This paper draws together the mortality experience for a cohort of some 11000 male Quebec Chrysotile miners and millers, reported at intervals since 1971 and now again updated. Of the 10918 men in the complete cohort, 1138 were lost to view, almost all never traced after employment of only a month or two before 1935; the other 9780 men were traced into 1992. Of these, 8009 (82%) are known to have died: 657 from lung cancer, 38 from mesotheliona, 1205 from other malignant disease, 108 from pneumoconiosis and 561 from other non-malignant respiratory diseases (excluding tuberculosis). After early fluctuations. SMRs (all causes) against Quebec rates have been reasonably steady since about 1945. For men first employed in Asbestos, mine or factory, they were very much what might have been expected for a blue collar population without any hazardous exposure. SMRs in the Thetford Mines area were almost 8% higher, but in line with anecdotal evidence concerning socio-economic status. At exposures below 300 (million particles per cubic foot) x years, (mpcf.y), equivalent to roughly 1000 (fibres/ml) x years-or, say, 10 years in the 1940s at 80 (fibres/ml)-findings were as follows. There were no discernible associations of degree of exposure and SMRs, whether for all causes of death or for all the specific cancer sites examined. The average SMRs were 1.07 (all causes), and 1.16, 0.93, 1.03 and 1.21, respectively, for gastric, other abdominal, laryngeal and lung cancer. Men whose exposures were less then 300 mpcf.y suffered almost one-half of the 146 deaths from pneumoconiosis or mesothelioma; the elimination of these two causes would have reduced these men's SMR (all causes) from 1.07 to approximately 1.06. Thus it is concluded from the viewpoint of mortality that exposure in this industry to less than 300 mpcf.y has been essentially innocuous, although there was a small risk or pneumoconiosis or mesothelioma. Higher exposures have, however, led to excesses, increasing with degree of exposure, of mortality from all causes, and from lung cancer and stomach cancer, but such exposures, of at least 300 mpcf.y, are several orders of magnitude more severe than any that have been seen for many years. The effects of cigarette smoking were much more deleterious than those of dust exposure, not only for lung cancer (the SMR for smokers of 20+ cigarettes a day being 4.6 times higher than that for non-smokers), but also for stomach cancer (2.0 times higher), laryngeal cancer (2.9 times higher), and-most importantly-for all causes (1.6 times higher).
Comment In: Ann Occup Hyg. 1997 Jan;41(1):3-129072948
Comment In: Ann Occup Hyg. 2001 Jun;45(4):329-35; author reply 336-811414250
Health administrative data can be a valuable tool for disease surveillance and research. Few studies have rigorously evaluated the accuracy of administrative databases for identifying rheumatoid arthritis (RA) patients. Our aim was to validate administrative data algorithms to identify RA patients in Ontario, Canada.
We performed a retrospective review of a random sample of 450 patients from 18 rheumatology clinics. Using rheumatologist-reported diagnosis as the reference standard, we tested and validated different combinations of physician billing, hospitalization, and pharmacy data.
One hundred forty-nine rheumatology patients were classified as having RA and 301 were classified as not having RA based on our reference standard definition (study RA prevalence 33%). Overall, algorithms that included physician billings had excellent sensitivity (range 94-100%). Specificity and positive predictive value (PPV) were modest to excellent and increased when algorithms included multiple physician claims or specialist claims. The addition of RA medications did not significantly improve algorithm performance. The algorithm of "(1 hospitalization RA code ever) OR (3 physician RA diagnosis codes [claims] with =1 by a specialist in a 2-year period)" had a sensitivity of 97%, specificity of 85%, PPV of 76%, and negative predictive value of 98%. Most RA patients (84%) had an RA diagnosis code present in the administrative data within ±1 year of a rheumatologist's documented diagnosis date.
We demonstrated that administrative data can be used to identify RA patients with a high degree of accuracy. RA diagnosis date and disease duration are fairly well estimated from administrative data in jurisdictions of universal health care insurance.
The authors analyzed age-related structure of miners population in major occupational groups with connection to special work conditions in one mine of Kouzbass. The data obtained prove certain influence of work conditions on age-related structure of occupational population.
Understanding the biogeochemical cycling of mercury is critical for explaining the presence of mercury in remote regions of the world, such as the Arctic and the Himalayas, as well as local concentrations. While we have good knowledge of present-day fluxes of mercury to the atmosphere, we have little knowledge of what emission levels were like in the past. Here we develop a trend of anthropogenic emissions of mercury to the atmosphere from 1850 to 2008-for which relatively complete data are available-and supplement that trend with an estimate of anthropogenic emissions prior to 1850. Global mercury emissions peaked in 1890 at 2600 Mg yr(-1), fell to 700-800 Mg yr(-1) in the interwar years, then rose steadily after 1950 to present-day levels of 2000 Mg yr(-1). Our estimate for total mercury emissions from human activities over all time is 350 Gg, of which 39% was emitted before 1850 and 61% after 1850. Using an eight-compartment global box-model of mercury biogeochemical cycling, we show that these emission trends successfully reproduce present-day atmospheric enrichment in mercury.
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A plant processing radium and uranium ores has been operating in the town of Port Hope since 1932. Given the nuclear industry located in the community and ongoing public health concerns, cancer incidence rates in Port Hope were studied for a recent 16 year period (1992-2007) for continued periodic cancer incidence surveillance of the community. The cancer incidence in the local community for all cancers combined was similar to the Ontario population, health regions with similar socio-economic characteristics in Ontario and in Canada, and the Canadian population. No statistically significant differences in childhood cancer, leukaemia or other radiosensitive cancer incidence were observed, with the exception of statistically significant elevated lung cancer incidence among women. However, the statistical significance was reduced or disappeared when the comparison was made to populations with similar socio-economic characteristics. These findings are consistent with previous ecological, case-control and cohort studies conducted in Port Hope, environmental assessments, and epidemiological studies conducted elsewhere on populations living around similar facilities or exposed to similar environmental contaminants. Although the current study covered an extended period of time, the power to detect risk at the sub-regional level of analysis was limited since the Port Hope population is small (16,500). The study nevertheless indicated that large differences in cancer incidence are not occurring in Port Hope compared to other similar communities and the general population.
Canadian chrysotile (white asbestos) could be a paradigm for those agents that are successfully exploited commercially long after they have been found to be lethal. Mining started in the late 1870s, and reports of disability and death followed in Britain (1898), in France (1906), and Italy (1908), but it was not until 1955 that Canada acknowledged asbestosis in its asbestos miners and millers. Even when shortly after asbestos was shown to be carcinogenic, Canadian Public Relations experts assisted by their scientists exculpated chrysotile by deeming other agents to have been causal.
The PR techniques that have been successfully used in the defense of chrysotile are reviewed, to forewarn scientists involved in formulating public health policy for similar agents, as to the tricks that will be played on them.
Examinations were made in 220 male workers exposed to dust-gas (low-silicon dioxide, nitric oxides, and carbon oxide) mixture, physical exercises, and cooling microclimate on deep-mined output of copper-nickel ore. Twenty-eight per cent of the workers were found to have evolving chronic bronchitis that did not substantially affect the patients' working capacity; 3.2% had chronic obstructive pulmonary disease and 1.4% had asthma that had developed before the onset of professional activity. 32.3% of the examinees were ascertained to have individual clinicofunctional disorders that permit their identification as a bronchopulmonary disease risk group to carry out early preventive and rehabilitative measures.
The authors considered topics of occupational and general comorbidity of occupational lumbosacral radiculopathy in coal miners (2791 examinees) observed over 1976-2014 in occupational center. In patients having lumbosacral radiculopathy without occupational mixed diseases, the occupational disease was diagnosed at the age 3-5 years younger, and 2-4 years earlier from primary visit. Analysis of occurrence of general comorbid conditions with lumbosacral radiculopathy revealed some regularities: patients manifested with symptoms due to vibration have more frequent arterial hypertension than in those with lumbalgia, whereas in risk group of hearing affected by noise IHD was more possible.
The author analyzed dynamics and structure of occupational morbidity including pneumoconiosis in Rostov region of Russian Federation, since 1990 until now. They were compared with analogous parameters of previous historical period. Findings are that contemporary dynamics of anthracosilicosis clinical features is characterized by severily reduced terms of the disease development from medical registration of the diseased miner, earlier addition of malignancy, respiratory failure and other complications--that in aggregate causes earlier disablement and drastically reduced survival rate in occupational patients with anthracosilicosis.