Silicon dioxide

Epidemiological data

Administrative data

Endpoint:

epidemiological data

Type of information:

experimental study

Adequacy of study:

key study

Study period:

not specified

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

comparable to guideline study with acceptable restrictions

Data source

Reference

Reference Type:

publication

Title:

Unnamed

Year:

2016

Report date:

2016

Materials and methods

Study type:

cross sectional study

Endpoint addressed:

respiratory irritation

respiratory sensitisation

repeated dose toxicity: inhalation

GLP compliance:

not specified

Test material

Test material information

Constituent 1

Reference substance name:

Silicon dioxide

EC Number:

231-545-4

EC Name:

Silicon dioxide

Cas Number:

7631-86-9

Molecular formula:

O2Si

IUPAC Name:

dioxosilane

Specific details on test material used for the study:

SAS from five german production plants

Method

Type of population:

occupational

Ethical approval:

not specified

Exposure assessment:

estimated

Details on exposure:

We like to emphasize that the average duration of exposure was 12.4 years in this study with a maximum of 42 years (Table 5 in the study by Morfeld et al). Although a cumulative exposure of 80 mg/m3-years is within the range of observed exposures (the 95th percentile is at 144 mg/m3-years, Table 7 in the study by Morfeld et al), an evaluation at 40 years (maximum working life time) means an extrapolation.

Statistical methods:

We used multiple linear and logistic regression models and Monte Carlo multimodel analyses of two exposure scenarios to evaluate the effect of cumulative exposure to inhalable SAS dust on symptoms, spirometry, and chest films in 462 male workers from five German SAS-producing plants.

Results and discussion

Results:

Exposure to SAS was associated with a reduction in forced vital capacity (FVC) in one of the two exposure scenarios but had no effect on forced expiratory volume in 1 second (FEV1) or FEV1/FVC in either exposure scenario. Monte Carlo analysis indicated a decline in FVC of -11mL per 10 mg/m3-years exposure (-6 to -0.4). Chest films showed no evidence of pneumoconiosis.

Confounding factors:

Smoking, Chronic Bronchitis, Atopy assessment by prick test, Atopy assessment by spec. IgE, Medication, Prior exposure to fibrogenic dust, Prior exposure to substances

Strengths and weaknesses:

The weakness of this study is its cross-sectional design with possible underestimation of the effects due to a healthy worker survivor effect (HWSE).
One of the strengths of this study is the high participation rate (96% of the active workforce), which will eliminate a potential selection bias by exposure circumstances.
Another strength is the multiple exposure assessment, partially based on a large number of personal inhalable dust exposure measurements.

Applicant's summary and conclusion

Conclusions:

Chest films showed no evidence of pneumoconiosis.
(This study provides limited evidence of minor dose-related effects of chronic exposure to SAS on lung function.)

Executive summary:

Objectives: The aim of this study was to assess the health impact of chronic exposure to synthetic amorphous silica (SAS) on nonmalignant respiratory morbidity. Methods: We used multiple linear and logistic regression models and Monte Carlo multimodel analyses of two exposure scenarios to evaluate the effect of cumulative exposure to inhalable SAS dust on symptoms, spirometry, and chest films in 462 male workers from five German SASproducing plants. Results: Exposure to SAS was associated with a reduction in forced vital capacity (FVC) in one of the two exposure scenarios but had no effect on forced expiratory volume in 1 second (FEV1) or FEV1/FVC in either exposure scenario. Monte Carlo analysis indicated a decline in FVC of -11mL per 10 mg/m3-years exposure (-6 to -0.4). Chest films showed no evidence of pneumoconiosis. Conclusion: This study provides limited evidence of minor dose-related effects of chronic exposure to SAS on lung

function.