Bisphenol A, or BPA, just can't stay out of the headlines these days. And while this is not an air pollution issue, we know that so many moms are concerned about it, so we decided to write about it.
Last week, a study of hundreds of children in New York City showed a significant relationship between levels of urinary BPA at ages 3, 5, and 7 and asthma diagnosis at ages 5-12. Previous studies with laboratory animals have found a similar link.
Researchers don't yet understand how BPA exposure -- via ingestion, not inhalation -- might increase risk of the development of asthma, an inflammatory disease. Some research in mice suggests that BPA exposure increases allergic inflammation.
Whatever the underlying mechanism, getting a handle on the causes of asthma is an urgent public health need. Asthma is a chronic disease that takes a grave toll on our children. Asthma affects more than seven million children nationwide, or 10 percent of all children. African Americans are disproportionately affected by the disease, with higher prevalence rates compared to white and Hispanic children. Asthma is a leading cause of school absenteeism, and the third leading cause of hospitalization among children.
We know some of the underlying causes of asthma. Genetics play a role, and so does exposure to cigarette smoke, household allergens (such as dust and dust mites), and air pollution. But with asthma rates soaring globally, it is clear that there is much more to learn about the causes of this complex disease.
Could a ubiquitous industrial chemical be part of the puzzle?
A synthetic chemical first synthesized in 1891, bisphenol-A was one of dozens of substances evaluated in the 1930s for its potential as an estrogen drug. Never used for that purpose, in part because its estrogenic activity was not as strong as other chemicals such as diethylstilbestrol (DES), it's nevertheless fair to say that scientists have known for decades that BPA has estrogenic properties.
(DES went on to cause cancer and reproductive abnormalities in the children of women who had used the drug during pregnancy. But that's another story.)
Starting in the 1950s, BPA was used in polycarbonate plastics, including water bottles, baby bottles, sippy cups, plastic dinnerware, toys, food can linings, dental sealants, and thermal paper products such as cash register receipts. Its production skyrocketed. By 2004, the U.S. produced over two billion pounds of BPA annually, and global production was around six billion pounds. It is one of the most highly produced chemicals in the world. (For an exhaustive and enlightening discussion of the public health and policy issues surrounding BPA, see the new book by EDF's Sarah Vogel.)
As BPA production expanded, so did BPA's access to our bodies. The chemical is ubiquitous. The Centers for Disease Control and Prevention reports that BPA can be found in the bodies of nearly all Americans, as determined through urine tests of a representative sample of Americans in the National Health and Nutrition Examination Survey, also called NHANES.
BPA gets into our body through our food and water. We ingest it. It stays in our bodies for a relatively short amount of time -- a couple of days. That the CDC found BPA in almost everyone means not only that exposure is widespread, but that it's constant.
But the implications of this widespread and constant exposure are contested. The chemical industry, and some government agencies, insists the chemical has a proven safety record. On the other hand, there is an increasing body of scientific research documenting health effects among laboratory animals. In recent years, human studies showing health effects of BPA exposure have entered the mix. In those studies, such as the one published last week, exposure to BPA has been linked to asthma, hormone abnormalities, obesity, behavioral problems, and heart disease. Last year, the FDA banned BPA from baby bottles and children's sippy cups, but left it in other food containers. Meanwhile, several states have passed their own forms of BPA bans.
At the same time, the manufacture of plastics, whether they contain BPA or not, contributes to air pollution at every stage of the life-cycle: from the extraction of oil or gas (the raw materials that most plastics are made of), to the refineries that pollute surrounding communities, to the chemicals that off-gas in your home, to the toxic air emissions from incinerators.
So, let's review: A chemical with documented estrogenic properties is manufactured at global volume of six billion pounds a year. It's introduced into the food and water supply of the planet, and is found in the bodies of almost everyone. Exposure to this chemical is linked to asthma and other health problems. Though this is a complex issue of public health, science, and policy, I have to ask: What's wrong with the system? Why don't our regulations prioritize the prevention of chronic health problems due to massive exposures to questionable chemicals?
As a mom, I don't want to have to wait for airtight evidence before taking action against chemicals that might harm my family. Do you?
Cartoon by Danny Shanahan -- see all of Danny's MCAF cartoons here.