Jonathan E Myers

Learn More
AIMS To measure the prevalence of silicosis among black migrant contract workers on a South African goldmine and to investigate exposure-response relations with silica dust. METHODS In a cross sectional study, 520 black goldminers (aged >37 years) were interviewed and had chest radiographs taken. Silicosis was defined as International Labour Organisation(More)
Five hundred and nine production workers at a manganese (Mn) smelting works comprising eight production facilities and 67 external controls were studied cross-sectionally for Mn related neuroehavioural effects. Exposure measures from personal sampling included Mn in inhalable dust as cumulative exposure indices (CEI) and average intensity (INT). Biological(More)
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(More)
Occupational exposure to airborne manganese dust has been shown to produce adverse effects on the central nervous system. Four hundred and eighty-nine blue and white collar manganese mineworkers from South Africa were studied cross-sectionally to investigate the nervous system effects of medium to low occupational manganese exposures. The different(More)
Long-term exposure to organophosphates (OPs) in the absence of acute poisoning is increasingly suspected of causing chronic neurologic and neurobehavioral effects. A cross-sectional survey of 163 spray operators on deciduous fruit farms in the Western Cape, South Africa, and 84 nonspraying labororers was conducted in 1993 to investigate the relationship(More)
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(More)
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(More)
The relationship between exposure to acrylamide monomer and neurological outcomes was investigated in 82 chemical industry workers. Vibrotactile thresholds were determined quantitatively with a Vibratron II device, using forced choice and method of limits procedures. Symptoms of numbness, limb pain, peeling skin, and sweating hands had significantly higher(More)
Five hundred and nine workers at a manganese (Mn) smelting works comprising eight production facilities and 67 external controls were studied cross-sectionally. Exposure measures from personal sampling included inhalable dust, cumulative exposure indices (CEI) and average intensity (INT = CEI/years exposed) calculated for the current job at the smelter and(More)
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(More)