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Toxicological information

Epidemiological data

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Administrative data

Endpoint:
epidemiological data
Type of information:
experimental study
Adequacy of study:
supporting study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: well-documented study, non-audited, no history on wives; parity not taken into account

Data source

Reference
Reference Type:
publication
Title:
Fertility of male workers exposed to mercury vapor or to manganese dust: A questionnaire study
Author:
Lauwerys R, Roels H, Genet P, Toussaint G, Bouckaert A & de Cooman S
Year:
1985
Bibliographic source:
American Journal of Industrial Medicine, 7:171-176

Materials and methods

Study type:
cohort study (prospective)
Endpoint addressed:
toxicity to reproduction / fertility
Test guideline
Qualifier:
no guideline followed
Principles of method if other than guideline:
The fertility of male workers exposed to manganese dust was assessed with the use of questionnaire. A fertility questionnaire was applied to the total male work force of a manganese salts and oxides factory and two control plants with comparable workload characteristics.
GLP compliance:
not specified

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
Name of test material (as cited in study report): Manganese dusts (dioxide, carbonate, sulphate) including manganese ore
Other: The concentration of manganese was measured as total dust

Method

Type of population:
occupational
Ethical approval:
not specified
Details on study design:
HYPOTHESIS TESTED : The possible interference of manganese on the reproductive system in male workers occupationally exposed.


METHOD OF DATA COLLECTION
- Type: Questionnaire and Clinical examinations.
- Details: The questionnaire contained questions on fertility along with questions on duration of employment, residence and smoking and drinking habits. Samples of blood and urine were collected for the determination of manganese.


SETTING: Occupational, the manganese exposed group were recruited from a factory producing manganese salts from concentrated ores


STUDY POPULATION
- Selection criteria: Only Belgian subjects were included, who had been married once. Subjects were excluded in they were widowed, divorced, separated or never married.
- Total number of subjects participating in study: 85 workers exposed to manganese, 81 control workers.
- Sex/age/race: All workers were male and Belgian
- Smoker/nonsmoker: Both were included in the study


COMPARISON POPULATION
- Type: Control or reference group
- Details: The control workers had never been occupationally exposed to manganese.


HEALTH EFFECTS STUDIED
- Disease(s): Fertility problems
Exposure assessment:
not specified
Details on exposure:
TYPE OF EXPOSURE: Occupational


TYPE OF EXPOSURE MEASUREMENT: Personal sampling. Personal samplers were employed to measure total dust during the whole shift.


EXPOSURE LEVELS: Total dust levels over the entire shift ranged from 0.07 to 8.61 mg/m^3 (N = 80) with a median value of 0.97 µg/m^3 (overall arithmetic and geometric mean values, 1.33 and 0.94 mg/m^3 respectively).


EXPOSURE PERIOD: 7.9 ± 5.5 years average
Statistical methods:
Results were analysed for statistical significance using a χ² test or the Student’s t-test.

Results and discussion

Results:
EXPOSURE
- Number of measurements: 80
- Average concentrations: 0.07 to 8.61 mg/m3
- Arithmetic mean: 1.33 mg/m3
- Geometric mean: 0.94 mg/m3
- Median: 0.97 µg/m3


FINDINGS

Please refer to section Remarks on results including tables and figures for full tabulated results.

The matching between the exposed and controls in regard to age of the subject and their wives, age of wife at marriage, age difference between husband and wide, duration of employment in the factory, smoking habits, alcohol consumption, educational level and professional activity of spouse. Very few differences between the groups reached statistical significance. Manganese levels in the urine fluctuated much more than levels in the blood. The median values in the control and exposed groups were 0.16 and 1.17 µg/g creatinine respectively. During the period of exposure to the metal, the number of observed children in the age groups 16-25 and 26-35 was significantly lower than the expected number. The sex ratio was not found to be significantly different. The was no indication that other factors might account for the marked observed fertility difference between the control and the manganese-exposed group. No difference between the wife’s occupations were detected. The proportion of wives performing clerical or manual work was not significantly different. The only statistically significant difference between the group characteristics that might have an influence on fertility (i,e, educational levels of the wives) would tend to decrease the fertility of the control group in comparison to that of the exposed group.
Confounding factors:
Past exposure to manganese may have been lower than the levels of the study as there was a higher volume of production during the study compared to past years. The only statistically significant difference between the group characteristics that might have an influence on fertility (i.e. educational levels of wives) would tend to decrease the fertility of the control group by comparison to that of the manganese group. This may have masked the effect of manganese on fertility.
Strengths and weaknesses:
No extensive monitoring data were available to assess past exposure to manganese. However the same production process had been used for at least 15 years.

Any other information on results incl. tables

Table 1: Characteristics of Control and Manganese-Exposed Male Workers

 

Control

Exposed

P

Number of subjects

81

 

85

 

 

Age (years)

39.5 ± 10.9a

(21-58)

37.4 ± 9.3

(21-59)

NSc

Age of wife (years)

38.0 ± 1.6

(17-61)

35.9 ± 9.4

(19-58)

NSc

Age of wife at marriage (years)

22.4 ± 3.5

(16-34)

21.4 ± 3.6

(17-33)

NSc

Duration of employment in the factory (years)

13.4 ± 10.8

(1-40)

8.1 ± 5.6

(1-19)

<0.001c

Years of exposure to manganese

-

-

7.9 ± 5.5

(1-19)

 

Percent smokers

73

 

86

 

NSd

Alcohol consumption

Yes (% of subjects)

73

 

79

 

NSd

Glasses of beer/week

18.2 ± 13.9

 

22.4 ± 20

 

NSc

Educational level

Primary and junior high school (%)

57

 

72

 

NSd

Senior high school and university (%)

43

 

28

 

 

Educational level of wife

Primary and junior high school (%)

54

 

75

 

<0.02d

Senior high school and university (%)

46

 

26

 

 

Wife with a job (%)

37

 

35

 

NSd

Percent desiring a child

27

 

25

 

NSd

Mn-B (µg/100 mL)

0.57 ± 0.26

(0.04-1.31)

1.29 ± 0.53

(0.10-3.30)

 

Mn-U (µg/g creatinine)

0.27 ± 0.31

(0.16)b

(0.1-2.00)

4.37 ± 15.65

(1.17)b

(0.09-140.6)

 

aMean ± SD (range)

bMedian

cStudent’s t-test

dx2 test

NS: Statistically not significant.

 

Table 2: Fertility of Male Workers Exposed to Manganese Dusts

 

Age groups

Exposure

Number of years of fertility

Number of children

P

Observed

Expected

16-25

Before

205

64

64.3

NS

During

123

17

38.6

<0.05

26-35

Before

277

37

28.4

NS

During

257

16

1.5

<0.05

36-45

Before

85

2

3.5

NS

During

195

6

 

NS

NS: Statistically not significant (critical ratio)

Applicant's summary and conclusion

Conclusions:
Due to the presence of more than one manganese substance, including possible exposure to manganese ore, it is not possible to make a conclusion about the effect of any particular substance on fertility, or whether the effect may be due to exposure to the ore rather than a single substance.