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Asbestos exposure and benign asbestos diseases in 772 formerly exposed workers: dose-response relationships.

BACKGROUND Since previous studies have provided conflicting results, we investigated the relationship between the risk of benign asbestos-related diseases and different aspects of asbestos exposure in previous asbestos workers who underwent low-dose computed tomography (CT). METHODS CT scans were carried out in 772 subjects. A questionnaire was employed to collect data on smoking habits and duration, peak and cumulative exposure, and time since first exposure to asbestos. Multiple logistic regression models with stepwise selection of variables were used to evaluate the associations. RESULTS Fourteen (1.8%) cases of asbestosis, 187 (24.2%) of pleural plaques (PP), and 50 (6.5%) of diffuse pleural thickening (DPT) were found. The significant risk factors were: cumulative exposure for asbestosis (P for trend = 0.004); time since first exposure (P for trend <0.001), and peak exposure (P for trend <0.001) for PP; and time since first exposure for DPT (P for trend = 0.024). CONCLUSIONS Parenchymal asbestosis and PP are associated with different aspects of asbestos exposure. DPT appears to be less specific for asbestos exposure.

Exposure to Hydrogen Peroxide and Eye and Nose Symptoms Among Workers in a Beverage Processing Plant

OBJECTIVES Two cross-sectional studies were undertaken on workers in a beverage processing plant to investigate the association between low H(2)O(2) exposure and symptoms of irritation (2005 study) and to investigate the effect of wearing respiratory protection (2006 study). METHODS The study comprised 69 workers exposed to H(2)O(2) in sterile chambers and 65 unexposed controls. The exposure was assessed from measurements and work task information from employment records. The severity of work-related symptoms was evaluated using questionnaires. Data were analyzed by the Students t-test, multiple linear regression and analysis of variance for repeated measures of symptoms. RESULTS Symptoms of eye, nose and throat irritation were significantly (P < 0.001) more severe among exposed workers compared to controls. Exposure values were occasionally above American Conference of Governmental Industrial Hygienists (ACGIH) threshold limit value-time-weighted average (TLV-TWA) in the sterile chambers. The relationship between the severity of symptoms and the number of entrances in the chambers was significant (P < 0.0001) in 2005 but not in 2006, when respirators were used during work in the sterile chamber. No differences were found between exposed who entered a sterile chamber in 2005 but not in 2006 and exposed who entered a sterile chamber both in 2005 and 2006. This suggests that respirators provided an efficient protection and that the irritative effects of exposure to H(2)O(2) in 2005 did not disappear after 1 year. CONCLUSIONS The source of risk was exposure in the sterile chamber, even though the time of exposure was generally only approximately 30 min. To ensure complete worker protection, there is a need for a short-term exposure limit for H(2)O(2) in addition to the existing ACGIH TLV-TWA value.

Epidemiological pattern of leprosy in an endemic area of North-East Brazil, 1996-2005: the supporting role of a Nongovernmental Organization

In an endemic area of North-East Brazil (the town of Picos, State of Piauí), a nongovernmental organization (NGO) supported the activity against leprosy in connection with governmental health organizations and local agents. The indicators of leprosy elimination were compared over time (within Picos) and across space (Picos versus Piauí). The case detection rate, above 8 per 10,000 people in the last two years of observation, increased over time in Picos (p=0.010). This finding could be due to active detection activities rather than expanding endemicity, as suggested by the reduction in leprosy in children (p=0.053) and the decrease in the proportion of new cases with grade 2 disability (p<0.001). These indicators showed a more favorable time trend in the city than in the State, suggesting that NGO activity was supportive in the battle towards leprosy control.

Urinary asbestos fibers and inorganic particles in past asbestos workers

ABSTRACT To assess the validity of the procedure as a test of asbestos exposure, we compared urinary asbestos fibers with occupational and environmental exposure data in a random sample of 48 subjects with high past asbestos exposure. Occupational and environmental exposure was estimated on questionnaire, pleural plaques were diagnosed with computed tomography, and inorganic fibers and particles were identified by scanning electron microscope with an energy-dispersive spectrometry. Few urinary asbestos fibers (in 15% of workers and 17% of cases with pleural plaques) and high amount of urinary silicate (particularly nonfibrous particles) were detected. Asbestos undergoes dissolution in lung tissues, but the secondary minerals are largely unknown. These materials, possibly nonfibrous silicates or metals, could be excreted with urine. Therefore, another study including a control group is warranted to discriminate the occupational origin of minerals in the urine.

Lung cancer risk in past asbestos workers a few decades after exposure cessation and prospects for screening.

ABSTRACT To ascertain whether the current risk of lung cancer in former asbestos workers was higher than in the general population, 1,557 past asbestos workers were recruited during statutory health examinations (from 2000 onward) and followed up for mortality. Standardized mortality ratios (SMRs) were calculated. Poisson regression was used to adjust the rate ratios (RRs) for confounders. SMR was about 1.00 in workers with or without pleural plaques and 4.62 (95% confidence interval: 0.61–18.1) in those with asbestosis. Adjusted RRs for lung cancer were 4.70 (0.99–22.5) for asbestosis, 4.35 (0.97–19.5) for former smokers, 6.82 (1.38–34.4) for current smokers. Currently, lung cancer mortality in past asbestos workers is similar to the general population, probably because workers more exposed /more susceptible could have died from lung cancer before the beginning of follow-up.