Calcium diformate

Epidemiological data

Administrative data

Endpoint:

epidemiological data

Type of information:

other: epidemiological study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Test procedure according to national standard methods

Data source

Reference

Reference Type:

publication

Title:

Plasma Folate Levels and Risk of Spontaneous Abortion

Author:

George L, Mills JL, Johansson ALV et al.

Year:

2002

Bibliographic source:

JAMA. 2002; 288(15); 1867-1873

Materials and methods

Study type:

case control study (retrospective)

Endpoint addressed:

developmental toxicity / teratogenicity

Principles of method if other than guideline:

Examination of plasma folate levels in case women with abortion and control women

GLP compliance:

not specified

Test material

Test material information

Constituent 1

Reference substance name:

Propan-2-ol

EC Number:

200-661-7

EC Name:

Propan-2-ol

Molecular formula:

C3H8O

IUPAC Name:

Propan-2-ol

Details on test material:

other: not applicable. Plasma folate levels of the general public were measured without any test substance administration

Method

Type of population:

general

Ethical approval:

confirmed and informed consent free of coercion received

Details on study design:

HYPOTHESIS TESTED:
correlation of folate plasma levels with incidence of spontanous abortion

METHOD OF DATA COLLECTION
- Type: Interview; Questionnaire, Clinical tests
- Details: folate plasma levels tested

STUDY PERIOD: January 1996 - December 1998

SETTING: Population-based, matched, case-control study of case women with spontaneous abortion and control women from January 1996
through December 1998 in Uppsala County, Sweden. Plasma folate measurements were available for 468 cases and 921 controls at 6 to 12 gestational weeks.

STUDY POPULATION
- Total population (Total no. of persons in cohort from which the subjects were drawn): 652 cases; 1037 controls
- Selection criteria: agreement of respective patient
- Total number of subjects participating in study: 468 cases; 921 controls; total 1389
- Sex/age/race: female/reproductive (>24 - >35 years)/ Sweden
- Smoker/nonsmoker: controls: 14.0%/85.9%; cases: 21.4%/78.2%
- Total number of subjects at end of study:


COMPARISON POPULATION
- Type: State registry / Regional registry / National registry / Control or reference group / Other comparison group:
- Details:

HEALTH EFFECTS STUDIED
- Disease(s): yes; including previous abortions
-- Diagnostic procedure: folate: inmmunoassay; plamsa cotinine; ultrasonic examination

Exposure assessment:

not specified

Results and discussion

Any other information on results incl. tables

Compared with women with plasma folate levels between 2.20 and 3.95 ng/mL (5.0 and 8.9 nmol/L), women with low (2.19 ng/mL [4.9 nmol/L]) folate levels were at increased risk of spontaneous abortion (adjusted odds ratio [OR], 1.47; 95% confidence interval [CI], 1.01-2.14), whereas women with higher folate levels (3.96-6.16 ng/mL [9.0-13.9 nmol/L] and 6.17 ng/mL [14.0 nmol/L]) showed no increased risk of spontaneous abortion (OR, 0.84; 95% CI, 0.59-1.20; and OR, 0.74; 95% CI, 0.47-1.16, respectively). Low folate levels were associated with a significantly increased risk when the fetal karyotype was abnormal (OR, 1.95; 95% CI, 1.09 -3.48) but not when the fetal karyotype was normal (OR, 1.11; 95% CI, 0.55-2.24) or unknown (OR, 1.45; 95% CI, 0.90-2.33).

Applicant's summary and conclusion

Conclusions:

Low plasma folate levels were associated with an increased risk of early spontaneous abortion.