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Endpoint:
epidemiological data
Type of information:
migrated information: read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
weight of evidence
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Acceptable, well documented publication which meets basic scientific principles.

Data source

Reference
Reference Type:
publication
Title:
Mental Abilities of Workers Exposed to Aluminium
Author:
Hosovski, E. et al.
Year:
1990
Bibliographic source:
Med Lav 81(2): 119-123

Materials and methods

Study type:
cross sectional study
Endpoint addressed:
neurotoxicity
Principles of method if other than guideline:
Assessment of aluminium exposure by measurement of aluminium levels in whole blood and urine. Comparison of psychomotor and intellectual abilities of aluminium foundry workers with non-exposed workers.
GLP compliance:
no

Test material

Constituent 1
Reference substance name:
Automatically generated during migration to IUCLID 6, no data available
IUPAC Name:
Automatically generated during migration to IUCLID 6, no data available
Details on test material:
- Name of test material (as cited in study report): Aluminium
- Analytical purity: no data

Method

Type of population:
occupational
Ethical approval:
other: subjects gave their individual consent prior to test (determination of aluminium body burden).
Details on study design:
HYPOTHESIS TESTED (if cohort or case control study): The aim of this study was to assess the psychomotorial and intellectual abilities in workers occupationally exposed to high aluminium concentrations for approximately 10 years.


METHOD OF DATA COLLECTION
- Type: Clinical tests / Psychomotor and intellectual ability tests / other data presumably obtained by questionnaire
- Details:
Environmental aluminium concentrations at the workplaces were measured for each worker separately during winter and summer periods. Size and number of dust particles in the air of the workplaces were determined in order to assess the possibility of aluminium penetration in the organism via the respiratory system.
Aluminium values in whole blood and urine were determined by atomic absorption flameless spectrometry using a PERKIN ELMER 1100 apparatus. After obtaining their individual consent, the subjects were given desferroxamine by intramuscular injections: 0.5 g every 12 hours for two days (total amount: 2.0 g). Two hours after the first desferroxamine injection, urine was collected over 72 hours. Blood samples were taken every 12 hours (total number: 6 samples). On the basis of these results, the aluminium body burden was estimated.
Prior to and after administration of desferroxamine, copper, lead, zinc, iron, cadmium, manganese, carbon monoxide and fluorides were determined in blood and urine; zinc-protoporphyrin was determined in blood; and aminolevulinic acid and coproporphyrin were determined in urine. These measurements were carried out in order to rule out a high body burden of or intoxication by these noxae in all the workers under study.
The psychomotor ability was assessed with tests for simple and complex reaction using Turner's apparatus, by recording the number of mistakes and the speed of test performance. Intellectual abilities were tested using the Wechsler's test; a quotient of verbal, performance and total intelligence was established and further analyses were made in subtests. The sum of the verbal tests and the sum of the performance tests were obtained based on the classification of the results as obtained in the subtests according to Wechsler's method.
The level of cerebral damage and mental decline was examined using the Bender's visual motor test and the Wechsler's test.


SETTING: occupational; the subjects were workers in an aluminium foundry. The group of exposed workers (E) consisted of 87 workers whose shortest exposure was 6 years. These workers were exposed to high aluminium levels in the form of fumes and dust.


STUDY POPULATION
- Total population (Total no. of persons in cohort from which the subjects were drawn): 87
- Selection criteria: Subjects who had taken psychotropic drugs a month prior to the test and who consumed alcohol were excluded prior to the beginning of the study.
- Total number of subjects participating in study: 87
- Sex/age: All workers were presumably male / 40.7 ± 7.4 years
- Total number of subjects at end of study: 87
- Other:
Total job seniority: 18.9 ± 6.9 years
Cumulative exposure: 12.0 ± 4.5 years

COMPARISON POPULATION
- Type: Control or reference group
- Details: The non-exposed group (NE) consisted of 60 workers who had not been exposed to toxic noxae at the workplace. Matching criteria were age, job seniority and social status. All workers were presumably male and 41.9 ± 9.3 years of age. The total job seniority was 18.9 ± 6.9 years.


HEALTH EFFECTS STUDIED
- Other health effects: psychomotorial and intellectual abilities
Exposure assessment:
measured
Details on exposure:
TYPE OF EXPOSURE: inhalation exposure to high aluminium levels in the form of fumes and dust


TYPE OF EXPOSURE MEASUREMENT: Personal sampling / Biomonitoring (urine) / Biomonitoring blood


EXPOSURE LEVELS: Environmental aluminium concentrations at workplaces ranged from 4.6 to 11.5 mg/m³ of air.
Aluminium concentrations in blood and urine were determined prior to and after administration of desferroxamine (see also table 1 under remarks on results):

Exposed group
Aluminium in blood: 136.85 ± 103.15 µg/L and 169.52 ± 75.65 µg/L before and after administration of desferroxamine, respectively.
Aluminium in urine: 45.38 ± 55.01 µg/L and 103.25 ± 115.77 µg/L before and after administration of desferroxamine, respectively.

Non-exposed group
Aluminium in blood: 58.09 ± 74.73 µg/L and 61.16 ± 81.94 µg/L before and after administration of desferroxamine, respectively.
Aluminium in urine: 7.25 ± 7.82 µg/L and 11.06 ± 13.35 µg/L before and after administration of desferroxamine, respectively.

EXPOSURE PERIOD: presumably 7 days per week


DESCRIPTION / DELINEATION OF EXPOSURE GROUPS / CATEGORIES: The group of exposed workers (E) consisted of 87 workers whose shortest exposure was 6 years. The non-exposed group (NE) consisted of 60 workers who had not been exposed to toxic noxae at the workplace.
Statistical methods:
The t-test was used to analyse mean aluminium values in blood and urine (before vs. after desferroxamine) as well as mean values of the test results for psychomotor and intellectual abilities (exposed vs. non-exposed).

Results and discussion

Results:
EXPOSURE
- Number of measurements: Environmental aluminium concentrations at the workplaces were measured for each worker separately during winter and summer periods.
- Aluminium concentrations:
- Environmental aluminium concentrations ranged from 4.6 to 11.5 mg/m³ of air.
- At certain places the number of particles was from 329 up to 1020/cm³ of air.
- Particle size distribution: 65.6%, <1 µm; 26.6% 1-5 µm; 7.6% >5 µm.
- Aluminium concentrations in blood and urine: refer to table 1.


FINDINGS

Aluminium burden
Aluminium concentrations in blood and urine were much higher in the exposed workers than in the non-exposed group. After administration of desferroxamine, blood aluminium was increased in all the tested workers, indicating mobilisation of aluminium from its deposits. This increase was statistically significant in the exposed group. Likewise, urinary aluminium was increased in all subjects after administration of desferroxamine. The increased elimination was significant in the exposed group (Table 1).

Tests for psychomotor and intellectual abilities
There were no significant differences between the exposed and non-exposed groups in the mean values of intelligence quotient as well as performance and verbal quotients of intelligence. Abilities for simple reactions and efficiency in solving verbal tests were not impaired. A significant dissociation of oculomotor coordination was observed in the exposed group, the complex reaction time was longer and psychomotor abilities were slower (Table 2).

Wechsler’s intelligence subtests
The results of the subtests on intellectual abilities (memory subtest, subtests of coding, picture completion and object assembling) for the exposed group indicated impairment of attention efficiency, learning ability, emotional stability, efficiency of mental control, capability of concept formation, visual-motor coordination, thinking and memory elasticity and efficiency of long-lasting psychic efforts (Table 3).

Mental deterioration test
According to the authors, the results of the tests on mental deterioration indicated that this disorder could be expected to occur more frequently in the aluminium-exposed subjects. However, no statistically significant differences in mental deterioration frequencies and quotients of mental deterioration were observed (Table 4).
Confounding factors:
Previous exposure to other chemicals and consumption of psychotropic drugs (only workers who had taken drugs one month prior to the study were excluded) were not controlled.
Strengths and weaknesses:
Strengths:
Aluminium body burden was determiend. By determination of copper, lead, zinc, iron, cadmium, manganese, carbon monoxide and fluorides in blood and urine, zinc-protoporphyrin in blood, aminolevulinic acid and coproporphyrin in urine, prior to and after administration of desferroxamine, a high body burden of, or intoxication by these noxae in all the workers under study was excluded.

Weaknesses:
Exposed and non-exposed workers were only matched for age, total job seniority and social stauts. Possible premorbid intelligence was not modelled. Limited statistical analysis (results were not analysed with covariance models).

Any other information on results incl. tables

Table 1. Aluminium values in blood and urine before and after administration of desferroxamine. (SD = standard deviation; t = result of t-test)

 

 

Exposed group

Non-exposed group

before

 

after

before

 

after

Blood (µg/L)

mean

136.85

169.52

58.09

61.16

SD

103.15

75.65

74.73

81.94

t

 

2.382*

 

 

0.214

 

Urine (µg/L)

mean

45.38

 

103.25

7.25

 

11.06

SD

55.01

115.77

7.82

13.35

t

 

4.211**

 

 

1.903

 

 

*p < 0.02 ** p < 0.001

 

 

Table 2. Results of tests for psychomotor and intellectual abilities. (E = Exposed,n =87; NE = Non-exposed, n = 60)

 

 

mean

SD

t

Simple reaction time

E

0.231

0.123

1.08

NE

0.215

0.052

Complex reaction time

E

0.847

0.366

3.33*

NE

0.642

0.368

Oculomotor coordination

E

416.7

122.0

3.40*

NE

348.4

117.7

Intelligence quotient

E

99.4

12.3

1.43

NE

102.2

10.7

Performance intelligence quotient (IQP)

E

98.3

13.5

0.33

NE

99.1

14.8

Verbal intelligence quotient (IQV)

E

100.2

11.7

0.94

NE

102.1

11.9

IQV-IQP

E

9.22

6.44

1.21

NE

7.55

5.67

Sum of verbal tests

E

38.19

8.92

1.34

NE

40.11

7.91

Sum of manipulative tests

E

29.44

8.99

3.90*

NE

35.06

8.27

 

*p< 0.001

 

 

Table 3. Results of Wechsler's intelligence subtests in the tested workers. (E = Exposed, n = 87; NE = Non-exposed, n = 60)

 

 

mean

SD

t

Information possession

E

10.130

2.830

0.57

NE

9.860

2.860

Memory

E

6.582

2.521

4.05*

NE

8.233

2.360

Understanding

E

11.100

2.960

0.25

NE

11.230

3.160

Calculation

E

7.924

2.339

1.46

NE

8.500

2.554

Coding

E

7.622

3.400

2.83**

NE

9.016

2.554

Test

 

Picture completion

E

7.880

2.841

2.81**

NE

9.066

2.261

Picture grouping

E

6.932

3.344

1.71

NE

7.872

3.220

Object assembling

E

8.850

3.290

2.56***

NE

10.116

2.344

Assembling of cubes

E

8.875

3.690

0.96

NE

9.366

2.511

Common concepts

E

10.290

3,610

0.19

NE

10.410

3.650

 

* p < 0.001 ** p < 0.01 *** p < 0.02.

 

 

Table 4. Results of mental deterioration tests. (E = Exposed, n = 87; NE = Non-exposed, n = 60)

 

 

mean

%

SD

test

Mental deterioration

E

 

19.54

 

Chi-square = 0.969

NE

13.33

Quotient of mental deterioration

E

80.04

 

16.17

t =1.09

NE

83.00

16.04

 

Applicant's summary and conclusion

Conclusions:
Psychomotor and intellectual abilities of 87 aluminium foundry workers were compared with those of non-exposed workers matched on age, job seniority and social status. Exposure to aluminium was assessed by measuring levels in whole blood and urine. Total body burden of aluminium was assessed following the administration of desferroxamine. Findings included slower psychomotor reaction, dissociation of oculomotor coordination, reduced memory ability and disturbed emotional balance in the exposed workers. The authors concluded that these differences could be due to long-term toxic effects of aluminium.