S Semple

Publications of S Semple

• Contribution of solid fuel, gas combustion, or tobacco smoke to indoor air pollutant concentrations in Irish and Scottish homes.

  Authors: S Semple, C Garden, M Coggins, K S Galea, P Whelan, H Cowie, A Sánchez-Jiménez, P S Thorne, J F Hurley, J G Ayres

  Indoor air. 10/2011;

  Abstract  There are limited data describing pollutant levels inside homes that burn solid fuel within developed country settings with most studies describing test conditions or the effect ofAbstract  There are limited data describing pollutant levels inside homes that burn solid fuel within developed country settings with most studies describing test conditions or the effect of interventions. This study recruited homes in Ireland and Scotland where open combustion processes take place. Open combustion was classified as coal, peat, or wood fuel burning, use of a gas cooker or stove, or where there is at least one resident smoker. Twenty-four-hour data on airborne concentrations of particulate matter <2.5 μm in size (PM(2.5) ), carbon monoxide (CO), endotoxin in inhalable dust and carbon dioxide (CO(2) ), together with 2-3 week averaged concentrations of nitrogen dioxide (NO(2) ) were collected in 100 houses during the winter and spring of 2009-2010. The geometric mean of the 24-h time-weighted-average (TWA) PM(2.5) concentration was highest in homes with resident smokers (99 μg/m(3) - much higher than the WHO 24-h guidance value of 25 μg/m(3) ). Lower geometric mean 24-h TWA levels were found in homes that burned coal (7 μg/m(3) ) or wood (6 μg/m(3) ) and in homes with gas cookers (7 μg/m(3) ). In peat-burning homes, the average 24-h PM(2.5) level recorded was 11 μg/m(3) . Airborne endotoxin, CO, CO(2) , and NO(2) concentrations were generally within indoor air quality guidance levels. PRACTICAL IMPLICATIONS: Little is known about indoor air quality (IAQ) in homes that burn solid or fossil-derived fuels in economically developed countries. Recent legislative changes have moved to improve IAQ at work and in enclosed public places, but there remains a real need to begin the process of quantifying the health burden that arises from indoor air pollution within domestic environments. This study demonstrates that homes in Scotland and Ireland that burn solid fuels or gas for heating and cooking have concentrations of air pollutants generally within guideline levels. Homes where combustion of cigarettes takes place have much poorer air quality.

• High prevalence of skin symptoms among bakery workers.

  Authors: M F C Steiner, F D Dick, A R Scaife, S Semple, P Paudyal, J G Ayres

  Occupational medicine (Oxford, England). 06/2011; 61(4):280-2.

  Occupational skin disease is common and bakery workers are at increased risk of hand dermatitis. To explore the frequency of, and to identify risk factors for, skin symptoms in a small bakery. AOccupational skin disease is common and bakery workers are at increased risk of hand dermatitis. To explore the frequency of, and to identify risk factors for, skin symptoms in a small bakery. A cross-sectional survey of workers in a small bakery in Scotland, using a self-completed questionnaire regarding skin symptoms over the last 12 months. Additionally, data on self-reported atopy status, glove use and daily hand washing frequencies were obtained. Workers were classed as being at low, medium or high risk of occupational skin disease based on their job titles. The overall response rate was 85% (52 women, 41 men) with a mean age of 41 (range 17-72). Eleven per cent of bakers, confectioners and packers and 31% of cleaners, cooks and food production workers reported at least one skin symptom. Thirty-three per cent of symptomatic low-risk workers, 50% of symptomatic medium-risk workers and 75% of symptomatic high-risk workers stated their symptoms usually improved away from work. While washing hands more frequently than 20 times a day had an increased risk of skin symptoms, this was not significant [OR 3.5 (95% CI 0.9-13.2)]. There was a high prevalence of skin symptoms among these bakery workers which was more than double that previously reported in UK bakeries. Frequent washing of hands as a risk factor for skin symptoms may warrant further investigation in bakery workers.

• Parental occupation is a risk factor for childhood wheeze and asthma.

  Authors: N Tagiyeva, G Devereux, S Semple, A Sherriff, J Henderson, P Elias, J G Ayres

  The European respiratory journal : official journal of the European Society for Clinical Respiratory Physiology. 11/2009;

  This birth-cohort study investigated whether childhood wheeze and asthma is associated with parental exposure to occupational sensitisers that cause asthma.Parental occupation from the AvonThis birth-cohort study investigated whether childhood wheeze and asthma is associated with parental exposure to occupational sensitisers that cause asthma.Parental occupation from the Avon Longitudinal Study of Parents and Children was related to wheeze, asthma, ventilatory function, airway responsiveness and atopic sensitisation in children aged 0-102 months.Occupation was recorded for 11,193 mothers and 9,473 fathers ante-natally, and for 4,631 mothers and 5,315 fathers post-natally. Childhood respiratory outcomes were not associated with parental occupational exposure to diisocyanates, glues/resins, dyes, animal dust, solder, enzymes, and wood-dust. Maternal post-natal occupational exposure to latex and/or biocide/fungicides increased the likelihood of childhood wheeze and asthma. High levels of latex or biocide/fungicide exposure were associated with odds ratios of 1.26 [1.07-1.50] and 1.22 [1.02-2.05] respectively for wheezing up to 81 months. Combined maternal latex and biocide/fungicide exposures increased the likelihood of childhood wheeze (OR 1.22 [1.03-1.43]) and asthma. High paternal occupational flour dust exposure was associated with an increased likelihood of wheeze after 30 months (OR 2.31 [1.05-5.10]) and asthma by 91-months (OR 3.23 [1.34-7.79]).Maternal occupational exposure to latex and/or biocides and paternal exposure to flour dust increases the risk of childhood asthma. Further studies in this area are justified.

• Sodium metabisulphite induced airways disease in the fishing and fish-processing industry.

  Authors: M Steiner, A Scaife, S Semple, G Hulks, J G Ayres

  Occupational medicine (Oxford, England). 11/2008;

  BACKGROUND: Sodium metabisulphite (SMBS) is recognized as a potential cause of airway irritation and possibly occupational asthma, but awareness of its use in the fishing and fish-processing industryBACKGROUND: Sodium metabisulphite (SMBS) is recognized as a potential cause of airway irritation and possibly occupational asthma, but awareness of its use in the fishing and fish-processing industry is low. Aims and methods To describe three cases of occupational airways disease due to SMBS exposure and to review the literature. RESULTS: Three patients, one trawlerman and two prawn processors, developed work-related airways disease due to exposure to SMBS, one with irritant-induced asthma with a positive-specific bronchial challenge associated with very high sulphur dioxide exposures, one with occupational asthma and one with vocal cord dysfunction and underlying asthma. Of the nine cases recorded in the literature, most were non-atopic and responses to specific bronchial challenge when undertaken showed an immediate response. Exposures to sulphur dioxide in these settings are very high, in excess of 30 ppm. CONCLUSION: SMBS should be regarded as a cause of occupational airways disease and its use in the fish and prawn-processing industry investigated further to better identify risks from exposure and handling of the agent in the workplace.

• Mineral dust exposure in young Indian adults: an effect on lung growth?

  Authors: D A Green, G McAlpine, S Semple, H Cowie, A Seaton

  Occupational and environmental medicine. 06/2008; 65(5):306-10.

  BACKGROUND/OBJECTIVE: Long-term occupational exposure to mineral dusts including quartz is known to cause pneumoconiosis but little is known about the effects of such exposure during the period ofBACKGROUND/OBJECTIVE: Long-term occupational exposure to mineral dusts including quartz is known to cause pneumoconiosis but little is known about the effects of such exposure during the period of lung development in childhood. The objective of this study was to investigate the effects on young people of exposure to mineral dusts. METHODS: We carried out a cross-sectional study of a group of 81 Indian stone crushers (average age 21) and a control group of 72 nearby slum dwellers (average age 21) in order to assess dust exposures, respiratory symptoms and lung function. RESULTS: Stone crushers' corrected 8-hour time weighted average concentrations of total inhalable dust, respirable dust and respirable crystalline silica were 143 mg/m(3), 39.7 mg/m(3) and 2.29 mg/m(3) respectively, which are 14, 10 and 23 times the UK workplace exposure limits, respectively. Both groups also had high exposures to outdoor and general domestic particulate matter. Compared to controls, stone crushers had significantly more symptoms, lower levels of forced vital capacity (FVC) and forced expiratory time (FET) and higher levels of forced expiratory volume in one second (FEV(1))/FVC ratio and mid-expiratory flow rate (MEF). There were no differences in FEV(1) levels. Symptoms and lung function were not associated with time lived on site or time spent in job. A selection of chest radiographs showed no silicosis by International Labour Office (ILO) criteria. CONCLUSION: Individuals exposed to mixed mineral dust in childhood and early adult life had excess symptoms and reduced vital capacity without airflow obstruction compared with control subjects. We interpret this as evidence of stunting of lung growth caused by exposure to respirable dust.

• Exposure to particulate matter on an Indian stone-crushing site.

  Authors: S Semple, D A Green, G McAlpine, H Cowie, A Seaton

  Occupational and environmental medicine. 05/2008; 65(5):300-5.

  BACKGROUND/OBJECTIVES: A large number of labourers work in the stone-crushing industry in India. Many of these workers are also exposed to high levels of particulate matter in their homes from theBACKGROUND/OBJECTIVES: A large number of labourers work in the stone-crushing industry in India. Many of these workers are also exposed to high levels of particulate matter in their homes from the use of biomass fuels. As part of our investigations to examine the health of these workers we characterised their exposure to respirable crystalline silica and a number of other particulate matter exposure metrics in both occupational and domestic settings. METHODS: We used a combination of direct reading and gravimetric sampling of respirable dust, total inhalable dust and particulate matter <2.5 mum in diameter (PM(2.5)) at work (n = 19), within the general environment (n = 6) and inside the home (n = 7). We used x-ray diffraction to quantify the level of crystalline silica in the respirable dust samples. RESULTS: After correcting for the length of the working week, the arithmetic mean 8-hour time-weighted average (TWA) total inhalable dust exposure for this group was 143 mg/m(3), the mean 8-hour TWA respirable dust exposure was 39.7 mg/m(3) and the 8-hour TWA crystalline silica exposure was 2.29 mg/m(3). Our real-time data showed peaks in exposure under certain environmental and/or working conditions. General environmental and domestic PM(2.5) exposures were also high. CONCLUSIONS: Particulate matter exposures experienced by this group of workers and their families are likely to produce impaired lung function within a short time-frame. There is a need to introduce simple measures to reduce particulate matter exposure from both occupational sources and the use of biomass fuels in homes on this and similar sites.

• Gene-environment interactions in parkinsonism and Parkinson's disease: the Geoparkinson study.

  Authors: F D Dick, G De Palma, A Ahmadi, A Osborne, N W Scott, G J Prescott, J Bennett, S Semple, S Dick, P Mozzoni, N Haites, S Bezzina Wettinger, A Mutti, M Otelea, A Seaton, P Soderkvist, A Felice

  Occupational and environmental medicine. 11/2007; 64(10):673-80.

  OBJECTIVES: To investigate associations of Parkinson's disease (PD) and parkinsonian syndromes with polymorphic genes that influence metabolism of either foreign chemical substances or dopamine andOBJECTIVES: To investigate associations of Parkinson's disease (PD) and parkinsonian syndromes with polymorphic genes that influence metabolism of either foreign chemical substances or dopamine and to seek evidence of gene-environment interaction effects that modify risk. METHODS: A case-control study of 959 prevalent cases of parkinsonism (767 with PD) and 1989 controls across five European centres. Occupational hygienists estimated the average annual intensity of exposure to solvents, pesticides and metals, (iron, copper, manganese), blind to disease status. CYP2D6, PON1, GSTM1, GSTT1, GSTM3, GSTP1, NQO1, CYP1B1, MAO-A, MAO-B, SOD 2, EPHX, DAT1, DRD2 and NAT2 were genotyped. Results were analysed using multiple logistic regression adjusting for key confounders. RESULTS: There was a modest but significant association between MAO-A polymorphism in males and disease risk (G vs T, OR 1.30, 95% CI 1.02 to 1.66, adjusted). The majority of gene-environment analyses did not show significant interaction effects. There were possible interaction effects between GSTM1 null genotype and solvent exposure (which were stronger when limited to PD cases only). CONCLUSIONS: Many small studies have reported associations between genetic polymorphisms and PD. Fewer have examined gene-environment interactions. This large study was sufficiently powered to examine these aspects. GSTM1 null subjects heavily exposed to solvents appear to be at increased risk of PD. There was insufficient evidence that the other gene-environment combinations investigated modified disease risk, suggesting they contribute little to the burden of PD.

• Environmental risk factors for Parkinson's disease and parkinsonism: the Geoparkinson study.

  Authors: F D Dick, G De Palma, A Ahmadi, N W Scott, G J Prescott, J Bennett, S Semple, S Dick, C Counsell, P Mozzoni, N Haites, S Bezzina Wettinger, A Mutti, M Otelea, A Seaton, P Söderkvist, A Felice

  Occupational and environmental medicine. 11/2007; 64(10):666-72.

  OBJECTIVE: To investigate the associations between Parkinson's disease and other degenerative parkinsonian syndromes and environmental factors in five European countries. METHODS: A case-controlOBJECTIVE: To investigate the associations between Parkinson's disease and other degenerative parkinsonian syndromes and environmental factors in five European countries. METHODS: A case-control study of 959 prevalent cases of parkinsonism (767 with Parkinson's disease) and 1989 controls in Scotland, Italy, Sweden, Romania and Malta was carried out. Cases were defined using the United Kingdom Parkinson's Disease Society Brain Bank criteria, and those with drug-induced or vascular parkinsonism or dementia were excluded. Subjects completed an interviewer-administered questionnaire about lifetime occupational and hobby exposure to solvents, pesticides, iron, copper and manganese. Lifetime and average annual exposures were estimated blind to disease status using a job-exposure matrix modified by subjective exposure modelling. Results were analysed using multiple logistic regression, adjusting for age, sex, country, tobacco use, ever knocked unconscious and family history of Parkinson's disease. RESULTS: Adjusted logistic regression analyses showed significantly increased odds ratios for Parkinson's disease/parkinsonism with an exposure-response relationship for pesticides (low vs no exposure, odds ratio (OR) = 1.13, 95% CI 0.82 to 1.57, high vs no exposure, OR = 1.41, 95% CI 1.06 to 1.88) and ever knocked unconscious (once vs never, OR = 1.35, 95% CI 1.09 to 1.68, more than once vs never, OR = 2.53, 95% CI 1.78 to 3.59). Hypnotic, anxiolytic or antidepressant drug use for more than 1 year and a family history of Parkinson's disease showed significantly increased odds ratios. Tobacco use was protective (OR = 0.50, 95% CI 0.42 to 0.60). Analyses confined to subjects with Parkinson's disease gave similar results. CONCLUSIONS: The association of pesticide exposure with Parkinson's disease suggests a causative role. Repeated traumatic loss of consciousness is associated with increased risk.

• Development of a biologically relevant dermal sampler.

  Authors: F E Lindsay, S Semple, A Robertson, J W Cherrie

  The Annals of occupational hygiene. 02/2006; 50(1):85-94.

  There are currently no appropriate methods for measuring dermal exposure to volatile agents. To address this we have produced a prototype Institute of Occupational Medicine (IOM) dermal samplerThere are currently no appropriate methods for measuring dermal exposure to volatile agents. To address this we have produced a prototype Institute of Occupational Medicine (IOM) dermal sampler consisting of an adsorbent sandwiched between a permeable membrane and an impervious backing. The concentration of solvent on the membrane surface may be estimated from the mass collected on the adsorbent and the known permeation rate through the membrane. We have developed the prototype IOM dermal sampler for measurement of toluene exposures. Evaluation of the prototype sampler was undertaken in two stages: laboratory performance in controlled exposure situations and two short-field evaluations, which included simultaneous measurement of inhalation exposure. In all cases we compared the prototype IOM dermal sampler with activated charcoal cloth (ACC). Laboratory trials were split into spray, pour and immersion tests. The data from these suggest that the sampler responds to concentration rather than the mass on the surface of the sampler. The field study showed that the prototype sampler was suitable for measuring dermal exposure. However, the mean permeation rate of the best membrane was 78 000 mug cm(-2) h(-1), which is higher than the permeation rate through skin. This high permeation rate created difficulties throughout the study, particularly as it allowed the adsorbent to become rapidly saturated. The prototype IOM dermal sampler is the first practical dermal exposure sampler to mimic uptake through the skin. The sampler gave reproducible results in the laboratory and field trials. Future work is required to identify a less permeable membrane, which has characteristics closer to that of human skin. Additionally, a higher capacity adsorbent would be desirable. We have demonstrated a major difference when calculating the total contribution to body burden via the dermal exposure pathway using the prototype IOM dermal sampler and ACC patches, 1.5% of the total body burden compared with 95%. The prototype IOM dermal sampler provides a more biologically relevant exposure metric than the alternatives.

• Assessing occupational and environmental exposure.

  Authors: S Semple

  Occupational medicine (Oxford, England). 10/2005; 55(6):419-24.

  Exposure assessment is a poorly understood component of the science of epidemiology. The relationship between exposure to chemicals and ill-health outcomes is often calculated using crude exposureExposure assessment is a poorly understood component of the science of epidemiology. The relationship between exposure to chemicals and ill-health outcomes is often calculated using crude exposure measures such as ever/never exposed or duration. When investigating subtle effects, exposures need to be characterized much more fully in terms of intensity, frequency, duration and route. While occupational exposures tend to be much greater than those experienced from the wider environment there is a need to remember that, for many chemicals, exposure can occur occupationally, environmentally and through consumer use of products containing the material of interest. Inhalation exposure has generally been the traditional focus for most epidemiological investigations but there is now growing awareness of the importance of the dermal and ingested routes of contact and internalization. Quantification of the exposure also needs to be related to a biological mechanism of action and exposure metrics need to be selected accordingly. Occupational exposures can generally be measured using simple well-validated techniques. Environmental exposures require much more sensitive instruments and are more difficult to assess. Exposure modelling, particularly for the environmental fate of chemicals has undergone many recent developments and Monte Carlo techniques can be used to characterize model uncertainty and variability. This approach to exposure assessment can now be used in the setting of the wider environment and will enable a far better understanding of the relationship between exposure and disease.

• Dermal exposure to chemicals in the workplace: just how important is skin absorption?

  Authors: S Semple

  Occupational and environmental medicine. 05/2004; 61(4):376-82.

• Is colour vision impairment associated with cognitive impairment in solvent exposed workers?

  Authors: F Dick, S Semple, A Soutar, A Osborne, J W Cherrie, A Seaton

  Occupational and environmental medicine. 02/2004; 61(1):76-8.

  AIMS: To determine whether acquired colour vision deficits in solvent exposed individuals are associated with cognitive impairment. METHODS: A sample of 82 painters and 38 other subjects wereAIMS: To determine whether acquired colour vision deficits in solvent exposed individuals are associated with cognitive impairment. METHODS: A sample of 82 painters and 38 other subjects were studied. Alcohol, drug, and smoking histories were obtained. Colour vision was tested using the Lanthony D-15-d colour vision test. Cognitive impairment was measured using the Benton visual retention test, Trail making A, and Trail making B tests. Pre-morbid IQ was estimated using the National Adult Reading Test. Solvent exposure in all subjects was estimated using a previously validated, structured subjective assessment methodology. RESULTS: After exclusion of subjects with competing causes of colour vision impairment the final group of men numbered 78. There was a significant association on multiple linear regression between the mean colour confusion index (CCI) and three measures of cognitive impairment, the Benton visual retention test, Trail making A, and Trail making B tests after adjusting for the effects of age (or IQ as appropriate), alcohol, and smoking. CONCLUSION: Acquired colour vision loss is associated with cognitive impairment in solvent exposed workers. However, given the prevalence of acquired colour vision losses in the adult population, colour vision testing is unlikely to be of value as a screening test.

• Organic solvent exposure, genes, and risk of neuropsychological impairment.

  Authors: F Dick, S Semple, A Osborne, A Soutar, A Seaton, J W Cherrie, L G Walker, N Haites

  QJM : monthly journal of the Association of Physicians. 07/2002; 95(6):379-87.

  BACKGROUND: Subtle cognitive and neurological impairments have been found in some workers exposed to organic solvents. Whether these effects occur at or below current legal limits for occupationalBACKGROUND: Subtle cognitive and neurological impairments have been found in some workers exposed to organic solvents. Whether these effects occur at or below current legal limits for occupational exposure is controversial. Aim: To determine whether occupational solvent exposure is associated with neuropsychological impairment and whether such risk is modified by polymorphisms in the genes for enzymes involved in detoxification. DESIGN: Retrospective case-control analysis. METHODS: We studied 78 former dockyard painters and 42 community controls. Individual respiratory and dermal exposures to solvents were estimated. Neuropsychological tests were administered, including paper and pencil tests, tests from the Neurobehavioural Evaluation System (NES2), together with a structured neurological examination and genotyping of polymorphic enzymes involved in detoxification: GSTM1, GSTT1, GSTP1, NAT1, NAT2, SOD1 and CYP1A1. RESULTS: While initial case-control analyses failed to identify any significant differences between symptomatic and asymptomatic painters, in regression analyses increasing solvent exposure was associated with increasing risk of cognitive impairment, after adjustment for IQ (or age, where appropriate), smoking and alcohol. There was also an association between exposure and reduction in grip strength. There was limited evidence of risk modification by some enzyme polymorphisms. DISCUSSION: This association between increasing intensity of solvent exposure and neuropsychological impairment may be important at current exposure levels in the UK.

• Organic solvent exposure, genes, and risk of neuropsychological impairment

  Authors: F Dick, S Semple, A Osborne, A Soutar, A Seaton, J W Cherrie, L G Walker, N Haites

  01/2002; 95:379-87.

  BACKGROUND: Subtle cognitive and neurological impairments have been found in some workers exposed to organic solvents. Whether these effects occur at or below current legal limits for occupationalBACKGROUND: Subtle cognitive and neurological impairments have been found in some workers exposed to organic solvents. Whether these effects occur at or below current legal limits for occupational exposure is controversial. Aim: To determine whether occupational solvent exposure is associated with neuropsychological impairment and whether such risk is modified by polymorphisms in the genes for enzymes involved in detoxification. DESIGN: Retrospective case-control analysis. METHODS: We studied 78 former dockyard painters and 42 community controls. Individual respiratory and dermal exposures to solvents were estimated. Neuropsychological tests were administered, including paper and pencil tests, tests from the Neurobehavioural Evaluation System (NES2), together with a structured neurological examination and genotyping of polymorphic enzymes involved in detoxification: GSTM1, GSTT1, GSTP1, NAT1, NAT2, SOD1 and CYP1A1. RESULTS: While initial case-control analyses failed to identify any significant differences between symptomatic and asymptomatic painters, in regression analyses increasing solvent exposure was associated with increasing risk of cognitive impairment, after adjustment for IQ (or age, where appropriate), smoking and alcohol. There was also an association between exposure and reduction in grip strength. There was limited evidence of risk modification by some enzyme polymorphisms. DISCUSSION: This association between increasing intensity of solvent exposure and neuropsychological impairment may be important at current exposure levels in the UK.

• Nasal, eye, and skin irritation in dockyard painters.

  Authors: R Chen, S Semple, F Dick, A Seaton

  Occupational and environmental medicine. 09/2001; 58(8):542-3.

  OBJECTIVES: To determine whether the risk of irritant symptoms in painters is related to their exposure to paint. METHODS: The prevalences of skin, eye and nasal symptoms were compared in 260 UnitedOBJECTIVES: To determine whether the risk of irritant symptoms in painters is related to their exposure to paint. METHODS: The prevalences of skin, eye and nasal symptoms were compared in 260 United Kingdom and 109 Chinese dockyard painters, 539 British community controls, and 255 Chinese dockyard controls, relative to their exposure to paints. RESULTS: Painters showed an excess of irritant symptoms compared with controls. Adjusted relative risks (RRs) (95% confidence interval (95% CI) were: for skin irritation 1.58 (1.19 to 2.08) in British painters and 2.68 (1.73 to 4.09) in Chinese painters; for eye irritation, 1.41 (0.98 to 2.05) and 3.01 (1.90 to 4.76); and for nasal irritation, 1.53 (1.10 to 2.14) and 6.73 (3.53 to 12.82), respectively. Exposure duration-response relations were found for these symptoms; the risks decreased with time after exposure ended. CONCLUSIONS: Irritant symptoms occur more often in dockyard painters than in controls, and this is likely to be a response to exposure to paint.

• A dermal model for spray painters. Part I: subjective exposure modelling of spray paint deposition.

  Authors: D H Brouwer, S Semple, J Marquart, J W Cherrie

  The Annals of occupational hygiene. 02/2001; 45(1):15-23.

  The discriminative power of existing dermal exposure models is limited. Most models only allow occupational hygienists to rank workers between and within workplaces according to broad bands of dermalThe discriminative power of existing dermal exposure models is limited. Most models only allow occupational hygienists to rank workers between and within workplaces according to broad bands of dermal exposure. No allowance is made for the work practices of different individuals. In this study a process-based, structured approach has been used to estimate dermal exposure from overspray generated by a spray painting process. Factors for spray technique, object shape and workers' individual work practices involved in the processes of droplet formation and deposition were incorporated into the model. The model was applied to predict dermal exposure of airless spray painters and the results were compared with exposure data. The predicted levels of exposure showed reasonable rank correlation with the measured exposure, although the model tended to over-predict the actual level of exposure. It was concluded that a structured, process-based approach has the potential to produce reliable estimates of dermal exposure. The reliability of exposure models of this type should be explored further and the relationship between the determinants of exposure should be validated by additional field studies.

• A dermal model for spray painters. Part II: estimating the deposition and uptake of solvents.

  Authors: S Semple, D H Brouwer, F Dick, J W Cherrie

  The Annals of occupational hygiene. 02/2001; 45(1):25-33.

  The contribution of dermal exposure to the total body burden of a given chemical is difficult to assess. However, it is possible that as regulatory pressures lead to reductions in inhalationThe contribution of dermal exposure to the total body burden of a given chemical is difficult to assess. However, it is possible that as regulatory pressures lead to reductions in inhalation exposure, the proportion of uptake via the dermal route will increase. This study brings together recent work in the field of dermal exposure to provide a model to estimate both exposure and uptake of solvents through the skin. Using spray painters as an example, the process of modelling exposure is described from identifying the determinants of exposure through to calculating the flux of solvent through the stratum corneum and thus the total dermal uptake. Results from a range of exposure scenarios are presented and areas requiring further research and validation are highlighted. The model should allow the estimation of combined dermal and inhalation exposure to solvents in both current work situations and retrospective epidemiological studies. Furthermore, it is envisaged that the model may provide the basis for generic assessment of dermal exposure and uptake.

• The importance of reliable exposure estimates in deciding whether trichloroethylene can cause kidney cancer.

  Authors: J W Cherrie, H. Kromhout, S Semple

  Journal of cancer research and clinical oncology. 02/2001; 127(6):400-4.

• Exposure to organic solvents and personality.

  Authors: R Chen, F Dick, S Semple, A Seaton, L G Walker

  Occupational and environmental medicine. 02/2001; 58(1):14-8.

  OBJECTIVES: Although cognitive and neuropsychological changes have been found after high cumulative exposures to solvents, it is not clear whether such exposures are associated with personalityOBJECTIVES: Although cognitive and neuropsychological changes have been found after high cumulative exposures to solvents, it is not clear whether such exposures are associated with personality characteristics. To study this two groups of British and Chinese dockyard painters who had been heavily exposed to paint solvents have been investigated. METHODS: 260 Male dockyard painters in the United Kingdom, 539 local community controls, 109 Chinese dockyard painters, and 255 dockyard controls completed the Eysenck personality questionnaire, neuroticism (N) and social conformity or dissimulation (L) scales. The non-parametric Kruskal-Wallis test was used to evaluate differences in scores of personality traits between painters and controls. Adjusted relative risks for painters having high N and L scores were calculated in a Breslow-Cox regression analysis, and exposure-response relations were examined in multivariate logistic regression analysis. Non-parametric Spearman's correlation was used to examine relations between previously determined neuropsychological symptoms and personality. RESULTS: Both British and Chinese data showed that mean neuroticism scores of painters were significantly higher than controls, whereas scores of social conformity did not differ. Relative risk of being a painter increased significantly with increasing N scores, but L scores showed no such trend. In a case-control analysis, there were significant exposure-response relations for the N score. In the United Kingdom the odds ratios (ORs) (95% confidence interval (95% CI), were 2.03 (0.79 to 5.22) for 1-4 years of exposure, 2.38 (0.82 to 6.91) for 5-9 years, 7.05 (1.27 to 39.25) for 10-14 years, and 1.76 (0.63 to 4.89) for 15-41 years. In the Chinese painters, ORs were 4.66 (1.38 to 15.75) for 2-14 years, 10.03 (2.96 to 34.04) for 15-18 years, and 13.56 (3.78 to 48.59) for 19-43 years. Neuroticism was significantly positively related to neuropsychological symptoms in all subjects. Social conformity showed no association with neuropsychological symptoms in British painters and a negative relation among the Chinese painters. CONCLUSION: Increasing symptoms suggesting neuroticism seemed to relate to the duration of painting whereas scores for social conformity and dissimulation did not. The relation between exposure time and response suggests that increased neuroticism may be caused by long term occupational exposure to organic solvents.

• Neurological deficits in solvent-exposed painters: a syndrome including impaired colour vision, cognitive defects, tremor and loss of vibration sensation.

  Authors: F Dick, S Semple, R Chen, A Seaton

  QJM : monthly journal of the Association of Physicians. 11/2000; 93(10):655-61.

  Five individuals are described who had participated in a study of former dockyard painters. All had worked between 16 years and 45 years as industrial painters, much of the time inside ships. AllFive individuals are described who had participated in a study of former dockyard painters. All had worked between 16 years and 45 years as industrial painters, much of the time inside ships. All underwent structured neurological examination, colour vision testing (allowing calculation of a colour confusion index corrected for age and alcohol), and detailed psychometric testing. An occupational history sufficient to allow estimation of past exposure to solvents was taken. All gave a history of exposure to high concentrations of solvents at work, and several described episodes of acute narcosis. All showed neurological deficits and some had overt neurological disease, although in no case had this previously been linked to their work. The most striking features, sufficient to constitute a syndrome, were acquired blue-yellow colour vision deficits, coarse tremor, impaired vibration sensation in the legs and cognitive impairment. Their estimated cumulative exposures to solvents ranged between the equivalent of 13 and 37 calendar years working at the Occupational Exposure Standard concentration (OES years). This study for the first time gives an indication of the concentrations of solvents likely to lead to serious neurological disease in humans. It serves as a reminder to physicians to take an occupational history from patients with obscure neurological or psychological impairment.