Anne-Helen Harding

The Effect of Smoking on the Risk of Lung Cancer Mortality for Asbestos Workers in Great Britain (1971–2005)

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.

The cost of hypertension-related ill-health attributable to environmental noise

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.

Cardiovascular disease mortality among British asbestos workers (1971–2005)

Objectives Asbestos is an inflammatory agent, and there is evidence that inflammatory processes are involved in the development of cardiovascular disease. Whether asbestos is a risk factor for cardiovascular disease has not been established. The objective of this study was to investigate cardiovascular disease mortality in a large cohort of workers occupationally exposed to asbestos. Methods Cardiovascular disease mortality in a cohort of 98 912 asbestos workers, with median follow-up of 19 years, was analysed. Unadjusted and smoking-adjusted standardised mortality ratios (SMRs) were calculated. The association between indicators of asbestos exposure and mortality was analysed with Poisson regression models, for deaths occurring during the period 1971–2005. Results Altogether 15 557 deaths from all causes, 1053 deaths from cerebrovascular disease and 4185 deaths from ischaemic heart disease (IHD) occurred during follow-up. There was statistically significant excess mortality from cerebrovascular disease (SMR: men 1.63, women 2.04) and IHD (SMR: men 1.39, women 1.89). Job and birth cohort were associated with the risk of cerebrovascular and IHD mortality in the Poisson regression model including sex, age, smoking status, job, cohort and duration of exposure. For IHD only, duration of exposure was also statistically significant in this model. Conclusions Cerebrovascular and IHD mortality was significantly higher among these asbestos workers than in the general population and within the cohort mortality was associated with indicators of asbestos exposure. These findings provide some evidence that occupational exposure to asbestos was associated with cardiovascular disease mortality in this group of workers.

Exposure to Diisocyanates and Their Corresponding Diamines in Seven Different Workplaces

Biological monitoring to assess exposure to diisocyanates in the workplace is becoming increasingly widespread due to its relative ease of use and ability to look at all exposure routes. Currently, biological monitoring measures the corresponding isocyanate-derived diamine in urine, after hydrolysis. Because of this, any exposure to the diamines themselves released during the industrial process could confound the assessment of diisocyanate exposure. This paper reports an initial assessment of the extent of diamine formation and exposure during different processes involving diisocyanates including casting, grouting, core making, spray painting, foam blowing, and floor screeding. Air monitoring and glove analysis were conducted for both the relevant diisocyanate (measured as total NCO) and its corresponding diamine; urine samples were analysed (after hydrolysis) for the isocyanate-derived diamine. Processes that generated aerosols (as demonstrated by impinger analysis) such as spray painting and foam blowing were associated with the detection of diamines. Those processes that did not generate aerosols (casting, grouting, core making, and screeding) had no diamines detected, either in air or on gloves. In spray-painting tasks, diamines were a minor component (<15%) of the ambient concentration whereas in the foam blowing processes, where water is added to the process, diamine generation is more marked (up to eight times the airborne NCO concentration). Some non-aerosol processes gave rise to substantial diamine levels in urine (in exceedance of international guidance values, >5 µmol mol-1 creatinine) despite airborne levels being well within occupational exposure limits (20 µg m-3 total NCO in Great Britain); measurement data and statistical modelling indicated that skin absorption was the most likely exposure route. Foam blowing exposures were more complex, but urinary levels were greater than those expected from diisocyanate inhalation alone (measured as total NCO). This study provides evidence that biological monitoring for diisocyanates based on measuring the corresponding diamine in urine is valid, although any co-exposure to diamines themselves should be considered when interpreting results. It also demonstrates the potential for substantial skin absorption of diisocyanates in certain processes such as floor screeding and foam production.

Investigation of saliva as an alternative matrix to blood for the biological monitoring of inorganic lead

INTRODUCTION Whole blood is the established matrix for biological monitoring of inorganic lead; however blood sampling is an invasive procedure. Saliva offers a potential non-invasive alternative. This study determines lead in whole blood and saliva. A novel method for saliva sampling and preparation is presented. METHODS Paired blood and saliva samples were obtained from 105 occupationally exposed UK workers. Saliva was collected using a StatSure sampling device, and a nitric acid digestion step was incorporated. The utility of the device for this application was evaluated. Whole blood was obtained by venepuncture. Analyses were carried out by ICP-MS. RESULTS The limit of detection for lead in saliva was 0.011 μg/L. Mean blank-corrected recovery from 10 μg/L spiked saliva was 65.9%. The mean result from blank saliva extracted through the StatSure device was 2.86 μg/L, compared to 0.38 μg/L by direct analysis. For the paired samples, median blood lead was 6.00 μg/dL and median saliva lead was 17.1 μg/L. Pearsons correlation coefficient for saliva lead versus blood lead was 0.457 (95% C.I. 0.291-0.596). CONCLUSIONS ICP-MS analysis allows sensitive determination of lead in saliva with low limits of detection. The StatSure device is effective for high occupational exposures, but contamination from the device could confound lower-level measurements. Saliva would only be effective as a surrogate for whole blood for highly-exposed populations, although with further work it may have applications as a biomarker of recent exposure.

Saliva as a matrix for biomonitoring of occupational and environmental exposure to lead

Abstract Background: To evaluate whether salivary lead can be used as a surrogate for blood lead, and if so, over what concentration range. Methodology: Three saliva devices were evaluated and one chosen to undertake this project. Paired saliva and blood samples were collected from 89 UK lead workers. Lead concentrations were determined using ICP-MS. In addition, haemoglobin and ZPP levels were determined in the blood samples and albumin was determined in the saliva samples to investigate standardisation using protein adjustments. Results: The chosen saliva device gave low but consistent recoveries for lead in saliva and the blank levels were low. The mean +/- SD blood lead level was 19.9 +/- 14 μg/dl; the mean +/- SD saliva lead level was 19.1 +/- 32.5 μg/l for 89 workers. Log10-transformed data showed correlation of r=0.69. The protein adjustments did not improve the blood-saliva correlation. Conclusions: This study has demonstrated that salivary lead measurement is feasible and correlated with blood lead levels, at least at occupational exposure levels, and may have value as a screening technique. Correlation may improve at environmental levels where exposures are generally more consistent and chronic, although this needs to be demonstrated in a genuine environmental population.

434 Farmer’s lung disease in a cohort of british agricultural workers

Introduction Farmer’s Lung Disease (FLD) is the oldest recognised form of occupational hypersensitivity pneumonitis (OHP) and remains one of the most commonly reported causes in Europe.The aim of this study was to provide novel data on the prevalence and demographic risk factors of FLD in a large cohort of British farm workers. Methods Farmers were identified from the baseline survey of the PIPAH cohort (Prospective Investigation of Pesticide Applicators’ Health). The demographics of workers, who self-reported a doctor diagnosis of FLD, were compared to the remainder of the cohort. Result Questionnaire data was available for 5115 current or former farmers, representing a cumulative total of over 210,000 years of farming practice. 26 farmers self-reported a diagnosis of FLD, representing a cohort prevalence of ~5 per 1000. Those with FLD were all male, and were older, more likely to be involved in animal production and less likely to be involved in crop production only than those without FLD. Those with and without FLD did not differ in respect of years lived or worked on a farm, or their smoking status. Median age of FLD diagnosis was 35 (IQR 25–43, range 16–62), with a median latent period from first farm exposure of 28 years (IQR 20–42). Discussion The prevalence of FLD in this British cohort (representing over 1% of British farmers) was in keeping with that reported from other countries. Age of diagnosis was very variable, with the majority of those affected having never smoked. Although most had worked on a mixture of farm types, workers with FLD were more likely to report only having lived on an animal versus cereal production farm

Prospective Investigation of Pesticide Applicators’ Health (PIPAH) study: a cohort study of professional pesticide users in Great Britain

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.

The Pesticide Users Health Study: past, present and future

Objectives After a successful feasibility study in 1996-97, the Health & Safety Executive established the Pesticide Users Health Study (PUHS) to monitor the health of workers occupationally exposed to pesticides in Great Britain. The history and findings of the PUHS are presented, and its future is outlined. Methods Individuals applying for a certificate of competence in the use of agricultural pesticides were recruited. Cancer and death events in the cohort were flagged from the national health information system. A survey of pesticide usage was conducted in a small proportion of the cohort. Findings from the PUHS are compared with other well-established cohort studies internationally, and methodological challenges are discussed. Results By 2003, nearly 66 000 men and women were members of the PUHS. Standardised incidence and mortality ratios (SIR/SMR) for cancers and deaths showed that overall these individuals were healthier than the British population (SIR all cancers: 0.86, 95% CI 0.81 to 0.90; SMR all causes: 0.58, 95% CI 0.55 to 0.61). There was weak evidence of elevated risks for some cancers. The PUHS findings were consistent with similar studies in the US. There was limited information to adjust for the Healthy Worker Effect and insufficient exposure data to interpret the findings. Conclusions The PUHS is a valuable resource, providing a foundation upon which to develop a nationally representative prospective study of British pesticide users. A systematic approach to the assessment of baseline and follow-up pesticide usage, confounding factors, health symptoms and conditions, and other more detailed substudies are proposed.