Arsenic acid

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

Study period:

2001

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Study well documented, meets generally accepted scientific principles but with deviations: ecologic study and low number of participants

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:

Unnamed

Year:

2001

Materials and methods

Study type:

cross sectional study

Endpoint addressed:

toxicity to reproduction / fertility

Principles of method if other than guideline:

Cross-sectional study was conducted on groups of 192 women (96/group) of reproductive age (15-49 years) who were chronically exposed to arsenic through drinking water to identify the pregnancy outcomes.

GLP compliance:

no

Test material

Test material information

Constituent 1

Reference substance name:

Arsenic

EC Number:

231-148-6

EC Name:

Arsenic

Cas Number:

7440-38-2

IUPAC Name:

arsine

Details on test material:

- Name of test material (as cited in study report): Arsenic-contaminated water

Method

Details on study design:

METHOD OF DATA COLLECTION
- Type: Questionnaire
- Details: Questionnaire included information on the respondents’ lifetime pregnancy history, which included the number of pregnancies, preterm births (live birth before completion of 8 months, or 37 weeks from the last menstrual period), live births, stillbirths, and spontaneous abortions (spontaneous expulsion of product of conception before completion of 5 months, or 22 weeks of gestation from the last menstrual period).

STUDY POPULATION
- Selection criteria: Exposed group consisted of married women of reproductive age (15–49 years) who previously had at least one pregnancy and had been drinking arsenic-contaminated water (> 0.05 mg/L arsenic) for at least 5 years, whereas the nonexposed group consisted of respondents who had been drinking arsenic-safe water (i.e., < 0.02 mg/L arsenic).
- Total number of subjects participating in study: 96/group
- Sex/age/race: Female/15-49 years/Asian
- Matching criteria: Subjects in the nonexposed group were matched for age, socioeconomic status (SES), education, and age at marriage.

COMPARISON POPULATION
- Type: Regional registry: Exposed group: Residents of Samta village, Dhaka; unexposed group: Residents of Katiarchar village, Dhaka
- Details: Samta village: Avg. As level: 0.240 mg/L, highest concentration: 1.371 mg/L, prevalence of arsenicosis: 10% (52.6% male and 47.4% female); Katiarchar village: Avg. As level ≤ 0.02 mg/L
- See table 1 for more details

HEALTH EFFECTS STUDIED
- Mean number of pregnancies, stillbirths, preterm birth and spontaneous abortions

Exposure assessment:

estimated

Results and discussion

Results:

FINDINGS
- Mean number of pregnancies, live births, stillbirths, spontaneous abortions and preterm births were 3.74, 3.33, 0.18, 0.23 and 0.23, respectively, among the exposed group and 3.22, 3.07, 0.07, 0.07 and 0.08, respectively, in the nonexposed group.
- In exposed and nonexposed groups, respectively, 89.1 and 95.5% of pregnancies ended as live births.
- Adverse pregnancy outcomes measured as spontaneous abortions, stillbirths and preterm birth rates were 68.8, 53.1 and 68.8 per 1000 live births, respectively, among the exposed group and
23.7, 23.7 and 27.1 per 1000 live births, respectively, among the nonexposed group.
- See table 2-4 for more details

Confounding factors:

No information on specific confounding factors but both populations have comparable intrinsic structure (age, socio economic status, education).

Strengths and weaknesses:

Limitations
- Small sample size.
- Rudimentary medical records system and tests for confirmation of pregnancy were rarely available in the rural areas.
- Limited information on confounding factors
- No age comparison between more and less than 15 years exposure.

Any other information on results incl. tables

Table 2. Respondents by mean pregnancy outcomes

 

Pregnancy outcome	Exposed	Nonexposed
Pregnancy	3.74 ± 1.8 (359)	3.22 ± 1.6 (309)
Live birth	3.33 ± 1.6 (320)	3.07 ± 1.6 (295)
Stillbirth	0.18 ± 0.69 (17)	0.07 ± 0.33 (7)
Spontaneous abortion	0.23 ± 0.57 (22)	0.07 ± 0.36 (7)
Preterm birth	0.23 ± 0.55 (22)	0.08 ± 0.28 (8)

 

Table 3. Adverse pregnancy outcomes per 1000 live births among the respondents.

 

Pregnancy outcome	Exposed	Nonexposed	z-Score	p-Value
Spontaneous abortion	68.8	23.7	2.66	0.008
Stillbirth	53.1	23.7	2.00	0.046
Preterm birth	68.8	27.1	2.35	0.018

 

Table 4. Adverse pregnancy outcome rates (per 1000 live births) by duration of drinking arsenic contaminated (> 0.1 mg/L) water

 

	Duration of drinking arsenic-contaminated water
Pregnancy outcome	< 15 Years	≥ 15 Years	z-Score	p-Value
Spontaneous abortion	43.5	133.3	3.0	0. 003
Stillbirth	43.5	77.5	2.0	0.046
Preterm birth	47.8	122.2	2.3	0.021

Applicant's summary and conclusion

Conclusions:

Under the studied conditions, chronic exposure to arsenic through drinking water produced adverse pregnancy outcomes in women.

Executive summary:

A cross-sectional study was conducted on groups of 192 women (96/group) of reproductive age (15-49 years) who were chronically exposed to arsenic through drinking water to identify the pregnancy outcomes in terms of live birth, stillbirth, spontaneous abortion, and preterm birth. Women in both exposed and nonexposed groups were matched for age, socioeconomic status, education and age at marriage. Of the respondents in the exposed group, 98% had been drinking water containing ≥ 0.10 mg/L arsenic and 43.8% had been drinking arsenic-contaminated water for 5-10 years.

 

Skin manifestation due to chronic arsenic exposure was present in 22.9% of the respondents from the exposed group. Adverse pregnancy outcomes in terms of spontaneous abortion (only for difference between more and less than 15 years exposure), stillbirth and preterm birth rates were determined to be significantly higher in the exposed group than those in the nonexposed group.

 

Under the studied conditions, chronic exposure to arsenic through drinking water in a population where most well are measured between 200 to 450 µg/L produced an increased incidence of adverse pregnancy outcomes when compared to groups exposed to less than 20 µg/L.