The type of chemicals someone is exposed to in the womb, or soon after
birth, may predetermine the risk for developing respiratory infections
as an infant and allergy and asthma as an adult, according to a study
that focused on PCBs and DDE.
Researchers
describe that some chemicals may pack a stronger punch during the time
when the immune system is developing than other chemicals -- a punch
that can last a lifetime.
In the study, both the amount and type
of PCBs a baby was exposed to in the womb, or in the first three months
after birth, affected the number of respiratory infections a child had.
Some types of PCBs seemed to be associated with increased respiratory
infections; other types seemed be associated with fewer infections.
Respiratory infections early in life are linked with more severe allergies and asthma later on.
PCBs,
or polychlorinated biphenyls, are industrial chemicals principally
manufactured during the middle of the 20th century. PCBs are
long-lasting. Even though they were banned in the early 1970s, people
are still exposed to them, mostly via food.
About 209 different
compounds are classified as PCBs. How they affect biological processes
is highly variable and diverse. A number of adverse health affects are
attributed to PCB exposure, including reproductive problems, nervous
system and cardiovascular system problems, diabetes, obesity and immune
deficiency. In this new study, scientists measured the amount and
type of PCBs in the umbilical cord of babies, in the breast milk of
their mothers three months after giving birth and again in the babies
at three months of age. This information was compared to the number of
respiratory infections the babies had during the first three months. | 
