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Epidemiological data

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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-referenceopen allclose all
Reason / purpose:
reference to same study
Reason / purpose:
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

Reference
Name:
Unnamed
Type:
Constituent
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.