Evaluation of Firefighter Exposure to Wood Smoke during Training Exercises at Burn Houses.

Smoke from wood-fueled fires is one of the most common hazards encountered by firefighters worldwide. Wood smoke is complex in nature and contains numerous compounds, including methoxyphenols (MPs) and polycyclic aromatic hydrocarbons (PAHs), some of which are carcinogenic. Chronic exposure to wood smoke can lead to adverse health outcomes, including respiratory infections, impaired lung function, cardiac infarctions, and cancers. At training exercises held in burn houses at four fire departments across Ontario, air samples, skin wipes, and urine specimens from a cohort of firefighters (n = 28) were collected prior to and after exposure. Wood was the primary fuel used in these training exercises. Air samples showed that MP concentrations were on average 5-fold greater than those of PAHs. Skin wipe samples acquired from multiple body sites of firefighters indicated whole-body smoke exposure. A suite of MPs (methyl-, ethyl-, and propylsyringol) and deconjugated PAH metabolites (hydroxynaphthalene, hydroxyfluorene, hydroxyphenanthrene, and their isomers) were found to be sensitive markers of smoke exposure in urine. Creatinine-normalized levels of these markers were significantly elevated (p < 0.05) in 24 h postexposure urine despite large between-subject variations that were dependent on the specific operational roles of firefighters while using personal protective equipment. This work offers deeper insight into potential health risk from smoke exposure that is needed for translation of better mitigation policies, including improved equipment to reduce direct skin absorption and standardized hygiene practices implemented at different regional fire services.

Increase in use of protective earplugs by Rock and Roll concert attendees when provided for free at concert venues.

OBJECTIVE: To determine the prevalence of hearing protection use among attendees of Rock and Roll concerts at baseline and in concerts where earplugs are provided for free at concert venue entrances. DESIGN: Six concerts performed at two music venues in Toronto, Canada were evaluated. Study personnel observed and recorded the use of hearing protection at three concerts where no earplugs were distributed, and three concerts where earplugs were provided for free at the concert venue entrance. STUDY SAMPLE: A total of 955 individuals over the age of 18 were observed at six concerts. Six hundred and thirty-seven individuals (64% male) were observed at concerts where no earplugs were provided, and 318 individuals (68% male) were observed at concerts where free earplugs were provided. RESULTS: Multivariate logistic regression demonstrated a significant increase in hearing protection usage at concerts where earplugs were provided for free at the concert venue entrance, odds ratio 7.27 (95% CI: 3.24-16.30). CONCLUSION: The provision of free earplugs at concert venues may be a simple and inexpensive intervention that could be a component of a larger public health campaign to prevent non-occupational noise-induced hearing loss.

Current perception threshold and the HAVS Stockholm sensorineural scale.

BACKGROUND: It is important to determine which tests of sensorineural dysfunction identify the neurological damage from hand-arm vibration exposure. AIMS: To examine the association between the hand-arm vibration syndrome (HAVS) Stockholm sensorineural scale stages and tests of peripheral neurological function including measurement of current perception threshold (CPT) and nerve conduction. METHODS: All the subjects were men who were assessed for HAVS with a medical and occupational history and physical examination to determine the Stockholm stage, CPT testing at frequencies of 5, 250 and 2000 Hz for the median and ulnar nerves and measurement of nerve conduction carried out in a blinded fashion. RESULTS: A total of 155 of the 157 recruited subjects agreed to take part in the study, a 99% participation rate. CPT was statistically significantly increased (P < 0.001) in both Stockholm sensorineural Stages 1 and > or =2 in comparison to Stage 0 for every frequency and nerve combination. However, CPT could not discriminate well between Stages 1 and > or =2. There was no association between median or ulnar neuropathy measured by nerve conduction and the Stockholm stages. Polychotomous multinomial logistic regression indicated that the CPT measurements at 2000 Hz, corresponding to damage to large myelinated nerve fibres, were most predictive of both Stockholm Stages 1 and > or =2 in comparison to Stage 0. CONCLUSIONS: Neuropathy measured by nerve conduction was unrelated to the Stockholm scale stages. CPT was increased above Stage 0 but did not distinguish well between the higher stages of the Stockholm scale.

Upper extremity disability in workers with hand-arm vibration syndrome.

BACKGROUND: Hand-arm vibration syndrome (HAVS) is a common occupational problem and it is important to understand the disability associated with this condition. AIMS: To measure upper extremity disability using the disabilities of the arm, shoulder and hand (DASH) questionnaire in workers with HAVS and to determine how this disability is affected by the vascular and neurological components of HAVS and other factors, in particular musculoskeletal variables. METHODS: Subjects were recruited from HAVS patients assessed at St Michael's Hospital, Toronto, Canada, over a 2-year period. All participants were assessed by an occupational medicine specialist to determine the specific components of HAVS and musculoskeletal variables including upper extremity pain score measured by the Borg scale. The DASH questionnaire was completed on the same day as the clinical assessment and before any feedback had been given about the clinical findings. RESULTS: A total of 141 workers with HAVS were recruited and 139 agreed to participate in the study. This study group had a statistically significantly higher mean DASH score than the US population (P < 0.001). The multiple linear regression analysis indicated that upper extremity pain score (P < 0.001), the Stockholm sensorineural scale (P < 0.01) and the number of fingers blanching (P < 0.05) had a statistically significant association with an increase in the DASH score. The highest partial R(2) value was for the upper extremity pain score. CONCLUSIONS: Workers with HAVS have significant upper extremity disability and musculoskeletal factors appear to make an important contribution to this disability.

The sensitivity and specificity of thermometry and plethysmography in the assessment of hand-arm vibration syndrome.

BACKGROUND: Finger plethysmography and thermometry are objective measures used to assess the vascular aspect of hand-arm vibration syndrome (HAVS). Research to date shows poor correlation between these tests and Stockholm Workshop Scale (SWS) vascular stage. Clinicians, researchers and compensation boards require objective means to diagnose and quantify HAVS. AIMS: To define the specificity and sensitivity of thermometry and plethysmography using the SWS as the reference criterion. A secondary goal was to consider cut points for the tests optimizing sensitivity and specificity. METHODS: A cross-sectional analysis was conducted on HAVS patients seen at an occupational medicine specialty clinic. Plethysmography and thermometry were analyzed using SWS vascular stage as the outcome variable. Logistic regression controlled for age, smoking and time since last vibration exposure and use of vasoactive medications. The sensitivity and specificity of the combined tests were calculated using varying cut points. RESULTS: A total of 139 patients consented to participate in the study. Plethysmography stage 1 or greater showed the highest sensitivity (sensitivity 94% and specificity 15%). Specificity was optimized combining plethysmography stage 3 and thermometry stage 3 (specificity 98% and sensitivity 23%). Maximal diagnostic accuracy was achieved by plethysmography alone setting the criteria for a positive test as being stage 1 or greater (70%). CONCLUSIONS: Neither plethysmography nor thermometry either alone or in combination demonstrated sufficient sensitivity and specificity to serve as an objective correlate for SWS vascular stage. All combinations of plethysmography and thermometry showed a lower specificity than sensitivity indicating that the SWS may be less sensitive in detecting vascular pathology than the objective tests.

Examining the Usefulness of ISO 10819 Anti-Vibration Glove Certification.

Anti-vibration gloves are commonly worn to reduce hand-arm vibration exposure from work with hand-held vibrating tools when higher priority and more effective controls are unavailable. For gloves to be marketed as 'anti-vibration' they must meet the vibration transmissibility criteria described in the International Organization for Standardization (ISO) standard 10819 (2013). Several issues exist with respect to the methodology used for glove testing as well as the requirements for glove design and composition in ISO 10819 (2013). The true usefulness of anti-vibration gloves at preventing hand-arm vibration syndrome (HAVS) is controversial, given that their performance is dependent on tool vibration characteristics and the anthropometrics of workers in real working conditions. The major risk associated with the use of anti-vibration gloves is that it will give employees and employers a false sense of protection against the negative effects of hand-transmitted vibration. This commentary examines the limitations of the current international standards for anti-vibration glove testing and certification, thereby calling into question the degree of protection that anti-vibration gloves provide against HAVS, and cautioning users to consider both their benefits and potential drawbacks on a case-by-case basis.

Investigation of pulmonary function among employees exposed to low levels of monomeric isocyanates and solvents at an automobile finishings plant.

There have been reports in the literature of decrements in pulmonary function associated with long-term, low-level monomeric isocyanate exposure combined with solvent exposure. This cross-sectional study examines the relationship between these exposures and pulmonary function in an automobile paint and coating (finishes) plant. A job exposure matrix was developed for isocyanate and solvent exposure; years in a work task were used as a surrogate for exposure. Recent pulmonary function tests were used as the outcome variables; specifically the difference between predicted and actual FEV1 and FVC. The results of the analysis demonstrated no statistically significant relationship between combined isocyanate and solvent exposure and decline in pulmonary function. There was a statistically significant negative correlation between solvent exposure and FEV1 and FVC.

Vibration induced white-feet: overview and field study of vibration exposure and reported symptoms in workers.

BACKGROUND: Workers who stand on platforms or equipment that vibrate are exposed to foot-transmitted vibration (FTV). Exposure to FTV can lead to vibration white feet/toes resulting in blanching of the toes, and tingling and numbness in the feet and toes. OBJECTIVES: The objectives are 1) to review the current state of knowledge of the health risks associated with foot-transmitted vibration (FTV), and 2) to identify the characteristics of FTV and discuss the associated risk of vibration-induced injury. PARTICIPANTS: Workers who operated locomotives (n=3), bolting platforms (n=10), jumbo drills (n=7), raise drilling platforms (n=4), and crushers (n=3), participated. METHODS: A tri-axial accelerometer was used to measure FTV in accordance with ISO 2631-1 guidelines. Frequency-weighted root-mean-square acceleration and the dominant frequency are reported. Participants were also asked to report pain/ache/discomfort in the hands and/or feet. RESULTS: Reports of pain/discomfort/ache were highest in raise platform workers and jumbo drill operators who were exposed to FTV in the 40 Hz and 28 Hz range respectively. Reports of discomfort/ache/pain were lowest in the locomotive and crusher operators who were exposed to FTV below 10 Hz. These findings are consistent with animal studies that have shown vascular and neural damage in exposed appendages occurs at frequencies above 40 Hz. CONCLUSIONS: Operators exposed to FTV at 40 Hz appear to be at greater risk of experiencing vibration induced injury. Future research is required to document the characteristics of FTV and epidemiological evidence is required to link exposure with injury.

Nerve conduction studies and current perception thresholds in workers assessed for hand-arm vibration syndrome.

BACKGROUND: Workers exposed to hand-arm vibration are at risk of developing the neurological abnormalities of hand-arm vibration syndrome (HAVS). The Stockholm classification of the neurological component of HAVS is based on history and physical examination. There is a need to determine the association between neurological tests and the Stockholm scale. AIMS: The main objective of this study was to compare the Stockholm neurological scale and the results of current perception threshold (CPT) tests and nerve conduction studies (NCS). METHODS: Detailed physical examinations were done on 162 subjects referred for HAVS assessment at a specialist occupational health clinic. All subjects had NCS and measurement of CPT. The Stockholm neurological classification was carried out blinded to the results of these neurological tests and compared to the test results. RESULTS: The nerve conduction results indicated that median and ulnar neuropathies proximal to the hand are common in workers being assessed for HAVS. Digital sensory neuropathy was found in only one worker. Neither the nerve conduction results nor the current perception results had a strong association with the Stockholm neurological scale. Exposure to vibration in total hours was the main variable associated with the Stockholm neurological scale [right hand: OR 1.30, 95% CI (1.10-1.54); left hand: OR 1.18, 95% CI (1.0-1.39)]. CONCLUSION: Workers being assessed for HAVS should have nerve conduction testing to detect neuropathies proximal to the hand. Quantitative sensory tests such as current perception measurement are insufficient for diagnostic purposes but may have a role in screening workers exposed to vibration.

Assessment of the hand-arm vibration syndrome: thermometry, plethysmography and the Stockholm Workshop Scale.

BACKGROUND: The Stockholm Workshop Scale (SWS) provides a staging scheme for hand-arm vibration syndrome (HAVS) based on subjective history. Cold provocation finger thermometry and plethysmography are commonly used objective tests for the vascular component of HAVS. AIM: To examine the correlation between the cold provocation tests and SWS vascular stage. A secondary goal was to evaluate the correlation between cold provocation finger plethysmography and thermometry testing. METHODS: Patients investigated for HAVS at St Michael's Hospital, Toronto, Ontario, were subjected to the same protocol including a questionnaire, clinical assessment and objective testing. Spearman correlation coefficients were calculated for the vascular tests with the SWS and for the vascular tests themselves. Logistic regression models controlled for age, smoking, use of vasoactive medications and time since last vibration exposure. RESULTS: One hundred and thirty-nine patients investigated for HAVS consented to participate in the study. The correlation coefficients for plethysmography (rho = 0.14) and thermometry (rho = 0.18) with the SWS were not statistically significant. Plethysmography and thermometry results were significantly correlated (rho = 0.47, P < 0.001). Logistic regression showed plethysmography and thermometry to weakly predict SWS vascular stage (OR 1.5 and 1.3, respectively). None of the potential confounders had a significant effect in the models. CONCLUSION: The results of plethysmography and thermometry did not significantly correlate with SWS vascular stage in this study. The objective tests did correlate with each other, suggesting that they are reliable measures of similar phenomena likely related to underlying vascular pathology.

Hand-arm vibration syndrome with concomitant arterial thrombosis in the hands.

BACKGROUND: Hand-arm vibration syndrome (HAVS) refers to the vascular, neurological and musculoskeletal effects that may occur in workers with prolonged exposure to vibrating tools. Hypothenar hammer syndrome (HHS) is a lesion of the ulnar artery at the level of the hamate bone secondary to single or repeated episodes of trauma to the hypothenar eminence. The literature suggests that digital arterial thrombosis and HHS may be associated with the use of vibrating tools. AIM: This study will familiarize investigators with the range of vascular abnormalities seen in workers using vibrating tools, and highlight the importance of screening for arterial thrombosis in the hand when assessing hand-arm vibration-exposed patients. METHODS: In the patients referred to our clinic for HAVS assessment, three were identified during the period 2001 to 2004 who had vascular occlusions in the hands in addition to HAVS. In addition to standardized HAVS vascular investigations, all three patients had arteriograms based on a significantly positive Allen's test. RESULTS: All three cases had documented HAVS based on vascular testing. Arteriograms revealed a spectrum of severity of arterial thromboses from severe HHS, to occlusion limited to the digital arteries. CONCLUSION: Our study reports three cases of HAVS with concomitant HHS and/or digital artery thrombosis. These findings support previous reports of an association between HAVS and vascular thrombosis in the hands. Screening for arterial occlusive problems in the hands should be included in the HAVS work up.