30-year-old Disaster Still Affecting Mothers And Newborns

Main Category:Public Health  Date:2008-8-18 17:52:00  view:42
A report published in the open-access journal PLoS Medicine findsthat maternal exposure to dangerous toxins damages thyroid function ofbabies. Andrea Baccarelli (University of Milan) and colleagues from theUnited States and Italy studied a 1976 accident at a chemical factoryin Seveso, Italy that exposed several residents of the town to the mostdangerous type of dioxin. The researchers found that newborn babiesborn to mothers who lived in contaminated areas at the time of theaccident are over six times more likely to present damaged thyroidfunction compared to babies born to mothers in non-contaminated areas.

Byproducts of waste incineration, dioxins are toxic chemicals thatlinger in the environment and build-up people. The toxin released inSeveso - 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) - is the mostdangerous type of dioxin, and it was declared a class-1 carcinogen bythe World Health Organization in 1997 was declared a class-1 carcinogenby the World Health Organization. Previous studies of animals andpeople have demonstrated that an offspring's thyroid gland can bedamaged after maternal exposure to dioxins.

This recent study analyzed the continuing effects of TCCD on childrenborn around Seveso, Italy, and the researchers focused on three groupsof child-bearing women. The sample included 1,772 women who were livingin Zone A - the most contaminated area in Seveso, very near to thefactory at the time of the accident - or in Zone B - a nearby area,less but still highly contaminated. These women were compared to 1,772women from the surrounding non-contaminated area, called ZoneReference. Between 1994 and 2005, these women had 1,014 babies.Baccarelli and colleagues analyzed blood samples to measure the amountof thyroid secreting hormone (TSH) in the children. It is known thathigh blood TSH levels are correlated with a failing thyroid, and thiscould lead to body and brain damage to the developing baby.

Children born decades after the accident are still experiencing theharmful effects of the Seveso disaster, according to the researchers. Ababy born in Zone A - the most highly TCCD-contaminated area at thetime of the accident - was found to be 6.6 times more likely to have ahigh blood TSH level than a baby born in the Zone Reference, ornon-contaminated area. The babies born in Zone B, a less contaminatedarea than Zone A, had moderate TSH blood levels. Using a subsample of51 pairs of mothers and children, the researchers compared dioxinlevels at the time of birth. They found that high blood TSH levels inbabies were more likely to be from mothers who had high levels ofdioxins in their blood.

The authors conclude: Our findings from the Seveso population indicatethat maternal exposure to persistent environmental contaminants such asTCDD produces effects on neonatal thyroid function that may occur farapart in time from the initial exposure. To clarify the clinicalsignificance of our findings, further investigation on developmentaloutcomes after maternal dioxin exposure is warranted.

Neonatal thyroid function in Seveso 25 years after maternalexposure to dioxin
Baccarelli A, Giacomini SM, Corbetta C, Landi MT, Bonzini M, et al
PLoS Medicine (2008). 5(7): e161.
doi:10.1371/journal.pmed.0050161
ClickHere to View the Article

About PLoS Medicine

PLoS Medicine is an open access, freely availableinternationalmedical journal. It publishes original research that enhances ourunderstanding of human health and disease, together with commentary andanalysis of important global health issues. For more information, visithttp://www.plosmedicine.org

About the Public Library of Science

The Public Library of Science (PLoS) is a non-profit organizationof scientists and physicians committed to making the world'sscientific and medical literature a freely available public resource.For more information, visit http://www.plos.org

Written by: Peter M Crosta
Copyright: Medical News Today
Not to be reproduced without permission of Medical News Today