November 29, 2012
Females 16-49 At Risk for Exposure to Multiple Pollutants
Connie K. Ho for redOrbit.com — Your Universe Online
Scientists from Brown University recently revealed in a study that women between the ages of 16 and 49 years of age had a high risk for various pollutants.
Pooled from the data of thousands of females, the new analysis demonstrated that almost 23 percent of women in the US met or exceeded the median blood levels for three environmental pollutants. Also, 89.3 percent of the women between the ages of 16 and 49 were at or above the median blood level for at least one of the chemicals; many of these substances have the ability to pass through the placenta to the fetus and trickle through breast milk to babies. As a result, females of childbearing age face increased risk endanger the brain development of fetuses and babies. In particular, lead, mercury, and polychlorinated biphenyls (PCBs) were found to be harmful.
The findings were recently published online in the journal Environmental Research and scientists explained how they are unsure as to whether co-exposure or single exposure to the chemicals is more harmful.
“Our research documents the prevalence of women who are exposed to all three of these chemicals,” explained the study´s lead author Marcella Thompson, who worked with co-author Professor Kim Boekelheide, in the statement. “It points out clearly the need to look at health outcomes for multiple environmental chemical co-exposures.”
In total, 3,173 women participated in the US Centers for Disease Control and Prevention National Health and Nutrition Examination Survey (NHANES) from 1999 to 2004. The survey looked at the national population of 134.5 million who were of childbearing age. The researchers were also able to determine particular risk factors related to greater chances of showing higher blood levels of lead, mercury and PCBs.
Based on the findings, the team of investigators discovered that, as women age, they have a greater risk of surpassing the median blood level in two or more of the pollutants. In particular, women between the ages of 30 and 39 had 12 times higher risk as compared to women ages 40 to 49 who had 30 times greater risk than women between 16 and 19 years of age. The researchers believed that women who are between the ages of 40 and 49 have the highest risk of accumulating the chemicals over time due to their age as well as the fact that these women were born before the environmental protection laws were created in the 1950s and 1960s.
Other risk factors observed included food and alcohol consumption. For example, women who consumed fish once a week during the 30 days before the exam demonstrated a 4.5 higher chance of exceeding the median in two or more pollutants. As well, women who drank a high amount of alcohol had an increased chance of risk but not as much as women who ate fish.
Interestingly, breastfeeding was a factor that lowered a women´s risk of having higher levels of pollutants in the blood. Specifically, women who had breastfed a minimum of one child for a minimum of a month at some point in their lives showed half of the risk of surpassing the median blood level for two or more pollutants. However, the scientists believe that, due to breastfeeding, the women passed the pollutants over to their infants.
Overall, the team of investigators believe that women should learn about the risk of being exposed to these chemicals prior to becoming pregnancy as a female in her 30s and 40s would have a higher risk for having increased levels of lead, mercury and PCBs.
“We carry a history of our environmental exposures throughout our lives,” concluded Thompson in the statement.