Magnesium

Epidemiological data

Administrative data

Endpoint:

epidemiological data

Type of information:

migrated information: read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

supporting study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Well documented study which meets basic scientific principles

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1989

Materials and methods

Study type:

cohort study (retrospective)

Endpoint addressed:

repeated dose toxicity: inhalation

carcinogenicity

Test guideline

Qualifier:

no guideline followed

Principles of method if other than guideline:

A study of the cancer incidence in male workers at a Norwegian plant producing magnesium metal from dolomite and sea water was conducted. The study was restricted to employees with more than one year of work experience between 1951 and 1974 for a total of 52,733 person-years of exposure. The cohort was observed from 1953 to 1984.

GLP compliance:

not specified

Test material

Test material information

Constituent 1

Reference substance name:

Magnesium oxide

EC Number:

215-171-9

EC Name:

Magnesium oxide

Cas Number:

1309-48-4

IUPAC Name:

magnesium oxide

Test material form:

aerosol dispenser: not specified

Remarks:

migrated information: aerosol

Method

Type of population:

occupational

Ethical approval:

confirmed, but no further information available

Details on study design:

A study of the cancer incidence in male workers at a Norwegian plant producing magnesium metal from dolomite and sea water was conducted. The study was restricted to employees with more than one year of work experience between 1951 and 1974 for a total of 52,733 person-years of exposure. The cohort was observed from 1953 to 1984. Altogether 152 new cases of cancer were observed versus 132.6 expected. Among the 393 workers whose longest duration of work had involved exposure to MgO and coal dust or coke (9082 person-years

Exposure assessment:

estimated

Details on exposure:

A study of the cancer incidence in male workers at a Norwegian plant producing magnesium metal from dolomite and sea water was conducted.
The study was restricted to employees with more than one year of work experience between 1951 and 1974 for a total of 52,733 person-years of exposure. The cohort was observed from 1953 to 1984

Results and discussion

Results:

The results from a cohort study on the incidence of cancer and the mortality in a cohort of 2391 male workers producing magnesium metal are presented. The study population was restricted to employees with more than one year of work experience in the study plant between 1951 and 1974 and the cohort was observed from 1953 to 1984.
The production of magnesium metal and alloys involved combined exposures to many agents, such as volatile coal tar pitch products, chlorinated hydrocarbons (mainly hexachlorobenzene), asbestos, magnesium oxide, and magnesium chloride. Due to the complexity of possible causes, the authors divided the population into 9 different exposure categories, membership of which was generally defined as that category with the longest duration of work.
One of the categories was designated as ‘magnesium oxide’ and comprised of 393 workers exposed to magnesium oxide and coal dust having 9082 person-years experience. Using a constructed Norwegian population with an identical age distribution as reference, observed/expected (O/E) ratios of 68/74.3 and of 35/25.2 were found for ‘all deaths’ and ‘all cancers’, respectively; the 95% confidence interval (CI) of the standardised incidence ratio (SIR) was 1.0-1.9. When selected for specific types of cancer, they found the following O/E ratios in the ‘magnesium oxide’ category: lung cancer: 6/3.5 (95% CI: 0.6-3.7); stomach cancer: 5/2.5 (95% CI: 0.6-4.5); and lip cancer: 1/0.4 (Hel89). From this study, the it is no clear evidence that exposure to magnesium oxide is carcinogenic, but feels that the number of subjects studied is too small to be conclusive.

Confounding factors:

see attached file

Strengths and weaknesses:

The production of magnesium metal and alloys involved combined exposures to many agents, such as volatile coal tar pitch products, chlorinated hydrocarbons (mainly hexachlorobenzene), asbestos, magnesium oxide, and magnesium chloride.
the observation was not statistically significant (CI 1.0-1.9)

Any other information on results incl. tables

A study of the cancer incidence in maleworkers at a Norwegian plant producing magnesium metal from dolomite and sea waterwas conducted. The study was restricted to employees with more than one year of workexperience between 1951 and 1974 for a total of 52,733 person-years of exposure. Thecohort was observed from 1953 to 1984. Altogether 152 new cases of cancer wereobserved versus 132.6 expected. Among the 393 workers whose longest duration of workhad involved exposure to MgO and coal dust or coke (9082 person-years), there weremore cases of death by cancer (35) than expected (25.2), however, this observation wasnot statistically significant (CI 1.0-1.9). In this group, the incidence of lung (6/3.5; CI 0.6-3.7) and stomach (5/2.5; CI 0.6-4.5) cancer was higher than expected

Applicant's summary and conclusion

Conclusions:

The results from a cohort study on the incidence of cancer and the mortality in a cohort of 2391 male workers producing magnesium metal are presented. The study population was restricted to employees with more than one year of work experience in the study plant between 1951 and 1974 and the cohort was observed from 1953 to 1984.
The production of magnesium metal and alloys involved combined exposures to many agents, such as volatile coal tar pitch products, chlorinated hydrocarbons (mainly hexachlorobenzene), asbestos, magnesium oxide, and magnesium chloride. Due to the complexity of possible causes, the authors divided the population into 9 different exposure categories, membership of which was generally defined as that category with the longest duration of work.
One of the categories was designated as ‘magnesium oxide’ and comprised of 393 workers exposed to magnesium oxide and coal dust having 9082 person-years experience. Using a constructed Norwegian population with an identical age distribution as reference, observed/expected (O/E) ratios of 68/74.3 and of 35/25.2 were found for ‘all deaths’ and ‘all cancers’, respectively; the 95% confidence interval (CI) of the standardised incidence ratio (SIR) was 1.0-1.9. When selected for specific types of cancer, they found the following O/E ratios in the ‘magnesium oxide’ category: lung cancer: 6/3.5 (95% CI: 0.6-3.7); stomach cancer: 5/2.5 (95% CI: 0.6-4.5); and lip cancer: 1/0.4 (Hel89). From this study, the it is no clear evidence that exposure to magnesium oxide is carcinogenic, but feels that the number of subjects studied is too small to be conclusive.

Executive summary:

Heldaas et al. performed a retrospective cohort cancer incidence and mortality study on workers of a magnesium metal and its alloys productionfactory in Norway. The cohort comprised of 2391 male employees with morethan one year of work experience in the study plant between 1951 and 1974. The cohort was observed from 1953 to 1984.

The production of magnesium metal and alloys involved combined exposures to many agents, such as volatile coal tarpitch products, chlorinated hydrocarbons (mainly hexachlorobenzene), asbestos,magnesium oxide, and magnesium chloride. Due to the complexity of possiblecauses, the authors divided the population into 9 different exposure categories,membership of which was generally defined as that category with the longestduration of work.

One of the categories was designated as ‘magnesium oxide’and comprised of 393 workers exposed to magnesium oxide and coal dust having9082 person-years experience. Using a constructed Norwegian population withan identical age distribution as reference, observed/expected (O/E) ratios of68/74.3 and of 35/25.2 were found for ‘all deaths’ and ‘all cancers’, respectively;the 95% confidence interval (CI) of the standardised incidence ratio (SIR) was1.0-1.9. When selected for specific types of cancer, they found the following O/Eratios in the ‘magnesium oxide’ category: lung cancer: 6/3.5 (95% CI: 0.6-3.7);stomach cancer: 5/2.5 (95% CI: 0.6-4.5); and lip cancer: 1/0.4 (Hel89). From thisstudy, the itis no clear evidence that exposure tomagnesium oxide is carcinogenic, but feels that the number of subjects studied istoo small to be conclusive.