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Have you ever wondered why some infants seem to be naturally heavier than others, even though they may not necessarily be eating more? New research is confirming this may have something to do with a baby's exposure to certain pollutants within the womb.
Research from Spain's Center for Research in Environmental Epidemiology has confirmed that exposure to certain environmental pollutants in the womb produces a greater incidence of obesity and rapid growth among infants and children.
In the most recent study, the researchers followed over 4,600 infants between 2003 and 2008 who were between the age of six months and fourteen months. Within this population they identified 1,285 children who had experienced rapid growth during their first year and 1,198 overweight babies by the time they were 14 months of age.
During the last trimester of pregnancy the mothers' blood was collected and analyzed for a number of pollutants, including polychlorinated biphenyls (PCB), dichlorodiphenyldichloroethylene (DDE) and hexachlorobenzene (HCB).
The researchers then collected data relating to the body mass index of each child – measuring that at six months and then again at 14 months.
The researchers found that DDE and HCB were both associated with rapid growth among the infants as well as being overweight at fourteen months.
The researchers concluded:
"Prenatal exposure to DDE and HCB may be associated with early postnatal growth. Further research is needed to evaluate the persistence of these associations at older ages."
Other research finds similar results for older children
This study confirms an earlier study done by some of the same researchers. This study, however, focused upon children who were older – with an average age of 6.5 years.
This study followed 344 Spanish children between 1997 and 1998, comparing their body mass index at 6.5 years old with their exposure to polychlorinated biphenyls (PCBs), dichlorodiphenyldichloroethylene (DDE), and/or dichlorodiphenyltrichloroethane (DDT) within the womb.
This study again found that the incidence of obesity among the children was significantly higher for those with higher exposures to PCBs and DDE. The increased obesity rate among those with heightened PCB exposure (third tertile) was 70%, while the heightened incidence of obesity among those exposed to greater levels of DDE (second tertile) was 67%.
In this study, DDE exposure did not relate to increased obesity – indicating the possibility of its relatively speedier clearance in comparison with the other two chemicals.
Interestingly, the link between DDT and obesity increased with greater intake of fats, confirming what other research has found about DDE, DDT and other chlorinated compounds – that they tend to be fat soluble, which leads them to bioaccumulate within fat cells of the body.
DDE is a derivative of DDT - absent one hydrochloride molecule. In other words, DDT will break down into DDE in nature. Past exposure to DDT comes either from pesticides sprayed or through foods. DDE has been linked to numerous ecological disasters, including the narrowly-avoided extinction of certain eagles and pelicans.
While DDT was theoretically banned by the U.S. Environmental Protection Agency (EPA) in 1972, its use has continued. Today, between three and four thousand tons of DDT are produced in the U.S. every year - and sprayed as vector control (mosquitoes mostly, but also other insect invasions). DDT is also still sprayed on cotton.
These chlorinated compounds have been found to be significant endocrine disruptors - possibly explaining why they appear to change the way children develop and gain weight. We have a lot more to learn about them as we continue being the subjects of this massive "human experiment" being conducted upon us by the world's chemical manufacturers.
Valvi D, Mendez MA, Garcia-Esteban R, Ballester F, Ibarluzea J, Goñi F, Grimalt JO, Llop S, Marina LS, Vizcaino E, Sunyer J, Vrijheid M. Prenatal exposure to persistent organic pollutants and rapid weight gain and overweight in infancy. Obesity (Silver Spring). 2013 Aug 20. doi: 10.1002/oby.20603.
Valvi D, Mendez MA, Martinez D, Grimalt JO, Torrent M, Sunyer J, Vrijheid M. Prenatal concentrations of polychlorinated biphenyls, DDE, and DDT and overweight in children: a prospective birth cohort study. Environ Health Perspect. 2012 Mar;120(3):451-7. doi: 10.1289/ehp.1103862.