Cobalt trihydroxide

Sensitisation data (human)

Administrative data

Endpoint:

sensitisation data (humans)

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

other: Any kind of reliability rating is not considered to be applicable, since human epidemiological studies, field studies and case reports are not conducted/reported according to standardised guidelines

Rationale for reliability incl. deficiencies:

other: reasonably well described case report with minor reporting deficiencies

Data source

Reference

Reference Type:

publication

Title:

Asthme aux sels de cobalt

Author:

Pilliere F et al.

Year:

1990

Bibliographic source:

Arch. Mal. Prof. 51, 413-417

Materials and methods

Type of sensitisation studied:

respiratory

Study type:

case report

Principles of method if other than guideline:

The reference is a a single case report of a 19 year old worker sensitised to cobalt resinate

GLP compliance:

no

Test material

Test material information

Constituent 1

Reference substance name:

cobalt resinate

IUPAC Name:

cobalt resinate

Method

Type of population:

occupational

Ethical approval:

not specified

Subjects:

- Number of subjects exposed: 1
- Sex: male
- Age: 19
- Race: no data
- Demographic information: no data

Clinical history:

For the past 6 months, the patient has worked in cobalt salt production. He was assigned to the bagging of cobalt resinate powder, protected by a dust mask.

Two weeks after starting this work he developed a cough and difficulty breathing, occurring at the end of the work shift. From the third week, symptoms included one-to-two typical asthma attacks per week. These attacks would only start after the patient arrived home, and were not accompanied by other respiratory, ocular or cutaneous allergic events. All respiratory symptoms disappeared during the weekends.

Controls:

No controls were used.

Route of administration:

inhalation

Details on study design:

TYPE AND DETAILS OF TEST(S) USED
- Skin prick test: conducted on other respiratory allergens (house dust, mites, pollens)
- Bronchial challenge test: with cobalt resinate
- Other immunological tests: total IgE
- Lung function measurements: baseline pulmonary function tests

Results and discussion

Results of examinations:

Clinical examination revealed no anomalies other than sibilant rales in both lung fields. Subsequent examinations, performed after exposure had stopped, auscultation of the lungs was normal. The additional respiratory symptoms also disappeared with the cessation of work.

Haematology did not show hypereosinophilia, total IgE was only slightly elevated (125kU/l : N<100); skin testing for respiratory allergens (house dust, mites, pollens) were negative.

Baseline pulmonary function tests were normal. There was, however, bronchial hyperactivity, the preliminary acetylcholine dose was 400µg. This functional profile is suggestive of an early asthmatic illness.

An initial exposure test was conducted in a hospital setting using cobalt resinate. A 5-minute exposure to the powder immediately provoked cough and respiratory irritation; the FEV1 dropped 26% from its initial value. This bronchospasm spontaneously corrected in a few minutes, however a delayed reaction then appeared at the fourth hour. This time the spontaneous return to normal commenced in the ninth hour. This initial test allowed the diagnosis of occupational asthma due to cobalt resinate. The assessment continued with exposure tests to cobalt stearate and to tall oil resin.

Cobalt stearate was chosen because it is one of the less irritating cobalt salts. Grinding and manipulation of the powder over 20 minutes was followed by a drop in the FEV1 starting at the third hour, culminating by the sixth hour (-30%), and accompanied by dyspnoea. The recovery was spontaneous over several hours.

Grinding and manipulation of tall oil resin over 20 minutes only induced a brief, spontaneously disappearing irritative response at the end of the exposure. Lung function testing was unchanged over a 24-hour period.

Applicant's summary and conclusion

Conclusions:

In a single-case study on occupational exposure to cobalt resinate via inhalation, precipitated a positive finding in a bronchio-constriction test (decrease of FEV1 by ca. 30%).