Cadmium sulphate

Epidemiological data

Administrative data

Endpoint:

epidemiological data

Type of information:

experimental study

Adequacy of study:

key study

Study period:

From 1940 to 1982

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: see 'Remark'

Remarks:

All selected studies were evaluated with a check-list relating to population, exposure, endpoints, biases and confounders. Used check-list are established by Professor Philippe Hotz from the Institut für Sozial- und Präventivmedizin der Universität Zürich (EU RA 2008).

Cross-reference

Cross-reference 1

Reason / purpose for cross-reference:

reference to same study

Cross-reference 2

Reason / purpose for cross-reference:

reference to other study

Data source

Reference

Reference Type:

publication

Title:

Lung cancer mortality in a cohort of workers employed at a cadmium recovery plant in the United States: an analysis with detailed job histories

Author:

Sorahan T and Lancashire R

Year:

1997

Bibliographic source:

Occup. Environ. Med. 54: 194-201

Materials and methods

Study type:

cohort study (prospective)

Endpoint addressed:

carcinogenicity

Principles of method if other than guideline:

Epidemiological study was conducted to determine the association between the risk of cancer and occupational cadmium exposure.

GLP compliance:

not specified

Test material

Test material information

Constituent 1

Reference substance name:

Cadmium sulphate

EC Number:

233-331-6

EC Name:

Cadmium sulphate

Cas Number:

10124-36-4

Molecular formula:

CdSO4

IUPAC Name:

cadmium sulphate

Details on test material:

- Name of test material (as cited in study report): Cadmium sulphate

Method

Type of population:

occupational

Ethical approval:

not specified

Details on study design:

HYPOTHESIS TESTED (if cohort or case control study): Association between the risk of cancer and occupational cadmium exposure

STUDY POPULATION
E: 571 (M only)
S: ”employed for at least 6 months as plant production workers between 1940 and 1969 and first employed after 1.1.1926”
Lost cases: N.I.

Exposure assessment:

measured

Details on exposure:

Exposure levels and categories:
air Cd levels, 1943-1976; personal sampling: 1973-1976
quantitative cumulative exposure (job histories)

< 400
400 – 999
1,000- 1,999
≥ 2,000
(mg Cd.days/m³)

Statistical methods:

no information

Results and discussion

Results:

Lung cancer (o/e) :
< 400 mg Cd.days/m³: 6/N.I.
400 – 999 mg Cd.days/m³: 6/N.I.
1,000- 1,999 mg Cd.days/m³: 4/N.I.
≥ 2,000 mg Cd.days/m³: 5/N.I.
SMR (95% CI) lung:
< 400 mg Cd.days/m³: 100
400 – 999 mg Cd.days/m³: 225 (72-702)
1,000- 1,999 mg Cd.days/m³: 341 (66-872)
≥ 2,000 mg Cd.days/m³: 413 (121-1403)*
trend: 156( 1.06-2.28)*
*p<0.05
→ Significant positive trend between cumulative exposure to Cd and risks of mortality from lung cancer only in the presence of concomittant exposure to As

Confounding factors:

Considered confounding factors:
- Smoking: no
- Other simultaneous exposures: CdO fumes & dust, CdSO4, CdS, arsenic

Strengths and weaknesses:

Weakness:
- Data on smoking habits were not available for the entire cohort and available data on smoking were not incorporated into the analysis.
- The lack of independent evidence of the reliability of the individual estimates of cumulative exposure to cadmium (no evidence was provided by a comparison of these estimates with in vivo measurements of cadmium in liver, for example).
- The non-availability of follow-up for the workers employed before 1940. One may conceive that only a small proportion of these employees first employed in the 1920s appear in the cohort as defined in 1997.

Any other information on results incl. tables

A significant positive trend was found for risk of lung cancer and cumulative exposure to cadmium in the presence of high exposure to arsenic only.

	N	Cancer of lung
Cumulative exposure to cadmium (mg-days/m³)	observed/expected	SMR	95% CI
Department with high cadmium and high arsenic exposures (excluding arsenic departments)
<200 200-499 500-999 ≥1000 Evaluation of trend	11/N.I. 2/N.I. 2/N.I. 6/N.I.	1.0 0.81 1.83 4.02*   1.54*	0.17- 3.82 0.36- 9.39 1.34- 12.03* 1.06-2.23*
Departments with high cadmium and minimal or no arsenic exposure
<200 200-499 500-999         ≥ 1000 Evaluation of trend	13/N.I. 4/N.I. 2/N.I. 2/N.I.	1.0 1.68 1.30 2.68   1.26	0.48-5.90 0.26-6.59 0.54-13.36 0.80-2.00   0.80-2.00

*: p<0.05

Applicant's summary and conclusion

Conclusions:

Hypotheses which are consistent with the study findings include: (a) cadmium oxide in the presence of arsenic trioxide is a human lung carcinogen, (b) cadmium oxide and arsenic trioxide are human lung carcinogens and cadmium sulphate and cadmium sulphide are not (or they are less potent carcinogens), or (c) arsenic trioxide is a human lung carcinogen and cadmium oxide, cadmium sulphate, and cadmium sulphide are not. There were only 21 deaths from lung cancer available for this analysis and it is impossible to gauge which, if any, of these hypotheses are correct.

Executive summary:

A study was conducted to identify and measure any relations between occupational exposure to cadmium compounds (oxide, sulphide, and sulphate) and the risk of mortality from lung cancer.

Analysis was restricted to 571 male workers first employed after 1 January 1926 and employed for at least six months between 1940 and 1969. Individual estimates of cumulative exposures to cadmium were re-assessed and the potentially confounding role of an exposure to arsenic was again thoroughly evaluated.

A significant positive trend between cumulative exposure to cadmium (<400, 400-999, 1000-1999, ≥ 2000 mg.m-3.days) and risks of mortality from lung cancer was found. A significant positive trend was found for risk of lung cancer and cumulative exposure to cadmium in the presence of high exposure to arsenic but not for cumulative exposure to cadmium received in the absence of high exposure to arsenic.

Hypotheses which are consistent with the study findings include: (a) cadmium oxide in the presence of arsenic trioxide is a human lung carcinogen, (b) cadmium oxide and arsenic trioxide are human lung carcinogens and cadmium sulphate and cadmium sulphide are not (or they are less potent carcinogens), or (c) arsenic trioxide is a human lung carcinogen and cadmium oxide, cadmium sulphate, and cadmium sulphide are not. There were only 21 deaths from lung cancer available for this analysis and it is impossible to gauge which, if any, of these hypotheses are correct.