Wireless phone use in childhood and adolescence and neuroepithelial brain tumours: Results from the international MOBI-Kids study

In recent decades, the possibility that use of mobile communicating devices, particularly wireless (mobile and cordless) phones, may increase brain tumour risk, has been a concern, particularly given the considerable increase in their use by young people. MOBI-Kids, a 14-country (Australia, Austria, Canada, France, Germany, Greece, India, Israel, Italy, Japan, Korea, the Netherlands, New Zealand, Spain) case-control study, was conducted to evaluate whether wireless phone use (and particularly resulting exposure to radiofrequency (RF) and extremely low frequency (ELF) electromagnetic fields (EMF)) increases risk of brain tumours in young people. Between 2010 and 2015, the study recruited 899 people with brain tumours aged 10 to 24 years old and 1,910 controls (operated for appendicitis) matched to the cases on date of diagnosis, study region and age. Participation rates were 72% for cases and 54% for controls. The mean ages of cases and controls were 16.5 and 16.6 years, respectively; 57% were males. The vast majority of study participants were wireless phones users, even in the youngest age group, and the study included substantial numbers of long-term (over 10 years) users: 22% overall, 51% in the 20-24-year-olds. Most tumours were of the neuroepithelial type (NBT; n = 671), mainly glioma. The odds ratios (OR) of NBT appeared to decrease with increasing time since start of use of wireless phones, cumulative number of calls and cumulative call time, particularly in the 15-19 years old age group. A decreasing trend in ORs was also observed with increasing estimated cumulative RF specific energy and ELF induced current density at the location of the tumour. Further analyses suggest that the large number of ORs below 1 in this study is unlikely to represent an unknown causal preventive effect of mobile phone exposure: they can be at least partially explained by differential recall by proxies and prodromal symptoms affecting phone use before diagnosis of the cases. We cannot rule out, however, residual confounding from sources we did not measure. Overall, our study provides no evidence of a causal association between wireless phone use and brain tumours in young people. However, the sources of bias summarised above prevent us from ruling out a small increased risk.

Use of mobile phones and changes in cognitive function in adolescents

BACKGROUND

Several studies have investigated the impact of mobile phone exposure on cognitive function in adults. However, children and adolescents are of special interest due to their developing nervous systems.

METHODS

Data were derived from the Australian Mobile Radiofrequency Phone Exposed Users' Study (MoRPhEUS) which comprised a baseline examination of year 7 students during 2005/2006 and a 1-year follow-up. Sociodemographic and exposure data were collected with a questionnaire. Cognitive functions were assessed with a computerised test battery and the Stroop Color-Word test.

RESULTS

236 students participated in both examinations. The proportion of mobile phone owners and the number of voice calls and short message services (SMS) per week increased from baseline to follow-up. Participants with more voice calls and SMS at baseline showed less reductions in response times over the 1-year period in various computerised tasks. Furthermore, those with increased voice calls and SMS exposure over the 1-year period showed changes in response time in a simple reaction and a working memory task. No associations were seen between mobile phone exposure and the Stroop test.

CONCLUSIONS

We have observed that some changes in cognitive function, particularly in response time rather than accuracy, occurred with a latency period of 1 year and that some changes were associated with increased exposure. However, the increased exposure was mainly applied to those who had fewer voice calls and SMS at baseline, suggesting that these changes over time may relate to statistical regression to the mean, and not be the effect of mobile phone exposure.

Healthy hire effect, job selection and inhalation exposure among young adults with asthma

The aim of the present study was to assess whether asthma onset prior to entering the workforce influences whether a person holds a subsequent job with asthma-related inhalation exposures. The data of 19,784 adults from the European Community Respiratory Health Survey were analysed. For each respondent, a current or previously held job was linked to a job exposure matrix assigning high, low or no exposure to dust, gases or fumes. Jobs were also categorised according to the risk of exposures related to occupational asthma. Associations between asthma and subsequent occupational exposures were assessed using logistic regression models, with a random intercept for study centre and fixed adjustment for age, sex, type of study sample and smoking status. Of the respondents, 8% (n = 1,619) reported asthma with onset before completion of full-time education. This population was at decreased risk of having a job with high (odds ratio 0.79; 95% confidence interval 0.68-0.92) or low (0.91; 0.80-1.03) exposure to dust, gases or fumes. The associations were consistent across exposure types (dusts, gases or fumes) and for jobs with a high risk of occupational asthma. Adults with asthma onset prior to entering the workforce may be less likely to hold jobs involving inhalation exposures.

Cancer incidence and mortality in a historical cohort of Australian pest control workers

OBJECTIVES

To determine the rates of mortality and incident cancer in a historical cohort of pest control operators.

METHODS

A retrospective cohort was assembled from former state government occupational health surveillance programmes. This cohort was linked to the Australian national registries of cancer and mortality and the results were compared with the general Australian population rates.

RESULTS

125 deaths and 89 incident cancers were found during the periods of observation (mortality 1983-2004 and cancer 1983-2002). Overall cancer incidence and mortality rates were not found to be significantly different from the general population. Among the specific causes of death, suicide (standardised mortality ratio; SMR 1.78; 95% CI 1.12 to 2.83) and unintentional falls (SMR 4.57; 95% CI 1.72 to 12.19) were significantly in excess, although the latter was based on only 4 deaths. Melanoma was the only specific incident cancer found significantly in excess (standardised incidence ratio 1.56; 95% CI 1.03 to 2.37).

CONCLUSIONS

Pest control workers have overall mortality and cancer rates similar to the general population. Excess rates of incident melanoma and intentional self-poisoning mortality are of concern and warrant further investigation. Follow-up of this cohort as its members age, will provide more insight into these possible associations.

Training and other predictors of personal protective equipment use in Australian grain farmers using pesticides

OBJECTIVES

To investigate patterns of use of personal protective equipment (PPE) to reduce pesticide exposure in a sample of Australian farmers and also to assess the influence of possible predictive factors.

METHODS

A cross-sectional survey of 1102 farmers recruited through the Victorian Farmers Federation (VFF) was conducted. A written questionnaire was filled out by participants at VFF meetings attended by a visiting research assistant. Participants answered questions about frequency of pesticide use and PPE items they usually used when doing two different pesticide-related tasks, mixing and application, of each of four classes of pesticides. They also answered questions about personal characteristics, farm characteristics, farming activities, career and health.

RESULTS

Nearly all surveyed farmers had ever used pesticides, and over 87% had used Herbicides or Animal Health Products in the previous 12 months. Non-use of PPE was frequently reported, with up to 10-40% of farmers routinely using no PPE at all when using pesticides. Across all pesticide classes, PPE use was higher for pesticide mixing than for application. In multivariate analyses PPE use appeared to be most strongly associated with younger age and farm chemical training.

CONCLUSIONS

PPE use across all pesticide classes was poor, indicating the possibility of clinically significant pesticide exposure in many farmers. Given that PPE use was found to be associated with farm chemical training, the authors suggest that training is likely to be an important intervention for reducing farmers' pesticide exposure. Poor uptake of farm chemical training by farmers and the aging farming workforce are causes for concern in the light of these findings.

Occupational exposure to power frequency magnetic fields and risk of non-Hodgkin lymphoma

OBJECTIVES

To investigate the risk of non-Hodgkin lymphoma (NHL) using a job-exposure matrix (JEM) to assess exposure to occupational magnetic fields at the power frequencies of 50/60 Hz.

METHODS

The study population consisted of 694 cases of NHL, first diagnosed between 1 January 2000 and 31 August 2001, and 694 controls from two regions in Australia, matched by age, sex and region of residence. A detailed occupational history was given by each subject. Exposure to power frequency magnetic fields was estimated using a population-based JEM which was specifically developed in the United States to assess occupational magnetic field exposure. The cumulative exposure distribution was divided into quartiles and adjusted odds ratios were calculated using the lowest quartile as the referent group.

RESULTS

For the total work history, the odds ratio (OR) for workers in the upper quartile of exposure was 1.48 (95% CI 1.02 to 2.16) compared to the referent (p value for trend was 0.006). When the exposure was lagged by 5 years the OR was 1.59 (95% CI 1.07 to 2.36) (p value for trend was 0.003). Adjusting for other occupational exposures did not significantly alter the results.

CONCLUSIONS

These findings provide weak support for the hypothesis that occupational exposure to 50/60 Hz magnetic fields increases the risk of NHL.

Occupational exposure to pesticides and risk of non-Hodgkin's lymphoma

Pesticide exposure may be a risk factor for non-Hodgkin's lymphoma, but it is not certain which types of pesticides are involved. A population-based case-control study was undertaken in 2000-2001 using detailed methods of assessing occupational pesticide exposure. Cases with incident non-Hodgkin's lymphoma in two Australian states (n = 694) and controls (n = 694) were chosen from Australian electoral rolls. Logistic regression was used to estimate the risks of non-Hodgkin's lymphoma associated with exposure to subgroups of pesticides after adjustment for age, sex, ethnic origin, and residence. Approximately 10% of cases and controls had incurred pesticide exposure. Substantial exposure to any pesticide was associated with a trebling of the risk of non-Hodgkin's lymphoma (odds ratio = 3.09, 95% confidence interval: 1.42, 6.70). Subjects with substantial exposure to organochlorines, organophosphates, and "other pesticides" (all other pesticides excluding herbicides) and herbicides other than phenoxy herbicides had similarly increased risks, although the increase was statistically significant only for "other pesticides." None of the exposure metrics (probability, level, frequency, duration, or years of exposure) were associated with non-Hodgkin's lymphoma. Analyses of the major World Health Organization subtypes of non-Hodgkin's lymphoma suggested a stronger effect for follicular lymphoma. These increases in risk of non-Hodgkin's lymphoma with substantial occupational pesticide exposure are consistent with previous work.

Biological dust exposure in the workplace is a risk factor for chronic obstructive pulmonary disease

BACKGROUND

Chronic obstructive pulmonary disease (COPD) is a major cause of morbidity and mortality. Although the main risk factor is smoking, 15-19% of COPD even in smokers has been attributed to occupational exposures. The aim of this study was to investigate the association between occupational exposure and risk of COPD.

METHODS

Participants were part of a cross sectional study of risk factors for COPD. A total of 1232 completed a detailed respiratory questionnaire, spirometric testing and measurement of gas transfer. Job histories were coded according to the International Standard Classification of Occupations. These codes were then used to establish occupational exposures using the ALOHA job exposure matrix.

RESULTS

The prevalence of emphysema was 2.4%, chronic obstructive bronchitis 1.8%, and COPD 3.4%. Subjects ever exposed to biological dusts had an increased risk of chronic obstructive bronchitis (OR 3.19; 95% CI 1.27 to 7.97), emphysema (OR 3.18; 95% CI 1.41 to 7.13), and COPD (OR 2.70, 95% CI 1.39 to 5.23). These risks were higher in women than in men. For biological dust, the risk of emphysema and COPD was also significantly increased in both the duration of exposure categories, again in women but not in men. No significant increased risks for COPD were found for mineral dust (OR 1.13; 95% CI 0.57 to 2.27) or gases/fumes (OR 1.63; 95% CI 0.83 to 3.22).

CONCLUSION

In this general population sample of adults, occupational exposures to biological dusts were associated with an increased risk of COPD which was higher in women. Preventive strategies should be aimed at reducing exposure to these agents in the workplace.

Asthma and vaccination history in a young adult cohort

BACKGROUND

It has been suggested that childhood vaccinations may be associated with the onset of asthma. We investigated the association between asthma, atopy and vaccination history in a cohort of young adults living in Melbourne, Australia.

METHODS

Subjects were aged between 22 and 44 years and were surveyed by an interviewer-administered questionnaire. Questions were asked about vaccinations to measles, mumps and rubella (MMR), triple antigen (DTP), hepatitis B and Sabin polio vaccine (OPV). Atopy was assessed by skin prick testing to common aeroallergens.

RESULTS

There was no significant association observed for subjects diagnosed with asthma who had received measles or MMR vaccinations compared with those who did not receive measles or MMR vaccinations (RR 1.33, 95% CI 0.98-1.80). Non-significant associations were also observed for OPV and hepatitis B vaccinations (RR 3.27, 95% CI 0.50-21.3 and RR 1.08, 95% CI 0.83-1.41, respectively). However, subjects reporting full immunisation were found to be at higher risk to asthma (RR 1.52, 95% CI 1.09-2.11) but not atopy.

CONCLUSIONS

Our results show relatively weak support for the hypothesis that childhood vaccinations may lead to increased risk of asthma, but caution is advised due to possible recall bias.

The diagnostic value of bone scintigraphy in patients with back pain

Background. The aim of the study was retrospective evaluation of planar bone scintigraphy in the diagnostics of back pain syndrome.<br /> Material and methods. The study included 252 patients referred to the Nuclear Medicine Department from the Rehabilitation and Spine Diseases Consulting Unit from January 2001 to June 2003. In all cases whole body radionuclide imaging was performed using Tc 99m -MDP. <br /> Results. Of patients suffering from a back pain 14% had normal scans. Among the causes of abnormal results in our study dominated changes of degenerative background - osteoarthritis (68,5%). In 26 patients (10,3%) pathological uptake was typical for metastatic disease.<br /> Conclusions. Bone scan offers the advantage of total body examination and images bone lesions earlier than other techniques. In selected cases, radionuclide imaging may explain the etiology of back pain syndrome and facilitate definite treatment.

Respiratory symptoms and lung function in bauxite miners

OBJECTIVES

To determine whether cumulative bauxite exposure is associated with respiratory symptoms or changes in lung function in a group of bauxite miners.

METHODS

Current employees at three bauxite mines in Australia were invited to participate in a survey comprising: questionnaire on demographic details, respiratory symptoms, and work history; skin prick tests for four common aeroallergens; and spirometry. A task exposure matrix was constructed for bauxite exposure in all tasks in all jobs based on monitoring data. Data were examined for associations between cumulative bauxite exposure, and respiratory symptoms and lung function, by regression analyses.

RESULTS

The participation rate was 86%. Self-reported work-related respiratory symptoms were reported by relatively few subjects (1.5%-11.8%). After adjustment for age and smoking no significant differences in the prevalence of respiratory symptoms were identified between subjects, in the quartiles of cumulative bauxite exposure distribution. The forced expiratory volume in I s (FEV1) of the exposed group was found to be significantly lower than that for the unexposed group. After adjustment for age, height, and smoking there were no statistically significant differences between quartiles in FEVI, forced vital capacity (FVC) and FEVl/FVC ratio.

CONCLUSIONS

These data provide little evidence of a serious adverse effect on respiratory health associated with exposure to bauxite in an open-cut bauxite mine in present day conditions.

Respiratory disorders and allergies in tea packers

The aim of this study was to determine whether respiratory symptoms or cross-shift declines in lung function were related to occupational exposure to tea dust. A cross-sectional epidemiological study was conducted at a tea-packing plant. Subjects completed a questionnaire, spirometry before and after a full work shift, skin prick testing and venipuncture. Among the 83% of the workers at the site who participated, the prevalences of asthma, wheezing, hay fever and atopy were similar to the general population. Work-related nasal symptoms were more commonly reported by blenders and operators. There were six (3.2%) subjects with a cross-shift decline in the forced expiratory volume in 1 s of > 10%. Specific immunoglobulin E antibodies to black or chamomile tea were observed in 10 (5.6%) employees. As there was little evidence of specific allergic sensitization to the tea varieties tested, the excess of work-related respiratory and nasal symptoms probably represented non-specific irritation.

Growth factors and gene therapy: the prospects for treating limited cartilage defects

The limited regenerative capacities of articular are well known. Among the many methods used to repair the joint surface, among the most innovative involve stimulating chondrocytes to grow and differentiate by local application of exogenous protein growth factors, and attempting to transfer the genes responsible for cell division and maturation. This article presents the current state of knowledge on the possibilities for the treatment of limited cartilage defects used these methods.

Methods for the isolation and culture of human articular chondrocytes

The tissue engineering of cartilage implants may open new paths for the surgical treatment of joint surface defects. Autologous chondrocyte transplantation (ACT) has been gaining in clinical significance over the last several years. This study presents the methods used for isolation, monolayer culturing, multipication and assesment in transmission light microscopy of human chondrocytes. The tissue was gained from resected fragments of joint during total knee replacement.

The use of carbon fibers to restore cartilage defects in the knee

Research on carbon biomaterials has Bern in progress at the Warsaw Orthopedic Clinic for more than 20 years. Recently these materials have also been used in clinical practice as matrix material for repairing tissue defects in the motor organs. In this article, a new method is presented using carbon fiber to treat cartilage defects in the knee. This study describes the authors experience with carbon fibers used as scaffolds in drilled cartilage lesions to enhance the in growth of regenerative tissue. The research involved 35 patients treated for cartilage defects from December 1993 to June 1997. The average age was 46 (range 19-68), and the average follow-up was 48 months (range 24-55 months). The results were assessed by applying the HSS knee scale, the Wallgren-Tegner activity score, the VAS (visual analogue scale of pain), and the patients subjective judgment of the surgery. Good or excellent outcomes were obtained in 25 of the 35 patients (71%). The most striking aspect of the outcome was good pain relief. Early follow-ups are necessary, but the results must be confirmed in long-term observations.

A task exposure database for use in the alumina and primary aluminium industry

A task exposure database (TED) was developed to facilitate data collation for construction of a task exposure matrix (TEM) for Healthwise, a series of studies on cancer and respiratory morbidity in the alumina and primary aluminium industry. Following the construction of job classifications for the eight study sites, the site hygienists identified all historical air monitoring time-weighted average (TWA) data, from their respective sites. The earliest data were sampled in the late 1970s, and over 17,000 personal samples were recorded over the eight sites over a twenty-year period. TED, a Microsoft Access database, was developed for use by site occupational hygienists to collate these exposure data across the mines, refineries and smelters. All data conforming to strict criteria for use were recorded using TED and provided to the study group. Following the individual data point entry, a calculator program in TED systematically calculated the geometric means, arithmetic means, and maximum and minimum results at the task level. Other features of TED included fields for flagging "significant changes" and "stepwise changes" in exposure. TED established a standardised means of data collation that later formed the basis for the construction of a TEM for the study. A TEM is similar to a job exposure matrix (JEM) except that the basic unit of categorization is at the task level instead of at the job level. Both a TEM and JEM have been constructed independently for Healthwise. The possible reduction of exposure misclassification and improvement in validity of exposure characterization with the use of the TEM, is currently under investigation. The Healthwise TEM consists of annual TWA and peak data results for each site for various airborne contaminants, including fluorides, coal tar pitch volatiles, sulfur dioxide, inspirable dust, alumina dust, bauxite dust, and oil mist. Construction of the TEM for the Healthwise study was completed in late 1998 and consists of over 33,700 TWA years of task exposure data.

Comparison of occupational exposure using three different methods: hygiene panel, job exposure matrix (JEM), and self reports

This study was undertaken to compare the agreement of occupational exposure assessment by a panel of occupational hygienists with a job exposure matrix and self-reported exposures in a community-based case-control study. We also investigated the intra-rater reliability and degree of attenuation of the hypothetical odds ratio of the panel in retrospective chemical exposure assessment. A panel of three occupational hygienists was recruited to assess exposure to chemicals for 5,620 jobs. The agreement between the panel, a job exposure matrix (FINJEM), and the self-reported exposures was then assessed. A further 172 jobs were resubmitted to the panel to assess intra-rater reliability. The kappa for intra-rater reliability ranged from 0.60-0.71. The agreement between the panel and FINJEM ranged from 0.07 to 0.46 (for similar exposures), and agreement between the panel and among the self-reports ranged from 0.00 to 0.48. Agreement between hygienists when rating exposure to the same chemical ranged from 0.48 to 0.57. Based on these findings, the degree of exposure misclassification by the panel where the true odds ratio was 2 would result in the observed odds ratio ranging between 1.70 and 1.88. The results indicated good intra-rater reliability for the hygiene panel. However, the agreement among the panel, FINJEM, and self-reported exposures was found to be only poor to fair. The attenuation of the odds ratios due to exposure misclassification by the panel was variable and dependent upon the exposure.

Beyond the job exposure matrix (JEM): the task exposure matrix (TEM)

The job exposure matrix (JEM) has been employed to assign cumulative exposure to workers in many epidemiological studies. In these studies, where quantitative data are available, all workers with the same job title and duration are usually assigned similar cumulative exposures, expressed in mgm(-3)xyears. However, if the job is composed of multiple tasks, each with its own specific exposure profile, then assigning all workers within a job the same mean exposure can lead to misclassification of exposure. This variability of exposure within job titles is one of the major weaknesses of JEMs. A method is presented for reducing the variability in the JEM methodology, which has been called the task exposure matrix (TEM). By summing the cumulative exposures of a worker over all the tasks worked within a job title, it is possible to address the variability of exposure within the job title, and reduce possible exposure misclassification. The construction of a TEM is outlined and its application in the context of a study in the primary aluminium industry is described. The TEM was found to assign significantly different cumulative exposures to the majority of workers in the study, compared with the JEM and the degree of difference in cumulative exposure between the JEM and the TEM varied greatly between contaminants.

Brain chirps: spectrographic signatures of epileptic seizures

OBJECTIVE

A chirp is a brief signal within which the frequency content changes rapidly. Spectrographic chirps are found in signals produced from many biological and physical phenomena. In radar and sonar engineering, signals with chirps are used to localize direction and range to the signal source. Although characteristic frequency changes during epileptic seizures have long been observed, the correlation with chirps and chirp technology seems never to have been made.

METHODS

We analyzed 19404 s (1870 s of which were from 43 seizures) of intracranially (subdural and depth electrode) recorded digital EEG from 6 patients for the presence of spectral chirps. Matched filters were constructed from methods in routine use in non-medical signal processing applications.

RESULTS

We found that chirps are very sensitive detectors of seizures (83%), and highly specific as markers (no false positive detections). The feasibility of using spectral chirps as matched filters was demonstrated.

CONCLUSIONS

Chirps are highly specific and sensitive spectrographic signatures of epileptic seizure activity. In addition, chirps may serve as templates for matched filter design to detect seizures, and as such, can demonstrate localization and propagation of seizures from an epileptic focus.

Respiratory symptoms and lung function in alumina refinery employees

OBJECTIVES

Employees in alumina refineries are known to be exposed to a number of potential respiratory irritants, particularly caustic mist and bauxite and alumina dusts. To examine the prevalence of work related respiratory symptoms and lung function in alumina refinery employees and relate these to their jobs.

METHODS

2964 current employees of three alumina refineries in Western Australia were invited to participate in a cross sectional study, and 89% responded. Subjects were given a questionnaire on respiratory symptoms, smoking, and occupations with additional questions on temporal relations between respiratory symptoms and work. Forced expiratory volume in 1 second (FEV(1)) and forced vital capacity (FVC) were measured with a rolling seal spirometer. Atopy was assessed with prick skin tests for common allergens. Associations between work and symptoms were assessed with Cox's regression to estimate prevalence ratios, and between work and lung function with linear regression.

RESULTS

Work related wheeze, chest tightness, shortness of breath, and rhinitis were reported by 5.0%, 3.5%, 2.5%, and 9.5% of participants respectively. After adjustment for age, smoking, and atopy, most groups of production employees reported a greater prevalence of work related symptoms than did office employees. After adjustment for age, smoking, height, and atopy, subjects reporting work related wheeze, chest tightness, and shortness of breath had significantly lower mean levels of FEV(1) (186, 162, and 272 ml respectively) than subjects without these symptoms. Prevalence of most work related symptoms was higher at refinery 2 than at the other two refineries, but subjects at this refinery had an adjusted mean FEV(1) >60 ml higher than the others. Significant differences in FVC and FEV(1)/FVC ratio, but not FEV(1), were found between different process groups.

CONCLUSIONS

There were significant differences in work related symptoms and lung function between process groups and refineries, but these were mostly not consistent. Undefined selection factors and underlying population differences may account for some of these findings but workplace exposures may also contribute. The differences identified between groups were unlikely to be clinically of note.

Respiratory symptoms and lung function in two prebake aluminum smelters

BACKGROUND

Respiratory symptoms are known to occur in some aluminum smelter employees working in the potroom department but little is known about the respiratory health of employees in other departments.

METHODS

This cross-sectional study examined the prevalence of work-related respiratory symptoms and levels of lung function in different departments of two aluminum smelters compared to administration employees. Multiple logistic regression was performed with each of four work-related symptoms as outcomes and multiple linear regressions were performed with FEV1 and FVC as outcomes.

RESULTS

There were 1,529 male participants in the two smelters representing a response rate of 89.6%. After adjusting for age and smoking, work-related respiratory symptoms were reported significantly more often among the ingot mill, anode, and potroom groups in Smelter A. In Smelter B, ingot employees were more likely to report work-related wheeze and potroom employees were more likely to report work-related rhinitis. Symptoms tended to increase with increasing time in the potrooms but were more likely to occur in new employees in the ingot mill and anode process groups. After adjusting for age, height, and smoking, there were no significant differences between the process groups for either FEV1 or FVC at Smelter A, and at Smelter B potroom employees had slightly greater FEV1 and FVC than the administration employees.

CONCLUSIONS

Work-related respiratory symptoms among aluminum smelter workers are not reported only by potroom employees but also by ingot mill and anode employees.

Exposures in the alumina and primary aluminium industry: an historical review

We reviewed specific chemical exposures and exposure assessment methods relating to published and unpublished epidemiological studies in the alumina and primary aluminium industry. Our focus was to review limitations in the current literature and make recommendations for future research. Although some of the exposures in the smelting of aluminium have been well characterised, particularly in potrooms, little has been published regarding the exposures in bauxite mining and alumina refining. Past epidemiological studies in the industry have concentrated on the smelting of aluminium, with many limitations in the methodology used in their exposure assessment. We found that in aluminium smelting, exposures to fluorides, coal tar pitch volatiles (CTPV) and sulfur dioxide (SO2) have tended to decrease in recent years, but insufficient information exists for the other known exposures. Although excess cancers have been found among workers in the smelting of aluminium, the exposure assessment methods in future studies need to be improved to better characterise possible causative agents. The small number of cohort studies has been a factor in the failure to identify clear exposure-response relationships for respiratory diseases. A dose-response relationship has been recently described for fluoride exposure and bronchial hyper-responsiveness, but whether fluorides are the causative agent, co-agent or simply markers for the causative agent(s) for potroom asthma, remains to be determined. Published epidemiological studies and quantitative exposure data for bauxite mining and alumina refining are virtually non-existent. Determination of possible exposure-response relationships for this part of the industry through improved exposure assessment methods should be the focus of future studies.

Retrospective assessment of occupational exposure to chemicals in community-based studies: validity and repeatability of industrial hygiene panel ratings

BACKGROUND

Occupational hygiene panels are increasingly being used to rate retrospective occupational exposures to chemicals in community-based studies. This study aimed to assess the validity, reliability and feasibility of using such an expert panel in a brain tumour case-control study.

METHODS

A panel of five experts was recruited to rate exposure to 21 chemicals for 298 job descriptions to investigate the level of agreement. Validity was assessed by comparing the ratings of the experts for 49 of the jobs with objective quantitative exposure data which existed for these jobs. Repeatability was assessed by comparing the results for 50 resubmissions.

RESULTS

Specificity was high for reporting that exposure occurred (all above 90%), but sensitivity was variable with values between 48% and 79%. Weaker validity was found for rating exposure level and exposure frequency. The raters showed the greatest inter-rater agreement for exposure to three of the 21 chemicals considered (kappa = 0.64 for cutting fluids, kappa = 0.57 for welding fumes and kappa = 0.42 for lubricating oils). Intra-rater reliability, based on the 50 resubmitted jobs, was fair to good (kappa = 0.46, 0.73).

CONCLUSIONS

The potential effect of exposure misclassification from using expert panels was quantified and found to be a significant source of bias. The optimum situation occurred where three of the five raters concurred, where an odds ratio of 2.2 was observed for a true odds ratio of 4.0. Future studies which plan to use expert panels should screen the experts for their suitability by validating their performance against jobs with known exposure data.

Spinal anesthesia with meperidine: will epinephrine prolong its duration?

Meperidine (Demerol) has local anesthetic properties separate from its opioid receptor agonist effect. Unlike morphine, meperidine is structurally similar to local anesthetics. Therefore, it is not surprising that it possesses some characteristics of local anesthetics. If meperidine acts like a local anesthetic, binding to the same receptor sites and inhibiting nerve conduction, then drugs that alter the action and duration of local anesthetics may have a similar effect on it. This double-blinded investigation used low-dose meperidine as the sole intrathecal agent to determine the effect of epinephrine on the duration of sensory blockade. Thirty male ASA physical status I through III patients between the ages of 58-81 years who were scheduled for transurethral resection of the prostate or of bladder tumors were randomly assigned to receive meperidine with or without epinephrine. A continuous spinal technique was utilized, and meperidine 0.5 mg/kg was administered after ascertaining the proper position of the catheter. Fourteen of the patients received epinephrine, and 16 patients did not. There were no statistically significant differences between the two groups in terms of age, height, weight, and ASA physical status. No statistically significant prolongation of the sensory blockade was observed with the addition of epinephrine. There were no statistically significant differences between the two groups with regard to onset time or the incidence of complications. The occurrence of a full motor block in the group that did not receive epinephrine was statistically significant.

["Taurolin-Gel" and Taurolin-Trockengel" in treatment of osseous tissue inflammation]

The activity and principles of administration of Taurolin have been presented. That drug was used in 15 patients with chronic osteitis. Healing by first intention was obtained in 10 patients, necrosis of the skin occurred in 3 patients, recurrence of inflammation was found in one patient in whom accessory sequestroctomy was performed in the last case of osteitis and arteriosclerosis healing was obtained by second intention. The clinical observation of 15 patients has revealed: a) irritating influence of Taurolin on the soft tissue, b) increased phase of secretion of exudate since the 5 day after surgery, c) bactericidal influence of the drug. Sterilization of the focus occurred at 2 to 3 weeks after surgery. The use of Taurolin requires experience, complete abiding by the principles of use of this drug and equipment with a set of Charrier's drains. The authors are carrying on further observation of the use of Taurolin in the treatment of osteitis.