Cumulative Exposure Index Research Articles

Development of Solvent Exposure Index for Construction Painters

This article describes methodological approaches for reconstructing long-term occupational exposure to organic solvents among construction painters. A detailed exposure questionnaire was administered to 125 painters to develop a job exposure matrix (JEM). The questionnaire inquired about painting activities with solvent-based paints and use of protection equipment for the previous 25 years in 5-year intervals. Current and historical distributions of solvent air concentrations were assessed for the same time period based on the following information: industrial hygiene measurements, paint composition changes, and VOC emission rate changes from architectural and industrial maintenance coatings. Changes in protection factors of respirators were also assessed. A cumulative solvent exposure index was calculated for each painter through Monte Carlo simulations by combining appropriate input distributions of solvent air concentrations and protection factors of respirators with JEM. Sensitivity simulations revealed that the historical variations in solvent air concentrations had a higher impact on the cumulative solvent exposure index than changes in protection factors for respirators. Fifty-eight percent of painters were classified with a different exposure quartile when the solvent exposure index was used vs. an exposure based only on years using solvent-based paints, suggesting the need for more detailed exposure analysis than just years working when conducting epidemiologic studies for this worker population.

Neuropsychological effects of low-level manganese exposure in welders

While the neuropsychological effects of high manganese (Mn) exposure in occupational settings are well known, the effects of lower levels of exposure are less understood. In this study, we investigated the neuropsychological effects of lower level occupational Mn exposure in 46 male welders (mean age = 37.4, S.D. = 11.7 years). Each welders’ cumulative Mn exposure indices (Mn-CEI) for the past 12 months and total work history Mn exposure were constructed based on air Mn measurements and work histories. The association between these exposure indices and performance on cognitive, motor control, and psychological tests was examined. In addition, among a subset of welders ( n = 24) who completed the tests both before and after a work shift, we examined the association between cross-shift Mn exposure assessed from personal monitoring and acute changes in test scores. Mn exposures in this study (median = 12.9 μg/m 3) were much lower, as compared to those observed in other similar studies. Increasing total Mn-CEI was significantly associated with slower reaction time on the continuous performance test (CPT; p < 0.01), as well as worse mood for several scales on the Profile of Mood States (POMS; confused, tired, and a composite of tired and energetic, all p ≤ 0.03). Increasing Mn-CEI over the previous 12 months was significantly associated with worse mood on the sad, tense, and confused POMS scales (all p ≤ 0.03) and the association with worse CPT performance approached significance ( p = 0.10). Higher Mn exposure over the course of a workday was associated with worse performance on the CPT test across the day ( p = 0.06) as well as declines in fine motor control over the work-shift ( p = 0.04), adjusting for age and time between the 2 tests. Our study suggests that even at relatively low Mn exposure levels neuropsychological effects may manifest particularly with respect to attention, mood, and fine motor control.

Frequency and severity approaches to indexing exposure to trauma: The Critical Incident History Questionnaire for police officers

The Critical Incident History Questionnaire indexes cumulative exposure to traumatic incidents in police by examining incident frequency and rated severity. In over 700 officers, event severity was negatively correlated (r(s) = -.61) with frequency of exposure. Cumulative exposure indices that varied emphasis on frequency and severity-using both nomothetic and idiographic methods-all showed satisfactory psychometric properties and similar correlates. All indices were only modestly related to posttraumatic stress disorder (PTSD) symptoms. Ratings of incident severity were not influenced by whether officers had ever experienced the incident. Because no index summarizing cumulative exposure to trauma had superior validity, our findings suggest that precision is not increased if frequency is weighted by severity.

Sleep apnoeas and neurobehavioral effects in solvent exposed workers

Exposure to organic solvents may cause an increase of sleep apnoeas, which may explain the excess of fatigue, concentration and memory problems reported in exposed workers. Polysomnography was performed in 21 long-term exposed printers and 27 controls. In addition, a questionnaire regarding sleep related complaints, Q16 questionnaire and computerized neurobehavioral tests were administered. The groups matched well regarding age, weight, neck circumference and schooling level. A semi-quantitative cumulative exposure index was calculated. Excessive sleepiness while watching TV (p<0.01) and diminished sexual interest (p=0.03) was found in the organic solvent-workers. The sleep complaints score correlated positively with the exposure index and duration (both p=0.01). The polysomnography results showed an increase of central apnoeas in the exposed workers (67%) compared to the referents (30%). The presence of central apnoeas was positively correlated with the exposure index (p<0.05) in regression models. Of the neurobehavioral test only hand-eye coordination was dose-related impaired in the exposed workers. The co-existence of abnormal values on at least one neurobehavioral test and the presence of central apnoeas was observed in the exposed workers, but did not reach significance. Workers chronically exposed to low organic solvent levels may experience mild sleeping problems, however, our data do not support the hypothesis that the clinical picture of chronic toxic encephalopathy can be primarily caused by the induction of sleep apnoea syndrome. It seems thus that the risk to experience central apnoeas rather accompanies the risk of impaired neurobehavioral performance with increasing exposure in a working population.

Use of hair cortisol analysis to detect hypercortisolism during active drinking phases in alcohol-dependent individuals

The assessment of cortisol levels in human hair has recently been suggested to provide a retrospective index of cumulative cortisol exposure over periods of up to 6 months. The current study examined the utility of hair cortisol analysis to retrospectively detect hypercortisolism during active drinking phases in alcoholics in acute withdrawal ( n = 23), the normalisation of cortisol output in abstinent alcoholics ( n = 25) and cortisol levels in age- and gender-matched controls ( n = 20). Scalp-near 3-cm hair segments were sampled and analysed for cortisol content. Results showed three to fourfold higher cortisol levels in hair samples of alcoholics in acute withdrawal than in those of abstinent alcoholics ( p < .001) or controls ( p < .001), with no differences between the latter two groups. The current hair cortisol findings closely mirror results of previous research using well-established measures of systemic cortisol secretion and thus provide further validation of this novel method.

Neuromotor effects of short‐term and long‐term exposures to trichloroethylene in workers

Health effects of long-term exposure to organic solvents at low levels are a major concern in industrialized countries. To assess the neuromotor impact of trichloroethylene objectively, static postural sway and hand tremor parameters, along with urinary trichloroethanol (TCOH) and trichloroacetic acid (TCAA) levels, were investigated in 57 workers without obvious neurological disorders and 60 control subjects. The workers had been occupationally exposed to trichloroethylene for 0.1-37 years. The cumulative exposure index (CEI) was calculated from their occupational history and total trichloro-compounds (TCOH + TCAA). Median levels in the workers were 1.7 mg/L for TCOH and 2.5 mg/L for TCAA, and the maximum ambient trichloroethylene concentration was estimated to be <22 ppm from the previously reported equation using TCOH + TCAA. Sway parameters with eyes open and tremor intensity in dominant hand were significantly larger in the exposed workers than in the control subjects when adjusting for possible confounders. A significant dose-effect association was seen between two sway parameters and urinary TCOH level in the workers. Tremor intensities in non-dominant hand differed significantly among three groups of the workers divided according to the CEI. These findings suggest that trichloroethylene exposure, even at low levels of less than the short-term exposure limit by the ACGIH, can affect the neuromotor function of workers. The postural instability appears to result from recent exposure, and the increased tremor may occur due to short-term and long-term exposures. Hereafter, such objective measures, along with subjective symptoms, should be carefully used for the occupational exposure limit setting.

Chlordecone Exposure and Risk of Prostate Cancer

Determining whether environmental estrogens are associated with the risk of prostate cancer may have important implications for our general understanding of this disease. The estrogenic insecticide chlordecone was used extensively in the French West Indies, contaminating the population for more than 30 years. We analyzed the relationship between exposure to chlordecone and the risk of prostate cancer. We investigated 623 men with prostate cancer and 671 controls. Exposure was analyzed according to case-control status, using either current plasma concentration or a cumulative exposure index based on years of exposure. We genotyped two single-nucleotide polymorphisms (rs3829125 and rs17134592) in the gene encoding chlordecone reductase. We found a significant increase in the risk of prostate cancer with increasing plasma chlordecone concentration (odds ratio [OR], 1.77; 95% CI, 1.21 to 2.58 for the highest tertile of values above the limit of detection [LD]; P trend = .002) and for cumulative exposure index (OR, 1.73; 95% CI, 1.04 to 2.88 for the highest quartile; P trend = .004). Stronger associations were observed among those with a positive family history of prostate cancer and among those who had lived in a Western country. The rs3829125 and rs17134592 allele variants were in complete linkage disequilibrium and were found at low frequency (0.04). Among subjects with plasma chlordecone concentrations above the LD, carriers of the allele variants had a higher risk of prostate cancer (OR, 5.23; 95% CI, 0.82 to 33.32). These findings support the hypothesis that exposure to environmental estrogens increases the risk of prostate cancer.

Association of allergic sensitization with infectious diseases burden in Roma and non-Roma children

The hypothesis whether exposure to certain infections protects from atopy remains equivocal. To further investigate this, we compared serologic markers of infection and allergic sensitization prevalence in Roma children, who live under unfavorable hygienic conditions that facilitate the spread of infections, and non-Roma children who live in the same area. Analyses included 98 Roma and 118 non-Roma children. Serum IgG antibodies for 13 foodborne- airborne- and bloodborne infectious agents were determined, and a cumulative index of exposure was calculated by adding one point for each positive infection. Specific serum IgE to certain common food- and aero-allergens was also tested. and positivity to any of them was defined as indication of atopy. Roma children were found significantly more seropositive for T. gondii, Hepatitis A, H. pylori, HSV-1, CMV, and Hepatitis B (p < 0.0001). Non-Roma children were found more seropositive for RSV and M. pneumonia (p < 0.0001). Regarding the overall prevalence of atopy or the specific IgE responses to the allergens tested, no statistically significant differences were found between Roma and non-Roma children. A positive association of the cumulative index of exposure to infections with atopy was found in the non-Roma children (OR: 1.38, 95% CI: 1.08-1.75, p = 0.01) and in the total population (OR: 1.42, 95% CI: 1.11-1.83, p = 0.01). Regarding the specific infectious agents tested, a statistically significant positive association of atopy with seropositivity was found for M. pneumoniae in the non-Roma children (OR: 3.93, 95% CI: 1.39) as well as in the total population studied (OR: 2.83, 95% CI: 1.32-6.07, p = 0.01). Despite the higher burden of exposure to the battery of the infectious agents tested among Roma children, no protective effect for allergic disease development was evident. On the contrary, a positive association of exposure to infections with evidence of atopy was found, especially evident in the non-Roma children.

Does Asbestos Exposure Cause Airway Obstruction, in the Absence of Confirmed Asbestosis?

Whether occupational exposure to asbestos causes airway obstruction remains controversial. This study evaluated lung function in relation to cumulative exposure to asbestos in a large cohort of retired or unemployed workers exposed to asbestos. The study population consisted of 3,660 volunteer subjects. An individual cumulative exposure index to asbestos was calculated for each subject, and information was obtained on smoking status. Pulmonary function tests were performed in all subjects; high-resolution chest computed tomography was also performed in 3,335 subjects. Values of FEV(1)/FVC and FEF(25-75%) did not differ between five classes (quintiles) of cumulative exposure to asbestos, and no significant correlation was observed between cumulative exposure to asbestos and pulmonary function parameters, after adjustment for sex, tobacco consumption, emphysema, and body mass index. Furthermore, the proportion of abnormal pulmonary function tests did not differ between the five classes of cumulative exposure to asbestos. The results do not support a causal relationship between asbestos exposure alone and airway obstruction. However, the study sample may not be representative of all people occupationally exposed to asbestos, because a fraction of subjects with previously diagnosed asbestosis probably did not participate in this screening program.

Violence Exposure in Multiple Interpersonal Domains: Cumulative and Differential Effects

To examine dose-response effects of cumulative violence exposure including parent-to-youth aggression, marital physical aggression, and community violence, and to explore whether separate interpersonal domains of exposure differentially influence adverse outcomes. The present study uses parent-reports and child-reports of youth violence exposure from the first three waves of a prospective, longitudinal study of 103 community-based families. Outcomes were criterion levels (T score >or= 60) of somatic complaints, depressive symptoms, anxiety, over-arousal, aggression, delinquent behaviors, and presence versus absence of academic failure. After controlling for initial symptoms, income and parents' psychopathology, adjusted relative risks showed that marital aggression contributed uniquely to anxiety, and parent-to-youth aggression contributed uniquely to somatic complaints and aggression. All three domains significantly contributed to academic failure. With each one-point increase on the cumulative violence exposure index that summed across interpersonal domains and across time, there was an increased risk of more than 50% for meeting criterion levels of depressive symptoms and anxiety, and a 10%-25% increased risk for somatic complaints, delinquent behaviors, and academic failure. Significant curvilinear effects showed high cumulative violence increased risk of comorbid symptoms; 76% of youth with higher cumulative violence met thresholds on 3+ adverse outcomes, compared to 36% and 7% for youth with moderate and low violence exposure. These data highlight the importance of assessing violence exposure across multiple interpersonal domains and across time. Awareness of the contributions of violence exposure to common symptoms and particularly comorbid symptoms can inform interventions for wide-ranging adolescent problems.

Prolonged Exposure to Occupational Noise and Hypertension among Workers in the Aviation Industry

ISEE-0252 Background and Objective: Several epidemiologic studies have reported that people living near airports with long-term exposure to aircraft noise had increased risk of hypertension, but such a relationship among aviation industry workers is uncertain. This cross-sectional study aimed to investigate the effects of chronic noise exposure on prevalence of hypertension among workers in the aviation industry. Methods: We recruited an aircraft manufacturing company with 2524 employees in 2008. There were 1412 volunteers who provided personal information on health checkups and potential confounders using a standardized questionnaire. We measured noise exposure and calculated the cumulative exposure index (CEI, dBA-year) for each subject. We divided workers into high-exposure, low-exposure, and control groups according to the quartile distribution of CEIs. Logistic regression models were used to associate occupational exposure to noise with hypertension between different groups. Results: High-exposure workers (≥1220 dBA-year) had the significantly highest proportion of using earplugs/earmuffs at work (46%), as opposed to 17% in the low-exposure workers (1220–870 dBA-year), compared with 12.9% in the control group (<870 dBA-year). Only high-exposure workers had significantly lower prevalence of hypertension (21.6%) than the control group (28.5%). We also found a significant inverse association between hypertension and noise exposure with adjusted odds ratios ranging from 0.15 (95% CI = 0.09–0.25) in high-exposure workers to 0.29 (95% CI = 0.19–0.45) in low-exposure workers compared to the control group. Conclusion: Our findings suggest that the implementation of guidelines for occupational noise management might have contributed to the prevention of hypertension caused by noise exposure at work.

Occupational asthma and allergy in snow crab processing in Newfoundland and Labrador

Background:Risk factors and prevalence of occupational asthma (OA) and occupational allergy (OAl) in the snow crab-processing industry have been poorly studied.Objective:To estimate the prevalence of OA and OAl in snow...

Genetic Susceptibility in Solvent Induced Neurobehavioral Effects

The aim of this investigation was to study the influence of genetic polymorphisms of biotransformation enzymes and dopamine receptors on neurobehavioral effects in referents (n = 53), solvent-workers (n = 144), and chronic toxic encephalopathy (CTE) patients (n = 33). All participants were interviewed for exposure data and confounding factors and underwent a clinical examination. Neurobehavioral complaints (neurotoxicity symptom checklist-60) and effects [simple reaction time (SRT), symbol digit substitution (SDS), hand-eye coordination (HEC), and digit span backwards (DSB)] were evaluated with a computer assisted test battery. The following genotypes were determined: GSTM1, GSTT1, GSTP1, DRD2 Taq1A, DRD2 Taq1B, and DRD2-141Cdel. Neurotoxic effects and complaints were significantly higher in CTE patients and were related to both duration and level of exposure. An equal distribution of genotypes was found between all groups. Logistic regression analysis revealed that GSTT1 was negatively associated with sleep and sensorimotor complaints. GSTM1 had a protecting influence on the relationship between logDSB and the cumulative exposure index and between logSRT and cumulative exposure index and degree of exposure, respectively. This effect was also found when correcting for age, education level, alcohol consumption, and smoking. DRD2-141Cdel polymorphisms had a negative influence on the relationship between logSDS and the total exposure time. GSTT1 might be protective against sleep and sensorimotor complaints, whereas GSTM1 seems to decrease sustained attention and short-term memory problems in relation to solvent exposure. Individuals possessing DRD2-141Cdel variant experienced more visuomotor problems.

Quality of life (EQ-5D) and hand-arm vibration syndrome

The aim of this study was to investigate the quality of life of a population of Finnish metalworkers who were exposed to hand-arm vibration (HAV) and who suffered from white fingers, tingling, or numbness of the fingers, musculoskeletal disorders of the upper extremities, or symptoms of carpal tunnel syndrome (CTS). A questionnaire on vibration exposure in the workplace and symptoms relating to the upper extremities was sent to a sample (n = 530) of members of the local Metalworkers Union. Of those who reported vibration-induced white fingers (VWF), numbness or tingling of the fingers, or symptoms of CTS, 131 men participated in clinical examinations. Their cumulative lifelong exposure to HAV was evaluated, and the health-related quality of life was assessed using EuroQoL(EQ)-5D. There was an inverse relationship between the EQ-5D index score and cumulative exposure to HAV: as exposure to HAV increased, the quality of life became more impaired (P < 0.001). Vascular, sensorineural, and musculoskeletal symptoms and symptoms of CTS decreased significantly with the EQ-5D index score, sensorineural symptoms causing the most significant impairment in EQ-5D dimensions of mobility, usual activities, pain/discomfort, and anxiety/depression). The mean EQ-5D index and the visual analogic scale (VAS)-score were lower for those patients who complained of difficulties at work or during leisure time due to HAVS symptoms. The findings of the present study suggest that symptoms related to HAV exposure significantly diminish the quality of life. This impairment can be seen in the different dimensions of well-being that are measured by EQ-5D. EQ-5D seems to correlate with both the severity of symptoms and the cumulative exposure index, and can thus be recommended as part of the health examination of workers exposed to HAV.

Urinary arsenic methylation capability and carotid atherosclerosis risk in subjects living in arsenicosis-hyperendemic areas in southwestern Taiwan

Long-term exposure to inorganic arsenic from artesian drinking well water is associated with carotid atherosclerosis in the Blackfoot Disease (BFD)-hyperendemic area in Taiwan. The current study examined the arsenic methylation capacity and its risk on carotid atherosclerosis. A total of 304 adults (158 men and 146 women) residing in the BFD-hyperendemic area were included. The extent of carotid atherosclerosis was assessed by duplex ultrasonography. Chronic arsenic exposure was estimated by an index of cumulative arsenic exposure (CAE) and the duration of artesian well water consumption. Urinary levels of inorganic arsenite [As(III)], arsenate [As(V)], monomethylarsonic acid [MMA(V)] and dimethylarsinic acid [DMA(V)] were determined by high performance liquid chromatography linked on-line to a hydride generator and atomic absorption spectrometry (HPLC-HG-AAS). The percentage of arsenic species, primary methylation index [PMI = MMA(V) / (As(III) + As(V)] and secondary methylation index [SMI = DMA(V) / MMA(V)] were calculated and employed as indicators of arsenic methylation capacity. Results showed that women and younger subjects had a more efficient arsenic methylation capacity than did men and the elderly. Carotid atherosclerosis cases had a significantly greater percentage of MMA(V) [%MMA(V)] and a lower percentage of DMA [%DMA (V)] compared to controls. Subjects in the highest two tertiles of PMI with a median of CAE > 0 mg/L-year had an odds ratio (OR) and a 95% confidence interval (CI) of carotid atherosclerosis of 2.61 and 0.98–6.90 compared to those in the highest two tertiles of PMI with a CAE = 0 mg/L-year. We conclude that individuals with greater exposure to arsenic and lower capacity to methylate inorganic arsenic may be at a higher risk to carotid atherosclerosis.

Longitudinal follow-up of oxidative stress and DNA damage parameters in detergent workers.

Background:The aim of this study was the follow-up of work place enzyme and detergent dust exposure effects and smoking habit on DNA damage parameters of workers and the evaluation of their antioxidant enzyme activities and lipid peroxidation with regard to bag-filter installation in the work place.Material and Methods:All investigated parameters were studied in a group of 153 workers of enzyme-free detergent production plant (E-free) and a group of 138 workers of enzyme-plus detergent plant (E-plus) and compared with 45 controls 7.2 years before and 3.1 years after filter system installation. The following methods were used: antioxidant enzymes by an ultraviolet–visibles spectrophotometer, malondialdehyde (MDA), 8-hydroxy-2'deoxyguanosine (8OH-2'dG) by high-performance liquid chromatography, trace elements by atomic absorption spectroscopy, and comet assay by single cell gel electrophoresis.Results:Compared with controls, significant increases were observed in both detergent-exposed groups with respect to the levels of MDA, antioxidant enzyme activities, and DNA damage parameters, including 8OH-2'dG, endonuclease III-sensitive sites, and DNA strand breaks, with enhancement effect of smoking before filter system installation. After filter installation, besides significant decrease in the detergent and enzyme dust of airborne and oxidative stress indicators, there was improvement in all DNA damage investigated parameters at the end of this study. The levels of cumulative exposure index of detergent dusts decreased significantly after airborne improvement and showed positive correlation with internal biochemical parameters.Conclusions:We concluded that high levels of enzyme and detergent contents of work place dusts had a cumulative effect and smoking had a synergistic effect on the imbalance of antioxidant status and lipid peroxidation, suggesting that oxidation stress is important in the occurrence and progression of DNA damage over this study. Detergent and enzyme contents in respirable and total dust had the main role and sufficient potential in their genotoxicity.

Effects of styrene exposure on vibration perception threshold

Objectives We aimed to investigate whether styrene can affect the vibration perception threshold (VPT) and to examine the dose–effect relationship at current and past styrene exposure levels. Methods VPT was examined using a Vibrometer (TM-31A) for 67 subjects exposed to styrene in a fiberglass reinforced plastic boat plant and 151 non-exposed subjects. We selected 67 age-matched controls out of the non-exposed subjects for the analyses. End shift urinary metabolites of styrene were measured for evaluation of the dose–effect relationship for the past eight years and at the time of VPT measurement. The current exposure level was expressed by the end shift urinary mandelic acid (MA) and phenylglyoxylic acid (PGA) levels. Cumulative exposure index (CEI) were calculated based on the exposure frequency and urinary MA concentrations measured for the past eight years. Results The VPT of the exposed group was higher than that of non-exposed group. Multiple regression analysis revealed that past maximum exposure level and age were significant factors explaining the variation of VPT. Dose–effect relationship was recognized in upper limbs but not in lower limbs among exposure groups. When the exposed group was divided into high- and low-level groups for the past maximum exposure level by the cutoff point of MA 0.83 g/g cr (equivalent to 50 ppm in air) and compared to the control group, we found significant differences in the VPT in upper limbs, between the high-level exposed group and control group, and in lower limbs, between both of the high- and low-level exposed groups and the control group. Conclusion If the maximum concentration of styrene exposure exceeded 50 ppm in the past, effects of exposure to styrene on the VPT are likely to persist.

Dose–Response Relationship Between Exposure to Hand-arm Vibration and Health Effects among Metalworkers

The aim of this study was to explore the relationship of exposure to hand-arm vibration (HAV) and vascular, sensorineural and musculoskeletal symptoms and symptoms of carpal tunnel syndrome (CTS) in a population of Finnish metalworkers. A questionnaire on HAV exposure and symptoms was sent to 530 metalworkers. Those who reported finger blanching, numbness or tingling of the fingers or symptoms of CTS were invited to further examinations (n = 133). Their cumulative lifelong exposure to HAV, the level of current exposure and the history of use of tools causing impulse vibration were evaluated. The association of different symptoms with the HAV exposure was assessed with logistic regression analyses adjusted for age and smoking. The vibration perception thresholds (VPTs) were tested according to ISO 13091-1:2001. The cumulative exposure index varied between 0 and 115,000 m(2) years d s(-4), the mean being 20,591 m(2) years d s(-4). The average of current daily vibration exposure was 1.6 m s(-2) and 39% of the participants had a history of exposure to impulse vibration. Of the respondents, 49% reported white fingers, 66% neurosensory symptoms, 56% symptoms of CTS and 75% musculoskeletal symptoms. The cumulative exposure index was associated with symptoms of white fingers [odds ratio (OR) 2.4-4.5], with symptoms of CTS (OR 4.6-6.1), with neurosensory symptoms (OR 5.7-17.3) and with musculoskeletal symptoms (OR 4.7-5.4). The risk of all these symptoms increased as the cumulative vibration dose increased. The history of exposure to impulse vibration had a significant effect on the occurrence of neurosensory symptoms (P = 0.024). The current exposure to HAV correlated significantly with all of the above-mentioned symptoms. The results of the VPT test were associated with the level of cumulative exposure to HAV. There seems to be a dose-response relationship between the cumulative lifetime vibration dose of the HAV and finger blanching, sensorineural symptoms, symptoms of CTS and musculoskeletal symptoms of upper limbs and neck in the group of metalworkers of the study. The risk for neurosensory symptoms was the most significantly related to exposure to HAV and also to impulse vibration. Further studies are needed to confirm the present results also in other occupational groups taking into account the possible synergistic effect of workload as well.

Vegetation exposure to ozone over the continental United States: Assessment of exposure indices by the Eta-CMAQ air quality forecast model

The main use of air quality forecast (AQF) models is to predict ozone (O 3) exceedances of the primary O 3 standard for informing the public of potential health concerns. This study presents the first evaluation of the performance of the Eta-CMAQ air quality forecast model to predict a variety of widely used seasonal mean and cumulative O 3 exposure indices associated with vegetation using the U.S. AIRNow O 3 observations. These exposure indices include two concentration-based O 3 indices, M7 and M12 (the seasonal means of daytime 7-h and 12-h O 3 concentrations, respectively), and three cumulative exposure-based indices, SUM06 (the sum of all hourly O 3 concentrations ≥ 0.06 ppm), W126 (hourly concentrations weighed by a sigmoidal weighting function), and AOT40 (O 3 concentrations accumulated over a threshold of 40 ppb during daylight hours). During a three-month simulation (July–September 2005), the model over predicted the M7 and M12 values by 8–9 ppb, or a NMB value of 19% and a NME value of 21%. The model predicts a central belt of high O 3 extending from Southern California to Middle Atlantic where the seasonal means, M7 and M12 (the seasonal means of daytime 7-h and 12-h O 3 concentrations), are higher than 50 ppbv. In contrast, the model is less capable of reproducing the observed cumulative indices. For AOT40, SUM06 and W126, the NMB and NME values are two- to three-fold of that for M7, M12 or peak 8-h O 3 concentrations. The AOT40 values range from 2 to 33 ppm h by the model and from 1 to 40 ppm h by the monitors. There is a significantly higher AOT40 value experienced in the United States in comparison to Europe. The domain-wide mean SUM06 value is 14.4 ppm h, which is about 30% higher than W126, and 40% higher than AOT40 calculated from the same 3-month hourly O 3 data. This suggests that SUM06 and W126 represent a more stringent standard than AOT40 if either the SUM06 or the W126 was used as a secondary O 3 standard. Although CMAQ considerably over predicts SUM06 and W126 values at the low end, the model under predicts the extreme high exposure values (>50 ppm h). Most of these extreme high values are found at inland California sites. Based on our analysis, further improvement of the model is needed to better capture cumulative exposure indices.

Vibration-induced white finger syndrome and carpal tunnel syndrome among Finnish metal workers

Officially 10-26 cases of vibration-induced white fingers (VWF) have been reported annually in Finland. It has been suggested that the numbers are underestimated. The purpose of the present study was to estimate the cumulative exposure to hand-arm vibration (HAV) and the prevalence of clinically diagnosed cases of VWF and carpal tunnel syndrome (CTS) in a population of Finnish metal workers and to determine the symptoms and clinical tests that would best predict the diagnosis. A questionnaire on vibration exposure at the workplace and symptoms of the upper extremities was sent to a sample (n = 530) of members of the local Metalworkers Union. Those who reported finger blanching, numbness or tingling of the fingers or symptoms of CTS were invited to take part in clinical examinations. Their cumulative lifelong exposure to HAV was evaluated. Those whose symptoms referred to VWF or CTS were given a cold provocation test with the measurement of finger systolic blood pressure and electroneuromyography of the upper arms. Altogether 285 metal workers (54%) responded to the questionnaire, and 24 new cases of VWF (8.4%) and 12 cases of CTS (4.2%) were diagnosed. In the group of VWF patients, seven workers had both VWF and CTS. All of the workers diagnosed as having VWF also had numbness or tingling in their fingers. Consequently, questions concerning numbness and tingling, a two-point discrimination test, Phalen's test, and Tinell's test had a high predicting value for VWF. The exposure time of the VWF cases did not differ significantly from that of the study group as whole, but the cumulative exposure index was significantly higher. The results suggest that VWF is underdiagnosed in Finland. In screening for the health effects of HAV, sensorineural symptoms of hands should be carefully inquired about and examined in patients complaining of white fingers. More education on the recognition and evaluation of HAV exposure and its health effects is needed.