John Osman

Cancer mortality in workers exposed to chlorophenoxy herbicides and chlorophenols.

Epidemiological studies have revealed an increased risk of cancer, notably soft-tissue sarcomas and non-Hodgkins lymphomas, in people occupationally exposed to chlorophenoxy herbicides, including those contaminated by 2, 3, 7, 8-tetrachlorodibenzo-p-dioxin (TCDD). We report here a historical cohort study of mortality in an international register of 18,910 production workers or sprayers from ten countries. Exposure was reconstructed through questionnaires, factory or spraying records, and job histories. Cause-specific national death rates were used as reference. No excess was observed in all-cause mortality, for all neoplasms, for the most common epithelial cancers, or for lymphomas. A statistically non-significant two-fold excess risk, based on 4 observed deaths, was noted for soft-tissue sarcoma with a standardised mortality ratio (SMR) of 196 and 95% confidence interval (Cl) 53-502; this was concentrated as a six-fold statistically significant excess, occurring 10-19 years from first exposure in the cohort as a whole (SMR = 606 [165-1552]) and, for the same time period, as a nine-fold excess among sprayers (SMR = 882 [182-2579]). Risks appeared to be increased for cancers of the testicle, thyroid, other endocrine glands, and nose and nasal cavity, based on small numbers of deaths. The excess of soft-tissue sarcomas among sprayers is compatible with a causal role of chlorophenoxy herbicides but the excess does not seem to be specifically associated with those herbicides probably contaminated by TCDD.

Spontaneous abortion in the british semiconductor industry : An HSE investigation

BACKGROUND The UK Health and Safety Executive (HSE) conducted a study to examine the risk of spontaneous abortion (SAB) in British female semiconductor industry workers, following reports from the USA which suggested an association between risk of SAB and work in fabrication rooms and/or exposure to ethylene glycol ethers. METHODS A nested case-control study based on 2,207 women who had worked at eight manufacturing sites during a 5-year retrospective time frame was established; 36 cases were matched with 80 controls. RESULTS The overall SAB rate in the industry was 10.0%. (65 SABs/651 pregnancies) The crude odds ratio (OR) for fabrication work was 0.65 (95% CI 0.30-1.40). This was essentially unchanged after adjustment for a range of potential confounding factors in the first 3 months of pregnancy and was reduced to 0.58 (95% CI 0.26-1.30) after adjustment for smoking in the previous 12 months. There were no statistically significantly elevated ORs for any work group or any specific chemical or physical exposure in the industry. CONCLUSIONS There is no evidence of an increased risk of SAB in the British semiconductor industry. Am. J. Ind. Med. 36:557-572, 1999. Published 1999 Wiley-Liss, Inc.

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.

An updated investigation of cancer incidence and mortality at a Scottish semiconductor manufacturing facility with case-control and case-only studies of selected cancers

Objectives An earlier investigation raised concern that some cancer cases might be linked to work at a semiconductor manufacturing plant. The aim of this study was to describe an update of the cancer incidence and mortality of these workers and assess whether workplace exposures contributed to any increased risk of selected cancers. Methods Standardised mortality ratios and standardised incidence ratios were calculated for cancer site groups of a priori interest in a cohort previously flagged against the National Health Service Central Register, with follow-up extended to the 2007 for deaths and 2006 for cancer registrations. Cases of female breast cancer, lung and stomach cancer, and male brain cancer, and a random sample of control subjects individually age-matched to the breast cancer cases, were identified from within the cohort dataset and invited to participate via General Practitioners. Exposures were estimated using a job exposure matrix developed from a historical hygiene assessment and assigned to job histories obtained from personal interview of subjects (or proxies). Results Though the findings were uncertain, there were no excesses of mortality or cancer incidence, either overall or for specific cancer sites, suggestive of a workplace effect. Logistic regression analyses comparing 20 cases of breast cancer with 83 matched controls showed no consistent evidence of any relationship with occupational exposures. Assessment of commonalities of workplace exposures among case sets for other cancer types was limited by the small numbers. Conclusions These results do not support earlier concerns about occupational cancer risks among this cohort.

Exposures and reported symptoms associated with occupational deployment to the Buncefield fuel depot fire, England 2005

Objectives: An explosion at the Buncefield fuel depot outside London occurred on 11 December 2005. We conducted a retrospective cohort study of airborne exposures and health status for workers deployed. Methods: Deployed individuals were identified through their occupational health departments. We sent a self-completion questionnaire asking about health symptoms during the burn and post-burn phases. The prevalence of health symptoms in workers was compared to symptoms in local residents not under the smoke plume. Results: Of 1949 eligible individuals, 815 returned questionnaires (response rate 44). Respiratory protection was used by 39. Symptoms were reported by 41 of individuals during the burn phase compared with 26 in the post-burn phase. In a final multivariable model, reporting of any symptoms was associated with deployment inside the inner fire cordon during the burn phase (OR 2.07, 95 CI 1.24 to 3.47) and wearing a face mask (OR 2.33, 95 CI 1.67 to 3.26). Compared with the general public, eye irritation (prevalence ratio (PR) 2.1, 95 CI 1.5 to 3.0), coughing (PR 1.3, 95 CI 1.0 to 1.8) and headaches (PR 1.7, 95 CI 1.2 to 2.5) were more common in workers deployed during the burn phase but not the post-burn phase. Conclusions: Increased reporting of symptoms close to the fire during the burn phase was consistent with increased exposure to products of combustion, although no major acute illness was reported. That only a minority of individuals used face masks, which were not protective for symptoms, raises questions about the availability of adequate respiratory protection for such incidents.

Cancer mortality from soft-tissue sarcoma and malignant lymphomas in an international cohort of workers exposed to chlorophenoxy herbicides and chlorophenols

Abstract Mortality from soft-tissue sarcoma and malignant lymphomas was examined in an international register including 18,910 production workers or sprayers from 10 countries. Exposure to chlorophenoxy herbicides and chlorophenols was evaluated from job histories in conjunction with information collected through company questionnaires and other exposure related documents. No excess was observed for malignant lymphomas. A two-fold excess risk, based on four observed deaths, was observed overall for soft-tissue sarcoma; the risk was concentrated as an about six-fold statistically significant excess, occurring 10 to 19 years from first exposure in the cohort as a whole, and was highest among sprayers. In the present set of data the excess does not appear specifically associated with those chlorophenoxy herbicides probably contaminated by TCDD.

An updated investigation of cancer incidence and mortality at a Scottish semiconductor manufacturing facility

Objectives To describe an update of the cancer incidence and mortality of workers at a Scottish semiconductor manufacturing facility to assess potential workplace cancer risks. Methods Company records had been used to identify a cohort of 4388 workers employed at the facility between 1970 and 1999. Subjects were flagged against National Health Service records for notification of cancer registrations and deaths. Standardised mortality (to end 2007) and cancer registration (to end 2006) ratios (SMRs and SRRs) were calculated for cancer site groups of a priori interest, comparing with Scottish rates adjusted for local deprivation status. Results There was a substantial deficit of mortality overall, particularly among men, compatible, at least in part, with a healthy work effect: SMR% (males) 45, 95% CI 34 to 57; SMR% (females) 73, 95% CI 58 to 90. Total cancer registrations were consistent with expectation for men (SRR% 90, 95% CI 69 to 116) and women (SRR% 102, 95% CI 85 to 122). SRRs for four cancer sites highlighted in an earlier analysis (lung, stomach and breast cancer in women; and brain cancer in men) were not statistically significantly elevated overall; neither were those for any other cancer site group. Analyses of cohort subgroups (including a group more likely to have worked in areas using carcinogens) by time since first employment, and analyses by duration of employment did not reveal any associations suggestive of a workplace effect on cancer rates. Conclusions This analysis does not support earlier concerns about a possible link between working at the facility and increased risks of cancer.

Case-control and case-only studies of selected cancers at a Scottish semiconductor manufacturing facility

Objectives HSEs 2001 report on cancer in a Scottish cohort of semiconductor manufacturing workers showed some statistically significant results, suggestive of increased risks. Recently, the follow-up in the cohort was extended. We report on a case-based study to investigate these suggestions. Methods From the extended follow-up, cases of breast, stomach and lung cancer in women, and of brain cancer in men were identified. It was planned that the lung and breast cancer cases would be interviewed and compared with matched controls, and that the rarer stomach and brain cancers would be examined case-only. A questionnaire was designed to collect detailed employment histories within the factory and elsewhere, information relevant to possible asbestos exposure, and lifestyle and environmental factors. A historical hygiene assessment was carried out at the factory, to inform construction of a job-exposure matrix. Results Attempts to recruit cases (or proxy respondents) were only partially successful; as a result, the lung cancers element was converted to a case-only study. Comparison with controls was possible for only 20 breast cancer cases (including 7 proxy respondents). From an extensive programme of conditional logistic analyses, statistical significance was achieved for exposure to arsenic compounds, antimony trioxide and sulphuric acid mist and to gases in general, but only in a few of the analyses. Examination of proxy responses for stomach, lung and brain cancers did not suggest any common workplace factors for any of these outcomes. Conclusions We interpreted this evidence as not supportive of an occupational risk for any of the cancers.