Evaluation of potential health effects associated with occupational and environmental exposure to styrene - an update.

The potential chronic health risks of occupational and environmental exposure to styrene were evaluated to update health hazard and exposure information developed since the Harvard Center for Risk Analysis risk assessment for styrene was performed in 2002. The updated hazard assessment of styrene's health effects indicates human cancers and ototoxicity remain potential concerns. However, mechanistic research on mouse lung tumors demonstrates these tumors are mouse-specific and of low relevance to human cancer risk. The updated toxicity database supports toxicity reference levels of 20 ppm (equates to 400 mg urinary metabolites mandelic acid + phenylglyoxylic acid/g creatinine) for worker inhalation exposure and 3.7 ppm and 2.5 mg/kg bw/day, respectively, for general population inhalation and oral exposure. No cancer risk value estimates are proposed given the established lack of relevance of mouse lung tumors and inconsistent epidemiology evidence. The updated exposure assessment supports inhalation and ingestion routes as important. The updated risk assessment found estimated risks within acceptable ranges for all age groups of the general population and workers with occupational exposures in non-fiber-reinforced polymer composites industries and fiber-reinforced polymer composites (FRP) workers using closed-mold operations or open-mold operations with respiratory protection. Only FRP workers using open-mold operations not using respiratory protection have risk exceedances for styrene and should be considered for risk management measures. In addition, given the reported interaction of styrene exposure with noise, noise reduction to sustain levels below 85 dB(A) needs be in place.

Risk of hospitalized bacterial infections associated with biologic treatment among US veterans with rheumatoid arthritis.

OBJECTIVE: The comparative risk of infection associated with non-anti-tumor necrosis factor (anti-TNF) biologic agents is not well established. Our objective was to compare risk for hospitalized infections between anti-TNF and non-anti-TNF biologic agents in US veterans with rheumatoid arthritis (RA). METHODS: Using 1998-2011 data from the US Veterans Health Administration, we studied RA patients initiating rituximab, abatacept, or anti-TNF therapy. Exposure was based upon days supplied (injections) or usual dosing intervals (infusions). Treatment episodes were defined as new biologic agent use. Hazard ratios (HRs) and 95% confidence intervals (95% CIs) for hospitalization for a bacterial infection were estimated from Cox proportional hazards models, adjusting for potential confounders. RESULTS: Among 3,152 unique RA patients contributing 4,158 biologic treatment episodes to rituximab (n = 596), abatacept (n = 451), and anti-TNF agents (n = 3,111), the patient mean age was 60 years and 87% were male. The most common infections were pneumonia (37%), skin/soft tissue (22%), urinary tract (9%), and bacteremia/sepsis (7%). Hospitalized infection rates per 100 person-years were 4.4 (95% CI 3.1-6.4) for rituximab, 2.8 (95% CI 1.7-4.7) for abatacept, and 3.0 (95% CI 2.5-3.5) for anti-TNF. Compared to etanercept, the adjusted rate of hospitalized infection was not different for adalimumab (HR 1.4, 95% CI 0.9-2.2), abatacept (HR 1.1, 95% CI 0.6-2.1), or rituximab (HR 1.4, 0.8-2.6), although it was increased for infliximab (HR 2.3, 95% CI 1.3-4.0). Infection risk was greater for those taking prednisone >7.5 mg/day (HR 1.8, 95% CI 1.3-2.7) and in the highest quartile of C-reactive protein (HR 2.3, 95% CI 1.4-3.8) and erythrocyte sedimentation rate (HR 4.1, 95% CI 2.3-7.2) compared to the lowest quartile. CONCLUSION: In older, predominantly male US veterans with RA, the risk of hospitalized bacterial infections associated with rituximab or abatacept was similar to etanercept.

Use of pharmacologic agents for the primary prevention of osteoporosis among older women with low bone mass.

UNLABELLED: We examined the use of pharmacologic agents for the primary prevention of osteoporosis among older women with osteopenia. We found that these individuals were not managed in concordance with the National Osteoporosis Foundation (NOF) guidelines and that self-perceived osteoporosis risk and lower bone density were strongly associated with receipt of treatment. INTRODUCTION: Although osteoporosis medications are used for the primary prevention of osteoporosis among persons with low bone mass (osteopenia), their use may be discordant with clinical practice guidelines. METHODS: We studied women 55 years and older participating in the Global Longitudinal Study of Osteoporosis in Women (GLOW). Eligible participants had a dual energy x-ray absorptiometry (DXA) test performed at the University of Alabama at Birmingham hospital and had an osteopenia diagnosis based on their DXA test results. Participants' demographics, fracture risk factors, and exposure to osteoporosis medications were determined from the GLOW survey. We examined the proportions of women managed in concordance with the National Osteoporosis Foundation 2008 guidelines, and we assessed factors independently associated with osteoporosis treatment decisions. Women with a prior spine or hip fracture were excluded. RESULTS: Among 597 eligible women from GLOW, the mean age ± standard deviation (SD) was 70 ± 7 years. Among all subjects, 309 (52%) were treated in concordance with the NOF 2008 guidelines. Greater self-perceived osteoporosis risk and lower bone mineral density were significantly and consistently associated with receipt of osteoporosis treatment, both for those considered appropriate and for those considered inappropriate for treatment based on the NOF guidelines. CONCLUSIONS: We found significant discordance between NOF 2008 guidelines and pharmacologic management of women with osteopenia. A person's self-perceived osteoporosis risk and bone mineral density were most strongly associated with receipt of osteoporosis medication use among women with low bone mass.

Incidence and risk factors for progressive multifocal leukoencephalopathy among patients with selected rheumatic diseases.

OBJECTIVE: To ascertain the incidence of progressive multifocal leukoencephalopathy (PML) in patients with selected rheumatic diseases, to describe the characteristics of PML cases occurring in this setting, and to evaluate the extent to which such cases occurred in the context of biologic therapies such as rituximab or tumor necrosis factor antagonists. METHODS: We conducted a large population-based study to describe the incidence and risk factors for PML among patients with rheumatoid arthritis, psoriatic arthritis, psoriasis, juvenile idiopathic arthritis, inflammatory bowel disease, and ankylosing spondylitis using national inpatient and outpatient administrative data from the entire Center for Medicare and Medicaid Services from 2000-2009. Suspected PML cases were identified using hospital discharge diagnosis codes. Risk factors for PML were evaluated using outpatient data ≥6 months prior to PML diagnosis. RESULTS: Among 2,030,578 patients with autoimmune diseases of interest, a total of 53 PML cases were identified (2.6 per 100,000 patients). Most PML cases had human immunodeficiency virus (HIV) and/or cancer. Nine PML cases had evidence for biologic use prior to PML hospitalization, of which 3 had neither HIV nor malignancy and were exposed to biologics within 12 (rituximab) or 6 months (all other biologics) prior to PML diagnosis. PML occurred at an estimated incidence of 0.2 per 100,000 patients with autoimmune diseases who did not have HIV or malignancy. CONCLUSION: PML occurs at a very low incidence among patients with rheumatic diseases but can occur even in the absence of HIV or malignancy.

Mortality following bone metastasis and skeletal-related events among men with prostate cancer: a population-based analysis of US Medicare beneficiaries, 1999-2006.

Information on the impact of bone metastasis and skeletal-related events (SREs) on mortality among prostate cancer patients is limited. Using the linked Surveillance, Epidemiology and End Results (SEER)-Medicare database, we identified men aged 65 years or older diagnosed with prostate cancer between July 1 1999 and December 31 2005 and followed to determine deaths through December 31 2006. We classified subjects as having bone metastasis and SREs as indicated by Medicare claims. Using Cox regression, we estimated mortality hazards ratios (HR) among men with bone metastasis with or without SRE, compared with men without bone metastasis. Among 126,978 men with prostate cancer (median follow-up, 3.3 years), 9746 (7.7%) had bone metastasis at prostate cancer diagnosis (1.7%) or during follow-up (5.9%). SREs occurred in 4296 (44%) men with bone metastasis. HRs for risk of death were 6.6 (95% CI=6.4-6.9) and 10.2 (95% CI=9.8-10.7), respectively, for men with bone metastasis but no SRE and for men with bone metastasis plus SRE, compared with men without bone metastasis. Bone metastasis was associated with mortality among prostate cancer patients. This association appeared to be stronger for bone metastasis plus SRE than for bone metastasis without SRE.

Clinical and demographic factors associated with fractures among older Americans.

UNLABELLED: Medicare claims data were used to investigate associations between history of previous fractures, chronic conditions, and demographic characteristics and occurrence of fractures at six anatomic sites. The study confirmed previously established associations for hip and spine fractures and identified several new associations of interest for nonhip, nonspine fractures. INTRODUCTION: This study investigates the associations of a history of fracture, comorbid chronic conditions, and demographic characteristics with incident fractures among Medicare beneficiaries. The majority of fracture incidence studies have focused on the hip and on white females. This study examines a greater variety of fracture sites and more population subgroups than prior studies. METHODS: We used Medicare claims data to examine the incidence of fracture at six anatomic sites in a random 5% sample of Medicare beneficiaries during the time period 2000 through 2005. RESULTS: For each type of incident fracture, women had a higher rate than men, and there was a positive association with age and an inverse association with income. Whites had a higher rate than nonwhites. Rates were lowest among African-Americans for all sites except ankle and tibia/fibula, which were lowest among Asian-Americans. Rates of hip and spine fracture were highest in the South, and fractures of other sites were highest in the Northeast. Fall-related conditions and depressive illnesses were associated with each type of incident fracture, conditions treated with glucocorticoids with hip and spine fractures and diabetes with ankle and humerus fractures. Histories of hip and spine fractures were associated positively with each site of incident fracture except ankle; histories of nonhip, nonspine fractures were associated with most types of incident fracture. CONCLUSIONS: This study confirmed previously established associations for hip and spine fractures and identified several new associations of interest for nonhip, nonspine fractures.

Exposure to airborne asbestos in Jamaican hospitals / Exposición al asbesto suspendido en el aire en hospitales de Jamaica

OBJECTIVE: Asbestos is an established human carcinogen and has been identified at 16 of 26 Jamaican hospitals surveyed. We sought to determine if hospital employees are exposed and if current asbestos exposure in Jamaican hospitals differed by job category. METHOD: At two of the largest hospitals with more than 10 permanent maintenance workers and where over 67% of bulk samples analysed contained asbestos, three groups of employees selected by stratified random sampling participated in a personal air sampling study for asbestos. One hundred and thirty-two personal air samples and 32 area samples were collected and analysed for asbestos fibres utilizing phase contrast microscopy (PCM) and transmission electron microscopy (TEM). RESULTS: Twenty-four (14.6%) air samples had fibre counts above the limit of detection (LOD) for the analytical method (PCM), ranging from 0.002f/cc to 0.013 f/cc. The fibres met the dimensional characteristics ofasbestos fibres. There was no difference in the median fibre concentration to which the groups of employees were exposed. Further testing of samples which had fibre counts above the LOD using TEM confirmed that the fibres were not asbestos. CONCLUSION: Despite not finding asbestos fibres in the air samples, most of the asbestos containing building material (ACBM) found in the hospitals was friable and in a poor condition indicative of fibre release. We recommend an ongoing monitoring programme for airborne asbestos fibres in hospitals until an abatement programme can be undertaken by the regulatory agencies in the country.

OBJETIVO: El asbesto, también llamado amianto, es un carcinógeno humano conocido, y ha sido identificado en 16 de 26 hospitales jamaicanos investigados. El presente trabajo tuvo por objeto determinar si los empleados del hospital están expuestos al asbesto, y si la exposición actual de asbesto en hospitales jamaicanos difiere según la categoría del trabajo. MÉTODO: En dos de los hospitales más grandes con más de 10 obreros de mantenimiento permanentes y dónde más del 67% de las muestras a granel analizadas contenían asbesto, tres grupos de empleados seleccionados por muestreo aleatorio estratificado participaron en una investigación de muestreo de aire personal en busca de asbesto. Ciento treinta y dos muestras de aire personal y 32 muestras de área fueron recogidas y analizadas en busca de fibras de asbesto, utilizando microscopía de contraste de fases (MCF) y microscopía electrónica de transmisión (MET). RESULTADOS: Veinticuatro (14.6%) muestras de aire tuvieron un conteo de fibras por encima del límite de detección (LDD) para el método analítico (MCF), que fluctuaba de 0.002 f/cc a 0.013 f/cc. Las fibras correspondían a las características dimensionales de las fibras de asbesto. No hubo diferencias en la concentración mediana de las fibras a la que los grupos de empleados estaban expuestos. Pruebas posteriores con las muestras que arrojaron conteos de fibras por encima del LDD usando la MET, confirmaron que las fibras no eran de asbesto. CONCLUSIÓN: A pesar de que no se encontraron fibras de asbesto en las muestras de aire, la mayor parte de los materiales de construcción que contienen asbesto (ACBM) hallados en los hospitales eran friables y estaban en mal estado, dando ya señales de desprendimiento de fibras. Se recomienda un programa de monitoreo de fibras de asbesto suspendidas en el aire en los hospitales hasta que pueda emprenderse un programa de eliminación de las mismas por parte de las agencias reguladoras del país.

Exposure to airborne asbestos in Jamaican hospitals.

OBJECTIVE: Asbestos is an established human carcinogen and has been identified at 16 of 26 Jamaican hospitals surveyed. We sought to determine if hospital employees are exposed and if current asbestos exposure in Jamaican hospitals differed by job category. METHOD: At two of the largest hospitals with more than 10 permanent maintenance workers and where over 67% of bulk samples analysed contained asbestos, three groups of employees selected by stratified random sampling participated in a personal air sampling study for asbestos. One hundred and thirty-two personal air samples and 32 area samples were collected and analysed for asbestos fibres utilizing phase contrast microscopy (PCM) and transmission electron microscopy (TEM). RESULTS: Twenty-four (14.6%) air samples had fibre counts above the limit of detection (LOD) for the analytical method (PCM), ranging from 0.002 f/cc to 0.013 f/cc. The fibres met the dimensional characteristics of asbestos fibres. There was no difference in the median fibre concentration to which the groups of employees were exposed. Further testing of samples which had fibre counts above the LOD using TEM confirmed that the fibres were not asbestos. CONCLUSION: Despite not finding asbestos fibres in the air samples, most of the asbestos containing building material (ACBM) found in the hospitals was friable and in a poor condition indicative of fibre release. We recommend an ongoing monitoring programme for airborne asbestos fibres in hospitals until an abatement programme can be undertaken by the regulatory agencies in the country.

"Pathologic" fractures: should these be included in epidemiologic studies of osteoporotic fractures?

UNLABELLED: Pathologic fractures are often excluded in epidemiologic studies of osteoporosis. Using Medicare administrative data, we identified persons with vertebral and hip fractures. Among these, 48% (vertebral) and 3% (hip) of the fractures were coded as pathologic. Only 25% and 66% of persons with these pathologic fractures had evidence for malignancy. INTRODUCTION: Analyses of osteoporosis-related fractures that use administrative data often exclude pathologic fractures (ICD-9 733.1x) due to concern that these are caused by cancer. We examined "pathologic" fractures of the vertebrae and hip to evaluate their contribution to fracture incidence and assessed the evidence for a malignancy. METHODS: We studied US Medicare beneficiaries age > or =65 with new fractures identified using ICD-9 diagnosis codes 733.13 (pathologic vert), 805.0, 805.2, 805.4, 805.8 (nonpathologic vert); and 733.14 (pathologic hip), 820.0, 820.2, 820.8 (nonpathologic hip). We further examined the proportion of cases with a diagnosis of a malignancy proximate to the fracture. RESULTS: We identified 44,120 individuals with a vertebral fracture and 60,354 with a hip fracture. Approximately 48% of vertebral fractures and 3% of hip fractures were coded as pathologic. For only approximately 25% of persons with a "pathologic" vertebral fracture ICD-9 code, but 66% of persons with a "pathologic" hip fracture, there was evidence of a possible cancer diagnosis. CONCLUSION: Among US Medicare beneficiaries, one fourth of pathologic vertebral fracture and two thirds of pathologic hip fracture cases had evidence for a malignancy. Particularly for vertebral fractures, excluding persons with pathologic fractures in epidemiologic analyses that utilize administrative claims data substantially underestimates the burden of fractures due to osteoporosis.

Estimated prevalence and patterns of presumed osteoporosis among older Americans based on Medicare data.

INTRODUCTION: Estimates of osteoporosis (OP) prevalence based on bone mineral density testing and fracture occurrence may be imprecise for small demographic groups. Medicare data are a useful supplemental source of information on OP. METHODS: We studied people ages > or = 65 years covered by Medicare 2005. Cases of presumed OP were beneficiaries with physician services or inpatient claims for OP or for an associated fracture (hip, distal forearm, spine) in 1999-2005. RESULTS: Among 911,327 beneficiaries with 6 or 7 years of Medicare coverage, the overall prevalence of OP and associated fractures was 29.7%. Prevalence was four times higher for women than men, increased with age, and was two times higher for whites, Hispanic Americans, and Asian Americans than African Americans. Among people with OP-associated fracture claims, the proportion with an OP diagnosis was 49.7% overall (women, 57.1%; men, 21.9%) and was lower for men than women and for African Americans than other ethnic groups. CONCLUSIONS: The low proportion of beneficiaries who had an OP-associated fracture and also had an OP diagnosis, particularly among men and African American women, suggests suboptimal recognition and management of OP. Study limitations included lack of validation of our definition of OP and potential misclassification of race/ethnicity.

RisedronatE and ALendronate Intervention over Three Years (REALITY): minimal differences in fracture risk reduction.

SUMMARY: The comparative effectiveness of alendronate and risedronate has received limited evaluation. Among 19,063 new users of bisphosphonates, risedronate users had a higher relative rate of hip fracture compared to alendronate users, but the difference in absolute fracture rate was small. We conclude that the agents have comparable efficacy. INTRODUCTION: Bisphosphonates differ in their in vitro potency, avidity for bone, and rapidity of onset in clinical trials. To address potential differences between bisphosphonates in comparative effectiveness, we compared new users of alendronate and risedronate to determine if there were differences in the risk of clinical fractures at 1 year and beyond. METHODS: Using claims data from a U.S. health care organization, we identified new, adherent users of weekly alendronate or risedronate and assessed subsequent fractures. We calculated fracture incidence rate differences and ratios between the two agents. RESULTS: There were no significant differences in fracture rates between alendronate users (n = 12,956) and risedronate users (n = 6,107) at 1 year. Using all available data, the rate of hip fracture was higher among risedronate users compared to alendronate users (absolute rate difference approximately five per 1,000 person-years). Risedronate users had a higher relative rate (RR) of hip fracture (RR = 1.77, 95% CI 1.15-2.74) and similar rates of clinical vertebral and nonvertebral fractures compared to alendronate users. CONCLUSIONS: The absolute rate of clinical fractures among alendronate and risedronate users was similar both at 1 year and beyond, suggesting comparable effectiveness between agents.

The geographic availability and associated utilization of dual-energy X-ray absorptiometry (DXA) testing among older persons in the United States.

UNLABELLED: Using national Medicare data from 1999-2006, we evaluated the relationship between travel distance and receipt of dual-energy X-ray absorptiometry (DXA). After adjusting for potentially confounding factors, travel distance was strongly associated with DXA testing. Rural residents were most strongly dependent on the availability of DXAs performed in physician offices. INTRODUCTION: Medicare reimbursement for DXAs performed in non-facility settings (e.g., physician offices) decreased in 2007. With declining reimbursement, some DXA providers may cease providing this service, which would increase travel distance for some people. The impact of travel distance on access to DXA is unclear. METHODS: Using national Medicare data, we identified claims for DXA to evaluate trends in the number and locations of DXAs performed. Travel distance was the distance from beneficiaries' residence and the nearest DXA provider. Binomial regression evaluated the relationship between travel distance and receipt of DXA. RESULTS: In 2006, 2.9 million DXAs were performed, a 103% increase since 1999. In 2005-2006, 8.0% of persons were tested at non-facility sites versus 4.2% at facility sites. The remainder (88%) had no DXA. Persons traveling 5-9, 10-24, 25-39, and 40-54, and > or = 55 miles were less likely to receive DXA (adjusted risk ratios = 0.92, 0.79, 0.43, 0.32, and 0.26, respectively, < 5 miles referent). Rural residents were more dependent than urban residents on the availability of DXA from non-facility providers. CONCLUSION: Approximately two-thirds of DXAs in 2005-2006 were performed in non-facility settings (e.g., physician offices). Rural residents would have preferentially reduced access to DXA if there were fewer non-facility sites.

Risk of hip fracture after bisphosphonate discontinuation: implications for a drug holiday.

UNLABELLED: Based upon interest in a bisphosphonate drug holiday, we evaluate the risk for hip fracture after bisphosphonate discontinuation. Among women compliant with bisphosphonates for > or = 2 years, the risk of hip fracture was increased after discontinuation, although with higher compliance and a longer duration of preceding bisphosphonate therapy, this risk was attenuated. INTRODUCTION: Recent data suggest that hip fracture risk was not significantly increased among women receiving 5 years of bisphosphonate therapy who were subsequently randomized to placebo. We studied older women compliant with bisphosphonates > or = 2 years to evaluate the risk of hip fracture after bisphosphonate discontinuation. METHODS: Using administrative databases from a large U.S. healthcare organization, we identified women initiating bisphosphonate therapy compliant (Medication Possession Ratio, MPR > or = 66%) for 2 years. We examined the rate of hip fracture among women who discontinued bisphosphonates versus those who remained on therapy. RESULTS: At 2 years, 9,063 women were eligible for analysis. Hip fracture incidence among women who discontinued bisphosphonates versus those who did not was 8.43 versus 4.67 per 1000 person years (p = 0.016). The adjusted hazard ratio of hip fracture per 90 days following discontinuation was 1.2 (1.1-1.3). For women with higher compliance at 2 years (MPR > or = 80%) or compliant for 3 years, there were no significant differences in risk associated with discontinuation. CONCLUSIONS: The rate of hip fracture was increased among women compliant with bisphosphonate therapy for 2 years who subsequently discontinued, suggesting that discontinuation is not advisable under these conditions. This association was attenuated with higher compliance and a longer duration of previous bisphosphonate therapy.

Cancer incidence among semiconductor and electronic storage device workers.

AIMS: To evaluate cancer incidence among workers at two facilities in the USA that made semiconductors and electronic storage devices. METHODS: 89 054 men and women employed by International Business Machines (IBM) were included in the study. We compared employees' incidence rates with general population rates and examined incidence patterns by facility, duration of employment, time since first employment, manufacturing era, potential for exposure to workplace environments other than offices and work activity. RESULTS: For employees at the semiconductor manufacturing facility, the standardised incidence ratio (SIR) for all cancers combined was 81 (1541 observed cases, 95% confidence interval (CI) 77 to 85) and for those at the storage device manufacturing facility the SIR was 87 (1319 observed cases, 95% CI 82 to 92). The subgroups of employees with > or =15 years since hiring and > or =5 years worked had 6-16% fewer total incidents than expected. SIRs were increased for several cancers in certain employee subgroups, but analyses of incidence patterns by potential exposure and by years spent and time since starting in specific work activities did not clearly indicate that the excesses were due to occupational exposure. CONCLUSIONS: This study did not provide strong or consistent evidence of causal associations with employment factors. Data on employees with long potential induction time and many years worked were limited. Further follow-up will allow a more informative analysis of cancer incidence that might be plausibly related to workplace exposures in the cohort.

An updated study of mortality among North American synthetic rubber industry workers.

AIM: This study evaluated the mortality experience of workers from the styrene-butadiene industry. METHODS: The authors added seven years of follow up to a previous investigation of mortality among 17 924 men employed in the North American synthetic rubber industry. Analyses used the standardised mortality ratios (SMRs) to compare styrene-butadiene rubber workers' cause specific mortality (1943-98) with those of the United States and the Ontario general populations. RESULTS: Overall, the observed/expected numbers of deaths were 6237/7242 for all causes (SMR = 86, 95% CI 84 to 88) and 1608/1741 for all cancers combined (SMR = 92, 95% CI 88 to 97), 71/61 for leukaemia, 53/53 for non-Hodgkin's lymphoma, and 26/27 for multiple myeloma. The 16% leukaemia increase was concentrated in hourly paid subjects with 20-29 years since hire and 10 or more years of employment in the industry (19/7.4, SMR = 258, 95% CI 156 to 403) and in subjects employed in polymerisation (18/8.8, SMR = 204, 95% CI 121 to 322), maintenance labour (15/7.4, SMR = 326, 95% CI 178 to 456), and laboratory operations (14/4.3, SMR = 326, 95% CI 178-546). CONCLUSION: The study found that some subgroups of synthetic rubber workers had an excess of mortality from leukaemia that was not limited to a particular form of leukaemia. Uncertainty remains about the specific agent(s) that might be responsible for the observed excesses and about the role of unidentified confounding factors. The study did not find any clear relation between employment in the industry and other forms of lymphohaematopoietic cancer. Some subgroups of subjects had more than expected deaths from colorectal and prostate cancers. These increases did not appear to be related to occupational exposure in the industry.

A cross-sectional study of triallate exposure and neurological health among workers at a pesticide manufacturing and formulating facility.

AIMS: To evaluate the relation between an indicator of cumulative exposure to triallate and selected measures of neurological function, including nerve conduction, the prevalence of certain neurological deficits as determined by a medical examination, and vibration perception threshold testing in workers at a pesticide manufacturing plant. METHODS: Subjects were 50 workers with high estimated triallate exposure ("high triallate" group) and 50 workers with no or low triallate exposure ("no/low triallate" group). Industrial hygienists used existing work histories and personal knowledge of plant operations to develop a triallate score. In-person interviews elicited information on past medical history and on occupational and non-occupational exposures. A neurologist carried out nerve conduction tests of the sural and the peroneal nerves, a standardised neurological examination, and vibration sensation testing. RESULTS: Differences between the high and the no/low triallate groups were minimal for all but one of the six nerve conduction tests, for the prevalence of neurological abnormalities, and for vibration sensation perception. The high triallate group had lower mean sural nerve peak amplitude than the no/low triallate group (11.7 v 15.2 microV, p = 0.03). This difference was reduced when adjusted for other potential risk factors (12.5 v 14.5 microV, p = 0.25) and was not associated with cumulative triallate score. We also noted several associations between factors other than triallate and nerve conduction measures. CONCLUSION: The results were consistent with the absence of an association between triallate and measures of neurological function.

Mortality and cancer incidence among alachlor manufacturing workers 1968-99.

BACKGROUND: Alachlor is the active ingredient in pre-emergent herbicide formulations that have been used widely on corn, soybeans, and other crops. It has been found to cause nasal, stomach, and thyroid tumours in rodent feeding studies at levels that are much higher than likely human exposures. AIMS: To evaluate mortality rates from 1968 to 1999 and cancer incidence rates from 1969 to 1999 for alachlor manufacturing workers at a plant in Muscatine, Iowa. METHODS: Worker mortality and cancer incidence rates were compared to corresponding rates for the Iowa state general population. Analyses addressed potential intensity and duration of exposure. RESULTS: For workers with any period of high alachlor exposure, mortality from all causes combined was lower than expected (42 observed deaths, SMR 64, 95% CI 46 to 86) and cancer mortality was slightly lower than expected (13 observed deaths, SMR 79, 95% CI 42 to 136). Cancer incidence for workers with potential high exposure was similar to that for Iowa residents, both overall (29 observed cases, SIR 123, 95% CI 82 to 177) and for workers exposed for five or more years and with at least 15 years since first exposure (eight observed cases, SIR 113, 95% CI 49 to 224). There were no cases of nasal, stomach, or thyroid cancer. CONCLUSIONS: There were no cancers of the types found in toxicology studies and no discernible relation between cancer incidence for any site and years of alachlor exposure or time since first exposure. Despite the small size of this population, the findings are important because these workers had chronic exposure potential during extended manufacturing campaigns, while use in agriculture is typically limited to a few days or weeks each year.

Cancer and benign tumor incidence among employees in a polymers research complex.

The detection of several intracranial tumors among employees in one building complex (C500) at a petrochemical research facility prompted investigation of a possible workplace cause. This retrospective follow-up study included 1847 subjects, of whom 1735 had worked in C500. Medical records, death certificates, and Illinois State Cancer Registry data confirmed self-reported cancers and tumors. Analyses compared the subjects' cancer and benign intracranial tumor incidence rates with national general population rates. C500 employees had 15% fewer than expected total cancers (92 observed/108 expected; standardized incidence ratio [SIR], 85; 95% confidence interval [95% CI], 69 to 104). An excess of brain cancer (6/2.0; SIR, 302; 95% CI, 111 to 657) was concentrated among white men who had 10 or more years since hire and 5 or more years of C500 employment (4/0.7; SIR, 602; 95% CI, 165 to 1552) and who had worked in a particular building of C500 (5/0.7; SIR, 735; 95% CI, 239 to 1716). An excess of benign intracranial tumors (6/1.6; SIR, 385; 95% CI, 142 to 839) was not restricted to a single type of tumor and was not concentrated in any particular building. Occupational exposure may have caused the increased rate of brain cancer but is a less likely explanation for the elevated rate of benign intracranial tumors.