Fumes, silica

Epidemiological data

Administrative data

Endpoint:

epidemiological data

Type of information:

experimental study

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: well documented study meeting basic scientific principles

Cross-reference

Reason / purpose for cross-reference:

reference to other study

Data source

Reference

Reference Type:

publication

Title:

A survey of respiratory symptoms and lung function in ferrochromium and ferrosilicon workers.

Author:

Langård, S.

Year:

1980

Bibliographic source:

Int Arch Occup Environ Health.46(1): 1-9.

Materials and methods

Study type:

cross sectional study

Endpoint addressed:

repeated dose toxicity: inhalation

Test guideline

Qualifier:

no guideline available

Principles of method if other than guideline:

Respiratory health of 140 ferrochromium and ferrosilicon workers was explored. The prevalence of generalized (chronic) obstructive lung disease (GOLD/COPD) was investigated by evaluating the prevalence of respiratory symptoms (British Medical Research Questionnaire) and abnormalities in respiratory function (FVC, FEV1) among the workers with long history at work at the plant (average duration of employment 25,8, 27,0 or 32,2 years, respectively). Chest x-rays and expectorate cytology were performed to exclude the pneumoconiosis and lung cancer.

GLP compliance:

no

Test material

Test material information

Constituent 1

Reference substance name:

dusts and fumes in ferrochromium and ferrosilicon production

IUPAC Name:

dusts and fumes in ferrochromium and ferrosilicon production

Method

Type of population:

occupational

Ethical approval:

not specified

Details on study design:

METHOD OF DATA COLLECTION
The prevalence of generalized (chronic) obstructive lung disease (GOLD/COPD) was investigated by evaluating the prevalence of respiratory symptoms (British Medical Research Questionnaire) and abnormalities in respiratory function (FVC, FEV1) among the workers with long history at work at the plant (average duration of employment 25,8, 27,0 or 32,2 years, respectively). Chest x-rays and expectorate cytology were performed to exclude the pneumoconiosis and lung cancer.


STUDY POPULATION AND SETTING: 140 workers were recruited in the study. The workers were divided into three groups ferrochromium (n=60), ferrosilicon (n=33) and maintenance workers (n=47). Reference group consisted of 25 males from the same region which were not currently working in the plant and had previous working history at the plant less than 5 years (average 2.5 years). Average age of the controls was significantly lower than that of study groups (controls 39.9, ferrochromium 56.2, ferrosilicon 55.8, and maintenance 55.5). Therefore, the results of the questionnaire were compared also to reference groups of two other Norwegian studies. Smoking habits of all the groups were approximately similar.


HEALTH EFFECTS STUDIED
- Disease(s): COPD, pneumoconiosis

Exposure assessment:

measured

Details on exposure:

TYPE OF EXPOSURE: Total dust levels at the ferrosilicon plant varied between 3-28 mg/m3 at furnace work and between 3-24 mg/m3 at maintenance work.

Statistical methods:

yes, but no further data

Results and discussion

Results:

No cases of pneumoconiosis were identified and all cytological samples were free of cell atypias or cancer-suspect cells. Prevalence of respiratory symptoms (cough, phlegm, wheezing and dyspnea) was slightly increased in all study groups when compared external control groups (from other studies) and the study control group. No statistical data were provided. At ferrosilicon workers prevalence was slightly higher than in ferrochromium or maintenance workers. A decrease in age-corrected FVC with exposure time was noted especially in maintenance workers but also in ferrosilicon workers, whereas no significant negative or positive slope was seen in ferrochromium workers. It was concluded that the prevalence of GOLD (COPD) was increased in these study groups when compared to the background prevalence of same age groups. It was hypothesised that this may be related to general mixed dust exposure at the plant. Also amorphous silica was suggested to contribute to the findings. Taking account that lung x-rays did not show any cases of pneumoconiosis this study does not support significant pneumoconiosis risk for these workers.

Confounding factors:

other exposures like asbestos, quartz

Strengths and weaknesses:

main weaknesses: small study population, representativeness of the control group

Applicant's summary and conclusion

Conclusions:

Exposure to dusts at ferrosilicon and ferrochromium plants increased the prevalence of COPD. Taking account that lung x-rays did not show any cases of pneumoconiosis this study does not support significant pneumoconiosis risk at these workers.

Executive summary:

Langård (1980)published a study on the respiratory effects of 140 ferrochromium and ferrosilicon workers. The workers were divided into three groups ferrochromium (n=60), ferrosilicon (n=33) and maintenance workers (n=47). The prevalence of generalized (chronic) obstructive lung disease (GOLD/COPD) was investigated by evaluating the prevalence of respiratory symptoms (British Medical Research Questionnaire) and abnormalities in respiratory function (FVC, FEV₁) among the workers with long history at work at the plant (average duration of employment 25,8, 27,0 or 32,2 years, respectively). Chest x-rays and expectorate cytology were performed to exclude the pneumoconiosis and lung cancer. Reference group consisted of 25 males from the same region which were not currently working in the plant and had previous working history at the plant less than 5 years (average 2.5 years). Average age of the controls was significantly lower than that of study groups (controls 39.9, ferrochromium 56.2, ferrosilicon 55.8, and maintenance 55.5). Therefore, the results of the questionnaire were compared also to reference groups of two other Norwegian studies. Smoking habits of all the groups were approximately similar. No cases of pneumoconiosis were identified and all cytological samples were free of cell atypias or cancer-suspect cells. Prevalence of respiratory symptoms (cough, phlegm, wheezing and dyspnea) was a little bit increased in all study groups when compared external control groups (from other studies) and the study control group. At ferrosilicon workers prevalence seemed to be a bit higher than in ferrochromium or maintenance workers. A decrease in age-corrected FVC with exposure time was noted especially in maintenance workers but also in ferrosilicon workers, whereas no significant negative or positive slope was seen in ferrochromium workers. It was concluded that the prevalence of GOLD (COPD) was increased in these study groups when compared to the background prevalence of same age groups. It was hypothesised that this may be related to general mixed dust exposure at the plant. Also amorphous silica was suggested to contribute to the findings. Taking account that lung x-rays did not show any cases of pneumoconiosis this study does not support significant pneumoconiosis risk at these workers. Dust levels at the plant were said to vary between 3-28 mg/m³total dust.