement. Further studies to explore its validity in relation to other well-recognised methods for detection of subtle neurotoxic impacts should be encouraged.

Adult↗
PubMed1999

Case-control study of mesothelioma in South Africa.

BACKGROUND: South Africa has, uniquely, mined, transported, and used crocidolite, amosite, and chrysotile. A multicenter case-control study was done in South Africa to examine the details of asbestos exposure in cases and controls, and to calculate relative risks for level of certainty of asbestos exposure, nature of exposure (e.g., environmental, occupational) and fiber type. METHODS: Cases and controls (one cancer and one medical per case) were collected by six study centers from referral hospitals, and exposure information was collected by interviewing cases and controls in life. RESULTS: One hundred and twenty-three cases were accepted into the study. None had purely chrysotile exposure. Twenty-three cases had mined Cape crocidolite; three had mined amosite; and three Transvaal crocidolite plus amosite. A minimum of 22 of the cases had exclusively environmental exposure, 20 were from the NW Cape crocidolite mining area. The relative risks associated with environmental exposure in the NW Cape (crocidolite) were larger than for environmental exposure in the NE Transvaal (amosite and crocidolite): 21.9 vs. 7.1 and 50.9 vs. 12.0 for the cancer control and medical control datasets, respectively. CONCLUSIONS: The results confirm the importance of environmental exposure in the Cape crocidolite mining area, the relative paucity of cases linked to amosite, the rarity of chrysotile cases and are consistent with a fiber gradient in mesotheliomagenic potential for South African asbestos with crocidolite > amosite > chrysotile.

Asbestos↗
PubMed1999

Neuropsychological function in solvent-exposed South African paint makers.

Neuropsychological and neurological function were investigated in 228 organic solvent exposed paint manufacturing workers in two factories. Solvent exposure was expressed as both American Conference of Governmental Industrial Hygienists 1990 Threshold Limit Value equivalents and total hydrocarbon parts per million. The World Health Organization (WHO) neurobehavioral core test battery, the Neurobehavioural Evaluation System--2 (NES-2), and the UNISA Neuropsychological Assessment Procedure (UNAP) were used to measure outcomes, and a Vibratron II was used to measure peripheral vibration sensation. Exposures were generally below the Threshold Limit Value, and no exposure effect was found. Possible explanations for this finding are discussed, including low exposure, exposure, and outcome misclassification, together with inappropriateness, nonvalidity, and relative insensitivity of neuropsychological tests. Only age predicted Vibratron score. Some tests were clearly inappropriate for use in developing countries. Neuropsychological tests were sensitive to educational level, age, alcohol consumption, and cultural indicators. The WHO tests in particular showed good construct validity for neuropsychological functions and should be more formally validated for use in developing countries. Nevertheless, a major problem of cultural dependence is evident for all neuropsychological tests used in this study, and methods for bypassing this problem in less developed settings are discussed.

Adult↗
PubMed1999

Long-term respiratory health effects of the herbicide, paraquat, among workers in the Western Cape.

OBJECTIVE: To evaluate the possible effects of paraquat spraying among workers on deciduous fruit farms in the Western Cape, South Africa. Paraquat is a commonly used herbicide world wide and is a well documented cause of pulmonary fibrosis in studies of laboratory animals and in humans after exposure to a high dose (usually accidental or as parasuicide). The respiratory effects of long term, low dose exposure to paraquat have not been fully evaluated. METHODS: A cross sectional study of 126 workers. Administered questionnaires generated information on exposure, respiratory symptoms, and potential 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 exposure to paraquat and reported symptoms, spirometry (forced vital capacity (FVC), forced expiratory volume in 1 second (FEV1), FEV1/FVC) and gas transfer (TLCO and KCO) or chest radiography. Multivariate analysis showed a significant relation between measures of long term exposure to paraquat and arterial oxygen desaturation during exercise independent of short term exposure. CONCLUSION: Previous studies have not shown a significant relation between measures of exposure to paraquat and standard tests of lung function. Arterial oxygen desaturation during exercise represents a more sensitive test. The findings indicate that working with paraquat under usual field conditions is associated with abnormal exercise physiology in a dose dependent fashion independent of recent exposure and acute poisoning events.

Adult↗
PubMed1998

Sustained withdrawal allows normalization of in vivo [11C]N-methylspiperone dopamine D2 receptor binding after chronic binge cocaine: a positron emission tomography study in rats.

In our previous positron emission tomography studies striatal binding for both [11C]SCH23390 and [11C]N-methylspiperone (NMSP) were decreased in the rat brain on the last day of chronic (14 days) binge cocaine administration. We have found that [11C]SCH23390 binding to dopamine D1 receptors returns to saline control levels within ten days withdrawal from chronic binge cocaine and remains at control levels after 21 days withdrawal. An 18% decrease in [11C]NMSP binding to dopamine D2 receptors was observed after ten days withdrawal. However, importantly, after 21 days withdrawal [11C]NMSP binding was at saline control levels. Changes of in vivo [11C]NMSP binding required a longer abstinence period for normalization than [11C]SCH23390 binding. The apparent recovery of dopamine D2 receptors after prolonged abstinence from chronic cocaine and the different rates of normalization for dopamine D1 versus D2 receptors may be critical information for development of pharmacotherapies for cocaine dependent patients.

Analysis of Variance↗
PubMed1998

Meta-analysis and occupational epidemiology.

Meta-analysis is increasingly appearing in the epidemiologic literature. Although originally performed in the context of experimental or randomized controlled study designs and with regard to problems that are amenable to these designs, the method has also been applied to studies in observational epidemiologic settings. This movement has generated considerable debate about the validity of meta-analysis in observational studies, which can be said to be rather shaky. Meta-analysis is also appearing in occupational epidemiology, and a recent application to studies of industrial cohorts exposed to organic solvents has illustrated many of the arguments against meta-analysis of observational study. The propensity of meta-analysis for disarming critical approaches to individual study methods such as the standardized morbidity or mortality ratio (SMR) as effect measure, and to application of commonly used biostatistical techniques is illustrated. A cautionary note is sounded.

Healthy Worker Effect↗
PubMed1998

Use of a crop and job specific exposure matrix for retrospective assessment of long-term exposure in studies of chronic neurotoxic effects of agrichemicals.

RATIONALE: Job exposure matrices (JEMs) are widely used in occupational epidemiology, particularly when biological or environmental monitoring data are scanty. However, as with most exposure estimates, JEMs may be vulnerable to misclassification. OBJECTIVES: To estimate the long term exposure of farm workers based on a JEM developed for use in a study of the neurotoxic effects of organophosphates and to evaluate the repeatability and validity of the JEM. METHODS: A JEM was constructed with secondary data from industry and expert opinion of the estimate of agrichemical exposure within every possible job activity in the JEM to weight job days for exposure to organophosphates. Cumulative lifetime and average intensity exposure of organophosphate exposure were calculated for 163 pesticide applicators and 84 controls. Repeat questionnaires were given to 29 participants three months later to test repeatability of measurements. The ability of JEM based exposure to predict a known marker of organophosphate exposure was used to validate the JEM. RESULTS: Cumulative lifetime exposure as measured in kg organophosphate exposure, was significantly associated with erythrocyte cholinesterase concentrations (partial r2 = 5%; p < 0.01), controlled for a range of confounders. Repeatability in a subsample of 29 workers of the estimates of cumulative (Pearson's r = 0.67; 95% confidence interval (95% CI) 0.41 to 0.83), and average lifetime intensity of exposure (Pearson's r = 0.60 95% CI 0.31 to 0.79) was adequate. CONCLUSION: The JEM seems promising for farming settings, particularly in developing countries where data on chemical application and biological monitoring are unavailable.

Agriculture↗
PubMed1998

Prevalence odds ratio or prevalence ratio in the analysis of cross sectional data: what is to be done?

OBJECTIVES: To review the appropriateness of the prevalence odds ratio (POR) and the prevalence ratio (PR) as effect measures in the analysis of cross sectional data and to evaluate different models for the multivariate estimation of the PR. METHODS: A system of linear differential equations corresponding to a dynamic model of a cohort with a chronic disease was developed. At any point in time, a cross sectional analysis of the people then in the cohort provided a prevalence based measure of the effect of exposure on disease. This formed the basis for exploring the relations between the POR, the PR, and the incidence rate ratio (IRR). Examples illustrate relations for various IRRs, prevalences, and differential exodus rates. Multivariate point and interval estimation of the PR by logistic regression is illustrated and compared with the results from proportional hazards regression (PH) and generalised linear modelling (GLM). RESULTS: The POR is difficult to interpret without making restrictive assumptions and the POR and PR may lead to different conclusions with regard to confounding and effect modification. The PR is always conservative relative to the IRR and, if PR > 1, the POR is always > PR. In a fixed cohort and with an adverse exposure, the POR is always > or = IRR, but in a dynamic cohort with sufficient underlying follow up the POR may overestimate or underestimate the IRR, depending on the duration of follow up. Logistic regression models provide point and interval estimates of the PR (and POR) but may be intractable in the presence of many covariates. Proportional hazards and generalised linear models provide statistical methods directed specifically at the PR, but the interval estimation in the case of PH is conservative and the GLM procedure may require constrained estimation. CONCLUSIONS: The PR is conservative, consistent, and interpretable relative to the IRR and should be used in preference to the POR. Multivariate estimation of the PR should be executed by means of generalised linear models or, conservatively, by proportional hazards regression.

Chronic Disease↗
PubMed1998

Effects of long-term organophosphate exposures on neurological symptoms, vibration sense and tremor among South African farm workers.

OBJECTIVES: This study assessed the relationship between long-term exposure to organophosphate insecticides and neurological symptoms, vibration sense, and motor tremor after control for the effect of past poisoning and acute exposure. METHODS: This cross-sectional study included 164 pesticide applicators and 83 nonspraying reference workers on deciduous fruit farms. The workers were tested on the Vibratron II, on tests of dynamic and static tremor, and for a set of neurological and "dummy" symptoms. Exposure was derived with the use of a job-exposure matrix for pesticides in agriculture. RESULTS: Compared with nonapplicators, current applicators reported significantly more dizziness, sleepiness, and headache and had a higher overall neurological symptom score. This association remained statistically significant after multiple logistic regression analyses controlling for a range of confounders and effect modifiers [odds ratio (OR) 2.25, for current applicators having high neurological score, 95% confidence interval (95% CI) 1.15-4.39]. The average lifetime intensity of organophosphate exposure was nonsignificantly associated with both neurological (OR 1.98, 95% CI 0.49-7.94) and "dummy" symptoms (OR 2.37, 95% CI 0.54-10.35). Previous pesticide poisoning was significantly associated with the neurological scores (OR 4.08, 95% CI 1.48-11.22) but not with the "dummy" symptoms. Vibration sense outcomes were associated with age and height, but not with the organophosphate exposure measures. In the multiple linear regression modeling for tremor intensity in the dominant hand, recent organophosphate exposure in the past 10 days was a significant predictor (partial correlation coefficient = 0.04), but none of the long-term organophosphate exposure measures were significant. CONCLUSIONS: Strong evidence was found for an association between symptom outcomes and past organophosphate poisoning and between symptom outcomes and current spray activity. In contrast to symptoms, there was no association between either past poisoning or current spray activity and vibration sense or tremor outcome. Long-term organophosphate exposure did not appear to predict symptoms, vibration sense, or tremor outcome.

Adult↗