THE VIRGINIAN-PILOT
Copyright (c) 1994, Landmark Communications, Inc.
DATE: Thursday, July 7, 1994 TAG: 9407070511
SECTION: FRONT PAGE: A1 EDITION: FINAL
SOURCE: BY DANIEL Q. HANEY, ASSOCIATED PRESS
DATELINE: BOSTON LENGTH: Medium: 56 lines
A study of more than 370,000 mothers provides some of the strongest evidence yet that where people live and work powerfully affects the risk of birth defects.
The study, conducted in Norway, followed women who gave birth to a child with a defect. Not surprisingly, it found that they face a high risk of producing a second child with the same birth defect.
However, the study also discovered that the risk is cut in half if the mother moves to another town. This suggests some environmental factors are at work in triggering birth defects and are more important than experts had suspected.
``It's surprising that we see evidence of environmental effects in the data we looked at. It suggests there are things out there that we just have not been clever or lucky enough to find so far,'' said Dr. Allen J. Wilcox, a co-author of the study.
Wilcox, a researcher at the National Institute of Environmental Health Sciences in Research Triangle Park, N.C., said the study could not discern the precise environmental hazards that contribute to birth defects.
``Moving changes a lot of things in your life,'' he said. ``But it suggests there may be certain factors linked to the household or related to a job change. It can only give us the barest kinds of leads.''
More than 150,000 babies are born with serious birth defects in the United States each year. In about two-thirds of the cases, the causes of the defects are a mystery.
Most of the known causes of birth defects are specific genetic mutations. Other causes include alcohol abuse, poor diets and some medicines and chemicals, such as mercury.
However, experts have long suspected that genetic tendencies and environmental hazards are involved in many more cases. One leading theory holds that some unidentified environmental substances are harmless to most people but can trigger birth defects in those who have a genetic susceptibility.
The study was directed by Dr. Rolv Terje Lie of the University of Bergen in Norway and published in today's issue of the New England Journal of Medicine. It was based on the records of first and second infants delivered by 371,933 women from 1967 through 1989.
For the 9,192 women whose first babies had a birth defect, the researchers determined the risk of defects in the second baby. This was compared with the risk in women whose first babies were normal. Overall, 2.5 percent of the first babies had birth defects.
KEYWORDS: STUDY BIRTH DEFECTS by CNB