Health
Effects of Occupational Exposure
to
Respirable Crystalline Silica
|
Table
19. Epidemiologic studies of immunologic, autoimmune, and chronic
renal disease
(including subclinical renal changes) in silica-exposed workers |
||||||
|
Reference
and country |
Study
design, cohort,
and followup |
Subgroup
|
Number
of deaths or cases in subgroup
|
Risk
measure* |
95%
CI†
|
Comments
|
| Boujemaa
et al. [1994], Belgium |
Cross-sectional
case-control study of 116 silicotic, male underground miners with
no history of diabetes, nephrolithiasis, or hypertension and 61 age-matched
controls from the general population.
Urine
samples were tested for albumin, retinol-binding protein, and NAG.
Serum samples were tested |
Silicotics
|
116
|
—†
|
—
|
Miners
were examined an average of 23 yr after cessation of exposure. Mean
duration of exposure was 14.9 yr.
Duration of exposure and severity of silicosis were not associated with the measures of renal dysfunction. Silicotic miners had significantly higher urinary concentrations of albumin (P=0.017), retinol-binding protein (P=0.0045), and NAG (P=0.0001). Results were similar to those found by Hotz et al. [1995]. |
| Bovenzi et al. [1995], Italy | Case-control study of 527 patients admitted to all hospitals in Trento province 1976–1991 and discharged with diagnosis of musculoskeletal disorder or connective tissue disease. Each scleroderma case was matched by age and gender to two controls who were without the disease under study and were from the same database. |
Patients
discharged with diagnosis of systemic sclerosis (according to specific
diagnostic criteria):
|
—
|
|||
|
Women
|
16
|
0‡
|
—
|
|||
|
Men
|
5
|
5.20§
|
0.48–74.1
|
|||
| Burns et al. [1996], United States | Population-based case-control study of 274 women with confirmed systemic sclerosis diagnosed in Michigan between 1985 and 1991 and 1,184 female controls matched by race, age, and geographic region. |
Women
with self-reported exposure to the following:
|
Adjusted
for age, race, and date of birth. Systemic sclerosis was not associated
with self-reported exposures to silica dust or silicone (including
breast implants).
Same study design was applied to Ohio women with systemic sclerosis, and results were published later in a letter [Lacey et al. 1997]. |
|||
| Abrasive
grinding or sandblasting |
3
|
0.34
|
0.10–1.10
|
|||
| Sculpting
or pottery making |
20
|
1.53
|
0.89–2.65
|
|||
| Working
in a dental laboratory |
3
|
1.52
|
0.44–5.26
|
|||
| Working
with or near silica dust, sand, or other silica products |
12
|
1.50
|
0.76–2.93
|
|||
| Calvert et al. [1997], United States | Cohort morbidity study of 2,412 white, male underground gold miners employed >1 yr between 1940 and 1965 and alive on January 1, 1977. | Miners with cases of treated end-stage renal disease |
11
|
1.37**
|
0.68–2.46
|
First
epidemiologic study to examine incidence of end-stage renal disease
in an occupational cohort.
Subcohort of gold miners studied by Steenland and Brown [1995b]. Mean respirable silica dust exposure of this subcohort was 0.05 mg/m3. |
| Nonsystemic†† |
6
|
4.22**
|
1.54–9.19
|
|||
| Systemic |
4
|
0.80**
|
0.22–2.06
|
|||
| Unknown |
1
|
1.54**
|
0.04–8.57
|
|||
| Cowie
[1987], South Africa |
Cohort study of incidence of scleroderma in black gold miners seen by the medical service from July 1981 to June 1986. | Miners with scleroderma that met diagnostic criteria |
10 |
81.8‡‡ |
— |
— |
| Hotz et al. [1995], Belgium | Cross-sectional
case-control study of prevalence of subclinical renal effects in 86
quarry workers employed 11 to 20 months with no clinical, spirometric,
or radiographic signs of silicosis. Controls were manual workers [Bernard
et al. 1994] matched by smoking status, body mass index, and age.
Urine samples were tested for albumin, transferrin, creatinine, β2-microglobulin, retinol-binding protein, silicon, and NAG. Serum samples were tested for creatinine and β2-microglobulin. |
—
|
86
|
—
|
—
|
Same
cohort studied by Bernard et al. [1994].
Quarry workers had significantly higher urinary concentrations of albumin (P<0.0004), transferrin (P<0.03), retinol-binding protein (P<0.001), NAG (P<0.001), and silicon (P<0.0001). Controls may have been exposed to silica dust—occupational history of controls was not reported. Narrow range of employment duration may have limited the assessment of effects. |
| Klockars et al. [1987], Finland | Cohort
morbidity study of 1,026 granite workers hired between 1940 and 1971
with followup until the end of 1981 for (1) incidence of disability pension awards for rheumatoid arthritis during 1969–1981, (2) prevalence of rheumatoid arthritis on December 31, 1981, and (3) prevalence of subjects receiving free medication for rheumatoid arthritis at the end of 1981. Referent group was composed of Finnish males. |
Granite
workers:
|
Mean
quartz concentrations measured in the granite quarries, processing
yards, and crushing plants in 1970–1972 ranged from 0.02 to 4.9
mg/m3.
1.6 recipients expected (P<0.001). 7.5 recipients expected (P<0.001). |
|||
| Awarded disability pensions for rheumatoid arthritis |
17§§ |
5.08*** |
3.31–7.79 |
|||
| Receiving
pensions for rheumatoid arthritis at end of study period |
10§§ |
— |
— |
|||
| Receiving free medication for rheumatoid arthritis at end of study period |
19††† |
— |
— |
|||
| Ng
et al. [1993], Singapore |
Cross-sectional study of subclinical renal effects in 67 granite quarry workers with no history of glomerulonephritis, urinary calculi, renal disease, diabetes, hypertension, or regular ingestion of analgesics. Workers' urine samples were tested for indicators of glomerular and tubular functions (i.e., albumin, AMG, BMG, and NAG). | Workers with low-dust-exposure jobs and no radiographic evidence of silicosis |
31 |
— |
— |
Workers
in the high-exposure group with >10 yr of employment had
significantly greater (P<0.05) urinary concentrations of AMG, BMG,
and NAG compared with workers in the low-exposure group. Quantitative
dust exposure data not available.
Preliminary findings were reported in Ng et al. [1992a]. Further studies are needed to define the clinical significance of AMG, BMG, and NAG as indicators of renal dysfunction in silica-exposed workers. |
| Workers
with high-dust-exposure jobs and <10 yr of employment |
17 |
— |
— |
|||
| Workers with high-dust-exposure jobs and >10 yr of employment |
19 |
— |
— |
|||
| Nuyts et al. [1995], Belgium | Case-control study of occupational exposures of 16 patients diagnosed with Wegener's granulomatosis at six Belgian renal units between June 1991 and June 1993. Each patient was matched (by age, sex, and region of residence) with two controls randomly selected from lists of voters. | Patients with Wegener's granulomatosis (renal involvement) and reported occupational exposure to silica |
5 |
5.0 |
1.4–11.6 |
Study had small sample size and was not designed specifically to examine exposure-response relationship of Wegener's granulomatosis with occupational exposure to silica. Further study is needed. |
| Rafnsson et al. [1998], Iceland | Population-based
case-control study of residents in a district with a diatomaceous
earth processing plant. Population included 8 sarcoidosis patients who were linked to a file of all past and present workers employed at the plant after it opened in 1967. 70 controls were randomly selected from the district population. |
Sarcoidosis patients with occupational exposure to diatomaceous earth and cristobalite at the community plant |
6
|
13.2
|
2.0–140.9
|
No
matching of cases with controls.
Mean values of personal samples of respirable cristobalite dust taken in 1978 and 1981 ranged from 0.002 to 0.6 mg/m3. Stratification by number of hr worked ( >1,000 hr or <1,000 hr) indicated a dose-response trend. Further study of sarcoidosis and silica exposure is needed. |
| Rosenman and Zhu [1995] | Cohort morbidity study of men and women aged >20 and discharged from Michigan hospitals 1990–1991. |
Patients
with silicosis and rheumatoid arthritis:
|
No patients had silicosis and scleroderma. | |||
|
Women
|
0
|
—
|
—
|
|||
|
Men
|
3
|
3.2**
|
1.1–9.4
|
|||
| Sluis-Cremer
et al. [1985], South Africa |
Case-control study of silicosis in 79 white gold miners diagnosed with "definite" or "probable" progressive systemic sclerosis between 1955 and June 1984. Randomly selected control group of 79 miners in same patient index examined between May 1970 and April 1971; matched by age; without progressive systemic sclerosis. |
—
|
79
|
1.18
|
0.26–5.38
|
Controlled
for cumulative dust exposure.
Although reported ORs suggested no association between silicosis and progressive systemic sclerosis, cases had higher cumulative dust exposure (P<0.001). This study was not designed to examine the possibility of a direct association between silica dust exposure and progressive systemic sclerosis. |
| Sluis-Cremer
et al. [1986], South Africa |
Case-control study of silicosis in 157 white gold miners diagnosed with "definite" or "probable" rheumatoid arthritis between 1967 and 1979. Each case was matched by age to a control subject without rheumatoid arthritis. | Miners with "definite" rheumatoid arthritis |
91 |
3.79‡‡‡ |
1.72–8.36 |
Although the reported ORs suggested that gold miners with probable or definite rheumatoid arthritis were more likely to have silicosis as well, the study was not designed to examine the possibility of a direct association between silica exposure and rheumatoid arthritis. The results could not be explained by cumulative dust exposure or the intensity of exposure to gold mine dust. |
| Miners with "probable" rheumatoid arthritis |
66 |
1.94‡‡‡ |
0.81–4.63 |
|||
| Steenland et al. [1990], United States |
Population-based case-control study of occupational exposures of 325 men listed in the Michigan kidney registry and diagnosed with end-stage renal disease (excluding diabetic, congenital, and obstructive nephropathies) between 1976 and 1984. 325 controls matched by age, race, and area of residence. | Men with end-stage renal disease who reported occupational exposure to silica |
87 |
1.67 |
1.02–2.74 |
Possible overreporting of exposure by cases. |
| Steenland et al. [1992], United States |
Proportionate mortality study of 991 granite cutters who died after 1960 compared with causes of death in U.S. population. |
Granite
cutters:
|
Study included all underlying and contributing causes of mortality after 1960 and other significant conditions that were documented on the death certificate. | |||
| Arthritis deaths |
17
|
2.01§§§
|
1.17–3.21
|
|||
| Chronic
renal disease deaths (ICD–9 categories 582, 583, 585, 587)**** |
26 |
2.18§§§ |
1.43–3.20 |
|||
| Steenland
and Brown [1995b], United States |
Mortality
study of 3,328 white male gold miners employed underground >1 yr between 1940 and 1965 and followed for mortality from 1977 to 1990. Mortality rates of U.S. males used for comparison. |
Arthritis
(ICD–9 categories 711–716, 720–721) (see comments) |
17 |
2.19†††† |
1.27–3.50 |
Study
included all underlying and contributing causes of mortality after
1960 and other significant conditions documented on the death certificate.
Statistically significant exposure-response trend (P<0.05) for chronic renal disease mortality and cumulative dust exposure. |
| Other musculoskeletal disease as well as sclerosis, scleroderma, and lupus (ICD–9 categories 710, 717–719, 722–729, 731–739) (see comments) |
10 |
2.14†††† |
1.03–3.94 |
|||
| Nonmalignant
skin diseases (ICD–9 categories 690–709) (see comments) |
10 |
2.45†††† |
1.17–4.51 |
|||
| Chronic renal disease in miners in highest cumulative dust exposure category (i.e., >48,000 dust-days) |
8 |
2.77†††† |
1.20-5.47‡‡‡‡ |
|||
|
*Odds ratio unless otherwise indicated. †Abbreviations: Dash indicates not reported; AMG=alpha-1-microglobulin; BMG=beta-2-microglobulin; CI=confidence interval; NAG=beta-n-acetyl-D-glucosaminidase; OR=odds ratio. ‡None exposed. §For history of silica dust exposure. **Standardized incidence ratio (SIR). ††That is, caused by glomerulonephritis or interstitial nephritis. ‡‡Incidence (cases) per million black gold miners. Incidence in general population of black men of similar age (33–57) was 3.4 cases per million (P<0.001). §§Disability cases. ***Rate ratio. †††Receiving arthritis medication through national insurance plan. ‡‡‡OR is for presence of silicosis. §§§PMR. ****ICD–9 is the International Classification of Diseases, 9th Revision [WHO 1977]. ††††SMR. ‡‡‡‡Reported in Steenland and Goldsmith [1995]. |
||||||
| <back | Table of Contents |