Cough Syrups and Kids: They Aren't Just Small Adults

I was reading an article on the New York Times website this afternoon. The essence of the article, 'Parents Warned Cough Syrups Imperil Infants,' discusses a Food and Drug Administration advisory issued yesterday. The FDA's website, says that in October the Nonprescription Drugs Advisory Committee will discuss the safety and effectiveness of cough and cold products for children. In particular, it says, "Questions have been raised about the safety of these products and whether the benefits justify any potential risks from the use of these products in children, especially in children under 2 years of age." (For parents and grandparents, it's definitely worth going to this site yourself, as FDA has an important statement on, "What should parents know about using cough and cold products in children?)

Back to the NYT article. The writer, Gardiner Harris, says,

"[T]he standards for drug approvals have changed sharply in the decades since many of the medicines in children’s cough and cold products were approved. If those drugs were currently up for review, they would not be approved for use in children because the manufacturers never tested them thoroughly in children.

Instead, the drugs’ makers performed studies in adults and then simply assumed that they would work in children. Such assumptions, once common, are no longer acceptable. Indeed, a growing number of studies in children suggest that cough and cold medicines work no better than placebos."

Harris' statement highlights something I've come to understand from my research into environmental health: "children are not just small adults,", a statement that researchers and physicians at the forefront of this topic make quite frequently. A growing number of their studies show that all kinds of exposures that would be inconsequential for adults have profoundly negative impacts on kids. Because they are going through frenetic development their bodies react differently to chemical exposures than an adult's would to the same exposure.

Children are generally the most vulnerable to exposures, so we need risk assessments that focus on them.

Lead in Toys

The latest issue of the Journal Environmental Health Perspectives has an article on how even relatively small exposures to lead can affect kids' learning abilities: "The results show that blood-lead levels far lower than 10 µg/dL in early childhood correlate with lower educational achievement in elementary school as measured by performance on end-of-grade tests," they report. And today there are news reports about the recall of Fisher-Price toys due to lead paint used on some 967,0000 toys of Chinese import, this right on the heels of the June recall of a million and a half more Chinese toys--Thomas the Tank, a wooden train set--for lead in the paint.

How concerned should parents and grandparents be? Well, most environmental health experts agree that lead is quite dangerous, and at least some experts are advising parents whose children may have been exposed should arrange to have them blood tested for lead. In just one example from an article in Forbes, Dr. John Rosen, lead poisoning specialist at the Children's Hospital at Montefiore (NY), is quoted as saying, 'it's better to be safe than sorry.'

Rosen points out, childhood exposures to lead from paint in old homes is more common than poisoning from consumer products, but in either case, we know lead is a toxin. It shouldn't be in kids toys.

Kids and Chemicals

Yesterday the World Health Organization (WHO) issued a report, PRINCIPLES FOR EVALUATING HEALTH RISKS IN CHILDREN ASSOCIATED WITH EXPOSURE TO CHEMICALS . As Dr Terri Damstra, WHO’s team leader for the project said, "Children are not just small adults. Children are especially vulnerable and respond differently from adults when exposed to environmental factors, and this response may differ according to the different periods of development they are going through. For example, their lungs are not fully developed at birth, or even at the age of eight, and lung maturation may be altered by air pollutants that induce acute respiratory effects in childhood and may be the origin of chronic respiratory disease later in life."

This is a critically important point to those researching the health impacts of environmental toxins. For example, I interviewed Dr. Cheryl Walker, a geneticist at the University of Texas’ MD Anderson Cancer Center Science Park a few months ago. Cheryl is one of the leading researchers in her field, carcinogenesis, or the study of genetics and cancer, and her lab is a state-of-the-art facility for investigating the link between cancer, genes, and environmental “stressors” that can interfere with gene activity. Her research cohorts—the term scientists use for the participants in studies—are rats, which she uses to explore the question of how exposure during uterine development to xenoestrogens, or the endocrine disrupting chemicals that mimic the naturally occurring female hormone estrogen, might influence later-life incidence of fibroid tumors. Fibroid tumors are generally benign, but they are the most prevalent type of tumor in women, and account for 25% of all hysterectomies performed in the United States.

In Walker’s study, female rats that are genetically predisposed to developing these tumors were exposed to different types of manmade chemicals that act like estrogen at ‘environmentally relevant’ levels, or levels similar to those that a developing human fetus could be exposed to in the womb. The exposure was very brief—just three days—but at a critical window of time when the uterus was developing. The result? “We saw a huge increase in the risk of developing these tumors in the exposed rats,” she told me. “In our control group, which also had the genetic defect that predisposed them to developing these tumors, but that we didn’t expose to the chemicals, only half of the females developed the tumors. In contrast, 100% of the rats that we exposed to the xenoestrogens had tumors.”

But the result didn’t end with a doubling of the number of tumors. “The rats that were exposed also had tumors that were much larger—on average five times larger than in the unexposed animals. This clearly demonstrated that we had increased the risk of developing these tumors by this extremely brief yet inappropriate exposure to the xenoestrogens!”

I asked Cheryl how a such a small exposure during development could result in more and larger tumors in adulthood. She explained, “We found that this inappropriate interaction between the xenoestrogens and the developing uterus led to the ‘turning on’ of many estrogen-responsive genes at a time when they are normally protected from estrogen. As a result these genes became active too early, were reprogrammed, and then in the adult, became hypersensitive to estrogen.”

These findings aren't unique. As the WHO Report points out, "For children, the stage in their development when the exposure occurs may be just as important as the magnitude of exposure. There may also be a long latency period between exposure and effects, with some outcomes not apparent until later in life."

One of the most alarming statistics to me in the WHO report is their estimate that over 30% of the global burden of disease in children can be attributed to environmental factors.