The article covers differential diagnostic features of pulmonary tuberculosis and pneumoconiosis in workers engaged into mullite refractories production. The authors suggest that the disease courses as a new form of lung disorder--mullitosis.
Alzheimer's disease is a progressive neurodegenerative disease characterized by the development of large numbers of neurofibrillary tangles in certain neuronal populations. Aluminum salts inoculated into experimental animals produce neurofilamentous lesions which are similar, but not identical, to the neurofibrillary tangle of Alzheimer's disease. Although a few reports suggest evidence of increased amounts of aluminum in the brains of Alzheimer's disease victims, such bulk analysis studies have been difficult to replicate. Using scanning electron microscopy with x-ray spectrometry, we have identified accumulations of aluminum in neurofibrillary tangle-bearing neurons of Alzheimer's disease. Similar accumulations have been identified in the neurofibrillary tangle-bearing neurons found in the brains of indigenous natives of Guam who suffer from parkinsonism with dementia and from amyotrophic lateral sclerosis. This ongoing research still cannot ascribe a causal role of aluminum in the pathogenesis of the neurofibrillary tangle; however, it does suggest that environmental factors may play an important part in the formation of this abnormality.
We evaluated a cytology screening program, offered by a large aluminum producer after the discovery of an excess of bladder cancer due to occupational exposure to coal-tar-pitch volatiles, in terms of early detection and survival, based on information in the public domain. From January 1970 through June 1986, 79 cases of bladder cancer were identified in this cohort of aluminum workers aged 65 years or younger. By the end of 1986, 36 had died, with bladder cancer as the primary cause of death for 53%. Cases diagnosed after the screening program was introduced in 1980 were compared with those diagnosed earlier. In cases diagnosed after 1980, the proportion identified at early stages was higher (77% v 67%) and survival seemed improved but the differences were not statistically significant. Although these results do not encourage an optimistic view of screening effectiveness in this population, the limits inherent in the present study make it impossible to draw any firm conclusion. Studies restricted to public domain information do not appear to have sufficient data to evaluate workplace screening programs.
The relationship between elevated internal aluminum loads and central nervous system function was studied among aluminum welders, and the threshold level for adverse effect was defined.
For 65 aluminum welders and 25 current mild steel welders body burden was estimated, and the aluminum concentrations in serum (S-Al) and urine (U-Al) were analyzed with graphite furnace atomic absorption spectrometry with Zeeman background correction. Referents and low-exposure and high-exposure groups were defined according to an aggregated measure of aluminum body burden, the group median S-Al levels being 0.08, 0.14, and 0.46 micromol/l, respectively, and the corresponding values for U-Al being 0.4, 1.8, and 7.1 micromol/l. Central nervous system functions were assessed with a neuropsychological test battery, symptom and mood questionnaires, a visual and quantitative analysis of electroencephalography (EEG), and P3 event-related potentials with pitch and duration paradigms.
Subjective symptoms showed exposure-related increases in fatigue, mild depression, and memory and concentration problems. Neuropsychological testing revealed a circumscribed effect of aluminum, mainly in tasks demanding complex attention and the processing of information in the working memory system and in the analysis and recall of abstract visual patterns. The visual EEG analysis revealed pathological findings only for aluminum welders. Mild, diffuse abnormalities were found in 17% of the low-exposure group and 27% of the high-exposure group, and mild to moderate epileptiform abnormalities at a frequency of 7% and 17%, respectively.
Both objective neurophysiological and neuropsychological measures and subjective symptomatology indicated mild but unequivocal findings dose-dependently associated with increased aluminum body burden. The study indicates that the body burden threshold for adverse effect approximates an U-Al value of 4-6 micromol/l and an S-Al value of 0.25-0.35 micromol/l among aluminum welders.
To study risk factors for Alzheimer's disease (AD) based on data from the Canadian Study of Health and Aging.
Population-based case-control study.
Communities and institutions in 10 Canadian provinces.
Two hundred fifty-eight cases clinically diagnosed with probable AD, with onset of symptoms within 3 years of diagnosis, and 535 controls, frequency matched on age group, study center, and residence in community or institution, clinically confirmed to be cognitively normal.
Odds ratios (ORs) were calculated using unconditional logistic regression for previously hypothesized and potential risk factors for AD.
The OR for family history of dementia was significantly elevated (2.62; 95% confidence interval [CI], 1.53 to 4.51) and increased with the number of relatives with dementia. Those with less education were at higher risk of AD, with an OR of 4.00 (95% CI, 2.49 to 6.43) for those with 0 to 6 years, in comparison with those with 10 or more years. Head injury achieved borderline significance. A history of arthritis resulted in a low risk of AD (OR = 0.54; 95% CI, 0.36 to 0.81), as did a history of use of nonsteroidal anti-inflammatory drugs. Initial analyses showed an increased risk of AD for occupational exposure to glues as well as to pesticides and fertilizers; the increased risk was greater in those with less education.
This study confirmed a number of previously reported risk factors for AD, but provided little support for others. A new finding was an increased risk for those with occupational exposure to glues as well as pesticides and fertilizers, but this needs further study.
OBJECTIVES: This study investigated associations between exposure to polycyclic aromatic hydrocarbons (PAH) and the incidence of lung, bladder, kidney, and pancreatic cancer among Norwegian aluminum plant workers. METHODS: Cancer incidence was investigated from 1953 to 1996 among 11,103 men employed for more than 3 years in the industry, giving 272,554 person-years during follow-up. A job exposure matrix was constructed to estimate exposure to particulate PAH and fluorides. The observed cases of cancer were compared with expected figures calculated from national rates. Dose-response relations were investigated by internal comparisons using Poisson regression and stratified analyses for standardized incidence ratio. Potential confounding by smoking was investigated in subanalyses restricted to 3 of the plants. RESULTS: The study showed an overall excess for bladder cancer, standardized incidence ratio 1.3 (95% confidence interval 1.1-1.5), which increased with increasing cumulative exposure to PAH and reached a relative risk of about 2 for the upper exposure category in the analysis with 30 years of lag time. There was no association between cumulative PAH exposure and lung cancer, but there were indications of an elevated risk of kidney cancer among the most heavily PAH-exposed persons in the analyses with a lag time of 30 years. For pancreatic cancer we found a higher incidence among the PAH-exposed persons than among the unexposed ones, but no clear dose-response association was found. CONCLUSIONS: The study showed an association between bladder cancer and exposure to PAH, but gave no support to an association between PAH exposure and lung cancer in the primary aluminum industry.
In a Swedish cohort of workers (n = 6,454) from seven aluminum foundries and three secondary aluminum (scrap) smelters there was no overall excess risk of cancer among male or female workers less than 85 years of age (males: 325 observed cases, standardized incidence ratio (SIR) 1.02, 95% confidence interval (CI) 0.91-1.13; females: 22 cases, SIR = 0.95, 95% CI = 0.60-1.44). In male workers, however, significantly elevated risk estimates were observed for cancer of the lung (51 cases; SIR = 1.49, 95% CI = 1.11-1.96), anorectal cancer (33 cases; SIR 2.13, 95% CI = 1.47-2.99), and sinonasal cancer (4 cases; SIR = 4.70, 95% CI = 1.28-12.01). There was no increase of urinary bladder or liver cancer. Lung cancer risks were highest in workers with a short duration of employment (