Documents Miller, Brian G. 3 results

"Following findings of the British National Coal Board's Pneumoconiosis Field Research (PFR) major research programme into the health effects of respirable coal mine dust, a new programme was set up to identify and quantify any relationships between mortality from lung, stomach and other cancers, and exposure to respirable dust and quartz, diesel exhaust particulates from underground vehicles, and radon and thoron daughters. The cohort for analysis was 18,166 men, entering follow-up at various surveys from the 2nd to 6th round of the PFR programme. These contributed over 408,000 person-years at risk up to the end of 1992, and 7002 deaths. Investigations of exposure-response relationships for specific causes of death were based on comparisons within the cohort, using the general framework of Cox's proportional hazard regression models to adjust for age, smoking hazards, periods of cohort entry etc. Mortality from pneumoconiosis showed a clear relationship with exposure to respirable dust, which was a better predictor of risk than respirable quartz. Neither bladder cancer or leukaemia showed a significant relationship with any of the exposures. Stomach cancer risks were not related to dust or quartz exposure, nor to time spent in the industry, suggesting that the explanation for the raised Standardised Mortality Ratio lies elsewhere than in the conditions of work. In most of the analyses of lung cancer, there was no strong evidence of exposure effects. In one series of analyses, exposure to respirable quartz was related to lung cancer mortality at conventional levels of statistical significance, but the effect was strongly confounded with pit differences. A similar but weaker effect was observed with radiation exposures. These findings could be artefacts of other factors which differed between the working practices or surrounding environments of the collieries involved. "

"When applying simple screening (Tier 1) tools to estimate exposure to chemicals in a given exposure situation under the Registration, Evaluation, Authorisation and restriction of CHemicals Regulation 2006 (REACH), users must select from several possible input parameters. Previous studies have suggested that results from exposure assessments using expert judgement and from the use of modelling tools can vary considerably between assessors. This study aimed to investigate the between-user reliability of Tier 1 tools. A remote-completion exercise and in person workshop were used to identify and evaluate tool parameters and factors such as user demographics that may be potentially associated with between-user variability. Participants (N = 146) generated dermal and inhalation exposure estimates (N = 4066) from specified workplace descriptions (‘exposure situations') and Tier 1 tool combinations (N = 20). Interactions between users, tools, and situations were investigated and described. Systematic variation associated with individual users was minor compared with random between-user variation. Although variation was observed between choices made for the majority of input parameters, differing choices of Process Category (‘PROC') code/activity descriptor and dustiness level impacted most on the resultant exposure estimates. Exposure estimates ranging over several orders of magnitude were generated for the same exposure situation by different tool users. Such unpredictable between-user variation will reduce consistency within REACH processes and could result in under-estimation or overestimation of exposure, risking worker ill-health or the implementation of unnecessary risk controls, respectively. Implementation of additional support and quality control systems for all tool users is needed to reduce between-assessor variation and so ensure both the protection of worker health and avoidance of unnecessary business risk management expenditure."