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Stepping between static and moving surfaces presents a locomotor challenge associated with increased injury frequency and severity in older adults. The current study evaluates younger and older adults' behaviours when overcoming challenges sampling moving walkway and escalator environments. Twelve younger adults (18-40 years, Male = 8) and 15 older adults (60-81 years, Male = 5) were examined using an integration of optoelectronic motion capture and mobile eye-tracking. Participants were investigated approaching and stepping onto a flat conveyor belt (static or moving; with or without surface (demarcation) lines). Specifically, the four conditions were: (i) static surface without demarcation lines; (ii) static surface with demarcation lines; (iii) moving surface without demarcation lines; and (iv) moving surface with demarcation lines. A two (age group) x two (surface-condition) x two (demarcation-condition) linear mixed-model revealed no main or interaction effects (p > .05) for perturbation magnitude, indicating participants maintained successful locomotion. However, different adaptive behaviours were identified between conditions with moving and accuracy demands (e.g., moving surfaces increased step length, demarcations reduced step length). Between subject effects identified differences between age groups. Older adults utilised different behaviours, such as earlier gaze transfer from the final approach walkway step location. Overall, the current study suggests that adaptive behaviours emerge relative to the environment's specific demands and the individual's action capabilities.
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Locomoción , Caminata , Humanos , Masculino , AncianoRESUMEN
Workplace-related outbreaks of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) continue to occur globally. The manufacturing sector presents a particular concern for outbreaks, and a better understanding of transmission risks are needed. Between 9 March and 24 April 2021, the COVID-19 (coronavirus disease 2019) Outbreak Investigation to Understand Transmission (COVID-OUT) study undertook a comprehensive investigation of a SARS-CoV-2 outbreak at an automotive manufacturing site in England. The site had a total of 266 workers, and 51 SARS-CoV-2 infections. Overall, ventilation, humidity, and temperature at the site were assessed to be appropriate for the number of workers and the work being conducted. The company had implemented a number of infection control procedures, including provision of face coverings, spacing in the work, and welfare areas to allow for social distancing. However, observations of worker practices identified lapses in social distancing, although all were wearing face coverings. A total of 38 workers, including four confirmed cases, participated in the COVID-OUT study. The majority of participants received COVID-19 prevention training, though 42.9% also reported that their work required close physical contact with co-workers. Additionally, 73.7% and 34.2% had concerns regarding reductions in future income and future unemployment, respectively, due to self-isolation. This investigation adds to the growing body of evidence of SARS-CoV-2 outbreaks from the manufacturing sector. Despite a layered COVID-19 control strategy at this site, cases clustered in areas of high occupancy and close worker proximity.
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COVID-19 , SARS-CoV-2 , COVID-19/epidemiología , Brotes de Enfermedades , Humanos , Control de Infecciones/métodos , Lugar de TrabajoRESUMEN
OBJECTIVES: To explore any age-related trend in workplace slip rate and assess the effectiveness of appropriate slip-resistant footwear in preventing workplace slips by age. METHODS: Secondary data analysis of the Stopping Slips among Healthcare Workers trial, a two-arm randomised controlled trial conducted between March 2017 and May 2019. 4553 National Health Service (NHS) staff across seven sites in England were randomised 1:1 to the intervention group (provision of 5* GRIP-rated slip-resistant footwear) or the control group (usual work footwear). The primary outcome was self-reported workplace slips, ascertained primarily through weekly text messages throughout the 14-week trial follow-up and analysed using mixed-effects negative binomial regression. This paper reports a control group-only analysis of the association between age and slip rate, and a full intention-to-treat analysis of the effectiveness of slip-resistant footwear by age. RESULTS: The mean age of participants was 43 years (range 18-74). In the control group-only analysis, slip rate differed by age (p<0.001) with those aged 60+ having double the slip rate of those aged <30 years (95% CI 1.40 to 2.87). In the intention-to-treat analysis, the interaction between allocation and age was statistically significant (p=0.002). In addition, for all age groups except those aged <30 years, the slip rate in the intervention group was statistically significantly lower than the control group; the smallest incidence rate ratio (ie, the biggest effect) was 0.39 (95% CI 0.24 to 0.64) in the 60+ age group. CONCLUSION: The provision of appropriate slip-resistant footwear was more effective at reducing workplace slips for older NHS staff.
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Zapatos , Lugar de Trabajo , Adolescente , Adulto , Anciano , Personal de Salud , Humanos , Lactante , Persona de Mediana Edad , Medicina Estatal , Adulto JovenRESUMEN
BACKGROUND: Occupational epidemiological studies on pesticide use commonly rely on self-reported questionnaire or interview data to assess exposure. Insight into recall accuracy is important, as misclassification of exposures due to imperfect recall can bias risk estimates. METHODS: We assessed the ability of workers in three UK cohorts (Prospective Investigation of Pesticide Applicators' Health [PIPAH], Pesticide Users' Health Study [PUHS], and Study of Health in Agricultural Work [SHAW]) to remember their working history related to pesticide exposure over time periods ranging from 3 to 14 years prior. During 2019-2020, cohort participants were re-surveyed using a similar questionnaire to that used previously. We compared recall of responses at follow-up to those reported at baseline related to crops/areas of work, use of personal protective equipment (PPE) items, hygiene habits, frequency of pesticide use, and application method. To assess the extent of recall, we used sensitivity, specificity, the percentage of overall agreement, and area under the curve (AUC) values. We also examined the presence of over or underestimation of recalled years, and days and hours per year, of working with pesticides using geometric mean ratios (GMR) and regression analysis to investigate any trends based on demographic characteristics. RESULTS: There were 643 individuals who completed both the baseline and follow-up surveys in the three cohorts with response rates ranging from 17 to 46%. There was a strong correlation (rho = 0.77) between the baseline and recalled years working with pesticides, though higher values were reported at follow-up (GMR = 1.18 [95% confidence interval: 1.07-1.30]) with no consistent differences by demographic characteristics. There was stronger agreement in the recalled days compared to hours per year in two of the cohorts. Recall for a number of exposure determinants across short and longer periods entailed overall agreement of >70%, though with some differences: for example, sensitivity for long-term recall of crops was poor (<43% in PUHS), whereas short-term recall of hygiene practices was good (AUC range = 0.65-1.00 in PIPAH). CONCLUSION: Results indicate that recall ability may deteriorate over a longer period. Although low-response rates may require these findings to be interpreted with caution, recall for a number of exposure determinants appeared reliable, such as crops and hygiene practices within 3 years, as well as days per year working with pesticides.
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Exposición Profesional , Plaguicidas , Agricultores , Estudios de Seguimiento , Humanos , Exposición Profesional/análisis , Estudios Prospectivos , Reino UnidoRESUMEN
OBJECTIVES: To define the prevalence and incidence of asthma in a large working population of pesticide workers and to assess which exposures are potentially of relevance to causing or aggravating this condition. METHODS: A baseline cross-sectional study at recruitment (2013-2017, n=5817), with follow-up in 2018 (n=2578), was carried out in predominantly Great Britain based pesticide workers. At baseline, participants completed a health and work questionnaire which included questions on demographic, lifestyle, socioeconomic and work-related factors, pesticide use and doctor diagnosed health conditions. In January 2018, a follow-up questionnaire focused on respiratory ill health, with questions covering self-reported respiratory symptoms and doctor diagnosed respiratory conditions. The associations of various exposures with asthma were estimated using logistic regression adjusting for age as a continuous variable, and for sex where possible. An estimate of hours worked with pesticides in the previous year was calculated for each participant. RESULTS: At baseline, 608 (10.4%) had doctor diagnosed asthma. In 2018 the figure was 297 (11.5% of the follow-up population); the incidence of new asthma cases between surveys was 1.7 cases per 1000 participants per year. At follow-up, 18.1% reported wheeze in the last 12 months, 73.2% of those with self-reported asthma noted it to be persistent and using a more specific definition of asthma (doctor diagnosed asthma with at least one asthma-related symptom in the last year); 6.8% (95% CI 5.9% to 7.9%) fulfilled this definition. At follow-up, 127 participants felt that their asthma was caused or made worse by their work, with 77 (63.6%) nominating organic dust, 13 (10.7%) unspecified dust, 12 (9.9%) chemicals, 9 (7.4%) mixed exposures, 7 (5.8%) physical agents and 3 (2.5%) fumes or other irritants. There was little or no association between high pesticide exposure and doctor diagnosed asthma or self-reported recent wheeze, although there was an elevated risk for work-related wheeze (OR for high exposure=2.67; 95% CI 1.16 to 6.18). High pesticide exposure (high vs low exposure category OR 2.68, 95% CI 1.28 to 5.60) was also associated with work-related chest tightness. Exposure to organic dusts was associated (significantly, p=0.026) with persistent asthma when adjusted for the effects of age and smoking. CONCLUSIONS: This large study of pesticide workers has identified expected levels of doctor diagnosed asthma, and high levels of self-reported respiratory symptoms. Pesticide exposure was associated with an increased risk of self-reported work-related wheeze, but not with asthma or wheeze in general. Further work is needed to identify more clearly which exposures within a complex mixed exposure profile are likely causative in order to best focus interventions to reduce work-related asthma and related conditions.
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Asma , Plaguicidas , Asma/inducido químicamente , Asma/etiología , Estudios de Cohortes , Estudios Transversales , Polvo , Humanos , Plaguicidas/efectos adversos , Estudios Prospectivos , Ruidos Respiratorios/etiología , Factores de Riesgo , Reino Unido/epidemiologíaRESUMEN
OBJECTIVES: Assess the effectiveness of 5* GRIP-rated slip-resistant footwear in preventing slips in the workplace compared to usual footwear (control group). METHODS: A multicentre, randomised controlled trial; 4553 National Health Service (NHS) staff were randomised 1:1 to the intervention group (provided with 5* GRIP-rated slip-resistant footwear) or the control group. The primary outcome of incidence rate of self-reported slips in the workplace over 14 weeks was analysed using a mixed-effects negative binomial model. Secondary outcome measures included incidence rate of falls from a slip, falls not from a slip, proportion of participants reporting a slip, fall or fracture and time to first slip and fall. RESULTS: 6743 slips were reported: 2633 in the intervention group (mean 1.16 per participant, range 0 to 36) and 4110 in the control group (mean 1.80 per participant, range 0 to 83). There was a statistically significant reduction in slip rate in the intervention group relative to the control group (incidence rate ratio (IRR) 0.63, 95% CI 0.57 to 0.70, p<0.001). Statistically significant differences, in favour of the intervention group, were observed in falls from a slip (IRR 0.51, 95% CI 0.28 to 0.92, p=0.03), the proportion of participants who reported a slip (OR 0.58, 95% CI 0.50 to 0.66, p<0.001) or fall (OR 0.73, 95% CI 0.54 to 0.99, p=0.04) and time to first slip (HR 0.73, 95% CI 0.67 to 0.80, p<0.001). CONCLUSIONS: The offer and provision of 5* GRIP-rated footwear reduced slips in NHS staff in the workplace. TRIAL REGISTRATION NUMBER: ISRCTN33051393.
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BACKGROUND: Norovirus (NoV) can survive in buffer at a range of pH values. However, when variations to pH are combined with the enzymatic conditions typical in gastric fluid, NoV survival is less predictable. Added to this, the material on which expelled vomitus fluid lands e.g. safety vinyl or carpet, might also affect the level of NoV survival in the environment. AIM: This study assessed survival of the NoV surrogate Feline calicivirus (FCV) after application onto four material types in the presence of synthetic gastric fluid of varying pH values. METHODS: Synthetic gastric fluid of varying pH values (1.5, 2.5, 3.5 and 4.5) containing FCV (1×106 PFU/100 µL of gastric fluid) was seeded (100 µL) onto four material types: Formica, safety vinyl, cotton sheet and carpet tiles (2 cm × 2 cm) and left for 0, 30 and 60 minutes before recovering and identifying any viable viruses via plaque assay. FINDINGS: FCV survived in synthetic gastric fluid at pH values as low as 2.5 and in some cases as low as 1.5 for at least 30 min when associated with certain materials. Greater average numbers of viable virus were recovered from the more absorbent materials of cotton (1900 PFU/sample) and carpet (1600 PFU/sample) compared with Formica (360 PFU/sample) and safety vinyl (380 PFU/sample). CONCLUSION: This study showed that FCV can survive in synthetic gastric fluids of low pH values for significant time periods especially on absorbent materials. This emphasises the importance of ensuring effective cleaning and decontamination procedures, particularly of soft furnishings and laundry, for infection prevention and control of NoV outbreaks.
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Introduction: The performance of 2 disinfectant chemicals, peracetic acid (PAA) and hypochlorous acid (HOCl), was evaluated using a Venturi-nozzle-based light decontamination system (LDS) for delivery. The atomization equipment combined low-pressure air and disinfectant via a handheld lance, producing a fine, dense aerosol. A range of microorganisms, including Bacillus cereus and Bacillus anthracis (Vollum) spores, were used as test challenges to evaluate chemicals and equipment. Methods: The tests undertaken included assessments over fixed and variable exposure times, use of multiple surface materials, and a live agent challenge. Results: Over a fixed-time exposure of 60 minutes, aerosolized PAA gave 7- to 8-log reductions of all test challenges, but HOCl was less effective. Material tests showed extensive kill on most surfaces using PAA (≥6-log kill), but HOCl showed more variation (4- to 6-log). Testing using B. anthracis showed measurable PAA induced spore kill inside 5 minutes and >6-log kill at 5 minutes or over. HOCl was less effective. Discussion: The results demonstrate the importance of testing decontamination systems against a range of relevant microbiological challenges. Disinfectant efficacy may vary depending on product choice, types of challenge microorganisms, and their position in a treated area. The most effective disinfectants demonstrate biocidal efficacy despite these factors. Conclusion: The data confirmed PAA as an effective disinfectant capable of rapidly killing a range of microorganisms, including spores. HOCl was less effective. The LDS system successfully delivered PAA and HOCl over a wide area and could be suitable for a range of frontline biosecurity applications.
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INTRODUCTION: Slips, trips and falls are common causes of injuries in the workplace. It is estimated that in Great Britain, nearly 1 million days are taken off work due to these injuries. There is some evidence to suggest this accident burden could be reduced by the use of slip resistant footwear. This protocol describes a multicentre trial investigating the effectiveness and cost-effectiveness of slip resistant footwear to prevent slips in National Health Service (NHS) staff working in clinical, general or catering environments. METHODS AND ANALYSIS: A two-arm, randomised controlled trial conducted within England, with 4400 NHS staff, aged 18 years and above, who adhere to a dress code policy and work in a clinical, catering or general hospital environment. Participants will be randomised 1:1 to the intervention or waiting list control group. The intervention group will be offered a pair of 5-star GRIP rated slip resistant footwear. The control group will be offered the footwear at the end of the trial. The primary outcome is the incidence rate of self-reported slips in the workplace over a 14-week period, as reported via weekly text messages. Secondary outcomes include: time to first slip/fall, proportion of participants who slip and fall over 14 weeks and incidence rate of falls resulting from and not resulting from a slip in the workplace over 14 weeks. An economic evaluation will assess cost-effectiveness, in terms of cost per quality-adjusted life year gained. A nested qualitative study will explore the acceptability of the footwear and compliance. ETHICS AND DISSEMINATION: This protocol received a favourable ethical opinion from the University of York, Department of Health Sciences Research Governance Committee. The trial results will be published in peer-reviewed journals and at conferences. A summary of the findings will be made available to participants. TRIAL REGISTRATION NUMBER: ISRCTN33051393; Pre results.
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Accidentes por Caídas/prevención & control , Personal de Salud , Traumatismos Ocupacionales/prevención & control , Zapatos , Accidentes por Caídas/economía , Accidentes por Caídas/estadística & datos numéricos , Adulto , Análisis Costo-Beneficio , Inglaterra , Femenino , Personal de Salud/estadística & datos numéricos , Humanos , Masculino , Persona de Mediana Edad , Traumatismos Ocupacionales/economía , Traumatismos Ocupacionales/epidemiología , Investigación Cualitativa , Zapatos/economía , Medicina Estatal , Adulto JovenRESUMEN
PURPOSE: The purpose of the study is to monitor the exposure and health of workers in Great Britain who use pesticides as a part of their job, and to gain a better understanding of the relationship between long-term exposure to pesticides and health. PARTICIPANTS: Study participants are professional pesticide users who are certified in the safe use of pesticides or who were born before 1965 and apply pesticides under 'grandfather rights'. Overall response rate was 20%; participants are mostly male (98%) and the average age is 54 years, ranging from 17 to over 80 years. FINDINGS TO DATE: Participants have completed a baseline general questionnaire and three follow-up questionnaires on the use of pesticides. These data will enable investigations into the relationship between occupational pesticide exposure and health outcomes taking into account non-occupational confounding factors. FUTURE PLANS: There is no set end date for data collection. Recruitment into the cohort will continue, and for the foreseeable future there will be annual pesticide use questionnaires and five yearly follow-up general questionnaires.The intention is to validate the pesticide use questionnaire, and to develop a crop/job exposure matrix (C/JEM) which can be updated regularly. This C/JEM will be able to look at general categories of pesticide, such as insecticides, structurally related pesticides, such as organochlorines, or individual active ingredients. Data collected on use of personal protective equipment and method of application will provide information on how potential exposure to pesticide during application may have been modified. The study will be able to estimate changes in individual pesticide use over time, and to examine the associations between pesticide use and both baseline and long-term health outcomes.The cohort members will be linked to national databases for notification of hospital episode statistics, cancer incidence and mortality for follow-up of health outcomes.
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Agricultura , Exposición Profesional , Ocupaciones , Plaguicidas/farmacología , Trabajo , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Empleo , Femenino , Encuestas Epidemiológicas , Humanos , Incidencia , Masculino , Persona de Mediana Edad , Exposición Profesional/efectos adversos , Plaguicidas/efectos adversos , Estudios Prospectivos , Factores de Riesgo , Encuestas y Cuestionarios , Factores de Tiempo , Reino Unido , Adulto JovenRESUMEN
Hydrogen sulphide gas (H2S) produced by sulphate reducing bacteria (SRB) in stored animal slurry is highly toxic and, if emitted into poorly ventilated confined spaces, can build up to concentrations capable of causing asphyxiation. Therefore it is important to understand factors influencing H2S emission from slurry. Powdered gypsum (hydrated calcium sulphate) may be used as animal bedding and, if it enters slurry systems, could be metabolised by SRB and further increase H2S generation. Cattle slurry and cattle bedding collected from farms was used in laboratory-scale experiments sealed in 20litre vessels fitted with mechanical stirrers. H2S was monitored in head space above the slurry using real-time gas detectors before and after stirring, and before and after adding 1% of two sources of gypsum powder. In one set of experiments, gypsum was already present in the slurry having been used in bedding on the farm. H2S monitoring continued daily for up to 25days. Before stirring, H2S levels in head spaces were minimal. After stirring, even without gypsum, maximum head space H2S levels with slurry or bedding ranged from 330 to 1190ppm. By comparison, the UK short-term (15min) Workplace Exposure Limit is 10ppm. Statistically significant increases in H2S levels were associated with gypsum addition, as high as 1772ppm with slurry and 3940ppm with bedding. Emissions peaked at around day 15 with slurry and bedding to which gypsum was freshly added, but within 5days when added to slurry already containing farm-added gypsum. Levels of H2S produced from stirred slurry would constitute a hazard to anyone exposed to it, and adding gypsum further increased emission levels. Therefore, if gypsum residues enter slurry it could increase the risk of H2S accumulation in confined spaces associated with slurry systems. It is important therefore to take this into account in managing risk.
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Prolonged exposure to respirable crystalline silica (RCS) causes silicosis and is also considered a cause of cancer. To meet emerging needs for precise measurements of RCS, from shorter sampling periods (<4 h) and lower air concentrations, collaborative work was done to assess the differences between personal respirable samplers at higher flow rates. The performance of FSP10, GK2.69, and CIP 10 R samplers were compared with that of the Safety In Mines Personal Dust Sampler (SIMPEDS) sampler as a reference, which is commonly used in the UK for the measurement of RCS. In addition, the performance of the FSP10 and GK 2.69 samplers were compared; at the nominal flow rates recommended by the manufacturers of 10 and 4.2 l · min(-1) and with flow rates proposed by the National Institute for Occupational Safety and Health of 11.2 and 4.4 l · min(-1). Samplers were exposed to aerosols of ultrafine and medium grades of Arizona road dust (ARD) generated in a calm air chamber. All analyses for RCS in this study were performed at the Health and Safety Laboratory. The difference in flow rates for the GK2.69 is small and does not result in a substantial difference in collection efficiency for the dusts tested, while the performance of the FSP10 at 11.2 l · min(-1) was more comparable with samples from the SIMPEDS. Conversely, the GK2.69 collected proportionately more crystalline silica in the respirable dust than other samplers, which then produced RCS results most comparable with the SIMPEDS. The CIP 10 R collected less ultrafine ARD than other samplers, as might be expected based on earlier performance evaluations. The higher flow rate for the FSP10 should be an added advantage for task-specific sampling or when measuring air concentrations less than current occupational exposure limits.
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Contaminantes Atmosféricos/análisis , Polvo/análisis , Monitoreo del Ambiente/instrumentación , Dióxido de Silicio/análisis , Difracción de Rayos X , Aerosoles/análisis , Arizona , Humanos , Exposición por Inhalación/análisis , Tamaño de la PartículaRESUMEN
Hypertension (HT) is associated with environmental noise exposure and is a risk factor for a range of health outcomes. The study aims were to identify key HT related health outcomes and to quantify and monetize the impact on health outcomes attributable to environmental noise-related HT. A reiterative literature review identified key HT related health outcomes and their quantitative links with HT. The health impact of increases in environmental noise above recommended daytime noise levels (55 dB[A]) were quantified in terms of quality adjusted life years and then monetized. A case study evaluated the cost of environmental noise, using published data on health risks and the number of people exposed to various bands of environmental noise levels in the United Kingdom (UK). Three health outcomes were selected based on the strength of evidence linking them with HT and their current impact on society: Acute myocardial infarction (AMI), stroke and dementia. In the UK population, an additional 542 cases of HT-related AMI, 788 cases of stroke and 1169 cases of dementia were expected per year due to daytime noise levels ≥55 dB(A). The cost of these additional cases was valued at around £1.09 billion, with dementia accounting for 44%. The methodology is dependent on the availability and quality of published data and the resulting valuations reflect these limitations. The estimated intangible cost provides an insight into the scale of the health impacts and conversely the benefits that the implementation of policies to manage environmental noise may confer.
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Enfermedades Cardiovasculares/economía , Costo de Enfermedad , Exposición a Riesgos Ambientales/efectos adversos , Exposición a Riesgos Ambientales/economía , Ruido/efectos adversos , Adulto , Anciano , Anciano de 80 o más Años , Enfermedades Cardiovasculares/epidemiología , Demencia/economía , Demencia/epidemiología , Demencia/etiología , Femenino , Humanos , Hipertensión/economía , Hipertensión/epidemiología , Hipertensión/etiología , Masculino , Persona de Mediana Edad , Modelos Econométricos , Infarto del Miocardio/economía , Infarto del Miocardio/epidemiología , Infarto del Miocardio/etiología , Años de Vida Ajustados por Calidad de Vida , Riesgo , Accidente Cerebrovascular/economía , Accidente Cerebrovascular/epidemiología , Accidente Cerebrovascular/etiología , Reino Unido/epidemiologíaRESUMEN
OBJECTIVES: Workers in the asbestos industry tend to have high smoking rates compared to the general population. Both asbestos exposure and cigarette smoking are recognized risk factors for lung cancer mortality, but the exact nature of the interaction between the two remains uncertain. The aim of this study was to examine the effect of smoking and smoking cessation among asbestos workers in Great Britain (GB) and investigate the interaction between asbestos exposure and smoking. METHODS: The study population consisted of 98 912 asbestos workers recruited into the GB Asbestos Survey from 1971, followed-up to December 2005. Poisson regression was used to estimate relative risks of lung cancer mortality associated with smoking habits of the asbestos workers and to assess whether these effects differed within various categories of asbestos exposure. The interaction between asbestos exposure and smoking was examined using the Synergy (S) and Multiplicativity (V) indices, which test the hypotheses of additive and multiplicative interaction, respectively. The proportion of lung cancers among smokers attributable to the interaction of asbestos and smoking was also estimated. RESULTS: During 1 780 233 person-years of follow-up, there were 1878 deaths from lung cancer (12% of all deaths). Risk of lung cancer mortality increased with packs smoked per day, smoking duration, and total smoke exposure (pack-years). Asbestos workers who stopped smoking remained at increased risk of lung cancer mortality up to 40 years after smoking cessation compared to asbestos workers who never smoked. The effects of smoking and stopping smoking did not differ by duration of asbestos exposure, main occupation, age at first asbestos exposure, year of first exposure, or latency period. The interaction between asbestos exposure and smoking for asbestos workers was greater than additive [S 1.4, 95% confidence interval (CI) 1.2-1.6], and the multiplicative hypothesis could not be rejected (V 0.9, 95% CI 0.3-2.4). For those asbestos workers who smoked, an estimated 26% (95% CI 14-38%) of lung cancer deaths were attributable to the interaction of asbestos and smoking. CONCLUSIONS: This study emphasizes the importance of smoking prevention and cessation among those who work in the asbestos industry.