silicon and Respiration-Disorders

To investigate the association between decline in lung function and production of alloys in the Norwegian smelting industry.. All employees (N = 3924) were examined annually for 5 years (16,570 examinations). The employees were classified into three categories: 1) line operators (employed full time in the production line), 2) nonexposed (no exposure last year), and 3) non-line operators (remaining subjects). The outcome variable was expressed as forced expiratory volume in 1 second per squared height (FEV1/height(2)).. In the subcohorts of the ferrosilicon/silicon metal and silicon carbide industries, the differences between line operators and nonexposed workers were -2.3 (-4.3 to -0.3) (CI = 95%) and -5.6 (-10.4 to -0.7) mL/(m(2) x year), respectively.. Line operators in the ferrosilicon/silicon metal and silicon carbide industries had a steeper annual decline in FEV1/height compared with nonexposed workers.

Topics: Adult; Analysis of Variance; Asthma; Carbon Compounds, Inorganic; Case-Control Studies; Cohort Studies; Forced Expiratory Volume; Humans; Male; Metallurgy; Norway; Occupational Diseases; Prospective Studies; Respiration Disorders; Silicon; Silicon Compounds; Silicosis; Smoking

Relations between pulmonary symptoms and exposure to respirable dust and sulphur dioxide (SO2) were evaluated for 145 silicon carbide (SiC) production workers with an average of 13.9 (range 3-41) years of experience in this industry. Eight hour time weighted average exposures to SO2 were 1.5 ppm or less with momentary peaks up to 4 ppm. Cumulative SO2 exposure averaged 1.94 (range 0.02-19.5) ppm-years. Low level respirable dust exposures also occurred (0.63 +/- 0.26 mg/m3). After adjusting for age and current smoking status in multiple logistic regression models, highly significant, positive, dose dependent relations were found between cumulative and average exposure to SO2, and symptoms of usual and chronic phlegm, usual and chronic wheeze, and mild exertional dyspnoea. Mild and moderate dyspnoea were also associated with most recent exposure to SO2. Cough was not associated with SO2. No pulmonary symptoms were associated with exposure to respirable dust nor were any symptoms attributable to an interaction between dust and SO2. Cigarette smoking was strongly associated with cough, phlegm, and wheezing, but not dyspnoea. A greater than additive (synergistic) effect between smoking and exposure to SO2 was present for most symptoms. These findings suggest that long term, variable exposure to SO2 at 1.5 ppm or less was associated with significantly raised rates of phlegm, wheezing, and mild dyspnoea in SiC production workers, and that current threshold limits for SO2 may not adequately protect workers in this industry.

Topics: Adult; Aged; Air Pollutants, Occupational; Carbon; Carbon Compounds, Inorganic; Dust; Humans; Male; Middle Aged; Occupational Diseases; Respiration Disorders; Silicon; Silicon Compounds; Smoking; Sulfur Dioxide

The relation between pulmonary function, cigarette smoking, and exposure to mixed respirable dust containing silicon carbide (SiC), hydrocarbons, and small quantities of quartz, cristobalite, and graphite was evaluated in 156SiC production workers using linear regression models on the difference between measured and predicted FEV1 and FVC. Workers had an average of 16 (range 2-41) years of employment and 9.5 (range 0.6-39.7) mg-year/m3 cumulative respirable dust exposure; average dust exposure while employed was 0.63 (range 0.18-1.42) mg/m3. Occasional, low level (less than or equal to 1.5 ppm) sulphur dioxide (SO2) exposure also occurred. Significant decrements in FEV1 (8.2 ml; p less than 0.03) and FVC (9.4 ml; p less than 0.01) were related to each year of employment for the entire group. Never smokers lost 17.8 ml (p less than 0.02) of FEV1 and 17.0 (p less than 0.05) of FVC a year, whereas corresponding decrements of 9.1 ml (p = 0.12) in FEV1 and 14.4 ml (p less than 0.02) in FVC were found in current smokers. Similar losses in FEV1 and FVC were related to each mg-year/m3 of cumulative dust exposure for 138 workers with complete exposure information; these findings, however, were generally not significant owing to the smaller cohort and greater variability in this exposure measure. Never smokers had large decrements in FEV1 (40.7 ml; p less than 0.02) and FVC (32.9 ml; p = 0.08) per mg-year/m3 of cumulative dust exposure and non-significant decrements were found in current smokers (FEV1: -7.1 ml; FVC: -11.7 ml). A non-significant decrement in lung function was also related to average dust exposure while employed. No changes were associated with SO(2) exposure or and SO(2) dust interaction. These findings suggest that employment in SiC production is associated with an excessive decrement in pulmonary function and that current permissible exposure limits for dusts occurring in this industry may not adequately protect workers from developing chronic pulmonary disease.

Topics: Adult; Air Pollutants, Occupational; Carbon; Carbon Compounds, Inorganic; Employment; Forced Expiratory Volume; Humans; Lung; Male; Occupational Diseases; Respiration Disorders; Silicon; Silicon Compounds; Smoking; Time Factors; Vital Capacity