Water nitrates and CNS birth defects: a population-based case-control study
The relation between maternal exposure to nitrates in drinking water and risk of delivering an infant with a central nervous system (CNS) malformation was examined by means of a case-control study in New Brunswick, Canada. All cases of CNS defects for a high and a low prevalence area of New Brunswick, for the years 1973-1983, were included in the study. Controls were selected randomly from the livebirth files for the province, matched on county of maternal residence and date of birth. One hundred and thirty (130) cases were identified and individually matched with two controls each. Individual water samples were collected from the case and control mother's address given on the birth or stillbirth records. The study revealed that the effect of nitrate exposure in water was modified by whether the source of the drinking water was a private well or a public municipal distribution system. Compared to a baseline nitrate level of 0.1 ppm, exposure to nitrate levels of 26 ppm from private well water sources was associated with a moderate, but not statistically significant, increase in risk (risk odds ratio = 2.30; 95% confidence interval = 0.73-7.29). If the source of drinking water was a municipal distribution system or a private spring, an increase in nitrate exposure was associated with a decrease in risk of delivering a CNS-malformed infant; however, these effect estimates were not statistically significant. The positive increase in risk with nitrate exposure from well water sources requires further study using a larger case series and a larger proportion of exposures to nitrate levels exceeding 5 ppm.
- Research Organization:
- Univ. of Toronto (Canada)
- OSTI ID:
- 6840055
- Journal Information:
- Arch. Environ. Health; (United States), Vol. 43:2
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
54 ENVIRONMENTAL SCIENCES
59 BASIC BIOLOGICAL SCIENCES
CENTRAL NERVOUS SYSTEM
CONGENITAL MALFORMATIONS
CONGENITAL DISEASES
EPIDEMIOLOGY
DRINKING WATER
CONTAMINATION
NITRATES
ECOLOGICAL CONCENTRATION
TERATOGENESIS
NEW BRUNSWICK
RISK ASSESSMENT
WATER POLLUTION
WATER SUPPLY
CANADA
DISEASES
HYDROGEN COMPOUNDS
MALFORMATIONS
NERVOUS SYSTEM
NITROGEN COMPOUNDS
NORTH AMERICA
OXYGEN COMPOUNDS
PATHOLOGICAL CHANGES
POLLUTION
WATER
560300* - Chemicals Metabolism & Toxicology
520200 - Environment
Aquatic- Chemicals Monitoring & Transport- (-1989)
550900 - Pathology