Work-related ill-health in radiographers.

BACKGROUND: In the UK in 2015/16, 1.3 million workers self-reported a work-related illness (WRI) of which an estimated 41% were due to musculoskeletal disorders (incidence rate 550 cases per 100000 people) and 37% were related to stress, anxiety and depression. Little is known about the incidence of WRIs in radiographers. AIMS: To analyse the medically reported incidence of WRIs among radiographers in the UK between 1989 and 2015. METHODS: Incident cases reported by physicians to The Health and Occupation Research (THOR) network through its specialist schemes from 1989 to 2015 were analysed, using the Labour Force Survey as denominator where appropriate. RESULTS: In total, 218 cases (966 estimated cases) were reported. Of these 190 were in women. The mean age was 40.2 (20-91 years) SD ± 11.8 years. Most cases were reported to the Occupational Physicians Reporting Activity (OPRA) scheme (n = 92). A skin diagnosis was the most frequently reported (n = 77), followed by musculoskeletal (n = 60). Within the EPIDERM scheme, radiographers had the highest incidence rate when compared to all other occupations. CONCLUSIONS: Radiographers had a higher incidence of WRI compared to all other occupations. The most frequently reported WRI was skin conditions. The observed increase in incidence is likely to be due to the increase in the number of radiographers over that time period, although there was no evidence that WRI within radiographers are declining.

An Assessment of Radiation-Associated Risks of Mortality from Circulatory Disease in the Cohorts of Mayak and Sellafield Nuclear Workers.

Mortality from circulatory disease (CD), ischemic heart disease (IHD) and cerebrovascular disease (CeVD) was investigated in relationship to cumulative doses of external gamma radiation and internal alpha radiation to the liver from deposited plutonium over long follow-up periods in two large cohorts of nuclear workers: the Russian Mayak Worker Cohort (MWC) and the UK Sellafield Worker Cohort (SWC). The MWC comprised 22,374 workers (74.6% males) with 5,123 CD deaths registered during 842,538 person-years of follow-up, while the SWC comprised 23,443 workers (87.8% males) with 2,322 CD deaths registered during 602,311 person-years of follow-up. Dose estimates for external gamma radiation and internal alpha radiation to the liver were calculated via a common methodology, in accordance with an agreed protocol. The mean cumulative external Hp(10) dose was 0.52 Sv for the MWC and 0.07 Sv for the SWC, while the mean cumulative internal dose was 0.19 Gy for the MWC and 0.01 Gy for the SWC. Categorical relative risks (RR) and excess relative risks (ERR) per unit dose were estimated for each cohort and for the pooled cohort when appropriate. The dose responses for CD, IHD and CeVD in relationship to internal alpha-particle dose did not differ significantly from the null for either the MWC, the SWC or the pooled plutonium worker cohort. The ERR/Sv estimates in relationship to external exposure were significantly raised for both cohorts (marginally so for the MWC) for CD and IHD (but not for CeVD), but differed significantly between the two cohorts, the estimate for the SWC being approximately ten times greater than that for the MWC. Examination of the ERR/Sv estimates for two periods of first employment at the two facilities revealed that the significant heterogeneity was confined to the earlier sub-cohorts, and that the estimates for the later sub-cohorts were compatible. The two sub-cohorts for the later first-employment periods were pooled, producing risk estimates that were raised, but not significantly so: ERR/Sv for CD, IHD and CeVD of 0.22 (95% CI: -0.01, 0.49), 0.22 (95% CI: -0.06, 0.57) and 0.24 (95% CI: -0.17, 0.80), respectively. The reasons for the complex pattern of results found in this study are unclear. Among potential explanations are the influence of differences in background CD mortality rates, an effect of other occupational factors, substantial uncertainties in doses, particularly during earlier periods of operations, as well as confounding and/or modifying factors that were not taken into account in the current analysis.

DNA methylation from birth to late adolescence and development of multiple-risk behaviours.

BACKGROUND: Risk behaviours in adolescence are linked to poor educational attainment and health and other outcomes in young adulthood. We explored whether there are molecular mechanisms associated with the development, or the result, of multiple risk behaviours (MRBs). METHODS: MRBs (antisocial behaviour and delinquency, traffic-related risk behaviour, risky sexual behaviour, lack of exercise) and their sumscore were characterized based on self-reported questions at age 7 and 17 within the ARIES subsample of the ALSPAC birth cohort, and were linked to DNA methylation at over 485,000 CpG sites at ages 0,7 and 17. Associations were determined for participants with complete data (n = 227-575). RESULTS: There was weak evidence of associations between cumulative MRBs and methylation at cg01783492 and cg16720578 at age 17. DNA methylation at age 17 was associated with risky sexual behaviour (cg22883332), lack of exercise (cg03152353, cg20056908, cg20571116) and substance use (cg02188400, cg13906377). No associations between DNA methylation and individual risk behaviours at age 7 were observed. DNA methylation at age 7 might predispose for traffic-related risk behaviour (cg24683561) and substance use (cg08761410) at age 17. LIMITATIONS: Main limitations are absence of information on directly measured blood cell type proportions and tissue specificity, and a modest sample size. CONCLUSIONS: Cumulative MRB in late adolescence was associated with effects on DNA methylation. More specifically, risky sexual behaviour and sedentary behaviour are associated with changes in DNA methylation, while DNA methylation in childhood may predict later traffic-related risky behaviour. For substance use effects in both temporal directions were observed.

Testing the impact of local alcohol licencing policies on reported crime rates in England.

BACKGROUND: Excessive alcohol use contributes to public nuisance, antisocial behaviour, and domestic, interpersonal and sexual violence. We test whether licencing policies aimed at restricting its spatial and/or temporal availability, including cumulative impact zones, are associated with reductions in alcohol-related crime. METHODS: Reported crimes at English lower tier local authority (LTLA) level were used to calculate the rates of reported crimes including alcohol-attributable rates of sexual offences and violence against a person, and public order offences. Financial fraud was included as a control crime not directly associated with alcohol abuse. Each area was classified as to its cumulative licensing policy intensity for 2009-2015 and categorised as 'passive', low, medium or high. Crime rates adjusted for area deprivation, outlet density, alcohol-related hospital admissions and population size at baseline were analysed using hierarchical (log-rate) growth modelling. RESULTS: 284 of 326 LTLAs could be linked and had complete data. From 2009 to 2013 alcohol-related violent and sexual crimes and public order offences rates declined faster in areas with more 'intense' policies (about 1.2, 0.10 and 1.7 per 1000 people compared with 0.6, 0.01 and 1.0 per 1000 people in 'passive' areas, respectively). Post-2013, the recorded rates increased again. No trends were observed for financial fraud. CONCLUSIONS: Local areas in England with more intense alcohol licensing policies had a stronger decline in rates of violent crimes, sexual crimes and public order offences in the period up to 2013 of the order of 4-6% greater compared with areas where these policies were not in place, but not thereafter.

Propensity score matching for selection of local areas as controls for evaluation of effects of alcohol policies in case series and quasi case-control designs.

OBJECTIVES: Area-level public health interventions can be difficult to evaluate using natural experiments. We describe the use of propensity score matching (PSM) to select control local authority areas (LAU) to evaluate the public health impact of alcohol policies for (1) prospective evaluation of alcohol policies using area-level data, and (2) a novel two-stage quasi case-control design. STUDY DESIGN: Ecological. METHODS: Alcohol-related indicator data (Local Alcohol Profiles for England, PHE Health Profiles and ONS data) were linked at LAU level. Six LAUs (Blackpool, Bradford, Bristol, Ipswich, Islington, and Newcastle-upon-Tyne) as sample intervention or case areas were matched to two control LAUs each using PSM. For the quasi case-control study a second stage was added aimed at obtaining maximum contrast in outcomes based on propensity scores. Matching was evaluated based on average standardized absolute mean differences (ASAM) and variable-specific P-values after matching. RESULTS: The six LAUs were matched to suitable control areas (with ASAM < 0.20, P-values >0.05 indicating good matching) for a prospective evaluation study that sought areas that were similar at baseline in order to assess whether a change in intervention exposure led to a change in the outcome (alcohol related harm). PSM also generated appropriate matches for a quasi case-control study--whereby the contrast in health outcomes between cases and control areas needed to be optimized in order to assess retrospectively whether differences in intervention exposure were associated with the outcome. CONCLUSIONS: The use of PSM for area-level alcohol policy evaluation, but also for other public health interventions, will improve the value of these evaluations by objective and quantitative selection of the most appropriate control areas.

Measurable effects of local alcohol licensing policies on population health in England.

BACKGROUND: English alcohol policy is implemented at local government level, leading to variations in how it is put into practice. We evaluated whether differences in the presence or absence of cumulative impact zones and the 'intensity' of licensing enforcement--both aimed at regulating the availability of alcohol and modifying the drinking environment--were associated with harm as measured by alcohol-related hospital admissions. METHODS: Premises licensing data were obtained at lower tier local authority (LTLA) level from the Home Office Alcohol and Late Night Refreshment Licensing data for 2007-2012, and LTLAs were coded as 'passive', low, medium or highly active based on whether they made use of cumulative impact areas and/or whether any licences for new premises were declined. These data were linked to 2009-2015 alcohol-related hospital admission and alcohol-related crime rates obtained from the Local Alcohol Profiles for England. Population size and deprivation data were obtained from the Office of National Statistics. Changes in directly age-standardised rates of people admitted to hospital with alcohol-related conditions were analysed using hierarchical growth modelling. RESULTS: Stronger reductions in alcohol-related admission rates were observed in areas with more intense alcohol licensing policies, indicating an 'exposure-response' association, in the 2007-2015 period. Local areas with the most intensive licensing policies had an additional 5% reduction (p=0.006) in 2015 compared with what would have been expected had these local areas had no active licensing policy in place. CONCLUSIONS: Local licensing policies appear to be associated with a reduction in alcohol-related hospital admissions in areas with more intense licensing policies.

The association between different night shiftwork factors and breast cancer: a case-control study.

BACKGROUND: Research on the possible association between shiftwork and breast cancer is complicated because there are many different shiftwork factors, which might be involved including: light at night, phase shift, sleep disruption and changes in lifestyle factors while on shiftwork (diet, physical activity, alcohol intake and low sun exposure). METHODS: We conducted a population-based case-control study in Western Australia from 2009 to 2011 with 1205 incident breast cancer cases and 1789 frequency age-matched controls. A self-administered questionnaire was used to collect demographic, reproductive, and lifestyle factors and lifetime occupational history and a telephone interview was used to obtain further details about the shiftwork factors listed above. RESULTS: A small increase in risk was suggested for those ever doing the graveyard shift (work between midnight and 0500 hours) and breast cancer (odds ratio (OR)=1.16, 95% confidence interval (CI)=0.97-1.39). For phase shift, we found a 22% increase in breast cancer risk (OR=1.22, 95% CI=1.01-1.47) with a statistically significant dose-response relationship (P=0.04). For the other shiftwork factors, risks were marginally elevated and not statistically significant. CONCLUSION: We found some evidence that some of the factors involved in shiftwork may be associated with breast cancer but the ORs were low and there were inconsistencies in duration and dose-response relationships.

Respiratory and dermal symptoms in Thai nurses using latex products.

BACKGROUND: Despite known health risks related to the use of powdered latex gloves (PLGs), they are still widely used in hospitals in developing countries due to the high cost of alternatives. AIMS: To determine the prevalence of dermal and respiratory symptoms associated with latex glove use in nurses in Thailand and evaluate the influence of previously reported occupational risk factors in this population. METHODS: A cross-sectional study in female nurses working in three Thai hospitals. Participants completed a questionnaire on demographics, occupational and personal history, use of latex products at work and dermal and respiratory symptoms attributed to occupational use of latex gloves. RESULTS: Of 899 nurses, 18% reported health effects attributed to the use of latex products. After adjustment for confounding, occupational risk factors associated with increased reporting of dermal symptoms included wearing more than 15 pairs of PLG per day (odds ratio (OR): 2.10, 95% confidence interval (CI): [1.32-3.34]), using chlorhexidine (OR: 2.07, 95% CI: [1.22-3.52]) and being an operating theatre nurse (OR: 2.46, 95% CI: [1.47-4.12]). Being a labour ward nurse (OR: 3.52, 95% CI: [1.26-9.85]) was the only factor associated with increased reporting of respiratory symptoms. CONCLUSIONS: Continuing use of PLGs in Thai nurses is associated with increased prevalence of dermal symptoms compared with data from developed countries. Measures to reduce such health effects are well established and should be considered. Additionally, replacement of chlorhexidine with an alternative detergent seems advisable.

Modelling air pollution for epidemiologic research--part II: predicting temporal variation through land use regression.

Over recent years land use regression (LUR) has become a frequently used method in air pollution exposure studies, as it can model intra-urban variation in pollutant concentrations at a fine spatial scale. However, very few studies have used the LUR methodology to also model the temporal variation in air pollution exposure. The aim of this study is to estimate annual mean NO(2) and PM(10) concentrations from 1996 to 2008 for Greater Manchester using land use regression models. The results from these models will be used in the Manchester Asthma and Allergy Study (MAAS) birth cohort to determine health effects of air pollution exposure. The Greater Manchester LUR model for 2005 was recalibrated using interpolated and adjusted NO(2) and PM(10) concentrations as dependent variables for 1996-2008. In addition, temporally resolved variables were available for traffic intensity and PM(10) emissions. To validate the resulting LUR models, they were applied to the locations of automatic monitoring stations and the estimated concentrations were compared against measured concentrations. The 2005 LUR models were successfully recalibrated, providing individual models for each year from 1996 to 2008. When applied to the monitoring stations the mean prediction error (MPE) for NO(2) concentrations for all stations and years was -0.8µg/m³ and the root mean squared error (RMSE) was 6.7µg/m³. For PM(10) concentrations the MPE was 0.8µg/m³ and the RMSE was 3.4µg/m³. These results indicate that it is possible to model temporal variation in air pollution through LUR with relatively small prediction errors. It is likely that most previous LUR studies did not include temporal variation, because they were based on short term monitoring campaigns and did not have historic pollution data. The advantage of this study is that it uses data from an air dispersion model, which provided concentrations for 2005 and 2010, and therefore allowed extrapolation over a longer time period.

Modelling air pollution for epidemiologic research--Part I: A novel approach combining land use regression and air dispersion.

A common limitation of epidemiological studies on health effects of air pollution is the quality of exposure data available for study participants. Exposure data derived from urban monitoring networks is usually not adequately representative of the spatial variation of pollutants, while personal monitoring campaigns are often not feasible, due to time and cost restrictions. Therefore, many studies now rely on empirical modelling techniques, such as land use regression (LUR), to estimate pollution exposure. However, LUR still requires a quantity of specifically measured data to develop a model, which is usually derived from a dedicated monitoring campaign. A dedicated air dispersion modelling exercise is also possible but is similarly resource and data intensive. This study adopted a novel approach to LUR, which utilised existing data from an air dispersion model rather than monitored data. There are several advantages to such an approach such as a larger number of sites to develop the LUR model compared to monitored data. Furthermore, through this approach the LUR model can be adapted to predict temporal variation as well as spatial variation. The aim of this study was to develop two LUR models for an epidemiologic study based in Greater Manchester by using modelled NO(2) and PM(10) concentrations as dependent variables, and traffic intensity, emissions, land use and physical geography as potential predictor variables. The LUR models were validated through a set aside "validation" dataset and data from monitoring stations. The final models for PM(10) and NO(2) comprised nine and eight predictor variables respectively and had determination coefficients (R²) of 0.71 (PM(10): Adj. R²=0.70, F=54.89, p<0.001, NO(2): Adj. R²=0.70, F=62.04, p<0.001). Validation of the models using the validation data and measured data showed that the R² decreases compared to the final models, except for NO(2) validation in the measured data (validation data: PM(10): R²=0.33, NO(2): R²=0.62; measured data: PM(10): R²=0.56, NO(2): R²=0.86). The validation further showed low mean prediction errors and root mean squared errors for both models.

Bayesian modelling of lung cancer risk and bitumen fume exposure adjusted for unmeasured confounding by smoking.

OBJECTIVES: Residual confounding can be present in epidemiological studies because information on confounding factors was not collected. A Bayesian framework, which has the advantage over frequentist methods that the uncertainty in the association between the confounding factor and exposure and disease can be reflected in the credible intervals of the risk parameter, is proposed to assess the magnitude and direction of this bias. METHODS: To illustrate this method, bias from smoking as an unmeasured confounder in a cohort study of lung cancer risk in the European asphalt industry was assessed. A Poisson disease model was specified to assess lung cancer risk associated with career average, cumulative and lagged bitumen fume exposure. Prior distributions for the exposure strata, as well as for other covariates, were specified as uninformative normal distributions. The priors on smoking habits were specified as Dirichlet distributions based on smoking prevalence estimates available for a sub-cohort and assumptions about precision of these estimates. RESULTS: Median bias in this example was estimated at 13%, and suggested an attenuating effect on the original exposure-disease associations. Nonetheless, the results still implied an increased lung cancer risk, especially for average exposure. CONCLUSIONS: This Bayesian framework provides a method to assess the bias from an unmeasured confounding factor taking into account the uncertainty surrounding the estimate and from random sampling error. Specifically for this example, the bias arising from unmeasured smoking history in this asphalt workers' cohort is unlikely to explain the increased lung cancer risk associated with average bitumen fume exposure found in the original study.

Elaboration of a quantitative job-exposure matrix for historical exposure to airborne exposures in the Polish rubber industry.

BACKGROUND: A job-exposure matrix (JEM) for inhalable aerosols, aromatic amines, and cyclohexane soluble matter (CSM) was elaborated based on measurements collected routinely between 1981 and 1996. METHODS: The data were grouped based on similarities in exposure levels and time trends in different departments, and were analyzed using smoothing splines and mixed effects models. RESULTS: Although higher than in western European countries, inhalable aerosol exposure decreased after changes in production volume and implementation of exposure reduction measures in mid-1980s. Aromatic amines concentrations first increased following the factory's production volume, but subsequently decreased in more recent years. CSM concentrations were uniformly distributed between departments. CONCLUSIONS: This JEM provides an overview of historical exposure levels in a large Polish rubber factory and will enable estimation of lifetime exposure for individual workers in a Polish rubber workers cohort and further investigation of the associations between specific exposures and cancer risk.

Exposure to inhalable dust and its cyclohexane soluble fraction since the 1970s in the rubber manufacturing industry in the European Union.

OBJECTIVES: As exposures to airborne particulates in the European rubber industry might still be causing genotoxic risks, it is important to assess trends in levels of inhalable dust and its cyclohexane soluble fraction (CSF) between the 1970s and 2003. METHODS: 13 380 inhalable and 816 respirable dust and 5657 CSF measurements, collected within the framework of the European Union Concerted Action EXASRUB, were analysed. Hierarchical mixed effects models were applied to assess exposure trends, taking into account between-factory, between-worker/location and day-to-day variances. RESULTS: Geometric mean levels of inhalable dust and CSF exposure changed by -4% (range -5.8 to +2.9%) and -3% (range -8.6 to 0%) per year, respectively. Significant reductions in inhalable dust concentrations were found in all countries for handling of crude materials and mixing and milling (-7% to -4% per year), as well as for miscellaneous workers (-11% to -5% per year), while significant CSF exposure reductions were found in curing (-8.6% per year) and maintenance and engineering departments (-5.4% per year). CONCLUSION: These analyses suggest that on average exposure levels of inhalable dust and its CSF in the European rubber manufacturing industry have steadily declined. Most likely genotoxic risks have also lessened over time since exposure levels have decreased and the most toxic chemicals have been replaced. In addition to differences in exposure reductions and levels among various stages of the production process, large differences across countries were noted. These patterns should be taken into account in retrospective assessment of exposure for epidemiological studies assessing cancer risk in the rubber industry.

Exposure to alternating electromagnetic fields and effects on the visual and visuomotor systems.

Acute effects on the visual and visuo-motor systems by exposure to electromagnetic fields (EMFs) at a frequency and amplitude similar to those produced by MR imaging gradient coils were assessed. 40 volunteers were exposed in random order to three, time varying, magnetic field gradients (0, 20 and 10 mT m(-1)r.m.s.). The waveform was 50 cycles of a 490 Hz sinusoidal waveform repeated every second with a total duration of 10 min for each trial. The EMFs were generated using an in-house designed and built magnetic gradient coil and waveform generator. During each trial, a test battery assessing the visual sensory (FACT) and visuo-motor (Pursuit Aiming II and visual tracking) neurobehavioral domains was completed by all volunteers. The sequence of these tests was assigned at random for each volunteer. Performance in these tests was analysed using linear mixed effects models adjusted for confounding factors collected in a pre-trial questionnaire. Variability of the estimates was assessed using a delete-1 jack-knife procedure. There was a trend for visuo-motor accuracy to be reduced (p = 0.06) by 1% during high exposure, but not at medium exposure. There was a weaker trend for visual contrast sensitivity to be improved by 12% and 21% during medium and high exposure, respectively, compared with the non-exposed sessions (p = 0.08). These effects did not reach 5% statistical significance within a population of 40 volunteers, but also the magnitude of these effects did not depend on single "extreme" observations.

Occupational exposure to NDMA and NMor in the European rubber industry.

Many nitrosamines are suspected of being human carcinogens, with the highest concentrations in the environment being measured in the rubber industry. Time trends of personal exposure to N-nitrosodimethylamine (NDMA) and to N-nitrosomorpholine (NMor) during the past two decades in the German rubber industry were analysed and compared with cross-sectional studies in the same period in the Netherlands, Poland, the UK and Sweden. In the majority of the surveyed departments exposures reduced over time, but considerable heterogeneity was present between departments and sectors. Significant reductions were primarily found in curing and post-treating departments and ranged from -3% year(-1) to -19% year(-1). In contrast, NDMA levels increased (+13% year(-1)) in maintenance and engineering in the tyres industry. Average NDMA-levels in general rubber goods (GRG) and NMor-levels in tyre production in Germany did not decrease significantly in the past two decades, whereas NDMA-levels in tyre production (-10% year(-1)) and NMor-levels in GRG (-7% year(-1)) declined significantly after the introduction of an exposure limit for total nitrosamines in Germany in 1988. Confidence intervals of average exposures in other studied countries largely overlap trends observed in Germany. Exposure to N-nitrosamines decreased on average two-to-five fold in the German rubber industry with comparable concentration levels in other European countries. Although average levels are well below the current limits exposure has not been eliminated, and incidental high exposures do still occur.

Cognitive effects of head-movements in stray fields generated by a 7 Tesla whole-body MRI magnet.

The study investigates the impact of exposure to the stray magnetic field of a whole-body 7 T MRI scanner on neurobehavioral performance and cognition. Twenty seven volunteers completed four sessions, which exposed them to approximately 1600 mT (twice), 800 mT and negligible static field exposure. The order of exposure was assigned at random and was masked by placing volunteers in a tent to hide their position relative to the magnet bore. Volunteers completed a test battery assessing auditory working memory, eye-hand co-ordination, and visual perception. During three sessions the volunteers were instructed to complete a series of standardized head movements to generate additional time-varying fields ( approximately 300 and approximately 150 mT.s(-1) r.m.s.). In one session, volunteers were instructed to keep their heads as stable as possible. Performance on a visual tracking task was negatively influenced (P<.01) by 1.3% per 100 mT exposure. Furthermore, there was a trend for performance on two cognitive-motor tests to be decreased (P<.10). No effects were observed on working memory. Taken together with results of earlier studies, these results suggest that there are effects on visual perception and hand-eye co-ordination, but these are weak and variable between studies. The magnitude of these effects may depend on the magnitude of time-varying fields and not so much on the static field. While this study did not include exposure above 1.6 T, it suggests that use of strong magnetic fields is not a significant confounder in fMRI studies of cognitive function. Future work should further assess whether ultra-high field may impair performance of employees working in the vicinity of these magnets.